my wr450f jerking at steady low speed and high gear

First, excuse my bad English!


I use my wr450f (50 hp on wheel) to drive to work, and the speed limit is often only 50-60 km/hour. The road is moastly horizontal.


The chain is chopping up and down because there is no need for torque when im driving in fourth or fifth gear. Therefore i  change gir all the time, so the torque from engine tighten the Chain (and it stops chopping/jerking).


Any riders out there experiences this, and what can solve this "problem"?


My Brothers Yamaha R1 do not have this problem - runs like a train at slow speed, but of course, that is another bike!

Edited by Jon E

unplug your tps sensor on the carb. this will cure your problem. It doesnt effect anything else with the bike.

Uplugging the Tps WILL change the power curve and torque, but it's not a huge deal.

You need make sure your chain is straight. 

Get or make a chain site (Motion pro) so you can verify you rear wheel is straight, hence the chain is straight.

Then if you really want the chain to be in control, put on a TM Design works pro glide swingarm rub strip. It keeps the chain straight with grooves.

When you install it (or with the stock one) you need to glue it in place with silicone seal. The rub stip slaps against the swingarm and doing this will quiet it down.

My yz426f does the same if I try do around 40-50km/h in 5th. It is because of the chain slack and that it is a big single cylinder 4 stroke. Everytime it fires the chain tightens up for a moment and then goes loose again and that makes the slaping noise. Unplugging the TPS will not help it, its is just the nature of the beast. I have the TM design works proglide chain slider and it doesnt seem to help much with the slapping only that it lasts alot longer then any other slider I have tried.

If you are describing 'drive line snatch' ( the slack in the transmission that is felt when you go from on to off throttle), that cannot be solved without opening up the motor and changing the clutch hub rubbers.  

You need to change your riding style to solve that.

Thanks for answers! I tried to unplug the tps sensor, but it just slightly helped - so i put it back on. The bike is obviously not made for slow running to work, so I Guess i need to change my riding style a bit... :ride:

Proper jetting helps a lot. 

TPS unplug even more.

A Dynatek ignition cures it.

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