Sorry....Another 300r question

[gimmeamidget]

My cylinder measures 76.5. I located a 76.25 piston and rings as well as a 77 piston and rings. I bought both. My question is if I bore over to fit the 77 piston (I believe that’s the last bore) can I resleeve the cylinder and bore to 76.25? Where can I purchase a sleeve? I have searched and I can’t even see where one was ever available?

[Dirtcrasher]

Is LA sleeve not around anymore??

Anyone who does big bores or cylinder plating probably makes sleeves too.

Even guys that offer services on Ebay would be something to look into.

[gimmeamidget]

Thanks ill try LA Sleeve....I thought they were the ones shaving the deck and using other pistons. Im really trying to keep it hondaline. Im not familiar with the process to replace the sleeve and I assumed I would need hondaline on it? thanks

[Hedbngr18]

I just had an LA Sleeve pressed into my 85 R. They don't fully replace the factory iron bore. The factory bore is increased and the new sleeve is interference fit into the cylinder. Cheaper than an entire cylinder, but you get less hones/bores out of them. Kind of a catch 22. I haven't actually reassembled the engine yet so I don't have any input as far as performance or issues, but it looks like everything will be just fine. Comes down to preference, really.

[yaegerb]

Is LA sleeve not around anymore??

Anyone who does big bores or cylinder plating probably makes sleeves too.

Even guys that offer services on Ebay would be something to look into.


Yes they are around. I use them almost exclusively.

[gimmeamidget]

LA sleeve does have sleeves and will bore and fit the Hondaline piston. Thanks Dirtcrasher for the info!

[sledcrazyinCT]

New 300r pistons are in the works from wossner there are facebook pages where people are keeping track of who needs which size over bore

[Red Rider]

I just had an LA Sleeve pressed into my 85 R. They don't fully replace the factory iron bore. The factory bore is increased and the new sleeve is interference fit into the cylinder. Cheaper than an entire cylinder, but you get less hones/bores out of them.This makes no sense to me. Why wouldn't the entire sleeve be replaced?

[yaegerb]

This makes no sense to me. Why wouldn't the entire sleeve be replaced?

X2.....they have never done this with any of the 20 or so cylinders I have sent them.

[bkm]

I've seen a few LA Sleeve jobs come back like that. I have an 85 cylinder that someone did the exact same thing to.

[Red Rider]

I've seen a few LA Sleeve jobs come back like that. I have an 85 cylinder that someone did the exact same thing to.If that's the case, you might get 1 or 2 overbores out of the new sleeve, then it would be too thin in the exhaust bridge area, and it will start bowing out & gouging pistons when it gets hot. Nikasil is the way to go in my book!

[gimmeamidget]

Finally getting around to assembling this kit and as I’m reading the instructions I see this...261655261656my bike is an 81 and kits for an 83. I always thought the motors were basically the same? Can anyone confirm this kit should work on an 81? If not I would like to know the issue. Thanks

[atc300r]

The kit will bolt on your 81 .You may have to clearance a couple of the fins on the head to clear the frame.These kit were more or less designed for the 83-84 250r.The kit came with a 135 jet for the 30 mill keihin.81-84 250r motors are the same with the shifter shaft being only significant difference.

[gimmeamidget]

Ok thanks for response.

[christph]

I just put a 300 kit on my 82 250R. You will have a clearance issue between the frame and center head fins. The clearance is fine once you get the head on, but it's getting the head on that is the challenge because the head studs are too tall. Rather than shave the central fins, I lowered the 3 studs in the front of the cylinder about 1/4 of an inch. This allows the head to slip on.

[gimmeamidget]

Ok thanks for the tip!

[Hedbngr18]

This makes no sense to me. Why wouldn't the entire sleeve be replaced?

As far as I was told by the shop that did my sleeve, the 85/86 R iron bores are not pressed in in the conventional sense. The are slightly bowed in the middle and the jug is apparently cast around it. This guy may be mistaken, but he's been in the small engine/2-stroke game since the 70s and I have no reason to not trust him. Any debate to the statement can be taken up with him. I am just repeating what I was told. :)

[ATC200X4716]

That is correct most sleeves are cast in place from the factory and then finish bored/honed so there is no guarantee the bore and the OD of the sleeve are perfectly concentric, so if you had to machine out the sleeve you may and up with a sliver of iron on one side and no sleeve on the other. The new sleeves are usually put in with several thousandths press fit depending on size and the cylinder is heated in an oven and sleeve goes in the freezer, and then drop them together. 2 strokes are tough cause you have about 2 seconds for it to drop together and rotate to line up the ports before it freezes in place. I usually put the sleeve in an upside down lathe chuck on the bench, and drop the cylinder down on the sleeve while looking at the exhaust port/bridge to make sure it is lined up.

[207wheelin]

That is correct most sleeves are cast in place from the factory and then finish bored/honed so there is no guarantee the bore and the OD of the sleeve are perfectly concentric, so if you had to machine out the sleeve you may and up with a sliver of iron on one side and no sleeve on the other. The new sleeves are usually put in with several thousandths press fit depending on size and the cylinder is heated in an oven and sleeve goes in the freezer, and then drop them together. 2 strokes are tough cause you have about 2 seconds for it to drop together and rotate to line up the ports before it freezes in place. I usually put the sleeve in an upside down lathe chuck on the bench, and drop the cylinder down on the sleeve while looking at the exhaust port/bridge to make sure it is lined up.

Always wondered about this process. Hard to find places around here to do this type of work.nowadays. Lots of the old school shops have closed and in the last few years the machine work I have had done was not satisfactory.
Take care
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