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Hey peeps,

Some of you may remember from this intro thread a few months back: http://www.caferacer.net/forum/general/21450-new-member-lewis-says-hello-4.html

My supposedly naive and delusional goal of building a cafe racer as my first bike has come to reality and I thought I'd share my progress with you all, maybe earn some street cred on this forum (or possibly lose more).

Anyway, I bought a running 1979 CB650 for a thousand bucks. It had an 82 CB650 engine on it already which was cool for me since it had 'better' carbs according to the interwebs. It was in rough shape and the biggest problem was an aggressive oil leak, but was ride-able and running decent enough...

Here's what I've done so far:

- disassemble as much of bike as possible to still be able to run engine, in prep for a sandblast and paint job of the frame
- pull engine and replace all top end gaskets, decarbonize pistons
- after-reassembly oil flush and filter change
- clean carbs, installed a DynoJet kit as I will be running a MAC exhaust and pod filters
- de-tabbed the frame for that clean triangle cafe look

what I'd like to do in the coming months:
- rear seat hoop and custom cafe seat (I ordered the Manx from Roccity Cafe Racer)
- relocate fuse box, batt and electronics
- strip and paint my tank to match seat
- sandblast and powdercoat frame

I frame the engine last week and finished putting on the carbs today and started her up for the first time... starts real nice. It's a preliminary assessment/tune as I didn't have the air filters on and had the stock exhaust on, but I got it to idle 'good enough.' Obviously the settings will be way different once the right parts are on there but I just got too excited to wait.

Pictures coming soon hopefully.

Question: I have exhaust pop at idle from the pipe that connects to cylinder 1 and 2... Does anyone know what that means?



Thanks and have a great week guys
 

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Question: I have exhaust pop at idle from the pipe that connects to cylinder 1 and 2... Does anyone know what that means?
Here are Some Clues :rolleyes: :

Here's what I've done so far:

- disassemble as much of bike as possible to still be able to run engine.......

- clean carbs, installed a DynoJet kit as I will be running a MAC exhaust and pod filters

........finished putting on the carbs today and started her up for the first time... starts real nice. It's a preliminary assessment/tune as I didn't have the air filters on and had the stock exhaust on, but I got it to idle 'good enough.' Obviously the settings will be way different once the right parts are on there but I just got too excited to wait.



Pictures coming soon hopefully.

 

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Lewisz,
Do what has been suggested elsewhere (do you read the forum other than your own threads?).

-Use quality pod filters as in Uni or K&N foam filters. The emgo (and similar) steel mesh filters don't filter anything but birds.
-use the rubber runners from the original intake (the part connecting airbox and carb) and rig the pods on the end of those. These velocity stack style runners will smooth out the air flow to the carbs. Jets alone will not solve your issues if using pods. Search, there is plenty of info on this. Its been covered a million times.
-Why did you disassemble the bike? Once the bike is ready it takes a relaxed weekend to disassemble the bike. Its not something that needs to be done before hand. Its much easier to put it back together 2 weeks after you disassembled it.
-I am against powder coating frames. Search on it. Touch ups are near impossible. Use paint. Its works well. Also don't sandblast and paint the frame before you have ridden a few thousand km. See above. Its not a big job to get the bike apart for it when the time comes. BUT its a pain to realize you want to weld a new bracket, move your pegs, whatever after you have painted the frame. This too has been said a million times by people far more experienced than you or me.
-Good on you for opening the engine - it was to fix the oil leak right?


People don't opose working on old bikes here. We just opose people repeating the same mistakes and "mistakes" despite good info to do the things right.

And yeah show us some pics.


cheers and happy wrenching.
 

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Discussion Starter #4
Here are Some Clues :rolleyes: :
Hi Dean, I know that all my parts are not on yet but I thought I'd try to catach a potential problem before putting it all together. The pop only occurs through one pipe... which is the reason why I think there might be a problem other than missing parts.

Lewisz,
Do what has been suggested elsewhere (do you read the forum other than your own threads?).

-Use quality pod filters as in Uni or K&N foam filters. The emgo (and similar) steel mesh filters don't filter anything but birds.
-use the rubber runners from the original intake (the part connecting airbox and carb) and rig the pods on the end of those. These velocity stack style runners will smooth out the air flow to the carbs. Jets alone will not solve your issues if using pods. Search, there is plenty of info on this. Its been covered a million times.
-Why did you disassemble the bike? Once the bike is ready it takes a relaxed weekend to disassemble the bike. Its not something that needs to be done before hand. Its much easier to put it back together 2 weeks after you disassembled it.
-I am against powder coating frames. Search on it. Touch ups are near impossible. Use paint. Its works well. Also don't sandblast and paint the frame before you have ridden a few thousand km. See above. Its not a big job to get the bike apart for it when the time comes. BUT its a pain to realize you want to weld a new bracket, move your pegs, whatever after you have painted the frame. This too has been said a million times by people far more experienced than you or me.
-Good on you for opening the engine - it was to fix the oil leak right?


