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Discussion Starter #21
Hi again guys,

So this time i have no progress to show but I have a question about the brakes and brake lines that I want to buy.

So I want to upgrade to the steel braided brake lines and I have concluded that I will go with the HEL brand.
They are close to where I am so postage will not be expensive, and they have a nice online tool for selecting a customised line, where you can choose your length, fitting types, etc. and it's done to the spec.

So my question is, does any one know what size banjo bolts and bleed screws are used on these calipers on my CB750? Or is there a standard size used on motorcycles that I can order blindly?

Their online tool gives me the option of M8, M10, M11 or M12 banjo fittings on the brake line, and corresponding banjo bolts.

They also have a selection of bleed screws, sizes M7, M8 or M10.

I know I could just take the calipers apart and measure it but at the moment I only have access to the bike on weekends due to my work situation. I would like to order the stuff so i can save time and get to work on one of the coming weekends.


I am also thinking about what kind of brake line setup i would like to do.

At first i thought that I might save some money (thinking that length of brake hose translates to price) and go for a setup where one long hose runs from the MC to one caliper and then a second shorter hose runs from the first caliper, jumps over the fender and connects to the second one.

However when I checked HEL's website, they have a set price for the custom hoses so that means any length, any fitting and any spec is the same price.
So that got me thinking that if the money is the same, I might go for the so called "race setup" where two separate full length brake hoses run from the MC to the calipers.




Any suggestions about which way to do this guys?

Both setups will need a double banjo bolt, so here I have another question:
Given that one hose will have a straight fitting, at what angle does the other hose fitting have to be so that they can be mounted in line, next to each other without interfering on the double banjo bolt?

In other words, what's the angle of the fitting of the outside hose in this example case:


I have an option of 20 or 45 degrees but i would like to keep things as clean and neat as possible.

Kind regards,
Lukasz
 

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Discussion Starter #22
Hello again guys,

Due to lack of time i only have a small update. I cant make any progress because I simply dont have any free time lately but i am arming my self with parts and tools and equipment to make a big push forward as soon as I will get some time.

I bought some hardware to mount the calipers on shiny stainless steel new bolts (and some other bolts for different bits around the bike).
I went with Allen key socket cap screws instead of the standard hex head flanged bolts that were there originally.
I am wondering how it will hold the caliper bracket since the flanged hex bolt spread the load better, but i might just use a washer to do that with the Allen socket cap bolt.

And just to share some information: the bolts holding the caliper on the slide pins are M8x1.25mm but the bolts holding the brackets to the forks are M10x1.25mm which is a fine thread (standard M10 bolt is 1.5mm pitch). They were quite difficult to find and even if, they are quite expensive at about 20USD for 4 bolts.


The steel braided brake hoses finally arrived and they are a work of art! I went for the smoked colour option, together with stainless banjos and bleed screws.


I got some safety wire to lock the oil drain plug in place at the next oil change, a feeler gauge for when I will adjust the valve clearances (shim tool is not shown on pic but I also bought one), and a thread pitch gauge. The tube thing is a road tax disc holder. Its a small piece of paper that we have to carry on the vehicle here in Ireland showing that we paid the tax.


I plan on hooking up this SAE connector for the battery so that i don't have to take it out of the bike to charge it. Same connector would go on the charger side so it makes things much easier.


I bought a new set of mirrors because the original ones look dated in my opinion


And lastly I bought a caliper painting kit, containing anti-corrosive primer, the base coat and clear coat. All heat resistant since its made for calipers. To go with that i decided to try this grip device for spray cans. At 2USD it was worth a try even if its garbage.




I'm very eager to get some work done but the lack of free time just doesn't let me. I hope to show you some more in the near future

Kind regards,
Lukasz
 

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Discussion Starter #24
Thanks for the comment Stephen!

I decided to go with the 'race' setup with 2 separate full length lines coming from the MC to the dual calipers.
Like I wrote before, the company I bought the brake hoses from had a set price for any length custom hoses so it was convenient, and in addition to that, I also read that this setup is much easier to bleed.

I really cant wait to get going with these bits and pieces !

