poor throttle response and pulling back at speed

Hi all,

My problem is when pulling away the bike needs a lot of throttle and even then it really lurches slowly into action. It's generally pretty boggy and erratic at all low speeds in fact. When it gets up to speed it does it weakly and then suddenly it hits the power band and screams right up there - then it feels like it should. At speed (60-200kmph) it also pulls back (quite rythmically, strangely enough). Feels like fuel starvation but I'm not sure how best to proceed. I've searched out the forum but can't pin it down enough to know where to start. Any suggestions would be greatly appreciated!

Bike is a KZ650B1 with a D4 engine in it (25k on the clock), pods, 105's jets + standard idle jets, needle position in the middle, has a fuel filter and a clean tank. Ignition is an old Newtronics unit. I set the timing, balanced the carbs etc.

Thanks!

Pete

turbokonijn wrote: Hi all,

My problem is when pulling away the bike needs a lot of throttle and even then it really lurches slowly into action. It's generally pretty boggy and erratic at all low speeds in fact. When it gets up to speed it does it weakly and then suddenly it hits the power band and screams right up there - then it feels like it should. At speed (60-200kmph) it also pulls back (quite rythmically, strangely enough). Feels like fuel starvation but I'm not sure how best to proceed. I've searched out the forum but can't pin it down enough to know where to start. Any suggestions would be greatly appreciated!

Bike is a KZ650B1 with a D4 engine in it (25k on the clock), pods, 105's jets + standard idle jets, needle position in the middle, has a fuel filter and a clean tank. Ignition is an old Newtronics unit. I set the timing, balanced the carbs etc.

Thanks!

Pete

Hello, Pete, and WELCOME to KZr!

If not already done, would assure that valve clearances are within specs, and assure that the timing advancer is properly functioning.

After that, would also address fuel supply, fuel levels, and pilot circuits.

Good Fortune!

You mentioned the 4-letter word (pods); does your bike have the CV carbs? Ed

Hi Patton and 650ed, thanks! Timing I'll look at again - the advancer may need an oiling or maybe replacing (no problem as I have a shed full of maybe 7 z650's in bits!)

ed, I still have the old standard mikunis on - I know, I don't feel comfortable with the p@%#s either. Maybe I should just go back to the standard filter as I have a nice one with soft boots. I guess Im just a lazy s$@...

I would put the airbox on and return the jetting to stock and see if that helps. Ed