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Motorcycle Repair/Honda xr50r dirt bike


So there is a honda xr50r dirt bike in my engine tech class and it won't start. It has spark and compression and the kill switch is not on. It won't start with starter fuel sprayed in it either. I feel it may have something to do with the timing because we have the carburetor cleaned out and timing is the only thing I can think of that would be wrong with it. How do I adjust the timing and what do you think I should do?

Grant, Its possible the timing is off but it wont be the ignition timing,unless the flywheel key is bent throwing the timing off its pretty much set. Turn the engine over by the flywheel and watch the intake valve close. Make sure the plug is out so it will turn over easy. Use a small screwdriver or pencil and poke it down into the cylinder and feel for the top of the piston and turn the flywheel untill you fell the piston at TDC and look at the flywheel and see if the timing mark is on the pointer. If it is then look at the cam sprocket as it should be at the top of the cylinder head and maybe a mark or line in the opening for the cam sprocket.If this off you will need to pull the chain tensioner out to loosen the chain and turn the sprocket untill the marks line up then put the tensioner back on and see if every thing lines up now. Also make sure there is some valve lash there. Honda does not use much so try about .003 to .004 gap now see if it fires.

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Gary Blake


I have built from ground up race winning motocross bikes and atvs as well as atv,s for flat track and TT racing. I am starting to take on the utv challenges now for racing. This is a new area for me so Im in a learning curve.


I have extensive experience in off road motorcycles and atv,s.I also work on street bikes and personal watercraft, Some experience was self taught and some was factory trained. I have been working in the powersports industry since the mid 70,s I hope I can help. Thanks Gary

Was a sponsor for K.O.R.R.(kansas off road riders) and now I am working with ROMEO,s (retired old motorcyclists eating out)and was in charge of the Quad Wars for the monster truck series in Central Kansas

Factory trained Kawasaki Heavy Industries. Factory trained GasGas motorcycles and atvs worked as a technician and was as a dealership owner.Kaw.Suz,Honda,Aprilia,Arctic cat,See Doo,Can Am, Bombardier,Yamaha,GasGas,Qingi,TM,Moto Guzzi,Harley,s

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