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oh400ex

Restoration | 2000 CR80R

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Hello again everyone!

 

This one is mine!

 

I picked up a 2000 model Honda CR80R 2-stroke motocross (big wheel) dirt bike non-running from a nice young man.

 

The previous owner smoked the top-end and bought a new sleeve but never put it in.

I plan on purchasing a new piston and top end gasket kit if the rod is tight but if not it's going to be an entire engine kit.

 

If you are unaware this 80cc monster can do 60+, jump and go straight through the woods. I love it but I'm only going with the latter. 🤣

 

Full treatment incoming but getting into the actual restoration bits after top end and the other project (250) is priority.

 

Thank you for looking!

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Can anyone tell me their experience with Vertex piston kits?

 

I'm looking at picking up a kit and want to get as close to OEM as possible. Replacement sleeve is in hand from LA Sleeve.

I'm planning on taking the piston/ring along with the top-end and sleeve when it goes to the machine shop.

 

I know this is considered blasphemy but I'm not a fan of Wiseco. I actually would go with Namura but have no experience with their 2-smoke line.

The Vertex would be coming from DB Electrical.

 

Thanks for looking!

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i run namura, i've had great luck with them in the past builds. i wont waste my money on wiseco, great name, too high dollar for little gain.

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Hello again!

 

Anyone have a recommendation on sending the cylinder out for a re-sleeve?

 

I need someone who is capable of working on a very small engine and doing a sleeve.

 

My local machine shops have failed me on this one. The good one doesn't go that small. Dead end.

The bad one (Yamaha shop) will do a bore for a very small cylinder but apparently doesn't have anyone in-house who is capable of doing a re-sleeve...

Let me in the shop for a day and I could do it myself. They have the equipment but either refuse or don't know how. The job is not as simple as just placing a jug in the machine which is apparently all the monkeys from yammahamma can muster... everyone in the know laughs at the idea of having that shop touch your bike.

 

Anyone sent a small 2-stroke cylinder off for re-sleeve? Know a machine shop that I can ship to for a reasonable price?

 

Thanks for reading!

oh400ex

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Yep everyone swears by that G&H place. I have never had to use them as i have a family friend that owns a machine shop and i can just go in and do it myself if he cant or doesnt feel up to the task. I personally would only evee run wiseco or CP. Had a bad experiance with namura on a blaster i raced as a kid. It detonated and sent shrapnal into the bottom end. Cant confirm if it was a shop issue or material failure. But it is the reason i did my first 300ex bottom end rebuild at the age of 15. Never trusted a shop ever again.

 

Have ran wiseco in every single build (10+) except this stroker build i have now. They wouldnt respond to my emails to make a custom piston. CP did and also did an amazing job with it.

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G+H will do a sleeve job , it use to cost  $100 if you supply the sleeve  , give them  a call , very nice guy , he will talk with you 

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Sent G&H a message and didn't hear back yet. I'll give them a call today.

Those website contact portals sometimes don't always work or stuff gets lost in the spam.

 

I decided to try the Vertex out. Never ran one before but I got a good feeling since it is coming from DB.

This is a 2-smoke after all so we will get to know how good it does and how it wears faster. Any piston will get replaced eventually.

 

Vertex is KTM's OEM piston and Austrian gear heads are known for lacking on the quality control. 😂

 

Edited by oh400ex
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I ran a Pro-X & wiseco piston in a blaster i had as a kid too... Put 4 top ends in it. Kept burning a hole in the top of the piston. And after the first rebuild i deleted the oil injection and mixed everything from there out.  This blaster was a little too decked out too, piped, jetted reeds, port, clutch etc. It had balls for a 200 but so many it would choke on them and be swallowed through the top of the piston. Sometimes it's more circumstantial than quality parts. I should have just bought a bigger machine if i wanted more power (but i was young and couldn't afford a $5000 machine).

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4 minutes ago, sled_22 said:

I ran a Pro-X & wiseco piston in a blaster i had as a kid too... Put 4 top ends in it. Kept burning a hole in the top of the piston. And after the first rebuild i deleted the oil injection and mixed everything from there out.  This blaster was a little too decked out too, piped, jetted reeds, port, clutch etc. It had balls for a 200 but so many it would choke on them and be swallowed through the top of the piston. Sometimes it's more circumstantial than quality parts. I should have just bought a bigger machine if i wanted more power (but i was young and couldn't afford a $5000 machine).

