SV1000 Portal - View Single Post - Setting cam lobe centers without adjustable gear sets
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post #11 of (permalink) Old 18th December 2014, 03:56 AM
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Join Date: Nov 2014
 ♂ United Kingdom
durham uk
Posts: 4
Originally Posted by schmidt314 View Post
I have been using a technique for several years now to reset the camshaft lobe centers on SV1000, TL1000, and DL1000 without using the expensive adjustable gear sets for low budget engine builds. It has taken me for ever to finally get a complete write up finished, but I think I have a pretty solid first draft that describes the technique and how to apply it to an SV1000.

I have attached the write up, but I am not able to attach the Excel sheet that does all the calculations for you. If you are interested in having a copy of the Excel sheet, please PM me your email address and I will send a copy.

Please note this my first complete draft, so if you see any issues with it please let me know and I can make edits to it if needed.

This is a simple method of unlocking more power in your motor.

An excellent write up. Mr Schmidt you are indeed a top man! I am considering this mod and would welcome your thoughts on the following:

1) Effectively the retiming involves a 26.226 crank degree advance of the idler pulley (one tooth on camchain side) compensated for by a 17.561 retard of the installed cams. The result being a 5.665 crank degree advance for both inlet and exhaust cams producing timing figs. of approx (+or- 1 degree) IN opens 13 deg BTDC, IN closes 45 deg ABDC, EX opens 47 deg BBDC, EX closes 9 deg ATDC. I calculated LC's of 106 inlet and 109 exhaust from this. Not identical to you but certainly in the ball park. My first question is have I got this right?

2) Would you recommend measuring std timing before beginning and then do the calculations, etc or is it safe to assume that differing tolerances will not be so great as to have to worry and just go for it? My greatest fear would obviously be Inlet valve/piston contact. But then you say it works with added compression so maybe it would be nicely safe with my standard K4 crowns. Unless of course you're talking HC pistons with deeper cut outs. Hmmm.

3) If the heads have got to come off to measure piston/valve clearance would you recommend a mild skim to raise compression? Or the barrels? It's very much a road bike so I'd be looking for 12:1 max.

4) If you see my first post (this is 3 of 3) you'll see my bike came without much of a top end at all. Both owners had literally kept it wrapped in blankets in dry sheds and cosmetically it is excellent but I think most of the maintenance stopped when it was out of warranty (@13k, now 26k). The chain alone made me cry and as for the of a minger! Hopefully a K and N, removal of STV butterflies, desnorkelling and a throttle valve balance will restore at least some top end. Can you reassure me that the cam advance won't take some of it away? Oh and finally (topic drift I know) I'll test compression, but do you have to remove cams, remove decompressors, refit cams, test, remove cams, etc, etc, what a pain. The manual says not but one of your posts indicates you need to. Confused.


Ps. For sake of amusement I should tell you that as a kid I thought the best way to set valve clearances was 1 thou IN, 2 thou EX, set at finger burning red hot. Not quite as daft now!
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