Kind regards,
Lukasz
 

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Discussion Starter #25
Hi everyone! I hope you all had a nice Christmas break! I had some time over the break to work on the bike and also received a shipment of parts so there is quite a picture heavy update coming!


Exhaust Hole

So I finally bought some exhaust putty and patched up the exhaust hole in the collector.
I actually used a hoover in reverse mode to blow air into the exhaust through a rubber glove to pressurise it.
I then used soapy water to locate the hole. Its a strange and goofy looking method but it worked.




Engine Bolts

I changed out all the bolts on the various engine covers to brand new stainless steel Allen head bolts.
It looks much better compared to the old ones that I cleaned up with a wire brush, after which they all rusted into a fresh orange colour.
I installed these new bolts on the covers where they are the most visible and also on the electric starter motor cover plate, but I still have plenty of bolts left over.
Any ideas where else its safe to change them? I think it might be the oil pan, but it might be other things and I don't want to unbolt something I shouldn't.




Oil Temperature Gauge Dipstick

Since this is an air cooled engine I figured it would be nice to know when its overheating or when its safe to let it rip after its all warmed up.
I bought this oil temperature gauge from a German website, that replaces the dipstick and i have to say that it is looking OK.
Not as intrusive as I thought it would be. After about 15 minutes the bike warms up to 80C no bother.




Speedometer Cable

I installed the new speedo cable. The new one is clearly a much better fit.
The one I had before was not dedicated for my bike at all and was rubbing against the brake disc.



SAE Battery Connector

I installed the quick battery connector and routed it so that its neatly dangling on one side.
Now I only have to pop the side cover to hook it up to the trickle charger.
I might also get a 12v -> 5v USB adapter in the future so that I can charge a phone from it.


Clutch And Mirror Mount

I repainted the bracket holding the mirror and clutch lever. I don't have a before picture but it was scratched a lot and looked bad.


Front Foot Rests

I thought that the original foot rests were ugly and bulky from the moment I bought this bike.
I got these generic foot rests that would probably fit many other bikes but not this one without a small modification.
I had to modify the bracket that the pegs mounted into. The new pegs were not pressing against the mount like the original ones and would just droop down.
I ended up welding in nuts which were the perfect thickness for the pegs to press against to keep them horizontal.
It's all tested and holds my weight when you jump around on them.
Next I had to remove some material from the mounts and put an angle on the cut surface so that the new pegs can lift up slightly like the original ones.
Overall I'm very happy with how it turned out. Looks neat. They are also spring loaded which push the pegs down just like the old ones.

I have yet to order the passenger foot rests and do a similar thing.










More updates to come really soon!

Kind regards,
Lukasz
 

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Discussion Starter #26
Key For Ignition And Fuel Tank

I have finally come up with a solution for my key issue.
Just to summarise the problem first: I had to buy a new ignition because the steering lock in the old one was seized.
This caused me to have two separate keys, one for the ignition and one for the fuel tank. I wanted to have one key for both, as it should be.

In hopes of finding a solution, I disassembled the old ignition by drilling through the stamped points and sliding the barrel cover off.
I then found out that the lock uses wafers instead of pins in the barrel.
Initially I thought that I can just swap the wafers from the old ignition into the new one, so that they match with the old key.
Unfortunately I later noticed that the two ignitions use two different types of keys. In fact these Honda's used these two key types depending on production year, so it wasn't the after market ignitions fault.
Basically the difference is in the side that the key is cut: S or Z cross sectional shape. I have indicated that on the picture below.

After realising this, swapping out just the wafers was not an option any more because the old key would not fit into the keyhole anyway, as the keyhole also has an opening shaped to match the key.
I ended up swapping the whole old lock barrel into the new ignition body.

I also ended up grinding down some of the wafers before swapping the barrels. With the key inserted they should all align to be flush with the barrel but some were worn out and were sticking out, causing me to have to wiggle the key to turn it in the old ignition. I sanded them down slightly so that they were flush and the key turned freely once again.

