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4 mill 421 cub cylinders


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I talked to jeff yesterday about some different kits and I am really no sure of what I want. However I am sure that I want to save money the best that I can. If I had Jeff do all the porting and weld the crank do you guys think that installing it would be beyond me. I am mechanically inclined. Ive been looking my clymers the past few days and it doesn't look that hard if you take your time. Anyone tried installing them themselves with no previous experience or should I leave it to a professional?

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I talked to jeff yesterday about some different kits and I am really no sure of what I want. However I am sure that I want to save money the best that I can. If I had Jeff do all the porting and weld the crank do you guys think that installing it would be beyond me. I am mechanically inclined. Ive been looking my clymers the past few days and it doesn't look that hard if you take your time. Anyone tried installing them themselves with no previous experience or should I leave it to a professional?

 

Jump in there and do it yourself! Its a piece of cake! If you do run into any problems we can help you out.

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unless you want to learn more, I'd send your whole motor to Jeff.

 

it's probably an hour of shop time, you get a complete solution, and won't be held up unnecessarily for missing something here or there (like losing a small screw, an o-ring for a coolhead, ie the little shit). I'd rather just get the whole motor back knowing that all of the tolerances have been checked, it's been leak down tested, compression is right, squish clearance is right, etc etc

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I had problems with my cub being out of square....top and bottom uneven.

 

I would at the VERY LEAST, have a good machine shop check top and bottom for flatness...after that it should be bolt on....

 

 

Odaen...

I totally agree...

 

I put my cub together 3 times....and got fed up. I was more an more careful each time to check, double check and seal every little item.

 

And I had my motor torn down to bare cases, cleaned, whitegloved the whole motor, after reading everyone's advice it's a "bolt on" motor...

 

Will....

 

If you're very proficient and have the tools and time to check clearances on everything, from piston to wall, ring end gap...and most importantly squish, go for it. I HIGHLY recommend a leak down test and then a compression test before you even attempt to fire it up...

 

I've rebuild dozens and doezens of motors, from your lawn mower to my CR dirtbikes and other banshees....but this cub motor was a whole new animal....and I had a real long thread on all the problems I had.

 

But...I'm happier than shit it's together and running fantastic...well worth it in the end, plus I met a whole new group of people at the track and dunes because of it....

 

So...just my own experience, and it was just this year....

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unless you want to learn more, I'd send your whole motor to Jeff.

 

it's probably an hour of shop time, you get a complete solution, and won't be held up unnecessarily for missing something here or there (like losing a small screw, an o-ring for a coolhead, ie the little shit). I'd rather just get the whole motor back knowing that all of the tolerances have been checked, it's been leak down tested, compression is right, squish clearance is right, etc etc

 

good point. my only argument is that its nice to be familiar with your motor in case something goes wrong. if he gets it back and something goes wrong after 6 months, hes still got no experience..other than that, yea itd be nice to get the motor, slap it in and ride..

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unless you want to learn more, I'd send your whole motor to Jeff.

 

it's probably an hour of shop time, you get a complete solution, and won't be held up unnecessarily for missing something here or there (like losing a small screw, an o-ring for a coolhead, ie the little shit). I'd rather just get the whole motor back knowing that all of the tolerances have been checked, it's been leak down tested, compression is right, squish clearance is right, etc etc

 

 

That's what I did. After I cold seized my cub back in January, I was fed up and boxed it up and sent it to Jeff. As mentioned, I felt safe knowing everything was checked out and a pressure test was performed. I've been having problems w/my YFZ motor(s) and got pissed and finally took then entire 4 wheeler to a shop and said FIX IT AND MAKE IT FAST!! I can work on things my self, but I get frustrated pretty easy, and probably drink too much beer putting things back together. LOL :yelrotflmao:

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