New Owner Y2K Blaster time to get dirt

TypicalGuy

Member
Apr 25, 2022
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Well this is what I have to start with. Hope I didn't bite off more than I can chew. Anything you see feel free to comment all help is welcomed ☺️
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Started taking it apart to replace what looks bad. It ran but not very well. Went through all the gears, rear brakes don't work, front are very weak, clutch grabs hard.
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Well I pulled the head off cause I saw gasket maker and I'm not sure what to make of it
Looks like a newer piston and rod maybe the did the crank as well???
 
Should the piston rod have this much room to move side to side like this?
There is no up and down movement of the rod to the crank and a little side to side like I've seen on YouTube rebuilds
 
Everything is wrong< Chinese Ebay cylinder, Junk Wiseco Crank, RVT used throughout. That entire motor needs to come completely apart. DO NOT watch YouTube to learn how to rebuild motors as 95% of those clowns are full of BS. You can't inspect a crank shaft with your hands and eyes. You need mag base dial indicators to inspect rod bearing Raidel deflection measurement and runout and feeler gauges to inspect side thrust washer clearance. That piston is like new but look at all the burn pattern below the second Ring?! Thats perfect indication that the piston had excessive blow bye because the rings never seated and sealed to the cylinder because the bore finish is not correct, and the piston fitment is most likely wrong. That motor would have shortly blown up caused by many factors involving junk parts and "TERRABLE" mechanic skills. You have a Bitten off more than you can chew here, I'm sure. Unless you go get a factory service manual and go out and buy all the necessary special measuring tools (To measure and compare to service specs) and special tools to build engines "Correctly" along with having someone check your work then I would Think twice before spending money just to have more headaches in the end. I rebuild and modify these and all other Quad and MX motors daily in my shop and I deal with this ALL the time with customers just like yourself and SO many people throw money away trying to build a motor and then bring it to us and have to have it done all over again "Properly". You Tube will never replace decades of study and experience. Read Books and learn by the engineers over in Japan not some Wanabee on You tube! Service manual is the Bible! Period! Those Ebay China Cylinders are good for one thing... Peeling potatoes (Sharp as razers port windows with no chamfering!) LOL!
 
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guess I have some work ahead of me. I thought weisco was good ? I'll get a topend kit if I have to, what do you recommend? I appreciate the help
 
Recommend All OEM (or Japanese Equivalent) Components for entire motor with the exception of a Wiseco "Piston". OEM Gaskets (or Japanese or USA Equivalent). The old style "Black Con Rod" Wiseco cranks are junk. Find a clean OEM Crank and have it rebuilt "With Japanese parts" and also find a good OEM Cylinder (close to stock bore size as possible) and have it Bored & Honed matched to a fresh Piston. Main Bearings and main seals. New reeds. This is the bare minimum in my book. If you need any of these special services like crank rebuilt and or cylinder work let me know if you don't already have someone. My shop does all this type of work. Good Luck
 
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Checked my ring gaps like suggested and you were correct. 0.19in when they should be 0.00
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8-0.014
 
So I'm guessing I'll need a whole new piston? I'll go to my local shop and ask them to match one for me.
 
Well my local shop just wants to order a new cylinder and piston ( something I can do myself ).
So I'm having a hard time finding a cylinder that's not Chinese made and OEM doesn't seem to be available from online stores. Does anyone know where to find a quality cylinder?
 
You buy a good used one as close to stock bore as possible(66mm) and send it off to a shop (like mine) to get bored and honed matched to a new Oversized piston. The cylinder gets measured and depending on how much material needs to be removed(bored) from the bore to get right then the machinist orders the piston and when it arrives the cylinder is then bored and honed to match that "Exact" Piston. This IS the only correct way to do it as there is OEM cylinders available from the Manufacture but Very expensive in comparison and are on backorder everywhere.
 
Also wanted to mention that you are incorrect with ring gap. first off you only measure the outer (smaller) gap and the specs are .008"-.014" and the larger the oversize piston the closer to the larger number you want. No piston ring is set at .000" clearance as it's there for thermal expansion of the ring and without its bad things happen. All those cheap Chinese kits on Ebay, Amazon or wherever it's sold from are complete sh*t on many levels.
 
Don’t waste your money putting a new piston in a worn out hole.

Here’s how you do it PROPERLY !!
1. Have cylinder professionally measured, to determine proper oversized piston needed.

2. Buy piston

3. Machine shop bores and hones to fit THAT piston.

4. NO CHINA PARTS !! Buy once, cry once
 
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Also wanted to mention that you are incorrect with ring gap. first off you only measure the outer (smaller) gap and the specs are .008"-.014" and the larger the oversize piston the closer to the larger number you want. No piston ring is set at .000" clearance as it's there for thermal expansion of the ring and without its bad things happen. All those cheap Chinese kits on Ebay, Amazon or wherever it's sold from are complete sh*t on many levels.
That's what I had but my picture cut off my text for whatever reason.
I did find OEM refurbished jug and piston on Ebay for $400.
 
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There's still hope for project Y2K, whoever deleted the oil injection did that correctly !
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