QuestionIf you dont rember im the kid making the dunebuggy out of this bike engine. I got everything working almost perfect but theres one problem, one spark plug hole got stripped from all the plug checking while tuning it. Iv looked around and found these things called Helicoils; what do you think of these, it seems like they should work. Also Im considering doing a complete overhaul in shop class I found a brand new cylinder, pistons, and rings for only 200 bucks and a gasket set for 80 US dollars. I will probably get a shop maunal also do you have any tips for rebuilding one of these? I will be on my own because nobody at school knows a thing about these engines. The main thing im worried about is getting the timing chain back on right and the transmission back together right. Thanks for all your help.
AnswerErik, if you can find a "TIME-SERT" http://www.timesert.com/ for best results, but you can use a Heli-coil, too. Just be sure to get the correct thread pitch. Spark plugs have a different pitch than regular metric bolts.
The timing chain is endless, so unless you tear it ALL the way down, you can leave it alone. If it seems loose on the camsprocket teeth, then it should be replaced.
You can use both the exploded views of the engine, on-line, plus the shop manual for 185-200-250 twins to take you through the process. A factory shop manual is always best. Check Ebay for possible sources.
Transmission gear illustrations here:
http://www.houseofmotorcycles.com/fiche_section_detail.asp?section=134285&catego...
Timing chain isn't difficult. Put pistons up to the top (TDC) which is the T mark on the flywheel/rotor. Thread the camchain onto the sprocket when the cam lobes are evenly matched.. one set in a downward V and the other side will be UP in a V shape.
Look for marks on the camshaft sprocket. If there are long lines stamped across the face of the sprocket, then align them to be horizontal with the top of the cylinder head/valve cover surface. If there is a "0" stamped on the sprocket, it goes to the 12 o'clock location. Put the camshaft sprocket bolts in finger tight and then recheck the marks and crankshaft location. TDC and camlobes in V and /\ locations with sprocket marks aligned properly, the you can continue to install the rocker arms, adjust the valves to .002" on the compression stroke (both valves closed), then rotate the motor ONE turn, to position the camshaft so that the opposite cylinder is on COMPRESSION stroke, adjust the valves, set camchain tension and you are almost ready to go..
Bill Silver
