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You can usually pick up an MB machine used for a little more than $1500.00. The cost usually depends with the tooling which goes along with it.
You forgot about the shipping cost to NZ. I still have to find space in my workshop for the Cylindrical grinder I'm collection tomorrow.
 

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Discussion Starter #642
Why is there such a long 'lead in' on cylinder sleeves ? My Maico has about 25 mm of narrowed section with is still withing the overall barrel length. So the last 25m of the sleeve is about 0.2 mm away from the barrel.

I would have preferred that the sleeve is parallel all the way down for maximum rigidity.

I don’t understand your question about the sleeve dimensions.
In the old days we would mandrel grind our liners on a very large Cincinnati 24” x 36” cylindrical grinder. Fast forward some years; we now install sleeves with only a lathe finish cut. LAS used to use a centerless grinder on their OD’s. NWS with their CNC equipment also finish turned the sleeve’s on the lathe. I’m not sure about other people in the business.

There is probably a hefty duty on machinery coming from the US. If you have a Craig’s list or something similar a Sunnen machine would surely shoe up in NZ.
 

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This lower portion is only machined smaller so it will fit in the cases.
The Maico cylinder is as long as the sleeve. The sleeve's diameter is 75 and the bottom of the barrel is around 100. The cases hole is > 100.

Which brings me back to the question, the bottom 25 mm of the sleeve (which is within the 100mm cylinder) is not actually touching anything ?

Maybe something to do the original manufacturing processes.
 

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Discussion Starter #646
Maybe a mistake or manufacturers tolerances are pretty loose. Perhaps the cylinder is for a different case.
Who the heck knows :Dope:
 

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This lower portion is only machined smaller so it will fit in the cases.
The Rotax 500, Honda 125/ 145, Maico all have 0.4-1 mm narrower section at bottom of the cylinder.

When I re-engineer something I like to know all the background in order to make the best decisions.

Cheers Wallace.
 

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Hi John

After marking with nitric, do you heat up the cylinder till the liner drops out or give it a gentle push in the press ?

I have never had one drop out.

Aly expansion 22 x 10-6 mDeg/m
Steel 12 x10-6

On a bore of 75 mm, 180 degrees gives me 0.13.

250 is 0.17.
 

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Discussion Starter #649 (Edited)
If the fit is correct; the sleeve should fall out. ½ the time it will take a push in the press. Make sure the ylinder is hot enough, 500 deg. A lazer temp gage from is what I use from Harbor Freight.

I use the expansion numbers from my own checking with my dial gage. At 500 deg. No need to check the sleeve only the aluminum cylinder
 

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Hello,

Il would like moving pin locating ring for a piston.

which difference in diameter between the hole and the pin for proper maintains ?

0,004" it's correct ?
 

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Discussion Starter #651
Call Wiesco (1-800-321-1364) & press 2 for motor sports, ask for Al; Al is the technical go to man.
I check fits by setting things up on pieces of scrap metal.
 

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FTZ used a yz-250 piston in a lt-250 motor with a relocated ring pin. dunno how they did it. remove the pin and re-drill. Reason being, the YZ piston ring placement would hang up on the LT-250 ports..being where they expanded. ring gap..
 

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Discussion Starter #653
I’ve never relocated a ring pin; I found a man back east who is good at it. Maybe someone will tell us who he is.
 

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Can't believe it has been this long since I was on this thread and my sleeve is still not complete.!!!

I have a Kawasaki KR150 on the dyno bench and I have a weird plot. Is the centrifugal exhaust valve working to soon or too late ? If this not the right forum, please point me to the correct one.

Brad_Dyno.JPG
 

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Discussion Starter #655
I’m not sure who knows about dyno tuning. Have you got an earlier plot to compare with? Did you study the factory repair manual?

You haven’t got a sleeve replacement in my shop, otherwise it would be finished

John Tice
503-593-2908 Alternate 541-508-3944
www.smallenginemachineworks.com & www.nwsleeve.com
Turning Custom Cylinder Sleeves Since 1971
 

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After much head scratching and trials of various parts, we changed the balls in the centrifugal advance last Saturday and it worked. Nice smooth plot. Of the 3 bikes I have trialled, it looks like each one has had some mods.
 

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DIY hone. I have finally got around to working on the Maico again. (The wife's broken leg too its toll on my shed time !!) This is what I have made. I think it should work fine. I need 68 mm. I can increase the hone by inserting 0.5 mm layers of film.

Hone.JPG
 

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Discussion Starter #658
Marsheng; I see you driving a Kart? Is there much Karting activity in NZ? I raced Karts for 10 years when I was a little tyke.
 

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Marsheng; I see you driving a Kart? Is there much Karting activity in NZ? I raced Karts for 10 years when I was a little tyke.

That was me in Lusaka Zambia when I was about 4. My dad made it, I rode it once on the track and then a few times in the yard and then it was mothballed. I was very disappointed.

Karting is here in NZ but grass karting is quite big. 30 or so karts on a day out.
 

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Early karting!! Go Kart, Bug Scorpion, Carretta, Bonanza, Dart, Fox, Xterminator, Rupp, . . . McCulloch, Homelite, Power Products, West Bend, Komet, B Bomb, . . . man, those were the days!!


An old story I heard or read somewhere: The racing season having ended, the Ferrari team manager and his wife went on vacation, in Brazil. While there, friends told him, "You have to come see this kid who races karts here, he's already a phenomenal driver!!" The Ferrari man just wanted to forget racing for a while, but they badgered him into going to a kart race . . .

By the end of his stay in Brazil, the team manager had the kid's signature to a contract to drive for Ferrari . . .

. . . Emerson Fittipaldi.
 
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