engine dies at stop after running at highway speeds

I have had this problem for some time now.After cruising down the road at 50+mph or make a hard run when I slow down and stop the engine dies!!Let it sit for a minuite or so she will fire up and down the road we go.But if I keep the rpms up around 2000 or better I have a better chance of keeping the engine from dieing.Ive cleaned the carbs (running vm26) eliminated the electrical problems.Any info please help Thanks

rammy wrote:

I have had this problem for some time now.After cruising down the road at 50+mph or make a hard run when I slow down and stop the engine dies!!Let it sit for a minuite or so she will fire up and down the road we go.But if I keep the rpms up around 2000 or better I have a better chance of keeping the engine from dieing.Ive cleaned the carbs (running vm26) eliminated the electrical problems.Any info please help Thanks

This happened to me in the past. For me, it was fuel starvation at my gas cap gasket. The float bowls get low, then fill after a moment's rest.

Try a highway/offramp experiment with the gascap unlocked and laying closed to let more air in.

Or, if you don't think that's safe, check it out for a clog or debris. There's a tinly little air passage in there that clogs easily.

Or it could be dirty fuel filters, etc...

Thanks you know you just turned on the light bulb.I repainted the bike last spring and it ran fine till then.I wounder if the vent is plugged with some debris (tape glue or over spray)I will have to go check this now.Thanks Again toast

well went and checked the vent on the tank and it is clean and clear so that rules out that problem:dry:Dam and I though that was it now to pull out the hair a little more:pinch:There is new fuel line and a new filter installed less than 50 miles ago so I would have to say that this is good.Also removed and cleaned petcock all is good there

Post edited by: rammy, at: 2006/03/15 00:13

Have You noticed any gas coming out of the overflow hoses,when this is happening?
I'm wondering if the floats are set too high.

you said you replaced the fuel line. if you routed the fuel line too close to the cylinder, it will ...... what is the term...... vaporize? there is a term for it.
the gas evaporates in the fuel line when the cylinder is getting hot. so the gas isnt getting to the carbs even.

just an idea that i had.... no i swear it never happened to me! :whistle:

well thanks for the replies the fuel line is routed toward the battery box before it goes to the carbs and there is no fuel coming out of the bowl vents/overflow.

Seems it may be a 77 Z 650 thing. Mine does this occasionally (although only in really hot weather) and I know of someone else with a 77 Z650 who has had it a little worse than me, and has spent a few dollars trying to figure it out.
My bike kind of idles rough and slowly dies though, but comes right back with some throttle. It sounds kind of like float level adjustment.
I just keep some throttle rolled on if I think it may do it.

Regards, Andrew.

Possibly a bit too rich. Mine does this if I fail open the choke completely, after warm-up.

If it's worse on hot days, it's probably valve adjustments. When did you check your valve clearances last?

That is THE classic symptom for valves needing adjustment. Also, when you come off the highway, if you really keep it revved, it probably doesn't die.

Post edited by: loudhvx, at: 2006/03/17 18:22

typhoon wrote:

Seems it may be a 77 Z 650 thing. Mine does this occasionally (although only in really hot weather) and I know of someone else with a 77 Z650 who has had it a little worse than me, and has spent a few dollars trying to figure it out.
Regards, Andrew.

That has never happened to my 77 650 B1. The only time I had really rough idle or hard starting was when I had a half dead battery and or the carbs were going out of synch, or one time a point arm was loose and almost closed its gap. As Loudhvx mentioned, I reshimed my valves last year also, only one was almost zero gap. I have often been amazed that the old nail has never left me stranded. The only time it has suddenly stoped on me was when a clutch cable went ping as I was leaving a stop sign and several times forgeting to turn the fuel back on at the petcock.:whistle: Oh ya, it wouldn't start a few times until I jiggled the kill switch, but that was a rare occurance. Rode the living hell out of the bike this year, no problems other than the clutch showing signs of needing work.

well to let every one know what i found was that all the intake valve clearances were XTREMELY tight and there were 2 exhaust valves that wereout of specs.The funny thing about it is that when I did all the clearances early last spring every thing was good and in specand i check them this year and they are tight:angry: Just got to go finish up the stripped thread syndrom now and i will be able to see if this takes care of my problem.