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06 rmz250 bogs

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Hey dudes ive got an 06 rmz250 which had an engine rebuild about 10hrs ago. All is running fine until one day it doesnt want to rev out properly. It revs smoothly up to a certain ( reasonably high) rpm then bogs. I've replaced the spark plug but that doesnt make a difference, it doesn't backfire at all and ive also had the carburettor cleaned but that didnt make a difference. The bikes done around 80hrs and the mechanic i take it to (which doesnt know alot about rmz's) suggested it might be ignition and apparantly the cdi box starts to fault after a while. Any thoughts because im at a loss

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Hey dudes ive got an 06 rmz250 which had an engine rebuild about 10hrs ago. All is running fine until one day it doesnt want to rev out properly. It revs smoothly up to a certain ( reasonably high) rpm then bogs. I've replaced the spark plug but that doesnt make a difference, it doesn't backfire at all and ive also had the carburettor cleaned but that didnt make a difference. The bikes done around 80hrs and the mechanic i take it to (which doesnt know alot about rmz's) suggested it might be ignition and apparantly the cdi box starts to fault after a while. Any thoughts because im at a loss

I have a 2004 RMZ250, from what I understand it has a different motor. Anyway I had exactly the same problem, result was to replace all 4 valves, now it runs perfectly. Probably need to check the valve clearances, compression etc.

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oh yip i had the valves done about 4 hours ago so i wouldnt have guessed that, do you happen to know if the valves move frequently?

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oh yip i had the valves done about 4 hours ago so i wouldnt have guessed that, do you happen to know if the valves move frequently?

Well mine is a 2004 model which I understand has more issues than the newer models, it also has the same motor as the KX250F Kawasaki. With the 2004 model you need to check the valve clearances around every 10 - 20 hours and then adjust if needed to prevent the valves from burning. I am looking at doing a mod on the head to increase the valve seats.

However chatting to other mates that have Honda's and Kawasaki's it would seem that it is good practice to check your valve clearances regularly so as to correct them before the valves burn, seems like these high performance motors have this issue.

I must say that I find this rather surprising as 4 strokes are now the preferred bike to have and I would have expected less maintenance.

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I also had a nother issue that you can check, the hot start plunger was not releasing properly due to the plastic linkage into the carb being broken, so effectively the choke was on all the time and then it wouldn't run well. Fitted a new part and this solved the problem. I must add that since I had the valves done it was only about 15 hours and the inlet valves needed their clearances set again.

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Does it bog down all the way to a stall? If so, I'm having the same problem. I've put about $500 into the problem and haven't gotten a solution. I'm starting to get very aggravated by the whole thing.

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Nope mine never stalled, it went fine at low/medium revs, but soon as I tried to open it up it would bog down. When you back off on the throttle it's fine again. Seemed to me that as soon as I experienced problems with starting, it was the valve clearances, but the hot start plunger thing threw in a curved ball. I had a workshop sort it out and he told me he needed to set the inlet valves, clean the carb and fix the hot start which was sticking.

Good luck...makes you want to throw a match in the tank doesn't it....

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hey guys i gave my bike a bit of a going over this afternoon, its still up to its same old tricks. i checked the kill switch but its sweet, i noticed the throttle position sensor was unplugged- would this cause the bike to run rough or would it not run at all as its possible i bumped it. also even when the bike is really warm when i pull the hot start lever in, or select the choke to on the bikes rpm increases by quite a bit. cheers

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First of all you have to check the commpression. If commpression level is to low, then check the valve cllerance, if after valve clleranc adjustment is the same problem with commpression, you have to take avay the head and check valves shape + seats condition and piston ring wor-nout (ring gap). Also check the cams timing, sometime cams gearwheel (usualy exaust) dsiplaced on the cam axle.

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