Restoration

[ALAN]

Hi guys,
Been a while but have decided during this lock down palava I would strip my bike down and give her a thorough once over clean and repair /replace as required. As most things will be run of the mill maintanance does anyone have a good way of compression testing the engine whilst its on the bench .Its 6yrs since she ran and would hate to do what I'm aiming for to find when she's back together (it will be next year in my timescale )to find out I've got a compression issue.
Thanks in advance ALAN

[lost1750GTV]

Good way? I'm sure most will point to a compression and leak down test.
Simple/old school primitive - if it starts easily and a hand behind each pipe feels the same pressure/heat.
And as noted on the forum, loss of gearbox oil to lower right cylinder indicates a bad crank seal - which most are going to suggest you replace even if its not a problem now.

[ALAN]

HI GUYS
Back on with the resto. Had cranks rebuilt ,rebored 1 over stock as 2 cyls. had grooved barrels and pistons .When dismantling crankcases there are 2 mushroom domed allen key head bolts is it critical for these to be domed or would normal caphead bolts do.As they where so difficult to remove the allen key rounded off and I had to weld an old key in to undo.Also a friend has just rebuilt a 125cc.with rebore and said he had to grind the power valve to accommodate new rings & piston is this going to be on the 500 that I have not been advised on when the rebore work was undertaken.

[tacky1]

I think you need the mushroomed heads Alan, the standard allan bolt heads hit the cylinder, I have had to replace a few over the years and always had to get the flat head bolts

[steveho]

I think you need the mushroomed heads Alan, the standard allan bolt heads hit the cylinder, I have had to replace a few over the years and always had to get the flat head bolts

Seems like there is some variability in the crank cases, as I replaced the domed head with regular capheads and they were not proud of the base gasket surface when torqued up (checked with a straight edge)———but they were close....
Alan, might be worth checking.