lucknuts

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Apr 27, 2019
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My buddy bought and put in a piston on my blaster while I’ve been busy with work. I rode it around for two full gas tanks somewhat easy with a dab extra 2stroke oil in the gas. It is still oil injected, no tors delete on it. He just said it’d be good for it.

It was more than a few days of riding it and finally I got wide open throttle on it and I believe I was in 4th and it just went poof. It does start but all I hear is metal screeching. Still great compression. I took it apart and checkout the piston and head. Checked out the shift crank gears and nothing there. Opened stator side and everything is alllll good.

Quite a few scratches inside. Head and piston scratches also. No real grooves though.

Should I just buy a new piston? If so 66mm is stock I believe, it’s been a while. Wiseco? Link me to a good deal.

Tried uploading different pictures, keeps saving pictures are too large and server can’t handle it. Idk their just pics from my phone. :/
 

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Several questions, some for you, some youlyo have to ask you buddy. No particular order.
Was a leak down test done? Did you do heat cycles and re-torque after? What brand piston? What was ring end gap? (Was it even checked?) Was a new piston put in an old hole? If so, why?

Check bearings on both ends of rod. Side clearance , Visually inspect small end bearing. Do not reuse piston pin clips.
 
Adding extra oil the the fuel creates more heat as the fuel quantity in the mix becomes less.

Was the oil pump bled of all the air before the engine was started..
 
Several questions, some for you, some youlyo have to ask you buddy. No particular order.
Was a leak down test done? Did you do heat cycles and re-torque after? What brand piston? What was ring end gap? (Was it even checked?) Was a new piston put in an old hole? If so, why?

Check bearings on both ends of rod. Side clearance , Visually inspect small end bearing. Do not reuse piston pin clips.

No leak down test. I have one at my house now that I got off eBay a while ago but it doesn’t fit properly so haven’t used it.

No to the heat cycles. I watched that video from ken O’Conner to damn late. I asked him about that and he said he’s never had to. When I opened it up they came off pretty simple.

I can’t tell the brand of piston, he said it’s either ace or top notch.

I’m going to assume no ring gap was checked. As far as I know I believe it was a top end kit he got. Guessing amazon. So, no to a new hole.

I’ll look up how to check bearings. Thanks
 
Photos.
 

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I haven't worked on this in a while, debating on what route to go with it. Sell it as is or take the engine out and do a top/bottom rebuild myself when I have time - been pricing parts out but figured I'd have to buy a tusk case splitter and crank puller (128.59) to figure out what the issue is. OR just plan on replacing crank, bearings, seals and clean everything out. Thoughts?

Was doing a quick scope and figured if I had to buy the splitter and go nuts this was my list since everything else is stock. Besides the Boysen 630 power reeds.

Wiseco Crankshaft (includes bearings) 186.99

Wiseco Piston Kit 117.04

New Primary Drive Gear 172.99 (current one has play in it and a piece of metal was missing off of it, found them both)

$605.61 for everything including case splitter/crank puller.

I don't need anything fancy or balls out. Just stock will be fine?

If anyone has time to take a moment and let me know what to all go through or main things to check or replace, I've been watching an ass load of videos lately, they definitely don't show everything - I'm just not wanting to throw $1000 into it.

Appreciate it.
 
https://www.harborfreight.com/autom...pullers/bolt-type-wheel-puller-set-62620.html
This is all you need for the cases.
I see no mention of gaskets or boring for new piston. I would consider looking for a used crank gear

I still don't like the look of the big end of the connecting rod being discolored like that :(

That will work to split the cases but I will still need to get the crank puller I suppose. Thanks.

90% of it has all new gaskets and seals on it already. When I take it apart I will get new ones as needed also. I won’t make it a one day and done deal. Want to thoroughly go through it.

Me either. My guess is I need a new one. No boring for larger piston. Keeping Everything stock.

Thank you
 
https://www.harborfreight.com/autom...pullers/bolt-type-wheel-puller-set-62620.html
This is all you need for the cases.
I see no mention of gaskets or boring for new piston. I would consider looking for a used crank gear

I still don't like the look of the big end of the connecting rod being discolored like that :(

Any ideas where to find a used crank gear? Any search terms I May be missing? Haha. I’m afraid if I get used there will still be slack in the gear if purchased then I got a duplicate of what I just had.
 
That will work to split the cases but I will still need to get the crank puller I suppose. Thanks.

90% of it has all new gaskets and seals on it

Me either. My guess is I need a new one. No boring for larger piston. Keeping Everything stock.

Thank you

https://www.blasterforum.com/threads/diy-crank-puller.43994/
I don’t recall exactly how I did it, but I thought I rigged my balancer puller to split cases and pull crank. That’s been several years, and I’m old enough to start forgetting things :p
If nothing else look at that thread on how to make a puller.

As to the gear, exactly how is it loose?
 
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Larry and awk thank you so much! I got it apart after waiting on a few tools to arrive. Going to make it a few month project. as informative as ken is i got the videos and I’ll get what I need to make sure motor gets put back together the right way. Thanks for all the help thus far.

Also, I never use Snapchat but used that app to take pictures and was able to upload those photos no problem. Guessing the ones from my phone alone are too large in size to upload. Think it takes 4K photos.

:)
 

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Good Job so far ! well on your way to seeing this thru to a great running engine
tu.jpg
 
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Seen a spot on here that someone else had bearing stuck on drive shaft. Can't find it again, maybe just used a bearing puller is my guess...work in progress I tell ya

....

If I'm able to get that bearing off is it ok to re-use it? If not, I believe this is the correct bearing (Drive axle (sprocket side)- 93306-30421-00) would make sense...I'm tired. Apologies. hahaha

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If you heat the case that bearing should drop right out. Clean cases very well, maybe even soap/water to avoid smell in oven. 170*/ low heat for maybe half hour. Bearing should fall or tap out easily. Put back in oven and turn off, let cool. Might have to run self cleaning cycle after. I’ve heard of using gas BBQ also.
Reverse process to install except freeze bearing overnight.
 
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