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Discussion Starter #1
So I've encountered this weird problem with my 2001 750 Monster with a stage 2 jet kit.

Historically my '01's been running great and dependably for years with very little maintenance involved. Lately, it's been running pretty crappily with some backfiring, hesitation and the like.

Most peculiarly, what it does is run for a few minutes after startup, and then putter out and strand me at the side of the road. I can hang out there for 3-5 minutes and then start it up, and ride for another minute or two and then it will happen again. Will turn over but wont even try to try start for another 3 minutes minimum. Not at 1 or two minutes- but a minimum of 3.
Following that, I can ride for another two minutes or so... repeat ad infinium. (or till I finally get home).

I seem to vaguely recall a similar situation once in which I replaced the plugs and all was well, but I went and did that and still it continues.

The bike had a valve adjustment right before I got it, and I took things apart to check the tolerances, and they still seem to be good. So I'm pretty well out of ideas as to how a a time factor figures into this odd situation. I was thinking fuel delivery, but this is a gravity fed bike if I recall correctly. It has a recent fuel filter. Then I was thinking maybe the ignition coil-- possibly effected by heat?

Anyway, I'm running out of ideas but miss riding my Ducati, so thanks in advance for any help!
-kevin
 

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you may have a pinched tank hose.
try opening the gas cap when it stalls...if it makes a sucking noise...thats it.

jeff h
monsterparts.com
 

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It could also be dirt under the needle valve or a sticky float. This would cause the engine to run fine until it empties the float bowl.. and since the fuel cannot get into the bowl fast enough it runs dry and causes a stall. After 3 minutes the fuel trickles fast the obstruction and your ready to roll for a few more minutes. Funny for both carbs to do it though. I would suspect its probably in your fuel supply line. Have you checked the fuel filter? Definitley sound fuel related though.
 

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Same thing happened to my 98 M750, the fuel tank is vented through the filler cap there is a small hole in the cap and a rubber seal in the tank some times the rubber seal can cover the hole in the cap causing a vacuum in the tank and the engine starves for fuel, so you can increase the size of the hole in the cap so the rubber seal does not cover it.

Cheers
Jack
 

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Discussion Starter #5
thanks!

Hey- that fuel-tank-vacuum theory makes a lot of sense in the grand scheme of things. I'm excited to go and troubleshoot with that in mind. Hopefully I'll report back with good news!
Thanks!
-k
 

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Discussion Starter #6
So, I made a 3/8" dia vacuum tube extension for the shop vac and I think I sucked out most of the debris blocking that hole under the gas cap. It WAS pretty dirty/rusty, but it also looks like its intended to mate to a hole in the actual cap assembly. So really, it looks to me like its missing something- an o-ring perhaps? Can anyone verify? Right now its just a crusty 1/4" dia or so hole.

Anyway, so it still runs not-quite-perfect, but I drove it a few blocks of highway and wound up stalling it briefly at an intersection, then driving it back okay. Seemed to be allright once it warmed up enough, so hopefully that was it. Still, with regards to the fuel system, I've never cleaned the screen filter inside the actual tank (assuming there is one), so maybe that's next on my todo list. Thanks for the help, and feel free to keep any other suggestions coming!
-k
 

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Discussion Starter #7
Well, I can conclude that cleaning out that hole certainly did effect the performance, and certainly contributed to the problem, and yesteday it actually ran to/from work without too much trouble. Today, however, it managed to slowly bump to a stall condition. While it was doing it- I had time to jiggle the key out of the ignition (which you can do while running after the last theft/recovery/ignition install) and open the gas tank lid. Doing so didn't prevent it from ultimately stalling and it was open/running for a few seconds before it continued into a stall.

Anyway, so after it stalled, I waited probably 30 seconds on the side of the road, closed the cap up then fired it back up and drove to work fine. Weird.

It still mis-fires, mostly while decelerating. I'll have to look into adjusting the timing- a task I've never done, it seems like the timing may be advanced too much.

Otherwise, I may continue investigating fuel issues. Since there's no pump (correct?) I suppose my investigations will be in pursuit of a clogged line somewhere in the system or possibly the carb?

Anyway, thanks for any more ideas!
-kevin
 

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Fuel Filter?

Have you checked /replaced your fuel filter?
Sounds like the vent tube helped you to get a faster flow, but I'm thinking the filter maybe clogged.
Easy fix.
Hope it helps.
Jeremy
 

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I had a similar problem, and turned out to be the plugs, like you said you've done. If you got some bad gas somewhere, it would continue to foul the new plugs until all the bad gas is used up. I don't know if you've manage to ride far enough to use it all up, if not I would try draining the fuel, replacing the fuel filter and at least trying to clean the plugs, if not replacing them again. Use some fuel treatment occaisionally, and I assume you only run premium, if not, start! Hopefully that, in combination of all the cleaning you've already done, will take care of it!!!
 

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Have you checked to see if your carbs are properly synched? That would definately cause the bike to run rough and backfire, although they would have to be very bad for the bike to stall.

And I agree that you should pull your plugs and check them again. I had a zx-7 that started running rough, and when I pulled the plugs one had a piece of carbon wedged in the electrode.


Certainly sounds like a fuel delivery or fuel/air mixture problem to me as well. You say you have a stage two kit, if you have pod filters they can be very sensitive to weather and temp changes. Try cleaning or changing the air filter, if it's dirty the engine will run rich when it's cold (when it needs to) but will stall as it warms up.

chris
 
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