I then drilled shallow holes in the new ignition body, and punched the barrel cover into these holes so that it was stamped in place once again.
Since these holes were drilled out to remove the cover, I couldn't use the same holes again.

In the end it all worked out great. New ignition with old key that works smoothly. I am really happy with it. I also got a blank key with a Honda logo. These little details count you know.













LED Rear Indicators

The rear indicators were a direct fit and replaced the old ones. They fit into the holes in the chassis without any modifications.




LED Front Indicators

The front indicators needed new mounting stalks since I didn't have any brackets.
I also didn't want to cut anything from the bike so I used the metal tabs that the old ones slotted into.
The pictures explain the process. I used a PCV pipe and created a rail inside it so that it slots onto the mount, then filled it with resin and drilled and tapped a hole for the indicator.
Once the wires were routed through, I used some silicone to seal it off from the rain.

I am using a new indicator relay compatible with these LED indicators. However I noticed a slight delay between when you flick the switch and when they start flashing.
It doesnt happen straight away. I wonder if its because there are two regular indicator lights on the dash that are in the same circuit, and the new relay only works with LEDs which draw much less current.











More to follow!
 

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Discussion Starter #27
Front Brakes

I have repainted the calipers and used new seals and rubber boots all around where it was needed.
I also put on new stainless steel Allen head bolts on the mounting brackets.
I put on a new brake lever and also stainless steel brake fluid reservoir lid bolts. I like details like that.
Funny enough I got more parts than I ordered. I bought 3 kits for 3 calipers, front and back.
2 of the 3 kits had enough parts to rebuild 3 calipers while the third kit had 2 sets of all parts except the caliper carrier pins boots.
All 3 kits had the same manufacturer part number. Weird.






Rear Brake

In the case of rear brakes I repainted and rebuild the caliper and also repainted the brake fluid pump.
I also bought a new hose that goes between the reservoir and pump.
The old pads on the rear still have plenty of life in them.
I have welded myself a tool to grab the pistons from the inside and pull them out/ put them in. It did its job fine













Side Cover Attachment Point Fix

One of the nipples on the left side cover was broken off so that it wasn't held in the rubber grommet. I made a mould of one of the other two and then cast a new one with resin.
It came out OK and I glued it in place of the broken off one.

My side cover was also cracked in a few places and also prevous cracks were fixed in other places by previous owner with fiberglass. I added some of mine to keep it from cracking.





 

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Discussion Starter #28
Hi guys, so here is a final update for a while. I finally got to write up everything I did over the Christmas break. Really happy with it but still a lot left to do!

I want to change the spark plug wires and caps because once I was working on the valve clearances, the act of unplugging those components made me loose spark on one of the cylinders. It was just a loose connection in the end but I also realised that one of the wires is different that the other 3. A new set will hopefully prevent these problems in the future and also god knows how old is the current set.

I am looking for black caps and red wire because you know, anything red adds at least 10 horsepower!

I am also preparing for repainting the tank and I thought I can go wild and might as well repaint the whole thing. I was thinking about metallic/pearl black. Maybe a red stripe going down the middle with white edge lines. I will still have to see. Ill get a new tap for the fuel tank once that's being done. I'm also looking at getting nice stickers once the paint job machine starts going.

Dash Bulbs

I took the clock apart and replaced all the bulbs in there.
All of the bulbs that illuminated the clocks were burned out, while the ones for neutral, oil pressure and high beam were fine, but I replaced them all so all the bulbs are all identical.
I also replaced the 4 dash bolts with nice stainless Allen ones that stand out. I really like it this way.



Valve Clearances, Compression and Charging Voltage

I took off the valve cover and measured the valve clearances.
The results are acceptable but the clearances could be a bit bigger according to the experience of Honda mechanics. I am going to leave it as it is.

I then put it back together using a new valve cover gasket and measured the compression. It turned out to be surprisingly low, but at least very similar across the 4 cylinders.
I think i might have a crappy pressure gauge. I'm not going to worry about it that much because the engine runs fine.
I just realised, I didn't use choke so that's good, but I also didn't open the throttle at all... That might have put error in the measurement and I should re-do it

The charging voltage at 4000RPM was measured at around 13.5V but the headlamp was turned on.
Could this affect the reading? This is lower than it should be (14.4v) but I'm not going to worry about it for now, but its best to repeat the measurement.

