GoodMachine
XS400 New Member
1982 Yamaha Seca XS400 cam timing (DOHC) craziness!!
Hi everybody, this is my first post to the forum. I've been looking for a solution to this problem I'm having with no luck - I did find someone having the same problem on a different forum, but his post went nowhere (no replies, 5 year old thread now). I've also found a mention of it here but the thread goes off topic and the question isn't solved. I am a professional motorcycle mechanic running my own little vintage bike shop, (so go ahead and get technical!). I have the manual for this bike but it's confusing. SO, here's the problem:
I am at the step of putting the cams back in and setting their timing after replacing the head gasket. I have the left cylinder at TDC, (timing mark lined up at crank, piston verified visually at TDC)....Then the service manual gets confusing. It talks about installing the cams with the "valve timing mark on the camshaft faces pointing up" -this is ok at first, the caps can all be installed without any lobes putting pressure on the valves. But then the manual says to rotate the cam so the cam timing mark is lined up with the cap... ok, so there's now 2 timing marks on the cam, but which is which? And I already was lined up with the cap.. so there's a mark on the cam "face", and I'm unsure what the "face" it refers to is, I originally assumed that it meant the dot/mark on the outside of the end of the shaft (facing up), but there's the mark on the bearing surface itself as well. The illustration in the manual shows the exhaust cam in a position that's impossible to get to, and then in the CAUTION! section it warns against turning the "left camshaft" - there is no left camshaft!
Basically I just need a reliable procedure for getting these camshafts back in! (It ran perfectly before I took it apart btw, and disassembly was followed with the manual)
Anyway I'm sure you guys know all about this cuz the cams need to be removed to adjust the valve lash, so this procedure can't be that messed up! Thanks
Hi everybody, this is my first post to the forum. I've been looking for a solution to this problem I'm having with no luck - I did find someone having the same problem on a different forum, but his post went nowhere (no replies, 5 year old thread now). I've also found a mention of it here but the thread goes off topic and the question isn't solved. I am a professional motorcycle mechanic running my own little vintage bike shop, (so go ahead and get technical!). I have the manual for this bike but it's confusing. SO, here's the problem:
I am at the step of putting the cams back in and setting their timing after replacing the head gasket. I have the left cylinder at TDC, (timing mark lined up at crank, piston verified visually at TDC)....Then the service manual gets confusing. It talks about installing the cams with the "valve timing mark on the camshaft faces pointing up" -this is ok at first, the caps can all be installed without any lobes putting pressure on the valves. But then the manual says to rotate the cam so the cam timing mark is lined up with the cap... ok, so there's now 2 timing marks on the cam, but which is which? And I already was lined up with the cap.. so there's a mark on the cam "face", and I'm unsure what the "face" it refers to is, I originally assumed that it meant the dot/mark on the outside of the end of the shaft (facing up), but there's the mark on the bearing surface itself as well. The illustration in the manual shows the exhaust cam in a position that's impossible to get to, and then in the CAUTION! section it warns against turning the "left camshaft" - there is no left camshaft!
Basically I just need a reliable procedure for getting these camshafts back in! (It ran perfectly before I took it apart btw, and disassembly was followed with the manual)
Anyway I'm sure you guys know all about this cuz the cams need to be removed to adjust the valve lash, so this procedure can't be that messed up! Thanks