[woodsman]

See if you can't figure out how to focus your camera before you take more pictures.

 

[46lukasz]

See if you can't figure out how to focus your camera before you take more pictures.

Do you mean the pictures in the last post are bad quality, or are you talking about the previous ones that got blurred out and watermarked by photobucket, because of their recently imposed user data storage limits?
Because if its the latter then there is no need for snotty remarks about my usage of a camera like that. They were all fine until recently and then photobucket screwed them up.

Kind regards,
Lukasz

 

[TrialsRider]

Yep, photo bucket sucks.

 

[46lukasz]

Hi all,
Since the last post i noticed I had a small oil leak from around the valve cover and from around the tacho cable opening in the valve cover.
I sealed it with some silicone gasket maker and enjoyed the bike all I could before winter kicked in over here.

After a few short trips the bike is running great, however there is a new small issue:

I am having a hard time hot starting the bike.
When the bike is cold, it starts right away without any problem, but when everything is up to operating temperature (e.g. after a 30-45min ride) it has a hard time starting.
For example the last time I took it out on the road i stalled it in traffic. I tried to start it again right away, but it would not fire.
It turns over on the starter but it sounds like the battery is low, and dies completely after a few turns.The battery is not weak at all, its in great condition.
The interesting part is that if I wait about 10 mins for it to cool down a bit, it starts right away again like nothing happened. Every time.
Needless to say it is a major annoyance.

In summary if it runs, it runs great, but the second you turn it off, you have to wait a while before starting it again.

It looks to me that the starter could be faulty, not strong enough to turn the engine over when everything heats up and gets tighter.
This lines up with the sound it makes when you attempt to start it again.
I also was suggested changing the ignition coils, i was told that when they run they heat up and if kept in use they keep going, but when stopped and still hot, they would make a weak spark when worked again. This could be an option but doesn't exactly like up with the engine cranking over with difficulty.
It it was the coils it would turn over normally just not start because of the weak spark.

What are your suggestions guys?
Maybe its just the nature of this motorcycle?

Kind regards,
Lukasz

 

[woodsman]

Run it until it's warm, stop at the top of a hill and see it it will bump start as it should.

 

[46lukasz]

Run it until it's warm, stop at the top of a hill and see it it will bump start as it should.

Good idea but what will it prove?

what will it mean if it does start and if it does not?

 

[TrialsRider]

Hi all,
... I am having a hard time hot starting the bike.
When the bike is cold, it starts right away without any problem, but when everything is up to operating temperature (e.g. after a 30-45min ride) it has a hard time starting.
...

I would be checking the valve clearances.


... but your description of the motor running tighter when it is hot is very concerning.

 

[46lukasz]

The valve clearances have been checked some time before and everything was perfectly within spec.

As to the engine running tighter when hot... well i would expect it to run a little tighter since things expand when heated up. Compression increases and so on.
If it was running tight when it warms up overall, it would let know of it during use, not just when starting up. Am i correct in saying this?

The thing is that when it runs, it runs perfectly (in my opinion), and will keep doing so when kept running. The problem is temporary and arises only right after its turned off following some use.

I'm leaning towards the starter, or at least I think it is something electrical.

Starter or something that heats up when in use, remains working even when hot if it isn't stopped, but fails when its started hot ...and works again when cools down a bit.

Kind regards,
Lukasz

 

[TrialsRider]

I'm really concerned one or more of your pistons and or something in your valve train is running too tight.

If it's one of those things it would be best to start taking things apart to inspect what's going on inside there,
instead of waiting for the whatever it is to seize while next season riding.

A fresh compression test might be the cheapest place to start.
woodsman was trying to help you rule out the starter as being an issue, if she bump starts easy that would suggest a starter problem,
if it's what I think it could be, your rear wheel will lock up and skid.

... maybe a real big Irish hill

 

[46lukasz]

Hello after a while. I was enjoying the bike and taking it for long and short rides to finally enjoy it, see what's what, and what still needs work.

Hot Start Issue
First of all I did solve the hot start issue I had. I bought a starter repair kit, I took it out, cleaned everything, put in new brushes, brush springs, o-rings, seal, cleaned the commutator and lubed everything up a little. It didn't look bad to begin with. I also did the winding continuity tests with the multimeter to determine if there were shorts in the windings. Everything was in order.

