Topic: Few general/tuning questions! 78 cb750f - clutch carbs lights brakes fuel!

[catsoup]

I have been trying to get my bike into tip-top shape, and have some minor tuning questions. It has been running incredibly well, and I have done a great deal of work already. It is a CB750F '78, basically all stock.

1. My bike rolls more smoothly in neutral than with the clutch fully engaged. ??

2. Put a superclean air filter in and it now seems to need less choke, if any, when starting. I am worried I may be running slightly rich now. I will check the plugs after i ride a little longer. If this is the case, I am assuming I need to change the fuel air mixture? where do I start with this? The carbs were tuned with the old filter, 3000m ago, could this be a sign that I should resync my carbs? It does sound and run well.

3. Headlight dims when I engage clutch and release throttle. I imagine this is normal though.

4. Any tips on where to find new front brake rotors? I believe mine are slightly bent, and produce squishy, oscillating braking (though decent performance).

5. minor point. I have been trying to use premium gas lately octane93 or so, and have actually noticed what I think is slightly lower gas milage. does this make sense? should I switch back to regular? I'm not 100% on this one though. at first it seemed better, then one tank was lower, I'm on my third since switching...


Thanks!

[Gordon]

1.  Do you mean it rolls more smoothly in neutral than with it in gear and the clutched fully disengaged?  As in you have the lever pulled all the way in?  If so, make sure your clutch is adjusted properly.  The clutch itself, not just the cable.  This can be expected to some extent, though.

2.  Are the old and new filter the same type/brand? 

3.  Again, I'm thinking you mean you're disengaging the clutch and releasing the throttle to let the engine idle?  With a good battery, good charging system, and no added resistance in the wiring due to corroded connections, this won't happen.  But on bikes this old it's fairly common.  It can be fixed.

4.  Look in the FAQ under "Where can I buy parts for my sohc4?".

5.  If you haven't made any modifications to your engine that would require high octane fuel to run properly, or you don't have excessive carbon build-up in the combustion chambers that would increase the compression, then you don't need the more expensive fuel.

[catsoup]

yes, disengaged, my bad.

I'll take a look at the clutch, never done this before, tips?

2. same type/brand

5. no modifications that require it specifically, just figured I would see if there was a perceptible difference.

[Gordon]

The procedure for setting the clutch adjustment is in the shop manual.  If you don't have one they can be downloaded in the thread at the top of the "sohc4 bikes" forum. 

The filter issue is strange since changing an old, clogged filter for a new one would typically have the opposite effect.  I'm wondering if the old one wasn't installed incorrectly allowing air to get past it rather than going through it.  If the plugs don't indicate a rich condition, then I don't see any problem.