Need help quick. Can you bore 2 strokes? I thought they were plated.

[Chris Long]

This is a general question regarding all 2 strokes even though my example is a minnie. My 2000 Suzuki RM80 cylinder is at the shop and he wants to bore it due to scoring. Correct me if my wrong, but I thought all 2 strokes are plated and need to be re-plated and not bored. He referred to my 2000 RM head as "old school" and they were not plated bac then.

Any help would be appreciated and I will call the guy back. Thanks, Chris

 

[hot125mod]

stock most of the 2 strokes are plated but they can only be bored a millimeter or not much over. Anymore and you will lose too much thermal efficiency, so they sleve the cylinder with a cast-iron barrel. but they dont transfer heat as well as a plated cylinder. The motor will run hotter too.

 

[rmc_olderthandirt]

Not all cylinders are plated. It has become common on the newer models, especially in the larger engines.

On the plated cylinders, the plating is very thin. If the cylinder has been scored then re-plating may not be enough to fix the gouge. In this case the cylinder would need to be bored out and then plated. If the cylinder has been bored out as far as it can go then they insert a sleeve inside, which then gets bored to size and then plated.

Rod

 

[cujet]

Two stroke cylinders with thick cast iron liners can be bored, honed and chamfered without any "post bore" plating or treatment required.

Aluminum cylinders that are plated with Nikasil (trade name, it goes by many other similar names) generally are not bored, just replated. However, there are big bore kits for some of these cylinders that involve a significant bore job and replating with Nikasil.

Some aluminum cylinders are plated in a very thin layer of steel, sometimes called electrofusion. Kawasaki is known for this. These are generally bored out and replated with Nikasil.

By the way, Nikasil cylinders are generally the longest lasting.

Chris

 

[cujet]

If a magnet sticks, it is highly unlikely you have a Nikasil plated cylinder.

Chris

 

[Chris Long]

I'm taking my machinists advice and believing him that this cylinder is not plated.

Since the scoring was bad, I'm boring it a tenth over with a new weisco piston to match. The machine shop is charging me $60 for the bore and $100 for the top end and gaskets. I also had the head resurfaced as some radiator fluid was getting by and I could smell it in the exhuast. Thats what originally made me pull the head apart was a pressurized cooling system and sweet rads smell in the exhasut. Thanks guys.

 

[Red Pinger]

I think you should call you local suzuki dealer. I think they stopped using cast iron cylinders a long time ago. Did you take it to a bike shop or just a machine shop. I can't believe a 2000 model year bike doesn't have a plated cylinder. I could be wrong but, I think your headed for a disaater.

 

[BLACKeR]

i would be pretty easy to tell if the sleeve is steel or aluminum. if its aluminum its plated and if bored will need a new plating. if its steel bore away. just make sure your ports are chamfered. nikasil plating is also not specific to 2-stroke engines.

 

[Rotorranch]

If you look at the fiche for the '00 RM80, you'll see Suzi shows OEM oversize pistons, therefore, it's not a plated bore. :nod: If I hadn't looked, I would have also thought it was plated.

Rotor

 

[ckassen]

I have just blown up my 00RM250, how can I tell if it is plated? A magnet will stick but not very much. I think that if I go to the 68.5MM piston it should be fine. (66.4) stock. But that is only if I dont have to resleeve. If I have to resleeve I dont know if I will go back to stock or not. What is smarter? If I blow it up again can I resleeve and stay with the 68.5mm piston? Or will I have to go larger?
Thanks,
Chris

 

[BLACKeR]

is the cylinder bore itself damaged? if its not scuffed, and the cross hatching is still good, there's no reason to bore.

 

[ckassen]

Unfortunately I was extremely ignorant and didnt change my piston when i should have. I myself(with an already worn top end) probably put over 50-60hrs on it, they were "easy" hours but still....

Basically I have been calling around and have found out that it will need to be replated(it has one good scrape that goes through the plating). I initially thought that resleeving was cheaper, i am wrong. I am going to send it to US Chrome. But I am deciding whether or not I am going to stay with the 250CC, 66.4MM or go to 265CC 68.5MM. Either way the scrape will have to be fixed by the $231 option. The pricing only varies by $25-30 and that is just to grind down the power valve by 1 MM(and the piston is $10 higher) How do they grind it? is it something that can easily be done myself or am I better off to pay the $25 and have it done? Also, how much more power am I looking at with the 265 over the 250? Not to change the subject, but is boyesen pro series reeds the best bang for the buck or does V-force make that much more of a difference?
Thanks,

 

[ckassen]

What els should be done when boring to 265? Like boring of the cylinder head ect?...