Hotcams exhaust installed: problems

I have just installed the stage 1 hotcam in my 04 WR250F. The timing marks all line up nice, there are 12 pins between the marks on the chain, a la YZ timing. The bike will start and run but backfire and die and refuse to start when hot. am I supposed to have 13 pins like the WR?

Jetting or timings off. Re-check the timing acording to hotcams instructions.

The timing marks all line up as they should. there isn't much more I can do with the timing

make sure the bike is at TDC when checking your timing. it could have moved while you installed your new cams.

all timing marks are spot on. is this cam supposed to be retarded one tooth when run in the wr, as the stock one is? 13 pins of chain vs 12 as with yz timing?

Well I have reinstalled the stock cam and it still will not start, worse yet it feels like it has low compression now. I am wondering if there is a defect with the hotcam. I know everyone is going to assume that it is mechanic error if in fact the piston did meet the valves ....but I had the timing marks spot on the whole time. The bike was a little hard to start the first time I ran it with the new cam, then I rode for about 10 min. and it backfired and died... it has run several times since then but will not stay running. The compression feels low...I don't know what happened: either the wrong cam was in the box or the timing marks are off from the factory. I really wish I had purchased a YZ250 two stroke

I feel your pain i went through similar thing rebuilt motor . Started 2nd kick ran fine COOL rode for 10 min then POP POP rechecked evrything 3 times Finally just bought all new valves, springs bla bla bla will put it together this week AND IF IT POPS lets just say the bike will have a bad day :thumbsup: when i did take the valves out they were dished so if nothing else at least i know everything is new now from the crank up . Just maybe i duno but maybe the new cam duration was to muth for the old valves and springs I dont know but i would look at the valves

hard to say what happened but I don't think it is a wear related issue, the bike has only 300 miles on is still new

did you pull the little plug on the flywheel cover and make absolute sure that the mark is on tdc cuz its acting like both cams are off the crank one tooth. the cam lobes should mirror themselves on the back side also.

During my install, the second mark on the intake cam was actually slightly below eye level when lining up with the head. It was correct but isn't quite as visible as they make you think it should be so you may very well be one tooth off.

Did you re-adjust your valves?

Make sure your valve clearances are all within spec and that you DON'T tighten the valve cover/caps too tightly - use 80 inch-lbs to be safe. Make sure you lube the cams well during the installation process. Check you compression, if you have compression, spark, fuel and your valve clearances are in spec then it should run. Also make sure you are jetted correctly for your area, it might just be jetting...

OK my appologies to the hotcams company, there was no problem with their product. No problem with my wrenching either: one of the two wires that goes into the ignition coil plug must be frayed under the casing- if you bend the wire one way it sparks, bend it the other way it doesnt. You can see how this led to erratic running, popping, backfiring, etc. I am glad to have figured this out before i freaked out and pulled the head off

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