The results are recorded in the table below.

I noticed that the new valve cover gasket was leaking, but I deducted that the fault lies with the valve cover bolt rubber washers.
The sealing rubber on my old ones was absolutely squished and the bolts were screwed in all the way, they pretty much bottomed out.
The rubber on the new washers is thicker and stiffer which puts more downward pressure on the cover and makes the gasket seal. With the new ones the bolts didnt bottom out and the gasket doesnt leak.
So a note for anyone changing the gasket is to order yourself a new set of these valve cover rubber washers as well














Test Ride

After all these bits were finished, I took this lady for a spin.
The brakes work and don't leak, but the new pads have to bed in.
Everything works very well, gears nicely click in and overall it runs like a scolded dog!
Very aggressive overall and especially in first gear!


I also checked the fuel filter I added and noticed that its already full of gunk so it was worthwile to put it in.


Here is an updated to do list, it is getting smaller and smaller, but i might be adding on some more things soon. After all, a project bike is NEVER complete

To Do List:

Sync carbs
Fabricate new steering bar ends
Repaint fuel tank due to bubbling from under paint + get clear vinly to protect knee area
Replace engine bolts with Allen head ones (partially finished, some bolts left)
Install new oil filter spring and washer on next oil change
Re-check charging system by measuring voltage of battery at 3-4k RPM with lights OFF (13.5v with lights on was lower than expected 14.4v)
Re-check compression with wide open throttle
Install new rear foot rests
Install new spark plug caps and wires


Done List:

Identify the exact model of machine: CB750FA 1980 based on frame number
Lubricate tacho, speedo, throttle and choke cables
Replace shift shaft seal
Replace oil filter and oil
Remove rust from inside of fuel tank with HCl
Lubricate brake lever
Adjust chain tension
Replace spark plugs
Replace front tyre and balance the wheel
Install new ignition to fix seized steering lock
Replace air filter
Replace fork seals
Replace indicator relay
Extract stripped bolt on on spark advancer cover and replace all 3
Replace front brake pads
Replace grips
Paint attachment base for clutch lever and mirror
Fix exhaust holes with putty
Add SAE connector for easy battery charging
Replace bulbs in clocks (takes x10 T4W or BA9S bulbs)
Install new black brake lever
Repaint calipers and brackets and use new seals
Replace brake lines with steel braided
Replace speedo cable
Figure out a way to have single key with new ignition
Install new front foot rests
Install new indicators
Check valve clearance and adjust if needed, use new head gasket cover
Install new mirrors
 

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If in the future you do decide to adjust the valves...... (depending on how you ride or how much time you spend in traffic) it is generally a good idea to give it a reasonable thrashing first or run some combustion chamber cleaner through it. Those engines can build up crap on the valve seats etc. On this side of the pond, you can buy the combustion chamber cleaner from Honda. Your cams look nice BTW.
 

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Discussion Starter #30
Thanks for the comment Cyorg, I will keep that in mind!
Although I think i will sooner change the cams to the ones from a cb900 and re-do the clearances, than i will readjust the clearances for those that I have right now, haha! We will see what the future will bring.

I have a set of new spark plug caps and wires on the way in the post. I was thinking about swapping the coils too, since the current ones are old.

So my question here is, since the bike starts fine as it is, is there any point in swapping the coils?
I read that a common mod is to install CBR coils, and they are quite cheap on eBay.
What advantages does that bring? Do the CBR ones have more "oomph" in them? How does that affect the ignition and overall engine performance?

Kind regards,
Lukasz
 

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Discussion Starter #31
So I cleaned the rotor rings. First I took a scotch brite pad to it, and then i polished them to something close to a mirror finish.










I also had a look at the stator 6 pin connection and it wasn't bad. no visible corrosion of horrible levels. I still took a small wire brush on a dremel tool and cleaned the contacts well.