 

Had a Blaster too but don't really remember what brands of piston I put back in it. Mine had pipe, reeds and jetting but stock motor until I needed to go up a size each time.


I locked it up on a ride once and did the first gear and pull it backwards to unlock it deal. That piston lasted a few more weeks after that lol

Stupid kid. Someone told me it would "fix" it and it did lol. I didn't know I was riding around a rod bomb at the time. That adventure ended with a hole in the case.

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G&H sound like great people but unfortunately they do not re-sleeve small two-smokes.

 

Might end up sending the 350x off to them and definitely would if I didn't have a local option.

 

Slightly over $200 to ship off an unknown quality cylinder and have it come back with piston kit to match the fresh bore is a good deal.

 

 

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G&H was going to be my suggestion as well.  Sucks that they won't do a small 2stroke.

 

I used a guy in Memphis for my last bunch of cylinders.  Old guy who has a vintage motorcycle shop.  I can ask if if there's anyone around here who does stuff like that (if he doesn't)

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My guy said he could do it,  does 50CC and up.  Charges $100 plus the sleeve for a 2 stroke.  I don't know if that's a good price or not (I'm not a 2 stroke guy).

 

He charged $50 each to bore my 300 and 500 cylinders, which around here is dirt cheap.  One of the 500's needed a sleeve, and he said on Honda 4 stroke motors the sleeves sometimes fall out when he puts them in the heated bath.

 

 

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12 minutes ago, jeepwm69 said:

My guy said he could do it,  does 50CC and up.  Charges $100 plus the sleeve for a 2 stroke.  I don't know if that's a good price or not (I'm not a 2 stroke guy).

 

Incredibly reasonable considering that I was going to have to ship it to god knows where and you have experience with his work!

I would be sending him the cylinder, sleeve, piston and ring so $100 would be awesome!

 

What is his information or do you want me to send to you?

 

Thank you very much for the time and effort!

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Look up “Vintage Motorcycle” on facebook. Guy is in Memphis. Not sure how backed up he is at the moment, but he’s pretty good at answering messages on FB

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I would spend the extra money and get the cylinder plated again. They last much much much longer, run cooler and you will save money in the long run due to boring, pistons and even rings. These 80cc cr's eat rings. Probably about 3 hours at race pace per set. New piston after the 4th or fifth set of rings. With a cast iron cylinder the bore will be worn out of spec after the piston is worn out. 

Edited by Misterclean
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MC , sounds kind of high maintenance to me.  I think if I was going to go with it , I would go big and go 500 X

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Those high revving small bore two strokes are maintenance heavy. They are easy to work on tho. My wife had a KX 125 and the top end needed refreshing often.

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1 hour ago, Misterclean said:

I would spend the extra money and get the cylinder plated again. They last much much much longer, run cooler and you will save money in the long run due to boring, pistons and even rings. These 80cc cr's eat rings. Probably about 3 hours at race pace per set. New piston after the 4th or fifth set of rings. With a cast iron cylinder the bore will be worn out of spec after the piston is worn out. 

 

41 minutes ago, Misterclean said:

Those high revving small bore two strokes are maintenance heavy. They are easy to work on tho. My wife had a KX 125 and the top end needed refreshing often.

 

Oh yeah! Can not beat 30 minutes to change a set of rings lol

 

I don't think that personally the coating would be worth my money or time.

Being that I am going with a re-sleeve and the sleeve is made of a hardened material meant to be stronger than a cast iron block would ever be... I don't see the need.

 

In my experience, nikasil plating is only best at saving money on the manufacturer side of things.

You almost never see plated cast iron but it is used as a cost saving measure for an aluminum alloy head.

 

I agree that a sleeved cylinder will wear a bit faster than a plated one but being that I can hone myself and go up in sizes as needed the sleeve give hours of life past this initial rebuild. I will be back into the top end no matter what as like you said they are maintenance heavy.

 

I'm considering taking this to a manual lathe and just doing it myself. 

If the PO hadn't bought the sleeve already I would just bite the bullet and get a new cylinder.

 

 

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Well @Misterclean was right. 

 

Turns out the best thing to do for this bike (according to a trusted machinist) is to re-plate.

For a bike this small he has less than perfect experience with sleeve fits and recommended plating.

 

In a perfect world... I could get it re-sleeved and do the rest of the bike's rebuilds myself but practically I will end up paying less for plating and get a longer life per dollar.

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