The exhaust camshaft on my 3LN1 is bent, and locks up when I tighten the caps down. This is my fault, I was tightening the bolts in no sequence at all to try and shortcut the valve timing procedure. Can these cams be straightened? Alternatively has anyone got a spare exhaust cam? I’ve seen some cams on EBay but unable to determine whether they are 2KR or 3LN1. If anyone knows of identifying marks for each type that would be useful in my search.
Are you sure it's actually bent? That sounds hectic It will usually be on one of the valve pairs when tightened down so won't rotate freely
Sequence, say whaaaat? That is more to stop you snapping the caps in half rather than bending the camshaft.
AAH - some thing I just remembered, th caps have to go back into their respective locations also - they are lined bored in place at the time of manufacture Double check everything
Thanks, I double checked everything and found that I had mixed up the caps.1 inlet and 1 exhaust interchanged. Changed them over, no problems. Hectic is a good word for suspecting a bent Camshaft. I think they would snap before they bend. So a cautionary tale, many thanks for good advice
It's easy to do. Yamaha don't mark the caps very well at all by the standards of the industry. I've had to sort an FZR1000 and an R!, both of which have had caps replaced wrongly - by people who should have known better. It is possible to line hone head and caps which have seized. Slowly and carefully until there's just clearance. If you've got a set of stamps, number the caps before removal.
That's a win - I can imagine how you would have felt if you'd spent time and money getting another cam to discover the same problem
