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Hello to all
I stumbled across thsi site looking for info related to the zr120 sleds.
I purchased one at a local auction yesterday for my 5 year old son to get a slightly safer intro to sledding than I got (I was riding a 440 rupp at his age, no way do I want him doing that without practice on something smaller)
I see that most people remove or bypass the governer at some point so I am adding that to my list, but first it looks like I may need to replace/rebuild the engine. I noticed a couple of posts with engines for sale and have sent a pm to the posters.
A couple questions regarding the engine, what is a decent compression for them, The one I bought doesn't seem to have more than maybe 50 psi at this point.
Could this be a valve problem or most likely a piston issue?
I found an engine rebuild kit at sportech for around $200 with a stock piston, Until I tear this one down i won't really know if that is the route to go though. I am thinking a used engine would at least get it on the snow and leave me enough time to rebuild/mod the engine I have.
Any advice or info is appreciated.
 

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I recieved your request for info on my engine and waiting for a call. on the compression issue, I am a service manager for a repair facility and wrenched for 20 years before that. I do have a snap-on compression gauge and could somehow send you a vid of the actual test if you like. as far as what is normal compression, I am not sure but if you get some info we can compare results so we both are well informed of the engines compression. I would also be able to use number/letter stamps on the engine block to verify the tests. I could video the actual stamping of something on the block and then video the test. when u recieve the engine u can verify its the same (I only have the one) stamping that you saw in the video when the test was performed. I never did bypass the governor as it doesnt seem right to screem these little motors beyond OEM specs, it cant be good for them unless they are modified. The price is very negotiable. Living in Idaho may be an issue on shipping, not sure what that will cost. You make a reasonable offer and figure out what shipping might cost and I am sure we can work something out.
 

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i have raced my kids on mod and stock 's since 2001 . with a 4-5 year old i would tie the springs back on the governor and change the clutch to a rancho clutch or a two shoe clutch and change the chain from a 420 chain to a 35 chain keep gearing ratio around 3:1 or 3.25;1 ratio . when your ready for more advanced mods just ask


Ken
 
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