Hi All,

1stly, I am new here. I have had a look through the posts but don't seem to find and info relating to my topic.

My reason for wanting to do this is I am building a super single race bike, Honda 500 XL motor in the MC18 chassis, and it's difficult to find race rubber in the stock 18" rear wheel of the MC18. I have got my hands on the rear end of a MC21 which includes the swingarm, axle, caliper and wheel.

I'm keen to know if this is going to be a straight swap or not. My initial measurement show the MC21 is about 5mm wider the the MC18, but the MC 18 seems to have more than that in excess space. Would it just be a case of swapping spacers etc? Has anybody done this before?

why dont you just put the 17inch wheel in if its just for tyre choise ?

id take the mc18 arm off and put it up against the mc21 arm
use the chain run marks on the chain guide on both the arms to see where you are
obvious you need to use the 18 arm as a template
then you will know where to take any metal off the pivot end of the 21 swingarm
if you can do that spot on it should be just bolt up and done as long as the suspension
mounting points are the same on both bikes and 18 shock is same length as 21 eye to eye
they look pretty much the same just looking at them
hope this helps

Thanks for the info and advice - much appreciated. I know I could just change the wheel, but that gullarm just looks so much tastier as well, and I have it..

Will upload a pic once the swingarm is in.

checked last night how the space is for the motor, going to work like a charm!

Aaaaagh! You will go to hell for that

[/quote]

its your bike and your choice mate
but your a bad man ! lol
good luck with the horrible thing

I bought only the rolling chassis guys, no motor etc, so I could build my race bike.

Another one here already on the track with exact same motor and frame look like this.

You won't find many interested here in a 4-stroke conversion!

Feel free to ask about the chassis etc., but please don't waste your time with more photos of thumpers on here.
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Andy.
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I was under the impression that super singles was a 450cc class mainly targeted at 450cc motocross engines. I don't see how a 500xl would be anywhere near competitive in that class?

That looks quite a tidy little conversion actually.

bundi wrote:

Each to there own I guesse.
At least it's part nsr but I'll always be a 2 banger addict, not diesel.
Looks pretty cute though.
Daz
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stink wheels forever.

it does look good ,as said above id be after allot more modern motor than An old xl500 engine
mind you if you allready have one why not use it , at least its all honda !
id better not mention what im going to do with some of the nsr stuff ive got

If you want to continue this thread, I will move it to Open Discussion.

The NSR250 Discussion is for exactly that -- not 4T discussion.

Thank you.
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Andy.
NSR-WORLD.COM

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I'd be interested in how you get along with mounting the 21 arm in the 18 frame.

Any one know which linkage is best suited for this swingarm swap? stock 18, HRC 18 link plates or stock 21 linkage?

It's really going to be a try it and see kind of thing, and report (if you want to!) your findings!

I've seen an R5K with a Gull-Arm, and it worked well, although did look a little high on the back end. Unfortunately, it was about 15 years ago, and I can't remember if it was using an MC21 or MC18 rear wheel.

A member on here tried to fit a Gull-Arm to an R6K a few years ago, but complained of the same issue, but never got round to fiddling with different dog bones, link plates, and wheels, and just reverted back to the R6K arm.

I've seen photos of an MC16 with a Gull-Arm too, but again, can say nothing more than it has been done in the past. Certainly, no-one that I know of who's currently active on the forum has done, or attempted it.
_________________
Andy.
NSR-WORLD.COM

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Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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