crank position sensor

[crf286]

Does a 2007crf250r have a crank position sensor?

[bucket list]

Well they have an ignition pulse generater, which serves as a position sensor. Why do you ask?

[crf286]

I have a bike that is firing on the down stroke. and everything is in time so my mechanic said that could be the problem.

[Eddie8v]

Remove flywheel and be sure the woodruff key is there and that the flywheel is correctly aligned. Spark timing is based upon gaps in flywheel pickup points.

[crf286]

I checked the key its there and everything is in line. This bike has been down for 4 months and been to 3 mechanic shops. This is the first guy to say ignition problems everything else in the bike is new piston,cylinder,crank,valves,and timing chain and its got a good blue spark.

[Eddie8v]

How did you check the key? How does he know it's "firing on the down stroke"? If crank is properly aligned and spark is good my bet is a fueling issue. I suppose if stator/etc parts were swapped in from a different year bike that could result in a spark timing issue, but I don't know squat about any ignition/stator configuration changes on those older bikes.

I will assume that all 4 valve clearances are good.

Edited May 29, 2014 by Eddie8v

[crf286]

I pulled the flywheel the key looked good and it was in the slot. I don't know how he determined the spark was on the down stroke. he just told me he was pretty sure it was the cps. The vales clearance is perfect. I tried another carb off a running bike no change. it runs but want idle you have hold it about half throttle to keep it running. It sounds like the motor is laboring like struggling. to role over.

[Eddie8v]

How did you install the cam chain tensioner?

[crf286]

It has a manual tensioner. that's what happened to it to begin with the tct failed anf it jumped time bent intake valves. So while i was in there i put new top end and a manual tensioner.hasn't been right since

[SLO_Rider]

Did you replace the cam?  We had an '07 that broke a valve which locked the motor and slightly spun the cam gear, causing the timing to be off.

[Eddie8v]

Yep, could be. Did you check the cam timing vs flywheel tick marks?

I will assume you put new valve guides in...

Edited May 29, 2014 by Eddie8v

[crf286]

Never hurd of that but i know my cam lobes are pointed back towards the intake. could it have just moved a little bit and still be tight?

[nesc103y]

Did you replace the cam?  We had an '07 that broke a valve which locked the motor and slightly spun the cam gear, causing the timing to be off.

 

 

What he said

Your cam is &%$#@!ed

[crf286]

Never hurd of that but i know my cam lobes are pointed back towards the intake. could it have just moved a little bit and still be tight?

[Eddie8v]

Never hurd of that but i know my cam lobes are pointed back towards the intake. could it have just moved a little bit and still be tight?

Check the cam timing vs flywheel marks, you'll know instantly. You need a degree wheel setup. Edited May 29, 2014 by Eddie8v

[crf286]

I called my mechanic and he said he had aready checked the cam is good.

[Eddie8v]

How did he check the cam?

[crfanth668]

On my 2010 on the stator side there's a hole. And there's two lines on the case , when I timed mine I had to make sure the line on the flywheel was in between those two on the case at TDC

[crfanth668]

And on clutch side there's another hole u have to line up the notches. Plus make sure your cam is lined up properly. Same thing happend to me when I first had to time mine after bore kit but then I found out about the spark timing and that was the issue

[crf286]

He lined the cam marks up and it was tdc and the flywheel was lined up right through the hole.