Good evening all . . . . slow but steady progress.
I rechecked the valve clearances today - not all of them . . . just the outliers and my measurements first time around were spot on.
I'm a little baffled by the exhaust valves since if they are being held open by carbon build up, I can't see how this would lead to crankus interruptus from a duff pressure sensor reading?? Hey ho - I'm probably over thinking things.
Anyway - all went smoothly enough, if rather slowly.
first off, I removed the cam chain tensioner. That was at mid travel and shows no signs of play whatsoever, even with the tongue fully extended. I plan to reinstall the existing tensioner and read through the instructions for reinstalling and was rather baffled by the description for installing a brand new replacement. I can't quite get my head around how the new one is supplied with the spring installed but the tongue fully in!!! Anyway . . . . .
Next to come off was the chain top cap, followed by the cam ladder and cam shafts. The manual contains various errors in this respect, commenting that it is important to check the orientation of the cam caps so they are installed the same way around . . . . clearly a cut & paste error in the manual as the caps are all integrated into the cam ladder and as long as that goes back correctly, the caps will all be correct by default.
Next to come off was the starter and crankcase covers, followed by the idler gears and entire sprag clutch assembly before the the cam chain itself. I marked the orientation of the chain so that if I do end up reassembling the engine, the chain will go back as it came out and any wear bias will thus be maintained.
I took on board the various remarks about leakdown testing and have watched a number of Youtube videos before deciding to order an al cheapo leakdown tester, which I plan to use before proceeding further. These cheap testers receive mixed reviews but consensus is that they are mostly rubbish but then . . . . what do we expect for a tool imported from China for £18 inc postage??

The truth is, I'm not worried about trying to accurately quantify the percentage leakdown but am rather more concerned in procuring a qualitative assessment as to where my compression is going!! I figured that by removing the cams, all the valves will remain permanently closed and I can conduct a leakdown test on each cylinder but also with the pistons in any position I choose. There will be no need to fanny around worrying about whether or not a piston at TDC is on its induction or compression stroke etc.
I plan to borrow a friend's compressor and simply connect it directly to each spark plug hole in turn, whilst holding the pistons in position by putting the bike in top gear and maybe tying down the rear brake if necessary.
I plan to drain down the coolant tomorrow and remove the exhaust system entirely and then with each bore pressured up in turn, I should be able to hear where any air is escaping but also, I can do the test in all piston positions and not just TDC. . . .
I've been thinking things through and it's not inconceivable that a barrel could be scored over its middle section such that it leaks in that area but perhaps seals at TDC . . . nothing to lose by testing at tdc, bdc and mid travel. If I do this, what sort of PSI should I be aiming to use?? I'm just wary of causing any damage by loading up a "jammed" crankshaft at mid throw. Perhaps I'm worrying unnecessarily and the same healthy 100psi won't be an issue, particularly if I build up to it . . . . I may well discover a healthy hiss at well below 100 psi anyway.
So . . that's the plan. There's nothing to do now for a day or two until I can get my hands on the compressor and the leakdown tester arrives and so I won't probably post again for a few days, that is . . . . unless draining the coolant and removing the exhaust system turns into an unexpected adventure - hopefully not!!!!!