I finally have the bar ends installed on the bike. They are custom and my own design. My friends from work dad turned them for me on a lathe. They are solid steel so quite heavy. First picture is a 3d render of the design which was then 3D printed to see what it would actually look like on the bike. Then I painted the actual ones gloss black to match the grips.












I also have yet another indicator relay since I was not happy with the quality of the last one and it was working when it wanted and now when I wanted it to work.
This new one needed to be grounded so I first tested it by connecting the ground terminal to the frame and it worked.
Then I remembered that these bikes have a green wire near the indicator relay connectors, that is not used for anything. I checked the schematics in the book and it looked like this unused connection was going to the regulator.
I also checked its continuity and it turned out that there is an electrical connection between this unused wire and the frame. So i plugged the new relay to this unused connector and it works.



I hope it wont burn.

I also installed new spark plug caps and red ignition cables so that everything on there is nice and fresh. With the old setup, one of the 4 cables was different than the rest and it was giving me trouble when the cables were moved by hand so the connection wasn't solid. It is now.













Kind regards,
Lukasz
 

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Discussion Starter #32 (Edited)
Hi again guys,

I have extracted the connectors from their plastic housing on both the male and female side of the alternator plug and cleaned them up with a wire brush on a dremel tool.
The female connectors were not that bad, I also compressed them with pliers to make them a tighter fit. The male spade connectors though were very dirty and the wire brush made a massive difference visually.

I also took a picture of the polished rotor rings after some idle time of the engine. Not bad in my opinion. The brushes on the stator are also well above their indicated wear lines. The rotor resistance measured 5 Ohms so its good as well.

I retook the reading at the battery with engine idling and this time with no lights on or anything and it was spot on 14.4V.
With engine was revved it was no higher than about 15V so that would indicate the regulator works fine too.











I also installed the new rear pegs. They look much nicer than the original bulky rubber ones.
They have a spring loaded ball bearing that clicks into notches on a plate I had to weld in so that they can be adjusted to fold up or down.
I also had to make a small cut in the mounting bracket so that they fold down all the way horizontally and rest on the bracket then. Other than that it was an easy job.







I finally balanced the carbs. I bought the gauges from Alpha Moto and they have really nice adjustable dampeners so that the needle doesn't jump around.
I got it fairly spot on, maybe the 4th cylinder is not perfect but I am really happy with myself especially when I didn't have a proper tool to turn the lock nut without also turning the balancing screw at the same time.
I made one out of an old socket so I could put a flathead screwdriver through it.
I also swapped the blanking bolts from the Japanese standard Phillips head look-alike to SS Allen head and threw in new copper washers as well

Video of it linked at the bottom










I think I will have to change the throttle cables for new ones because I noticed that my throttle was sticking open, and when I undid the adjustments screws on the carbs side it suddenly fixed itself.
The old cables are also kinked on the handlebar side.

I will also look into getting a new tacho cable to go with the new speedo cable. The indicated RPMs are quite jumpy especially at low RPMs.
I suspect I will also have to change the seal that is between the tacho cable and the head cover because I noticed a small leak there.


Question:


I recently noticed that once the engine warms up and is taken off choke, it runs really well, BUT...
Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
You can kind of see this happening on the carb balancing video linked above
Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.




Kind regards,
Lukasz
 

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Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
You can kind of see this happening on the carb balancing video linked above
Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.
I might be completely wrong, but assuming your carbs are balanced, your idle circuit may be too lean. When you cut the throttle, the sudden switch to the idle circuit causes a lack of fuel and kills the bike.
 

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...
I recently noticed that once the engine warms up and is taken off choke, it runs really well, BUT...
Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
You can kind of see this happening on the carb balancing video linked above
Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.

Kind regards,
Lukasz
CV carbs are a pain in the ass.
If your float levels are off that could induce the problem you described, unfortunately several other CV fuel circuit issues may also be the cause of the problem including fuel delivery pressure.

#2 carburetor probably has some kind of fuel pump thingy on it yes? That could be an accelerator pump or it could be a decelerator fuel pump. You might want to research that part because it seems to me they added a decelerator pump to some motors to deal with over-lean operating conditions when the throttle is chopped.

