Yamaha TRX850 Enthusiasts Forum

Hi guys and girls,
I am now at the end of my USD front end/digital speedo modification on my 97 TRX. Have fitted a KOSO DB02 dash. Everything works well except 2 things:

Firstly, the speedo reads ok up to about 35kph but then it only goes up to approx 45kph(I know I'm going faster than that) I have fitted the magnets to the front wheel disc bolts and mounted the sensor there. I'm not into wheelies and the like so didn't see the need to run it to the back wheel. Anyone with one of these KOSO speedos have any thoughts on this??????

Secondly, and more of an issue, is that the bike now has a top end misfire, well more like it bogs when on anything more than half to 3/4 throttle. The bike was of the road for 6 months so my first thought was stale fuel. New fuel has made no difference. I have checked all the fuel lines etc and nothing is amiss there. I had dynoed the bike and re-jetted it and it was running super sweet right before i started the mods.
I have the tacho connected to the signal wire of the left hand coil and it works fine.

Just looking for any pointers to help me out here please..........

Will upload some pics FYI

First thing to check with the Koso dash is your fitment of the pick up magnets - each magnet has a small 'N' printed on the outer face, if these are fitted the wrong way round ('N' should face the sensor on all magnets) you will get an incorrect or inaccurate reading. Might also be worth checking the magnet/sensor gap?

Bogging problem sounds like fuel starvation to me - have you checked fuel line routing with tank re-installed? Any sharp returns in the hoses can turn into 'kinks' once the engine is warm.

Hi....Also with the koso you have to configure it to the distance of the front wheel circumference and the number of magnets being use if I remember correctly

Thanks guys......

I'll double and triple check the wheel circumference setting and clearance to sensor. Have definitely got the magnets in the correct way though.

Time to go over the whole thing with a fine-tooth-comb to check all hoses etc. Neato!!!!!

Similar to what I experienced. Put a tape measure on the floor and a mark on the wheel. Start the mark at the end of the tape and wheel it one rotation, you can get a proper size that way.
I unravelled all sorts of stupid little gremlins when I rebuilt mine and spent hour upon hour looking and getting nowhere. My boggy top end ended up being resolved with a valve fettle and new needles in the carbs. I just couldn't see it with my eyes. It does your head in, take off, put back exactly the same way but aaahhhhhhhhh, no no no no aaaahhhhhhhhh Sometimes it pays to let someone else have a butchers.

Problem solved......
After walking away from the bike for my xmas break I revisited it today. Turns out there was an obstruction in the air box intake. Remove one roll of insulation tape and voila!!!!!!! All good. I did wonder where I had put that tape.

LMAO!!!!!!!

Thanks for the advice anyway.