Rev counter jumping and engine spluttering/stumbling

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gavinfdavies
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Joined: Sat May 25, 2019 6:25 pm

Rev counter jumping and engine spluttering/stumbling

Post by gavinfdavies » Wed Jul 03, 2019 12:29 pm

HELP : Rev counter and power issues.

Took the Yamaha TRX 850 out for it's first proper ride today after giving it a bit of a service. New rear tyre/bearings/seals, new sprockets, new air filter, fuel tap, carb balance. All fuel/air/vacuum hoses checked and seated. Fuel tank cleaned out too.

Ran amazing the first 40 miles or so, including a stop for breakfast. Real power house. Then after about 20 miles of the return trip it began spluttering/stumbling a bit on acceleration, felt similar to running out of fuel, some times there was a bit of a knocking sound, but it was the same noise you get if you lug the engine, so might just be due to the power cutting in & out. At this point the Rev counter also began jumping up if I opened the throttle more than about 1/4, even though the revs were actually stable (apart from the coughing etc). I could gently cruise home at 4k rpm (allegedly), but any more throttle and it would a) stumble & cough, and b) the rev counter would start jumping wildly. For reference, I'd done only 58 miles on a full tank of fuel.

I'm about to head down and start testing everything with a multi-meter and checking electrical connections. Before I do, does any one have any ideas what it might be?

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HolerTogni
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Re: Rev counter jumping and engine spluttering/stumbling

Post by HolerTogni » Wed Jul 03, 2019 8:03 pm

Hi gavinfdavies!

Methinks checking the throttle sensor seems like a good idea - for basic adjustment see TRX-manual or do a search here.

Guessing greets from Munich!
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Nothing against four cylinders:
TRX 850 & Racetrack-TRiXie :twisted: 8)

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