Author Topic: Stalls after hard ride let sit couple min runs fine  (Read 1215 times)

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Offline 1974cb550k

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Stalls after hard ride let sit couple min runs fine
« on: September 05, 2011, 04:04:09 PM »
Hey guys lost my other username so i started a new one. Went on a two hour ride this weekend and my bike would stall out if you make a sudden stop from anything more than 3/4 throttle. It just dies completely. Let it set for 4 min and it starts right back up. When it dies if feels as thought it is starving for fuel and sounds like it is running on two cylinders. If you make a slow gradual stop coming off the highway it is fine, but if you see a red light, goose it and stop sharp it will just quit. Feels like what happens when you realise you left your petcock off. I wont have time to mess with it until Friday but i was just looking for any suggestions. I'm leaning towards a sicking float or the return spring on the carbs. I have to twist the throttle back manually slightly.. BTW it has a 650 cam.
Here are the bike details
1974 Honda Cb550 k
New rings with less than 200 mi
Adj valves 50 mi ago stock settings
650 cam
stock points just adjusted and dressed
I have 2 vented gas caps tried em both
synced carbs 50 mi ago
50 mi on new freshly gapped ngk d7ea's (old plugs removed were mint the best set i have ever seen)
k&n pods
115 mains
Carbs completely disassembled new mains, slows and pilots (done by me) hand drilled float hinge holes submerged floats
new resistor plug ends
adjusted cam chain 200 mi ago
Just wondering if anyone else had same issue. thanx

Offline 1974cb550k

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #1 on: September 05, 2011, 04:05:29 PM »
oh yeah MAC headers and hand made pipe

Offline phil71

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #2 on: September 05, 2011, 06:51:10 PM »
May I say, that thing is beautiful.!

Offline Spanner 1

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  • CB 750 K0 ( always thought it was a K1!) + CB750K8
Re: Stalls after hard ride let sit couple min runs fine
« Reply #3 on: September 05, 2011, 08:01:09 PM »
Engine vacuum at WOT or big throttle openings is 'helping' the slow fuel delivery to maintain enough fuel in the bowls to immerse the main jet in fuel = runs, but with the throttle released the fuel level is below the slow jet ( which sits higher in the fuel bowl )........... long way of saying 'Gummed-up petcock ' IMO.
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline 1974cb550k

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #4 on: September 06, 2011, 05:17:32 AM »
Definetly something to look into. Thanx

Offline WarwickE36

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #5 on: September 06, 2011, 05:33:22 AM »
When you give up can I have your exhaust?

J.k.

I would definitely check float height and and check the idle jets.  But maybe you have a condenser on the fritz.  What are the header temps at failure?  is 1/4 or 2/3 cold?
" Why does anyone get offended by what someone does to their own bike? I dont get it. "

You made me think about it after I cheered knowing someone else would like to know what these control freaks are up to.
 Every time any owner strips whatever precious Honda part the horrified purists parts go up in value. That's not the part that bothers them.
 What bothers them is they sat up late at night, their breast full of wonder and estrogen, unable to sleep, dreaming about their lovely darling and all her glory... and next thing you know someone else doesn't share their emotional deluge and their reaction is they must spread their mind museum as far as they possibly can, taking over as much of the real world as possible.

Drink fast, drive slow, but ride it like you stole it

1974 Cb550 with style
2004 SV650s

Offline 1974cb550k

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #6 on: September 06, 2011, 05:43:31 AM »
All pipes hot. Not thinking condenser because it only does under certain conditions. I am running a single feed cb400f petcock with single feed, need to swap to dual feed I think for the early style Kehins. Def feels like fuel starvation not dropped spark. I will check condensers anyway though. No dice on exh. Thanx

Offline wrenchmuch

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #7 on: September 06, 2011, 06:05:56 AM »
Is the fuel cap's vent clear ?
CB750K1
CB750K4

Offline 1974cb550k

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #8 on: September 06, 2011, 06:14:05 AM »
Trashed OE flip cap and welded in a spin on style bung. I was thinking the same so I bought an extra cap thinking same thing. Same issue with both brand new caps.

Offline 1974cb550k

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Re: Stalls after hard ride let sit couple min runs fine
« Reply #9 on: September 06, 2011, 06:15:45 AM »
Wrong pic here is the the cap.