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Engine cold, turn key, choke it, give it some gas, check kill switch, stands up, gears right, push button....

work it work it.... dedicated work it, sometimes it starts....
like only one or two cylinders then they each fire up as it warms up....

But then there is the syndrome....

Engine cold, turn key, choke it, give it some gas, check kill switch, stands up gears right, push button

grind grind.... spits some gas through the air jet.... grind grind....
refuses to spit gas through air jet. battery fails....

new plugs and wires, coils all check out. This happens mostly when the tank shows nearly empty. I have not cleaned the tank but I did drain it and clean the petcock. fuel pump ok. No errors on dash idiots.

IF it was something bad it wouldn't start at all.... its like its trying to tell me something....
1983 Yamaha Venture Royale XVZ12TDK
 

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Do both sequences happen when the tank is near empty, or just the second?

Valve timing a bit off? Or, valves sticking?
 

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What's it do on a spritz of starter fluid?

Edit: Good thought re: the valves.
 

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My Yami.

My 79 XS11. Key on, fuel taps on, full choke, no throttle, press button, vroom in an instant, even if sitting for a while.

My 83 XS400. Key on, move choke lever full on, press button, crank crank, fire, little rattle, putter putter putter.

Same program for the other XS1100. None of them will start if they are given any throttle. These enrichener dohickies work different than the old chokes.

Will not do the fuel injected bike.

Unkle Krusty*
 

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I know the single-cylinder Yamaha dual sports will not start if the throttle is played with. It actually somewhat defeats the purpose of the enrichener if the throttle is opened because the open butterfly allows more air to flow through.

I'm not familiar with that model and not sure if it works the same way, but it's worth a try.
 

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My Yamaha Vstar 650 doesn't start right if I give it throttle either, the way to start these things when it's cold is full choke ( it's not really a choke), don't touch the throttle, press and hold the starter button and in 3 or 4 seconds its running just fine. If you let go of the key too quickly it tries to stall, keep cranking for a second longer until both cylinders are firing and it's good to go.Let it run that way at fast idle and then in 15 seconds put the choke in half way and ride away, and a minute down the road reach down and push it in the rest of the way.
I think the problem with giving throttle when starting is 2 fold, it messes up the action of the enriching circuit ( faux choke) and it advances the timing too far for the rpm.

The only quirk with mine is that when it's very cold often as soon as you hit the key it gives a bang out of one exhaust, not sure why but it always does it and only once so it's not a big deal..just keep cranking it and it starts right up every time. My neighbors probably love that bang at 4am when I leave for work..but oh well :)
 

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My Yamaha Vstar 650
The only quirk with mine is that when it's very cold often as soon as you hit the key it gives a bang out of one exhaust, not sure why but it always does it and only once so it's not a big deal..just keep cranking it and it starts right up every time. My neighbors probably love that bang at 4am when I leave for work..but oh well :)
For the first time ever my XS400 was slow to start yesterday. He made a few bangs as well. It is slowly getting warmer, and the bikes might not need as much choke / enrichener.

Unkle Krusty*
 

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The only quirk with mine is that when it's very cold often as soon as you hit the key it gives a bang out of one exhaust, not sure why but it always does it and only once so it's not a big deal..just keep cranking it and it starts right up every time. My neighbors probably love that bang at 4am when I leave for work..but oh well :)
That's built in for your benefit, to make sure you're wide awake and alert at 4am before hitting the road! ;)

:p
 

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:coffeescreen:

That's built in for your benefit, to make sure you're wide awake and alert at 4am before hitting the road! ;)

:p
 

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Engine cold, turn key, choke it, give it some gas, check kill switch, stands up, gears right, push button....

work it work it.... dedicated work it, sometimes it starts....
like only one or two cylinders then they each fire up as it warms up....

But then there is the syndrome....

Engine cold, turn key, choke it, give it some gas, check kill switch, stands up gears right, push button

grind grind.... spits some gas through the air jet.... grind grind....
refuses to spit gas through air jet. battery fails....

new plugs and wires, coils all check out. This happens mostly when the tank shows nearly empty. I have not cleaned the tank but I did drain it and clean the petcock. fuel pump ok. No errors on dash idiots.

IF it was something bad it wouldn't start at all.... its like its trying to tell me something....
1983 Yamaha Venture Royale XVZ12TDK
Enrichener hole restricted? If the tank is nearly empty, it may not be getting enough fuel to start other than the little bit in the line. Don't know if this has a fuel pump like the 650 does, but if the tank is low, it may not be getting enough fuel to push to the carbs.


