Is the skorpion cylinder nikasil coated

[Srinath]

The title says it all. Is it regular steel ? or nikasil lined.
Thanks.
Srinath.

[Srinath]

And what other years of raptor cylinder pistons work on the 00 skorpion. Would an 02 660 piston and cylinder set work ?

I am thinking of buying something like that and swapping it in if my rings are frozen to the piston ... which may be the only possiblity @ this point. This motor may have started to melt itself.

Cool.
Srinath.

[Hajok]

Regular steel it is, so you can swap your melted piston with any oversize: 101 mm, 102 mm, 105 mm... NiKaSil coating is only used directly onto aluminium cylinders using a kind of anodising process. This gives better heat transfer, the same expansion coefficent as the piston and therefore smaller tolerances are possible.

Any 5 valve yamaha piston will do; XTZ, SZR, Raptor.

Question is: what cause is melting your engine?

[Srinath]

Regular steel it is, so you can swap your melted piston with any oversize: 101 mm, 102 mm, 105 mm... NiKaSil coating is only used directly onto aluminium cylinders using a kind of anodising process. This gives better heat transfer, the same expansion coefficent as the piston and therefore smaller tolerances are possible.

Any 5 valve yamaha piston will do; XTZ, SZR, Raptor.

Question is: what cause is melting your engine?

I am not sure it is melted, I will check into why ... clogged oil passage maybe - the supply to the head goes through the left case, and I did have that apart recently.
I have to check ... And thanks much for the info.

Now is it worth swapping to a 700 top end ? the whole kit and kaboodle - pistons, cyl, head etc ... cos I can snag one of those cheap.

I also plan to hack that cross brace and make it unboltable. Or even make it a different location if I need the clearance.

Cool.
Srinath.

[Hajok]

You recently had questions about your idle mixture screw in another topic. Maybe you run very lean what causes an overheated piston. The piston is lubricated from underneath, it should not run dry very easily causing failure.

BTW: JE pistons for example have several pistons, "one 5 valve type fits all": 2001-2005 YFM Raptor 660, 2002-2007 Grizzly, 2006-2007 Rhino. This gives a reference what will fit.

Before swapping the top end, try to salvage the original parts. Might be a cheaper solution in the end. Look around in this forum, the 700 has 4 valves, symmetrical intakes, so it might be a cascade of trial&error and a lot of different/new/expensive parts.

[Srinath]

Perfect sir I will stay with 660 parts. The 5 valve is a cool feature IMHO in a single. In a 700cc 4 cyl like my maxim X, not quite.

OK Now the thing may not have been lean ... it may have been too rich.
The reason it may have galled ... well I dunno, I am still working on it. I hope I didn't burn a valve though. I may have run it with a tight set of valves ... although I do have clearance, not 0 when cold.

OK so I'll get into it in a few days.
Cool.
Srinath.