Difference between slant angle head and normal

[alecwhardy]

What will fit better in a smaller frame? Whats the difference?

 

[Al.Fisherman]

What will fit better in a smaller frame? Whats the difference?

The angle will produce more compression. To reduce the compression if need be, add a extra gasket or two.

 

[F_Rod81]

The slant head was designed to allow more clearance for tighter frames.

 

[Mozenrath]

Yes, the slant head is mostly for clearance. People say that it creates more compression, but I'm not sure how true that really is. Not saying it's not true, but if I were to look into increasing power, I'd look more towards expansion chambers, thinner head gaskets, and head milling/sanding. Those are things proven to work.

On my frame, the engine fit fine but from where I put the CDI the plug wire couldn't reach the spark plug and probably would at least have a difficult time doing so with a straight head. All I had to do was rotate the head and that problem was solved.

Rotating the slant head makes no noticeable difference in performance. Ideally, you'd want the plug pointing towards the intake so that the explosion pushes the exhaust towards the exhaust port, but on these small engines this doesn't make any difference. I had the head both ways and it ran exactly the same.

 

[brett7777]

I need more clearance in my frame & I have a straight head motor. I've been told that if I change my straight head for a slant head, that the piston may not have clearance & may hit the slant head. Does anyone have experience with this? I really need the extra clearance.

 

[Greg58]

The piston does not rise out of the cylinder so it can not hit the head, the only thing that might hit would be a spark plug with the extended tip. I would bolt the head on without a plug and see if it clears by rolling the bike, on most engines the heads are interchangable.

 

[brett7777]

Thanks for the help Greg58

 

[alecwhardy]

Yes, thank you very much! Exactly what I was looking for as well