People don't opose working on old bikes here. We just opose people repeating the same mistakes and "mistakes" despite good info to do the things right.

And yeah show us some pics.


cheers and happy wrenching.
Hi kerosene, thanks for the advise. I will do some more research in regards to the filter type and intake boots. I took apart the bike because I had plans to move a lot of things around (electronics and such). Most of the rear and front end are intact. I also removed the controls for a while so I could play around with the handlebar and see what position i liked.

I opened up the engine to fix the leak, it seems to be fixed but only time will tell how good of a job I did. I try to avoid the most common mistakes people make when doing this kind of thing but sometimes it's hard to sit in front of the computer all day when I could be learning hands-on with the bike - I just try to read and research as I start doing different jobs on the bike.

ty for the response
 

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I wish people would stop saying don't powder coat because it is so hard to touch up. That's the whole reason you should powder coat it. Powder is 10x's more durable and chip resistant than paint so the need to touch up virtually goes away. Why would you paint something you know will probably need fixing because it has no durability when there is a better option available to you. I shoot samples of powder on 4" square pieces of aluminum foil and paint some of the same. You can wad up the powdered pcs. and unfold them and do this over and over until the foil tears before the powder fails. One wad up of the paint and when you unfold it it all falls on the floor.
 

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I wish people would stop saying don't powder coat because it is so hard to touch up. That's the whole reason you should powder coat it. Powder is 10x's more durable and chip resistant than paint so the need to touch up virtually goes away. Why would you paint something you know will probably need fixing because it has no durability when there is a better option available to you. I shoot samples of powder on 4" square pieces of aluminum foil and paint some of the same. You can wad up the powdered pcs. and unfold them and do this over and over until the foil tears before the powder fails. One wad up of the paint and when you unfold it it all falls on the floor.
We all know PC is durable, but in most cases when we are talking to people who are building a bike it's mostly a "work in progress" type of thing where there will be something they missed either welding on or cutting off the frame.

That's why it's a better idea to paint than PC.
 

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We all know PC is durable, but in most cases when we are talking to people who are building a bike it's mostly a "work in progress" type of thing where there will be something they missed either welding on or cutting off the frame.

That's why it's a better idea to paint than PC.
It is never a better idea to do things the wrong way. If you are building a bike, and not just cutting tabs and modifying a few things as you go, you will assemble all the parts, do all the modifications and then when it is complete and running and finished you will disassemble it and paint polish and powder coat everything so when you reassemble it it is done. How many paint their frames while the bike is assembled? Rattle canning bits as you go is fine if that's the budget and mind set you have. It's not my idea of how to "build a bike". None of what I just explained has anything to do with those who say "don't powder coat because it is hard to touch up." It makes me laugh that the attitude they have is " I'm going to do this the cheap way that I know will fail so when it does (not if) I can cheaply fix it. Instead of "If I spend a couple more dollars and do it this way there is less chance of failures I will have to fix after putting this hard work into this build."
 

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Stop sniffing the powder dude - it ain't that big a deal.
I understand the "work in progress" thing , just don't make excuses and blame powder for other shortcomings. Just saying. I gave up sniffing powder years ago.
 

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Discussion Starter #11
Lol, I'm not quite at the painting stage yet so I have some time to figure exactly what I want to do.

Back to the topic of the popping in my exhaust. I noticed that cylinder #1's header pipe (which is also the side of the exhaust pipes that the popping occurs) doesn't warm up as quickly as the other three head pipes do. it gets hot but just not as quickly so I think it's firing. this leads me to believe the popping might be sourced at #1. maybe I'm running rich? how can you determine this and what are the other reasons a cylinder might not heat up as quickly?
 

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I noticed that cylinder #1's header pipe (which is also the side of the exhaust pipes that the popping occurs) doesn't warm up as quickly as the other three head pipes do. it gets hot but just not as quickly so I think it's firing. this leads me to believe the popping might be sourced at #1. maybe I'm running rich?
clean or replace the pilot jet. its a common problem. if you have a 82 engine your good cause the pilot screws in/out. is its a 81 set of carbs- good luck
 

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Discussion Starter #13 (Edited)
clean or replace the pilot jet. its a common problem. if you have a 82 engine your good cause the pilot screws in/out. is its a 81 set of carbs- good luck
I've already cleaned the pilot jets with a ton of carb cleaner. The main jets are brand new. Maybe I haven't done a good enough job of cleaning the pilots and here's a question for you all:

I used a very fine sewing needle to poke into the pilot jets. And it wouldn't go all the way through. I've heard that a high E guitar string will go through and is good for cleaning. Would an E string be thinner than a needle? Also, spraying carb cleaner directly into the pilot, it wouldn't come out the other end. On any of the four jets. Are they clogged or just that narrow?
 