You have to remember that on a CV carb your throttle cable controls a butterfly valve but that valve precedes the vacuum operated slide valve. By design there is a lag time between the operation of the butterfly valve and response to open the slide valve. On closing the throttle both valves slam shut very effectively, fuel circuits were added to the design of later CV carbs to accommodate that operating condition, your carbs could have as many as 5 fuel circuits to control air and fuel ratios throughout normal operating conditions, blockage in any of those tiny passages is a common problem.

 

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Discussion Starter #36
Hi guys,

A little bit happened since the last update:

Shortly after balancing the carbs I noticed that the throttle is sticking open, so I replaced the push pull throttle cables with new ones.
One of the old ones had a kink in it and it was causing the problem. I lubed the new cables nicely put some grease on the bars underneath the throttle tube.
I also got a new tachometer cable just because.

It was a very noticeable improvement, throttle was very smooth, and after adjusting the idle speed slightly I could take the bike off choke in about 20 seconds so that was great.

I started playing with carbon fibre and epoxy resin, just out of curiosity of how you work with this stuff. It comes out really nice and i might do something cool for the bike soon.





I'm also slowly buying/preparing equipment to repaint the bike.
I plan to go for deep metallic black with a red stripe running down the middle.
There will be a chrome-looking Honda sticker with the wings on the tank, and a red CB750F on the side cover.
The side cover stickers I got are reflective stickers, i don't know if its a good or a bad thing yet, but i like them.
I did a mock up on the computer just to see how it would look in black (just inverted colors) and I am happy with it.







So I was really happy, bike running best I ever saw it run, just the paint job and the project is complete, but then disaster struck!
I fired the bike up and noticed that fuel is pissing out of one of the overflow tubes at the carbs. Small tear-down to take out the bank of carbs with the airbox.





I also noticed that the fitting at the top of the airbox which is the input of the crankcase ventilation system has this yellow goo on it. What could that mean?



I took off the float bowls, and saw that they are really quite clean on the inside. No fuel turned into varnish anyway!





With the carbs and float bowls off, I poured some fuel into the input tube, and tested the float valves individually, by keeping 3 closed and opening one at a time by hand.
None of them was leaking! So I'm not sure what was going on (maybe one stuck open). I guess it works as expected and it would be fine now if i threw it back on the bike.
One other thing I'm going to check though is maybe one of the overflow tubes that stick up in the bowl is cracked along the sides or at the bottom. If that's the case then the fuel doesn't have to reach the top of the tube to go into overflow.





And because its taken off now I thought I might as well take some time and clean it up a bit later. Any tips on this?


I was quite surprised to see that there is no diaphragm underneath the top caps of the carbs. Instead, they use a metal puck and very tight tolerance to make a seal and work in the same way as a diaphragm (vacuum created on intake pulls the puck with the needle up etc).

I have a couple of questions:

1. Should I use some lubricant between the puck top ring and the inside of the top cap to make a better seal? Maybe polish the two surfaces?


2. Should I also use some lubricant on the slides that go up and down inside the throats? There seems to be a lot of rubbing action there, and the slides of carbs 1 and 4 have visible scoring marks on engine side. 2 and 3 are very smooth


3. Could someone explain what's the function of the air cut-off diaphragm? there is one on each carb.


4. I totally don't have an accelerator pump on the #2 carb. I also cant see an accelerator nozzle anywhere in the throat of the carb. I thought these bikes came with one. Is this normal?




Thanks!
-Lukasz
 

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Discussion Starter #37
Hi again everyone, i have some updates on the build:

1. Carbs cleaning was completed
I took the carbs apart but not completely, just the main parts. I cleaned them real good and polished the top caps and float bowls.
I put on new Allen socket head hardware, new drain screws and bowl gaskets. All the jets were really clean actually and there was no gunk in the bowls at all.
I also got stainless band clamps to go on the insulators.
I really don't know why they were pissing out the over flow but they stopped now. I guess there was some dirt on the needle valves that prevented them to close fully.
I synchronised the carbs again after all that and its now running right again.







