Topic: Did some work today, which raised some questions (carb, compression, susp.)

[50words]

1) I changed my front fork oil. It needed it badly. I apparently filled them too full, though, so I bled some off. All of this was very unscientific, and I'm quite certain the two forks are now uneven. Does this matter? How do you go about refilling the forks?

2) I tried to sync my carbs, and it was a disaster. First, I was using the screws indicated for adjustment. Do I have the right ones? ('77 CB750F Super Sport with Kei-Hin carbs).



Here's the view from the top with everything hooked up:



I screwed the adjustment screws (the ones I tried to use, anyway) all the way in, backed them out a full turn, plugged in the CarbTune, and got this reading, which didn't change much as it warmed up:



So it looks like I have a compression problem in the no. 3 cylinder, right? How do I track down the problem and fix it? (Also, just recently did a valve job in which I am reasonably confident, and the plugs are new.)

No amount of fiddling with the adjustment screws made much difference, although when I tried closing down the no. 4 screw all the way, the engine died.

Can I do anything to balance the carbs as the bike is now, or do I need to address the compression problem first? Am I even using the right screws? Where do I start when trying to fix the compression issue, assuming it exists?

TIA.

[eldar]

When syncing, look at the top of the carbs. There is a cap that is rounded on one end and square on the other. These come off and there is a screw/nut combo like on the valve tappets. You set your idle and then adjust 1,3,&4 to sync with #2. Those screws on the bottom are your low speed screws and control your low speed air/fuel mix.

[TwoTired]

If the ones on the bottom are my low-speed screws, where should they be set?

You set them after the carbs are synced.  The book value is 1 1/2 +or- 1/2 turn.  But, this only applies if you have the stock air filter and exhaust system.
Cheers,

[Bob Wessner]

Uneven amounts of oil in the front forks is not a good thing. Best bet is drain them measure and pour in the appropriate amount of oil in both.

[eldar]

Yes use a measuring cup but make sure it is a good glass one. Not the cheap plastic ones as they do not read very well unless you fill to the rim for both shocks.