cylinder replating - a couple ??'s

[jim v]

Need two cylinders replated and after some searching it seems like most people consider Millennium Technologies the go-to. As a 2-stroke newb I thought it would be a good idea to ask a few questions here -


-Is there a local shop to do the work? Or do the locals just send it out to MT?
-Do I need to send the pistons as well? I've asked MT this is exact question 3x and haven't received a yes or no.
-Not getting any power valve work done - should I?
-Anything I should be watching out for?


Bike in question is a Honda RS250. Any info or advice would be much appreciated

[Kurlon]

Send pistons with the cylinders and your desired target clearance and they will go based off your pistons.

[jim v]

Awesome. Thanks for the info (runs off to look up clearances in manual)

[carsick]

The piston manufacturer may have different clearance specs than OEM (assuming new aftermarket pistons).

[jim v]

I have OEM pistons, but the manual doesn't have any numbers for piston-cylinder clearance or piston diameter. Cylinder bore is listed as 54mm (not 54.0 or 54.00). Why would they be so imprecise? I did some googling but that didn't help........

[Kurlon]

Ping Rising Sun Cycles, bet they'll know.

[jim v]

Ping Rising Sun Cycles, bet they'll know.

I emailed Steve at RSC. When he responds I'll post the info here - threads with questions that don't get answered are a pet peeve

[05RC51]

I've used USchrome a few times for snowmobile cylinders. There turnaround time was quick. I've also used millennium tech with good results

[carsick]

I emailed Steve at RSC. When he responds I'll post the info here - threads with questions that don't get answered are a pet peeve

Bless your kind, that's a great idea to spread!

[timmyho414]

what Kurlon said. or you can measure and send them the numbers.

I used Millennium for my 749. They hit my target clearance right on, .0025 on the nose.

[jim v]

I think Steve from RSC has retired, but they recommend a clearance of 0.06mm, or about 0.0025"

Ian E, Honda 125/250 specialist from the UK recommends .055-.065mm or .0022-.0026"

I'll include the pistons ask for .0025" clearance

[jim v]

Figured I'd close the loop on this thread....

Sent off to MT - 2 cylinders for replating along with 2 pistons to target .0025" clearance. Plus one cylinder head that need to be cleaned up. Got it all back a few weeks later
- head looks great (did they weld some material on and then machine?)
-pistons and cylinders we're packed as sets so you can't confuse them. they look good but I don't have a bore gauge, can't tell you if they hit the clearance