Off the subject of porsche but....

[pwm74]

if i can ask a question. Besides tinkering with porsches, I am also restoring a 1974 Honda cb450.One of the intake valves stick so bad that it will only come back up when the piston hits it on the way back up. the bike has been sitting for 3 years (inside).
have you ever seen this. i would not think it is bent it ran fine three years ago. any ideas?

[Rot 911]

Sounds like either a broken valve spring or the keepers holding down the valve spring have broken or popped off. That is if you are sure it is not a bent valve.

Kurt V
72 911E

[Jdub]

When storing motorbikes it is essential to kick them over a bit so that no single valve/spring is compressed over time where the others are not...this is probably true for all vehicles.

Allthesame, this seems weird. I concur with Kurt that the collets are out or the spring is broken. I'd assume the collets as a spring just doesn't go south like that during storage. Have you looked at the valve by pulling the header and peering in there while the valve is open? Check for foreign material on the valve stem proper. Also make sure that your rocker arms are set asymetrical on the valve end. This helps turn the valve as it opens and closes and keeps the valve from operating always in one position within the valve guide.

Neat bike. I'd love a sandcast Honda 750cc! One that had sat in a Honda dealership window for years, faded and all, went off to Japan for $8,000.00. I am also just now selling my '75 400/4.

Jw

[machintek]

If my memory can go back that far, The CB450 was twin OHC. I remember having to deal with a long chain when doing a top end on it. But it had a very strange valve return arraingement. I believe it had small torsion bars with forks on the end that pulled the valves back up. It really used a good fit of the valve to the seat for the actual seal. Maybe this is somehow the problem. Is my memory still decent?

George
83 911SC Cab/Euro

[pwm74]

Yes it does have torsion bars instead of coil spring on the valves. I want to do anything possible before taking the head off.
vintage bikes especially japanese bikes are becoming popular. Mine has cafe style bars so it looks brit. Much cheaper to maintain than my porsche 10x. i would like to see a pic of that cb400/4.