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Discussion Starter #14 (Edited)
One more question... and I have searched high and low for this with no luck.

The cam chain tensioner. I know how to properly adjust the cam chain... However, there are two bolts that hold the cam chain tensioner on the 82 CB650 motor. One at the top, referred to as the 'cam chain tensioner SET bolt' in the shop manual. And the other at the bottom of the cylinder jugs, referred to as the 'cam chain tensioner LOCK nut.' I have torque values for the lock nut and the lock nut is the one to tighten slowly while hand-cranking the engine to adjust the tensioner. What the hell do I do with the SET bolt? There are instructions to remove this bolt during head removal in the shop manual, but no reference back to it during head installation, and no torque values are provided. Is this also an adjustment bolt to tinker with? Please help!

Here is the shop manual I used:

http://www.jasonkent.ca/manuals/79 CB650 Service 006.pdf (SET bolt reference at 6-9)
http://www.jasonkent.ca/manuals/79 CB650 Service 003.pdf (LOCK nut reference at 3-7)
 

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Not familiar with the camchain tensioner, but with regards to #1 carb it is running lean and you need to adjust the idle mixture screw to fix it. There's one on each carb - 2 1/2 turns out on each is probably a decent starting point - if there's popping then adjust them out further by 1/4 of a turn increments until the popping has gone.
 

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I've already cleaned the pilot jets with a ton of carb cleaner. The main jets are brand new. Maybe I haven't done a good enough job of cleaning the pilots and here's a question for you all:

I used a very fine sewing needle to poke into the pilot jets. And it wouldn't go all the way through. I've heard that a high E guitar string will go through and is good for cleaning. Would an E string be thinner than a needle? Also, spraying carb cleaner directly into the pilot, it wouldn't come out the other end. On any of the four jets. Are they clogged or just that narrow?
first take the jet out of the carb body. a wire brush you clean the outside grill w/ will work. take 1 strand and use that. yes you should be able to see thru and squirt carb cleaner thru mif its is not its clogged. you also need to take them out to clean the 6-8 little holes that are in the side of the pilot jets. pilot jets are cheap. don't be cheap. replace them . as hillsy said - set your idle screws.
 

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as far as the cam chain, if I can recall all you had to do is loosen a bolt, turn the engine over(by hand ) a few times and tighten. it was simple. get the hard copy manual
 

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Discussion Starter #18
Not familiar with the camchain tensioner, but with regards to #1 carb it is running lean and you need to adjust the idle mixture screw to fix it. There's one on each carb - 2 1/2 turns out on each is probably a decent starting point - if there's popping then adjust them out further by 1/4 of a turn increments until the popping has gone.
Hi hillsy. I turned out the mixture screw about a 1/4 of a turn. No difference, turned it out another 1/4. It was better. But today while I was replacing all my spark plugs, as #1 came out I smelled fuel and it was moist. So the adjustments made it rich. Anyway, after replacing the plugs, and reversing the #1 mixture adjustments, the popping seem to have gone away. So problem solved (for now). Thanks for everyone's help on this.
However, #1 header still heats up MUCH slower than 2, 3, 4. WHYYYYY?

first take the jet out of the carb body. a wire brush you clean the outside grill w/ will work. take 1 strand and use that. yes you should be able to see thru and squirt carb cleaner thru mif its is not its clogged. you also need to take them out to clean the 6-8 little holes that are in the side of the pilot jets. pilot jets are cheap. don't be cheap. replace them . as hillsy said - set your idle screws.
I'm just going to spend the $20 and replace all the pilot jets.
 

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But today while I was replacing all my spark plugs, as #1 came out I smelled fuel and it was moist. So the adjustments made it rich.
there is a good forum you should check out -honda ohc. there is a "sub- forum" to the 650. I( and everybody else w/ a 650) had the same problem as you. the plug looks wet. its gotta be rich, right. not always the case w/ the 650. mine did the same thing. "wet plugs" how could it be the idle jets (and lack of gas). its not the spark (1&4 run off same ig. pickup and coil). your spark plug/wires and cap are good. you have the stock airbox right? unscrew those pilot jets and throw em out and put in new ones.all the air passages in the carb are clear? I spent weeks w/ the same problem. (I had a 81 w/ "push in " idle jets) I cleaned and poked for weeks. finally got fed up and got a year 82 set of carbs w/ removable idle jets. new jets no more problem. go to the 650 Honda forum and run it past the guys there. chances are the guy from Germany will help you
 

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This: Fusion for Plastic® - | Krylon look so similar to powdercoat that you can't tell it's been used for touchup unless your head is only about a foot away from the touchup spot.
 
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