mikeyp
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| Tue May 27, 2008 9:48 pm Few tips on Big Bore Fitting. |
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Hi, thought I would share a few tips with you all about fitting a big bore kit to your QMB motor.
The most time consuming job is removing all the panels, remove the under seat bucket as well, this gives good access to carb and cam chain tensioner.
quick break down ( check out GY6 manual on this site, very informative):
Remove side covers etc
Remove fan shroud ( gives access to timing marks )
Remove carb ( 2 M6 studs)
Remove Exhaust ( 2 m6 studs )
Remove cylinder head, barrell shrouds.
remove cylinder head cover.
Set the T mark on flywheel inline with line on flywheel cover. This is TDC and both valves SHOULD be closed, if not rotate flywheel 360 deg.
Remove camshaft caps
Remove cam chain tensioner
Remove Cam
Remove Cylinder head
Remove chain tensioner ( long black bit)
remove Cylinder.
remove piston ( dont drop circlips in motor, major prob if you do!)
Installation is same procedure in reverse.
Care needed when fitting new rings to new piston, very brittle, get them in the right order.
Make sure the timing mark on the flywheel is at the T mark, and there are three holes on the cam gear, the largest on should be away from the engine, and the other two level with the cyinder head, there is a line scribed also, this will be flush with the top of the cylinder head, to line them up, move cam chain of, and rotate cam a bit, dont move flywheel
use new gaskets, they are supplied with most kits
You must use torque wrench when tighteneing cylinder head/barrel bolts, they are very long, and not brilliant quality, very easy to stretch one and snap it.
I changed the oil to good quality semi-synthetic at the same time, will change again when run in.
In my case it was definatly worth the time and expense ( £65 and 4 Hrs ).
Just as an after thought I am mid 40's, and have held my Full Motorcycle license since 1979!
This isnt a rip of of the PDF posted here, just sharing my expierence's |
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