When I put it back together the sound of the engine being started was different, a different pitch. I took it for a few rides and got it nice an warm every time. Each time when I came back i shut off the engine and then started it up again. Sometimes it would start again no problem and sometimes the issue would happen again (slow cranking as if the starter was struggling).

One time, the engine would not even crank over slowly, I thought the starter gave up completely. That's when I connected up a brand new battery and she fired right up. The starter was not an issue it was a bad battery that would not hold a solid charge apparently.

Clutch
I also noticed that the clutch is slipping. Sometimes i would drop a gear and twist the throttle and the revs would go up but I would not go anywhere.
Maybe the friction plates are worn or maybe the previous owner used a wrong kind of engine oil at some point. Either way i would like to replace the whole set for my own peace of mind. (friction plates, steel plates and springs)

I need some help here when it comes to selecting the parts. I need 8 friction plates (7xA and 1xB) and 7 steel plates (6xA and 1xB)
Does it matter if i buy the 2 sets of plates from 2 different brands? Its important the original stack height is kept and using the same brand would ensure it.
The brand EBC is popular where I am, but they only do the friction plates
This other brand Gecko does both sets of plates but i never heard about them.
I was thinking of geting Gecko steels and EBC friction plates.
Also another option is Barnett. They have a kit with both set of plates and its kevlar lined. The thing is the kit includes 8 of both types of plates. What's up with that? Shouldn't at least the number of steel plates be 1 less than friction plates?

79-83 Honda CB750 Barnett Friction and Steel Clutch Plates kit - Kev. | eBay

79-83 Honda CB750 Barnett Friction and Steel Clutch Plates kit - Kev. | eBay Motors, Parts & Accessories, Motorcycle Parts | eBay!

www.ebay.ie

Chain
My chain also badly needs replacing so that's next on the list. I have it at the right tension but i can see that its just stretched so much that it doesn't align with the sprocket teeth well and its making some rattling noises when I ride. Ill get a new set of sprockets too. I'll also need to get a chain breaking and riveting tool while I'm at it.

Rear Shocks
My rear shocks are in a really bad state, hissing like i shower earlier and rusted everywhere. I'll try to get a set of nice black ones. Maybe I'll go for some cheaper (maybe Chinese). I think even those will be better than the current ones.

Tank Heatshield
I was quite surprised to find out I boiled my fuel the last time i came back from a ride. I was just standing there and heard bubbling noises. I thought its the oil or something but it was not overheating (is it even possible to boil engine oil?). I then put my ear next to the tank and there it was. Is that a normal thing? Is is dangerous when the tanks vent works fine? I will get some heat shield gold foil or whatever it is and stick it under the tank.

 

[TrialsRider]

Hey how's it going, riding is good here, hope it is good there too,
personally I would take the clutch apart, clean it all up, put it back in with nice regular dino oil and try it again.
you don't need to replace your steels :| corks maybe. They always alternate steel, cork, steel, cork, etc.
New chain is good idea.
No they won't, buy better shocks.
No, only fuel injection bikes are prone to boil the fuel, yours should not.

 

[46lukasz]

Riding is awesome, i was waiting for it for a really long time. And we even got some good weather here in Ireland finally.

I'm aware that the steel plates go between the friction plates, meaning that the number of steel plates should always be one less than the number of friction plates.
That's why the Barnett kevlar clutch kit has me puzzled, 8 of each type of plate. Makes me question the compatibility if i ever was to go with that kit.

I was looking at reproduction shocks that are quite cheap from US sites like www.partsnmore.com. They are no-brand shocks as well. Nearly sure they could be Chinese too.
Then I found a decent looking set of fully adjustable (preload and damping) shocks from china. Not RFY just to be clear.
I don't need Ohlins quality shocks, this bike will not be going on the track nor ridden hard on the street. Just better what's current, which is on its last legs, it,'s so bad.
Would you recommend a decent suspension brand that's not going to break the bank?

Could you elaborate a little why injected bikes could boil fuel but this one, and old, air cooled engine and so on, should not?

