Yamaha TRX850 Enthusiasts Forum

Here's a little anecdote for everyone. About 6 months ago my speedo stopped working. Thinking it was the cable I bought one on the way home. Upon inspection I found it wasn't the cable and the speedo still worked when I spun the drive end so assumed a worm drive problem. I hadn't been bothered to pull the front wheel as I don't really have a decent setup for lifting the front of the bike but finally motivated myself to do last weekend. Anway once I got the wheel off I found it to be the drive washer that has the two tabs on it was bent out of the way. Straightened it all up and now works great. Now for the reason for posting. I did a search but couldn't find any definite comments on a rev limiter on the TRX. I found when the speedo wasn't working the engine would pop and fart when it got to 7500rpm (approx.) and wouldn't drive above that. At first I thought it a co-incident and had a look at other things that might have caused that. I found nothing and upon fixing the speedo the engine sings all the way round the other side now. It's a Japanese import so has that got anything to do with it? I imagine the computer limits the revs when there isn't a signal coming from sensor in the speedo.

You got me,normally rev limiters work from the ignition pick-up pulses and the CDI or whatever ignition system there might be that gives the signals to the coils and on to the high tension plug leads.
If you try to rev the bike through the redline at standstill(don`t do it with a cold engine)does your rev limiter cut in?

I am thinking the computer isn't picking up the signal from the speedo so it then cuts the ignition to a pre determined limit. Will try the at standstill rev out and see, after warm up of course.

i also have an import model. just recently got mine serviced/dyno tuned(just to see how much power she had) my mechanic told me that the wouldn't rev past 7g, which he found very strange. so he had look in it. and found that there was a restricter in the carbs. and that he had never seen those carbs on a trx before(i have no idea what carbs r on it) he told me that if i wanted to fix the problem i'd need to change over the the aus delivered carbs

That`s another one I`ve not heard of,I thought the rev limiter/restriction was controlled through the CDI on the Japanese market versions.
I stand corrected,seems on some it IS in the speedometer:

http://trx850.motomaniac.net/forum/view ... ion#p48041

FNTIM wrote:i also have an import model. just recently got mine serviced/dyno tuned(just to see how much power she had) my mechanic told me that the wouldn't rev past 7g, which he found very strange. so he had look in it. and found that there was a restricter in the carbs. and that he had never seen those carbs on a trx before(i have no idea what carbs r on it) he told me that if i wanted to fix the problem i'd need to change over the the aus delivered carbs

Someone has put a different set of carbs on teh bike - the TRX has NEVER been restricted via the fuelling

Mincehead wrote:That`s another one I`ve not heard of,I thought the rev limiter/restriction was controlled through the CDI on the Japanese market versions.
I stand corrected,seems on some it IS in the speedometer:

http://trx850.motomaniac.net/forum/view ... ion#p48041

The rev limiter is controlled via the CDI and can be sorted by simply swapping out the JDM CDI. It is also linked to teh JDM speedo and can be removed by 'playing' with the metal tab on the back of the JDM speedo

Mincehead wrote:

I stand corrected,seems on some it IS in the speedometer:
viewtopic.php?f=37&t=4640&p=48041&hilit=CDI+restriction#p48041

Hey look at that. I even knew the situation from that thread. I swear I'm going senile.......... where am I?

Never mind Devlin,let me wish you HAPPY EASTER and all the best for 1982,from all of us at the alzheimers society.
Oh and will we see you at the bonfire next week?
Don`t forget your swimming shorts.

Posted before about all the fun and games re the rev limiter, Mine is a Japanese import, in standard imported trim it won't rev past 7,000 in any gear, and it is also governed top end by the speedo, 112.5 mph, go on try it!! It does now lol. Beware playing with the tab washer inside the speedo or you may find it doesnt rev at all!! Then you have to throw it away and start again.

Dave E

slow codger wrote: Posted before about all the fun and games re the rev limiter, Mine is a Japanese import, in standard imported trim it won't rev past 7,000 in any gear, and it is also governed top end by the speedo, 112.5 mph, go on try it!!

Yep A fuse went on mine when I had the Japanese cdi fitted and it took a while to work out the why the derestrictor wasn't working.