O.s. 21 Rz

[Mudbug]

i bought an OS 21 rz from ebay with a broke connecting rod. i changed the connecting rod and it seems to be lacking alot on the low end. the piston was all the way up to the button head. it runs tank after tank without dieing. i am wondering if i need to chnage the piston and sleeve or if the problem could be somewhere else

 

[beason]

if it runs that good i would check the tuneing and maby clean the carb real good

 

[Bouzouki]

You dont need a new piston/sleeve unless you have lost compresion.

If you still have good compresion, you probably just need to tune it.

Do you have a temp gun availible?

 

[Plaidfish]

If the piston was ALL the way up I'd say have it pinched before you really fiddlesticks it up...that's probably what broke the Conrod...the piston should be stopping lower than the button head for sure....when the sleeve is letting it go further you have little compression and it's letting your new Conrod stretch too much......I assume you know how to tune (at least identify if it's the problem) since you're rebuilding engines.....that mill rocks but it's getting hard to find parts for....good luck w/ it

 

[vbgagnon]

If you plan on replacing the piston/sleeve you need to make sure that it is a rz-V01b or a 99b.

 

[Plaidfish]

they're different??
If it was me I'd check for scoring and pits...if it's clean just pinch it....rayracing seems to be the way I'd go if I didn't have a local guy that's really good...

 

[Mudbug]

it makes good power. it is just that it kinda hesitates a lil on the low end. no matter what i do. richer or leaner it catches that little bog and then takes off like a rocket. i figured it was a good deal when i got it for 39.00 off of ebay.

 

[Rustler.152.5]

I'm just thinkin its rich if it bogs at first then takes off, i say tune it