Lukasz

 

[woodsman]

Hagon is in the UK, they make pretty good shocks for the money 150- 200 BPS. Might see if you can find used, quality and rebuild. There have to be some nice old Honda race parts sitting on shelves in shops across Ireland.

 

[TrialsRider]

...
Could you elaborate a little why injected bikes could boil fuel but this one, and old, air cooled engine and so on, should not?

Lukasz

On a fuel injected bike the fuel travels through the pump which uses the fuel for cooling, then the fuel that does not go through the stinking hot fuel rails and injectors, that heated fuel returns to the fuel tank to do it all again. Is best to keep lots of fuel in your Fi tank. Fuel is a one way gravity trip on your carburetor bike.
Nice rear shocks are a good investment. Keep them for the next bike and put the stock ones on when you sell it
I have a secret weapon, I have a huge motorcycle scrap yard near me and the owner just started riding and selling trials bikes.

 

[46lukasz]

I decided to stay with the current steel plates and ordered the EBC friction plates. It only started slipping recently and not much so i think the steels will be fine. I also ordered the EBC springs and a new gasket.

While I'm waiting for these parts I installed an new chain and sprocket set. Its a stock setup so 18T front 46T Rear and a 108 link chain.
The chain is DID VX Heavy Duty X-Ring Gold and Black Chain with a rivet master link and the sprockets are from JT.

The area surrounding the front sprocket behind the metal cover was full of dirt and sticky gunk. When I bought the bike I noticed oil leaking from the gear shift leaver and I changed that seal a long time ago.
However this was not the issue. The oil leak was coming from the shaft that the sprocket is mounted to. Its a hollow shaft, probably lubricates the gear cogs using the centrifugal force as it rotates.
The bolt that holds the sprocket gets an o-ring around it and is then tightened, sealing the shafts inside. This o-ring was perished in my case so I changed that too. And of course I cleaned the area as much as I could.

Among the gunk that was there I noticed lots of broken o-rings. I also saw lots of them when I was changing the above mentioned shift lever seal a long time ago. Now I realised they were from the old chain.
That's how bad it was and it needed replacing a long long time ago.

The chain riveting tool that I bought for this task also proved to be total junk as the riveting bit included was softer than the master link pins. So it took the shape of the pin instead of flaring out the pin.
In the end I put a ball bearing in the tip tool instead of the riveting bit and flared the master link this way.
I decided to leave the chain guard off because the new gold chain looks soo nice, I'll see how that really goes after a few trips.

The clutch is next, I'm just still waiting for the friction plates and the clutch basket locknut socket.
I'll do an oil change at this opportunity even though i didn't ride a lot, because i have to drain the oil before i take off the cover. Its still fresh oil in there but hell, it'll make the engine happy.

I also bought a cheap starter sprag gear from an R6 that can be adapted to my 750 DOHC starter. The stock sprag has 3 rollers and is known to unbolt itself over time giving the sound of marbles flying around in the engine.
This one has sprag teeth all around and the diameter of the starter gear matches. The stock one has 3 screw holes but at a different distance from centre, so you cant use 3 out of 6 holes in the new one and have to drill new ones.
This mod is offered by someone on eBay but the price is very high.

Honda CB750 CB900 CB900C CB900F CB1000 CB1100F CB1100R Sprag type Starter Clutch | eBay

When it comes to shocks, i think you have me convinced. I also found a UK brand YSS and they make classic/stock looking shocks for about 160EUR which is acceptable for me.
The nicer sporty looking ones can very quickly go up to 800EUR which is a no go for me but such is life.

Kind regards,
Lukasz

 

[TrialsRider]

Function of the chain guard is to protect the chain from being dirt blasted from the rear tire :| if fenders and a chain guard was not an important item, a trials bike would not have them.
nothing else you wrote was surprising. Been in the fork rebuild service business here today myself.

Any oil coming out past your countershaft sprocket is leaking past an oil seal, that's engine oil unless you have a separate oil supply for your transmission. Gears in your transmission splash around in a bath of engine oil, filtered oil under pressure is saved for the crankshaft and camshaft only.