Hello Andy and Charles!! Nice job on this Forum, looks great !! Kind of makes me jealous Anyway I thought I would give you guys an ask about this...came across a nice set of NX5 RS250 cylinders(barrels) in very nice shape for a nice price. Do you guys think it would be worth picking these up and trying to make them work on my MC28 engine? I would like to use the stock NSR pistons and cylinder heads for reliability. Do I need to modify my case beyond recognition and just wondering if this conversion would be worth it or would I be better of with the Tyga300 kit or a Eric Gorr 268kit?? Just curious....still thinking about this myself and would be glad to hear some input from other NSR riders about this too, thanks !!
Jamie

Jamie,

Fist - Thanks for stopping by, and the good words on the look of the forum. I spent a little time getting the look to fit in line with the NSR-WORLD look, and I think it came out nice.

As for the RS250 barrels, I will leave that answer up to Andy... the more technical one when it comes to internal engine thingies. I basically just start and ride my bikes :)

Okay, I have done a full engine build with the help of a friend, and I can rejet my race bike pretty quickly when I am not dropping bolts into the intake manifold, but major mods... I simple stick to as stock as it can be.

Thanks,
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Charles Gallant

Hello Jamie,

First, let me say thanks for dropping by, and for the kind comments on the new forum.

How does this look to you?! :D



This motor is basically what you are interested in doing, and shows that it is possible.

All I can say really, is that the benefit of using RS cylinders is really the "WOW!" factor at the local bike meet! There are some technical benefits, such as closer tolerance of the RC Valve components, but on the street it's more of an exercise in "I told you it could be done"!

If you were racing, then you would notice more benefits. Again, the better (more efficient) RC Valve clearances and the rod actuator set-up make setting much more accurate, and the central (vertical) spark plug location is ideal for combustion. The porting is largely irrelevant because the NSR barrels can be ported to match the RS anyway. Of course, these modifications wouldn't be legal in most race classes anyway!

The barrels will need a little machining to make sure they fit the NSR cases, and you will need to measure the crown height of the NSR piston against that of the RS piston, and then machine the heads accordingly. The NSR heads will not be compatible with the RS cylinders.

Don't get me wrong, if I had a set of RS cylinders, I'd too want to get them on my NSR cases, just to say I'd done it, but it's not a simple job. Compression ratios and head volume alone will be a job in itself to get right as don't forget, there won't be any official spec's out there for these figures! It's a very specialist job!

Regards,

Andy.
NSR-WORLD.COM

I think the main question for me is this...

Was any machining done to the cases?

Cause in the club that I run in, that is all that matters to keep the bike legal for Super Bike racing. This is how the TZR get away with (cheating, I mean) using the TZ engine parts.

So if I could somehow get a full RS top end, onto a NSR bottom end without touching the cases, except for a little porting and cleaning work, then all should be okay.

Thanks,
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Charles Gallant

The bolt pattern on the base of the RS cylinder is the same as the NSR, so in that respect, any machining of the cases could be argued that it was entirely for performance purposes, not for fitting of the RS cylinder... er, technically!

If I remember correctly, the base of the cylinder needs to be cut to clear part of the casing, but I will make some enquiries to find out for sure.

Watch this space!

Andy.
NSR-WORLD.COM