Rear cylinder removal with the engine still in the frame

[Panzer]

Hi guys,

Need a little help here.... After removing the front head and front cylinder in order to fix an oil leak at the base of the cylinder, further investigations of the piston revealed a fair bit of scrathes (dont know the correct english word for it...). I'm able to feel them when dragging my fingernail across them.
Had an experienced guy (or so they told me...) to look at it, and he wanted me to change the piston and rings and hone the cylinder. He also told me to do the rear one as well.
The engine is still in the frame, but when I'm looking at the clearances above the rear head I start to wonder if its possible to pull the rear head and cylinder with the engine still in the frame?

All replies are very much appreciated!

[caschnd1]

Panzer,

I have a panhead in a '53 wishbone frame. Although my frame has been cut and raked at the neck, I believe the clearance at the rear cylinder is stock. I'm able to pull the rear head with the motor in the frame. I've never tried pulling the cylinder with the motor in the frame but once the head is off it looks like it would be possible.

-Craig

[sleeper]

Panzer-
It does look close, but as Caschnd said, rear head is removable "in frame"....
The R. cyl is removable too, (in frame) just make sure piston is at BDC= Bottom Dead Center,
(of course).....

[Panzer]

thanks guys!

I really appreciate it!!

Not that removing the engine would be such a big problem, but it its May and I really want to ride....

So I'm gonna try to remove the rear head without denting the tin pan into the frame

By the way, as far as I can tell, the frame is a 1972 model, does that make a difference?

Rgds

Panzer

[Panzer]

Well, I forgot one thing...

When buying new pistons, any particular brand that I should look for or avoid?

Rgds

Panzer

[mbskeam]

hello,
KB's are good and dont cost much more than the junk ones out there. mail order was 120.00.
mbskeam

[Cotten]

I have never tried KB's, but the local 'modern' builder has had enough of them break to never use them again.
Normally a piston is not the weak link!

The 'generics' are usually all the same, no matter where they are boxed. (Well, maybe CCI's are seconds)
They are quite durable, accurately sized, and of proper weight.

PS: If the other cylinder is not scored, don't fix it.
The notion that having both cylinders the same size is critical is boloney. BS. Barroom bull. Seriously.

Don't trust anyone who swears otherwise. They just want your money.

[mbskeam]

cotten...

break?..... please explain, from abuse or just normal riding?

mbskeam

[Cotten]

I never inspected them, so it is hearsay, but apparently the skirts like to split.

Face it, pistons usually survive lots of abuse, as other parts of the motor usually break first. Normal piston destruction, such as galling or burning through, can be blamed on heat from other concerns. But cracking a skirt sounds like an engineering problem, as it isn't historically common.

[Panzer]

Ok, guys!

Thanks for all the advices.

I'm gonna pull the rear head and cylinder this weekend, and hopefully things will go smoothly....

Rgds

Panzer