cam belt timing

530 Views 2 Replies 3 Participants Last post by sandiegobrass, Jun 15, 2009

boboon

Discussion Starter · Jun 15, 2009

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hi, i have a 1983 gl1100 which came out of a barn. runs very bad at low revs, spits back, sparks from exhaust etc. checking the cam timing i found the left hand side to be incorrect. following the clymer manual, i was unable to get the cam pulley to the right position without the valves fouling the piston, i assume the straight cut line on the pulley is the mark as there are also other pips and marks but not as obvious. eventually i removed the head and found at some point the belt had broken and the valves had hit the pistons. i removed the valves and spun them in my lathe and they run true, so i assume these are not the same valves. the cutouts in the pistons were quite badly burred, do they run close enough for these to be causing the valve / piston fouling problem ? i have removed these with a dremel and cutter but have not yet reassembled. any thoughts? thanks

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BenMC

· #2 · Jun 15, 2009

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Dings on the pistons will be normal after the valves hit them. Once the piston isn't cracked you won't have any problems.

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sandiegobrass

· #3 · Jun 15, 2009

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Usually it is just the valves that get ruined.. pistons marked but should be okay... Once assembled correctly, and your valves are good, you should be good to go..

PS.. with timing belt(s) off, you can only rotate the cam(s) freely without danger of hitting the pistons if the pistons are not at TDC (backoff 90 degrees on the crank)... set the cam(s) where you want them (on the correct outward mark), now bring the pistons back up where they belong by forward 90 degrees with the crank (to T1 timing mark)

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