cam timing again.

Hello all, busy rebuilding my top end and have a question about which timing Mark to use. My manual shows the 1/4 tdc in the diagram but says to use the tdc Mark in the following paragraph. I may however have already bent some valves as I stupidly set my exhaust cam 180 degrees out. I turned it over by hand and initially thought I had great compression (having just had a rebore) until no.4 inlet valve snapped back into position. I then realized it must have been in contact with no.4 exhaust valve. My phoned my local bike shop and they doubted any damage would have been done with the valves being 8mm. Having just read similar problems on site I'm now more worried about the expense I've caused.

What kind of bike might help

Sorry forgot to say, mk2 z1000 from 1979. I know I may have damaged valves, I just hope my new wisecos are ok. Simon.

1 or 4 at top dead center

that's T on advancer

1 or 4 ? I presumed it meant a quarter before tdc. Should I be setting it at T then ? Thank you.

crackfox wrote: 1 or 4 ? I presumed it meant a quarter before tdc. Should I be setting it at T then ? Thank you.

Yes. the T for 1 and 4... it's the same thing and completely different from the T for 2 and 3

both pistons in cylinder 1 and 4 are at the top of there stroke at the same time ........ 2 and 3 pistons are at the bottom of stroke at same time

not a 1/4 before anything.

when I time my cams, I set cylinder 4 at top dead center on cylinder 4 by viewing the advancer as I turn advancer bolt.

since everything I have to do is all on left side I don't have to move from side to side.

Thanks for the help. I think I've found the real problem. Wrong cams. I used my mk2 cams on an earlier head. Apparently the cam sprockets have different amounts of teeth. Simon.