Compression release on a 250 Monza

[Snakeoil]

The head I got with my 250 has a compression release installed. I assume this is not a factory item since it does not appear in the parts manual.

So, I understand that the kick start on these is not the most robust of designs. I assume it is the ratchet that wears out over time. So, is a compression release a desireable feature for a 250 or it is overkill and better suited to the larger displacement singles?

The release is only the valve assembly. No operating mechanism is there. So, I need to figure out how it was operated and probably make the missing pieces. I'm tempted to simply use a different head. This head is stripped of it's parts short of the valves and springs so there are a number of reasons to want a different and complete head assembly. Eliminating the compression release is just another reason.

regards,
Rob

[motoital]

The release most likely is a factory part but they didn't come on a Monza but usually a scrambler.

You probably have a high compression aftermarket piston in your engine.

[Snakeoil]

Well, if I had the piston, that might be the case. But I ain't got no stinkin' piston... yet.

But the question was, is it worthwhile to use the head with a CR to help relieve the stress on the kick start ratchet or is it overkill for a 250?

Thanks,
Rob

[motoital]

As long as you stay close to the standard compression ratio and ignition timing. A release won't be necessary.

The standard kickstart mechanism is weak but it's been my experience that most damage comes from an improper starting technique or ignition kick back.

For awhile all I could find where the Asso high compression aftermarket pistons so a lot of people were using the scrambler valve cover release.

[Snakeoil]

This is an actual compression release with the port drilled and tapped into the head. Can't find any like it on the web. Everything they seem to sell now is a button type. I suspect this was the type used on two stroke woods bikes when I was a kid with the trigger on the handlebars.

regards,
Rob

[Jordan]

I don't think a compression release would necessarily protect the kickstarter mechanicals, because it just makes it slightly easier to get to the correct starting position - slightly past TDC. You shouldn't be pushing hard on the lever before you get to this position.
With more than one cylinder, generally you can kick over the engine from any position. Also, small capacity singles can often be started without the TDC ritual. But a kickstarter that is known to be troublesome should indicate the proper starting technique, even if it's just a low compression 250.

[Jon Pegler]

The only compression release mechanisms that screwed directly into the head, near the oil return tube, were those fitted to the 450 RT and the Spanish 350 Road models.
If I remember correctly, the RT uses a 10 x 1 mm thread whereas the Road release valve uses a 10 x 1.25 mm thread.
The two valves do not look the same.
You may find that you have a 350 Road head.
Is it a Spanish casting?
Post a photo of the head and/or the release valve and it will confirm what you have.

Jon