I've got a 2006 YFM660 Grizzly that is losing power at high speed in High gear (but not in Low gear) and is flashing the Reverse indicator when the power is lost. I suspect the speed sensor, but I don't want to go replacing things ***** nilly without being sure. I bought a Clymer service manual and, while the sensor is shown in the wiring diagram, it doesn't appear ANYWHERE that I can find in the text of the manual.

Does anyone have any information on this issue and/or a factory original service manual that might have this information? I'd really appreciate it!

 

Workshop manual is listed here https://www.501parts.com/service-manuals/

However extremely unlikely to be the speed sensor at fault. I would have thought that the gear indicator switch would be the culprit, if the reverse light is on, it thinks it is in reverse, so would signal the CDI to switch the rev limiter on. I don't know the 660, as bikes over 500cc are rare in the UK, but find a lot of Yams with slightly dodgy gearchange indicators. Often they can be got at from the outside, unlike modern Hondas and Suzukis where the switch is inside the engine so, on some Yams, switches can be easily removed and the contacts cleaned.

 

I downloaded that (thank you) and it at least MENTIONS the speed sensor, as in where it's located, but for some odd reason, still nothing on testing it or it's operation! smh... but.... I did see something in there about 4wd having a speed limiter. I'm going to check that. The Reverse light isn't ON when it's running in limit mode, though, like a gear select switch would do. It's flashing more like a warning. If I figure it out, I'll report back.

 

OK... I take it back. It's a rev limiter. The R indicator comes on in High, Low and even Neutral when reved up. But I cannot find anything in the manuals that says WHY it would do this at driving speed in gear.

 

Reverse switch is bad/intermittent. Thank you for your help!