Topic: cb750 carb problem

[gregk]

efyou

i would like to welcome you to the forum and 4Q2.


greg

[mrbreeze]

Hey Greg.......you shoulda put a smiley after that post ya know!!!!!!

[manther]

........................................

I think your mains are plugged right up, clean them..

good luck..

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From the way I understand things if his main's were clogged he'd be having more trouble in the first 1/4 of the throttle. With the way he's describing the problem sounds more like lean needle clip position.

Man I'm an idiot I don't know what I was thinking, the main's don't effect the first 1/4 of the throttle, thats part is controled by the piolt jet, and the fuel mixture screws. But, the needle IS between 1/4 throttle and the main circuit.

[754]

So, if the mains are working, explain why after crapping out in the midrange, it does not ever get on the mains & run clean?

[manther]

Well I had the same symptoms he had and my mains were fine but the clip position was lean. The needle circuit doesn't abruptly end, it bleeds into the main cicuit. I too could get my throttle well into the 3/4 range and still have poor response. But when I dropped the clip position two levels everything above 1/4 throttle woke up. I'm not saying there is absolutley no way his mains are clogged. Just saying it sounds like my problem. But, I mispoke earlier when I said mains were for the first 1/4 throttle and I wanted to correct that.

[ajinreno]

OMG! Did anyone notice what the OP's username is?!?!

[1080]

I would try to take off the shiny metal part of the air filter, and run it open, so that the air turbulence inside the empty air filter covers is not generated.

Some times air turbulence can mess the carb air flow in. May be it is just a Amen Savior frame thing.

My brother had the same thing happening with his 650 Amen ( he ran the rectangular air box from Amen. Solution was additional foam inside the air box.

My Amen with RC big block with KZ1000 carbs also using the same rectangular air box as my brother used no air filter, I had to shorten the the metal mesh 1/2 inch to tune it in.

Presently running the same air filters ,but mine have the foam filters with covers being meshed.

[mrbreeze]

SAWeeeet!!!

[754]

Heh, heh.its ..me-on-my73..in the top pic.. looks like I am running seatless..

[cherry bomb]

I posted earlier on my carb issue...when i rev up the motor it holds RPM until I adjust the Idle screw then it comes down and dies.

udate on carb status:
I have checked the rubber boots for leaks-there are none
Throttle cable-there is no binding
Main Jets- they are Stock #105

There is no doubt that the bike is running lean...the plugs are showing white/gray it still backfires and what not...BUT...I think the holding RPMs is due to the carbs not being sync'd correctly...anyone want to weigh in on that? Then the question becomes...should i re-jet the mains and then sync or sync then re-jet...or is it just a personal preference.
Thanks for the suggestions!