one cylindar out? 96 Sprint

[menelfloss]

So after a 650 mile hard ridden trip without a glitch, I get a mile from home and when I give it a lot of gas the engine sort of bogs like one cylindar is not firing, runs rough like when you need to go to reserve tank. If you don't crank hard or if you rev while sitting still things seem fine.

Thoughts?
Mike in Minneapolis

[mjac62]

My '95 Trident did that and I found it to be a bad fuel valve ( petcock) I replaced the whole valve and internal screen assembly and fixed it. I ordered the whole assembly from my Triumph dealer parts dept and it was $ 96.00 USA. This just happened about 2 months ago.

Check for spark at all your plugs to make sure you have firing on all cylinders. too if thats what you suspect.

[menelfloss]

Yup,
I thought about the spark thing, but the fact that the bike is running smooth until strain is put on the engine makes me think it is fuel starved. The petcock thing could be it I suppose. I was invisioning a piece of crud in an inlet jet of one of the carberators...
It is a bit of a pain to check things out since the fairing panels need to come off..

Thanks for the reply,
Mike

[tealetm]

I agree- its fuel. Or should I say lack of fuel.

[j98sprint]

Could also be a bad coil. If it starts running rough long enough to make a temperature difference, by touch, on the headers, swap the coils around to see if the cold header follows the suspected bad coil.

Bad coils are quite common.

j98sprint

[menelfloss]

Thanks for your ideas everybody.
I rode the bike again today and it seems wierd that it works fine until you give it a lot of throttle. In one way I don't think it is a source fuel problem because the other cylindars that are working during this "bog" seem fine as though their float bowls have plenty to deliver.
Then I was thinking it could be electrical since it only happens during a big demand and occurs and stops occuring quickly as I hit the throttle hard and back off.
Right now the engine works well enough that there is no temprature difference in the headers.
I was even thinking a cracked spark plug that starts to arc. or something. Perhaps I will pull and look at the plugs next and report back.

Any other suggestions?
Mike

[idahotb]

I had a very similar experience with my TBS. I was out on a spirited run when it suddenly sputtered and died. It would start right up and spin up just fine, but under a load when it got above 3,000 rpm it would spit and cough and die. Turned out that a pair of mice had made a nest in the airbox over the winter. When I goosed it once to often it sucked that***** up against the air filter and choked it out. A quick test to see if this might be the problem is to give it a little choke and see if that makes the symptoms worse or not. If it does pull the airbox and take a look.

[daveforty]

I had a fuel problem on my '96 Trident, it would misfire and cut out after a fast (ish) run, by the time I had coasted to the side of the road and stopped it would re-start. Turned out to be partially blocked fuel filters in the carburettors, 'witches hats' was what the dealer mechanic called them. I had suspected fuel starvation and had checked the filter on the petrol tap - it was as clean as the day it was new.

[menelfloss]

The wierd thing is that it never dies. It is not like there is not enough gas to keep her going.
I would think if it were starving for gas, eventually you would get the float bowls down far enough that even when backing off of the throttle it would be boggy and rough, in this case it is not.
I really appreciate the replies guys.

Mike

[menelfloss]

I got to the plugs and this is what I found.
Center plug kinda fouled.
What do ya think?

http://www.kodakgallery.com/PhotoVie...vfolderid=2006