I don't remember our 650 doing that, but it was a temperamental thing when it was cold. Most times it would start with the choke and no throttle, but sometimes it would need some throttle to go, then it was stepping down the choke every couple minutes before it would idle. This was cold weather though, during the summer, the choke never got used and it would start up and idle right away. Could never tell if it backfired, had straight pipes on it and it was a noisy thing anyway.
 

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That sounds like the way my wife's Vstar 650 runs, its got Cobra pipes and never was re-jetted so it's running pretty lean, it's cranky when cold and has to be finessed till it's running smoothly enough to ride. I really need to fix it for her one day, she has new HardKrome pipes, a hypercharger, and a jet kit sitting and waiting in the living room waiting for me to install.

Mine has V&H pipes but was re-jetted to match and it's actually a bit on the rich side, much easier to deal with. You'd know if it backfired, mine sounds like a shotgun when it goes "Bang!"

I don't remember our 650 doing that, but it was a temperamental thing when it was cold. Most times it would start with the choke and no throttle, but sometimes it would need some throttle to go, then it was stepping down the choke every couple minutes before it would idle. This was cold weather though, during the summer, the choke never got used and it would start up and idle right away. Could never tell if it backfired, had straight pipes on it and it was a noisy thing anyway.
 

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Choke it.

With my XS400 which quickly got a hard starting problem: I think it is the enrichening thingys. The idle also got funny about a week ago.
So, next thing to study is the enricheners.
You may recall Eye mentioning it as a potential problem for Roy's Harley, since fixed.

I am not in the mood to remove the carbs on Deep Purple, but if I have to, it will be done. Warmest day so far this year which is helping.

Unkle Krusty*
 

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I haven't experienced an enrichener circuit having problems in the past. Most carb problems I have dealt with are simply gunk from old fuel clogging the jets.
 

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Problems.

I haven't experienced an enrichener circuit having problems in the past. Most carb problems I have dealt with are simply gunk from old fuel clogging the jets.
I will report my findings after I work on the carbs. First I will mess with the enricheners and see what happens.
If there is no change I will visit the jets. Full throttle is still working fine.
This bike has had plenty of fresh fuel through it, but it is always possible to get some crappy stuff. New idea, I will swap the fuel filter first.

Unkle Krusty*
 

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The Yamahas I work with are the TW200 and XT225. Each has their small quirks. The XT bikes often will not start if fuel is left in the carb for a week. Drain the carb, and they pop right off. I still haven't figured that one out yet. It might not be all of them, but enough that it's standard policy to shut off the fuel to run them dry after use.
 

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I haven't experienced an enrichener circuit having problems in the past. Most carb problems I have dealt with are simply gunk from old fuel clogging the jets.
With the Suzi carbs, it is not uncommon for the enricher to have problems, not with the valve itself, but the mounts for the control cables. Seems they are plastic, and you have to be careful with them. Of course, if the pilot jet is clogged, the enricher doesn't work, either.

For those who may not know how they work, the starting enricher is a valve that gets the fuel/air mixture from the pilot circuit, which also feeds the idle control, but bypasses the idle port through additional ports downstream of the throttle plate. So, when the throttle is opened, the enricher stops providing fuel, for the same reason the idle system does; this also means you can leave the enricher on and ride away, and it doesn't affect your fuel economy much, but you will notice it when you stop after the engine is hot.

In many carbs, those ports are also used by the transient enrichment system, AKA coast valves, which work much like the starting enricher, but are opened by high vacuum, as when the throttle is abruptly closed, to supplement the now over-lean idle supply; many designs use the same pilot circuit source.
 

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Flat gas.

The Yamahas I work with are the TW200 and XT225. Each has their small quirks. The XT bikes often will not start if fuel is left in the carb for a week. Drain the carb, and they pop right off. I still haven't figured that one out yet. It might not be all of them, but enough that it's standard policy to shut off the fuel to run them dry after use.
We had this happen with new XL185 Hondas. Same plan, drain the gas until it ran clear. Always thought it was how the carb was vented. The original plug on those bikes often failed. We figured they must put some anti rust type preservative in the tank, and that killed the plug. And it also may have had an effect on the fuel.

Wintr. Thank you for the info. I have yet to take one of these enrichener things apart. I usually ride off with the device still on, and slowly return it to off as the engine warms.

Unkle Krusty*
 

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It's strange that the TW doesn't have that problem at all. They are very similar engines, but the carbs are different.

The XT engine will get really hot with the enrichener left on full for more than a minute or so. The exhaust pipe will glow bright red. The TW will just foul the plug up if it is accidentally left on. The Honda 250 twins will foul the plugs fairly quickly as well.
 
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