Hi all, Ive recently bought a 2018 trs rr 300 that has hardly been used and went out on it for the first time yesterday but I’m having a problem with it when your riding it at a constant speed it’s slightly surging forward and back, I wouldn’t say it’s missing firing.

what are the problems when the cdi is playing up 

thanks

chris

Doesn't sound like CDI,sounds more like carburation.CDI causes bad misfiring,won't rev or won't start.Id have the carb off ,clean it out and check the jetting,could be someone's been altering things.

Thanks huski, I’ll take it off and give it a good blow out with a airline 

6 minutes ago, Chrisjenko said:

Thanks huski, I’ll take it off and give it a good blow out with a airline 

Idle mixture screw wants to be about 1/1.5 turns out

Is that the black plastic screw or the brass one that is counter sunk into the carb

Sometimes people lose the needle jet when cleaning the carb. Some bikes run poor to fair in this condition but will not run great.If you take the airbox off at the carb, there should be a brass coloured bit sticking up from the bottom of the carb. That part is the needle jet.  Good luck.

Ok will have a look 

thanks

On 12/16/2020 at 5:26 PM, Chrisjenko said:

Is that the black plastic screw or the brass one that is counter sunk into the carb

It's the the horizontal brass one that is closest to the airbox Other one alters the tickover speed,gets faster the more you screw it in

Edited December 17, 20205 yr by huski

Ok brilliant ?

 Before you start spending any money, I would remove the ball from the gas cap vent. They are known to stick, and you don`t actually need it.

Ok lineaway, I’ll have a look at that when I get home from work 

thanks

chris

Is it worth getting a csp cap.