Author Topic: RPMs hanging  (Read 2637 times)

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hnhracing

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RPMs hanging
« on: August 17, 2006, 08:18:16 PM »
Finally got around to working on the 750. Last time I rode it ,2 months ago, it seemed like it was only runinng on 3 cylinders. The time before that , two weeks, ran great. Found two things, glogged slow jet and stuck float needle. Bike runs good now, little lean, could use next size main( 122s, 4-1 , pods). But it seems like when shifting and sometimes when blipping the throttle that it hangs up or closes slowly. All four slides are smooth and work great, but I could see them start to snap closed like normal then close very slow for the last 1/8 of an inch while I was blipping the throttle. Is this just the slight lean condition? I never noticed it before but I have not done any real ridin on it, just trips around and up and down the block.

Offline HondaMan

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Re: RPMs hanging
« Reply #1 on: August 17, 2006, 09:07:31 PM »
What model 750 is it? Does it have cables on each carb, or is it the bellcrank "Grand Prix" arrangement?
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hnhracing

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Re: RPMs hanging
« Reply #2 on: August 18, 2006, 05:27:40 AM »
Hondaman- Its a 76 with just one cable. Gonna try to get out there today and play with it.

Offline StevieMac

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Re: RPMs hanging
« Reply #3 on: August 18, 2006, 08:04:00 AM »
I'd check for intake leaks next.  With the bike running try spraying some carb cleaner around the rubber boots between the carbs and head.  If the rpm goes up you have a leak somewhere.
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Offline dusterdude

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Re: RPMs hanging
« Reply #4 on: August 18, 2006, 10:30:08 AM »
or possibly a sticky advance unit.
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Offline HondaMan

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Re: RPMs hanging
« Reply #5 on: August 20, 2006, 08:13:03 PM »
Hondaman- Its a 76 with just one cable. Gonna try to get out there today and play with it.

It's probably the 1-cable part. The 4-1 linkage system does not close to the idle level by spring pressure alone: the linkage is just a bit too clunky for that. Add the 2nd cable and the problem will go away.
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
Link to My CB500/CB550 Book: https://www.lulu.com/search?sortBy=RELEVANCE&page=1&q=my+cb550+book&pageSize=10&adult_audience_rating=00
Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

hnhracing

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Re: RPMs hanging
« Reply #6 on: August 21, 2006, 04:08:40 AM »
Pulled the carbs off and found the little gasket in the slide retaining nut was causing my hanging throttle. Rode around for a little bit, doing short runs and then going over the bike. I never used the e-starter, it seamed like the battery never had a good charge and would not start the bike. It wouldn't pull in the start, the lights would go real dim. So after riding for awhile I thought I'd use the starter, I hit the button and bang. No lights, nothing. Checked the fuses, disconnected both sides of the relay ( thinking the starter had a dead short)and nothing. I'm getting 13 volts after a night on the charger but drops to almost 0 when the ignition switch is turned on. I'll try to get some time to troubleshoot today. Thanks for everyones help.

benny365

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Re: RPMs hanging
« Reply #7 on: August 21, 2006, 06:45:01 AM »
Pulled the carbs off and found the little gasket in the slide retaining nut was causing my hanging throttle. Rode around for a little bit, doing short runs and then going over the bike. I never used the e-starter, it seamed like the battery never had a good charge and would not start the bike. It wouldn't pull in the start, the lights would go real dim. So after riding for awhile I thought I'd use the starter, I hit the button and bang. No lights, nothing. Checked the fuses, disconnected both sides of the relay ( thinking the starter had a dead short)and nothing. I'm getting 13 volts after a night on the charger but drops to almost 0 when the ignition switch is turned on. I'll try to get some time to troubleshoot today. Thanks for everyones help.

New battery? Maybe

hnhracing

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Re: RPMs hanging
« Reply #8 on: August 21, 2006, 06:18:41 PM »
Benny nailed it. Bad battery, and I just got it a few months ago but never really ran the bike. Weird thing is it always had good voltage just no balls, starter was slow when it did turn kinda like a dirty terminal or something. Had a battery for another bike, hooked it up and bam, bike starts with ease. Thanks again guys