2. Gas recirculation hoses
The T connector that connected the two crankcase breather hoses to the air-box was perished and cracked. I got a brass T and some rubber hoses to fix it up. I kept the plastic adaptors.
Its by no means a perfect solution but its sealed now so its better than it was. I still need to get hose clips and put them on.








3. Fuel line routing changed
I decided to remove the vacuum operated safety valve after reading that its known to give problems and its nicknamed SOS (spawn of satan). As long as the fuel petcock on the tank is good then things should be OK.
Now, if it ran a hose from the petcock straight to the carbs i wouldn't have a place for the inline fuel filter. So I bent some 7mm aluminium tubing and made a rigid fuel line to accommodate the filter. Looks neat.





4. Rear suspension
I noticed that the rear shocks make a hissing sound on the way back up after being compressed. Is that normal? Please take a look at the video of it:
The springs do absorb the shock, and the dampening does slow down the rebound travel, so technically they do work as intended but I'm still not sure.
Also could someone please explain the settings of these shocks to me? what is the purpose of the lever indicated on the photo? it goes from left to right.
I realise that they have spring preload adjustment at the bottom. Is this to compensate for rider weight?
They also have a numbered cog at the top that can be rotated with numbers 1 and 2 on it. Is that also for spring preload?




I started on the respray. I have some parts primed already but i will make a separate post about that when its finished.

Kind regards,
Lukasz
 

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the hissing noise is because they are presurised with nitrogen and the fluid and gas mix
if the pressure remains high enough the gas remains dissolved into the fluid and makes less hissing
so they may have lost some pressure over time
the top is rebound damping the bottom high speed comp damping
spring preload cam to be adjusted so you have about 1/3rd of wheel travel with rider on board
and at this setting there should be some amount of sag albeit small without rider
after setting rider sag if the shock tops out without rider the spring rate is too soft
neither damping adjustemernt have any effect on sag
set it up and ride it if is shit on a bumpy road at good pace get some good shocks on there
those oem shocks were pretty good for stock shocks but time takes its toll
 

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Discussion Starter #40
Hi again after a long while.

I finally finished spraying the CB and the project is very close to being finished. Thanks a lot XB33BSA for the feedback about the rear shocks. I will need a few more test rides to figure those out.

So i disassembled the bike and made stands for the parts that needed a respray. I sanded and primed everything first.







There was a surprise with the fuel tank, because underneath the blistering paint there was filler and under the filler there were welds.
someone must have crashed it and the bar must have gone through the tank and ruptured it. The weld job wasn't great on it as there still were 2 pin holes left behind and that was causing the blistering. The picture where I use a flash light shows the pinholes well.
I ended up grinding off the welds with a dremel to get a clean look (which created even more holes) and then I actually soldered the holes up. Came out quite alright for a first time. Then filler and primer.









I used the black spray can guide coat + block sanding technique to find any low spots and that turned out to be a great technique. Then everything got sprayed with a of base and top coat of red, was masked off and got sprayed with black.
Then I sprayed everything with 2 coats of clear, sanded it and put down another 2 coats of clear.









Its a pearly red and metallic black and I absolutely love the flakes in the black.

Unfortunately the clear coat finish did not come out perfect. I was doing it in a garage and using a compressor from a supermarket so I cant expect much, the gun was spitting water even though i had a water trap on which created fisheyes in the clear coat.
Because there are 4 layers of it there, its possible to cut and buff it but for now i just accepted the fact and I'm living with it.

Here is a few pics of the bike put back together. I'm really happy with the results and I already did about 300km on it ;)




I will put up a proper finished project gallery when i find a nice spot to take a few photos at and after I fix a small oil weep.
Its weeping oil out of the tacho cam holder opening in the valve cover. It was my mistake because I replaced the main gasket and the bolt rubber washers but i completely missed the tacho gasket. The pain in the butt is that I have to buy all the gaskets again since I cant reuse the valve cover gasket nor the bolt rubber washers...

Talk to you soon and sorry for the huge pictures in my last post.

Kind regards,
Lukasz
 
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