Vintage Dirt Bike Q & A

finished my cr but it wont start.new engine 4 mm longer rod kit with spacer under barrell 2 gaskets 1 each side.reed valve.reco ignition.38mm carby.have spark.timing at 1.5mm btdc.even sprayed areostart in plug hole still no starting.new plug new ignition coil.checked kill button (also new) its ok.nave good spark on plug.
any help would be great.
cheers

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Jim Garvey
1x honda cr250m 1973 in bits
1x honda cr250 champion dirttracker
1x yamaha tt500 dirttracker 1976
1x yetman triumph dirttracker
1x tt500 longtack speedway bike
1 x 1940 350 ariel speedway bike
1 x bultaco astro grasstrack bike antig

If all the items mentioned checked out and the motor has compression with no major air leaks the only thing left is fuel/carb/jetting.. Good luck

I'd go for timing if you've got a spark and put petrol down the plug hole the timing must be out , are you on points or electronic

it started today!!!!!!
changed the ignition coil for the old one 1973 honda and it fired 2nd kick.
now my bigest problem is the circle f pipe.kick startig bike heel of boot hits pipe.for a brand new pipe it sure dose look second hand arounf kick start area.i am not to pleased about this either.will have to take bike to custom pipe maker to rectify the problem.
any one else had this problem
cheers
jim

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Jim Garvey
1x honda cr250m 1973 in bits
1x honda cr250 champion dirttracker
1x yamaha tt500 dirttracker 1976
1x yetman triumph dirttracker
1x tt500 longtack speedway bike
1 x 1940 350 ariel speedway bike
1 x bultaco astro grasstrack bike antig

Glad you got it fired up!. My pipe is from Vintage Iron and yes the kickstarter does come very close to it when I'm kicking it over, the heel of my boot is what hits the pipe. Its a pain but I just try to be careful.

On my 1974 CR250M I had a Circle-F pipe too but didn't have that problem. I'm left footed and had to kick from the opposite side standing up! I also use a dryer stainlees steel clamp around my pipe and attache it to the frame for no side to side movement. Carefull not to over tighten the clamp or you can smash the pipe.

Good luck.
frohrs1

I had that problem with the circle f on my cr 250 and dont get caught without the boot. My shin will testify. I ended up with a pro form pipe after the f got smashed at a race. and also will note that the pro form has more top end power.

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72 maico 400
73 elsinore 250
74 yamaha mx 360
04 yamaha yz 250