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View Full Version : TRX850 running as a single banger under load...


R6_kid
16th February 2010, 11:29
The only change I've made since it was running fine was that I've put Gull Force 10 (ethanol blend) in the tank.

Is it possible for a bike to run fine on idle and then have one cylinder pack up under load due to contaminants in one of the carbs? Or should I be focusing my efforts on the ignition system?
CookMySock
16th February 2010, 11:41
My guess, is the ethanol blend flushed some crap out of the tank and blocked an emulsion tube. That will make it run fine at idle and very low speed, but over 2500 rpm and at partial throttle it will miss and backfire real bad. If the miss is further up the rpm range, then the main jet is blocked.

In any case, it is trivial to whip them off and blow them out, even without compressed air. A can of flyspray will do at a pinch.

Steve
R6_kid
16th February 2010, 13:35
Well, it has nothing to do with the fuel or the ignition. I took the float bowls off and one of the main jets fell out. Don't know how it's come undone as I've never touched it before.
onearmedbandit
16th February 2010, 14:48
Don't know how it's come undone as I've never touched it before.

Soooo, you're saying that things you normally put in place eventually fall out/off?
imdying
16th February 2010, 15:04
Well, it has nothing to do with the fuel or the ignition. I took the float bowls off and one of the main jets fell out. Don't know how it's come undone as I've never touched it before.Don't be tempted to rape it with the screwdriver when you put it back in.
R6_kid
16th February 2010, 16:12
Soooo, you're saying that things you normally put in place eventually fall out/off?

LOL, that came across wrong! I was surprised, I'd think that with something like a main jet you'd torque it up, or at least tighten it more than finger tight. I do have a history of losing fairing fasteners though.


Don't be tempted to rape it with the screwdriver when you put it back in.

Learnt that lesson on a very old set of RGV250 carbs, good thing they were already fucked.
quickbuck
16th February 2010, 18:36
LOL, that came across wrong! I was surprised, I'd think that with something like a main jet you'd torque it up, or at least tighten it more than finger tight. .

Umm,
You know about vibrations and Frequencies right??

At least you discovered why.... Always better than putting it all back together, and it works, but not sure what you changed to fix it...
R6_kid
16th February 2010, 21:59
Yeh but surely a correctly fastened jet shouldn't come undone?