Yamaha TRX850 Enthusiasts Forum

Hi all,

I have recently emigrated from the UK to New Zealand and decided to take my trusty TRX with me - no laughing now. After a lot of faffing over NZ compliance I finally got it registered and road legal. To my surprise it started pretty easily after coming out of the shipping container, although it ran a bit rough. I've had a few relatively short outings on it, each time seemingly running worse.

Up to the last run, the symptoms were: difficult starting; very rough running on idling and low throttle openings; but strong and even acceleration on high throttle openings. I'm no expert by any measure, but reading up on these symptoms seemed to point to blocked carbureter pilot jets.

As per the shipping regulations, the fuel tank was drained for the sea journey and so the bike sat in the container for around 12 weeks with only what fuel was left in the carbs. I reasoned that maybe the fuel had evaporated and gummed up the jets. Not wishing to start immediately working on the carbs I thought I'd try some (Penrite) fuel additive that promised to "clean and protect fuel injectors and carbureters in one tank of fuel". So I bunged some in and did about 100km. I can't say I noticed much difference by the time I got home, and when I tried it today it won't start at all

So, advice please. Do the described symptoms really indicate blocked idle jets, and does my theory of fuel evaporation/gumming make any sense. And, did I make things worse with the additive?

Incidentally, to eliminate ignition failure, I have checked that there is a good ignition spark to both plugs.

Cheers,
Barry

Does the choke make any difference?

Don't worry about the additive, it won't make anything worse.

It's a long coincidence, but difficult to start cold can be a symptom of neglected valve adjustment. Rough running could be from carbs needing sync. Nothing of which probably happend during transit. Another guess is an air leak somewhere that seals when bike revs, vaccum-related.

Planx wrote:
So, advice please. [1] Do the described symptoms really indicate blocked idle jets, [2] and does my theory of fuel evaporation/gumming make any sense. [3] And, did I make things worse with the additive?

Incidentally, to eliminate ignition failure, I have checked that there is a good ignition spark to both plugs.

[1] Yes (maybe)
[2] yes
[3] no

I would pull the carbs and clean them out. Check the fuel tap and filter (if you have one) too while you're at it.