Interesting, I hadn't seen this info on nsr-world, which is where I've got most of my knowledge so far (I'm new to nsr's). Tucker - Yeah I've stumbled across his NSR blog and conrods.Originally Posted by Neal
Fair weather rider
Interesting, I hadn't seen this info on nsr-world, which is where I've got most of my knowledge so far (I'm new to nsr's). Tucker - Yeah I've stumbled across his NSR blog and conrods.
Forum whore
Yes to all those questions
"more than two strokes is masturbation"
www.motoparts-online.com
Forum whore
A 21 crank any good to you?
Moped rider
They don't like to give out that kind of info because it is part of their business . They won't sell you crank bearings either .
Fair weather rider
Yes, I was thinking about just getting a 21 or 28 crank and modifying it to fit.
Forum whore
I am unsure of the specifics of NSR cranks, but like has been said, there are plenty of options available round the place for rod kits (meaning rods, shims, big end bearing and crank pins).
Mr H is well known for not supplying rebuild kits for his 2 strokes, so experienced people have done the work for you there.
You seem really serious about the rebuild (opposed to a can of spray chrome and polished top yoke as many do), so a word to the wise is to rebuild your crank if at all possible, as if you fit another one, it is of unknown anything, and will likely bite you in the ass sooner rather than later (in any event, if you have to machine the webs to fit a later model one, it will need splitting anyway, and you 50% there at this point.
I appreciate you may be unable to do the crank yourself, but a competent machinist should be able to do a twin cylinder 2 stroke crank in about 2 hours (if they speciaise in certain models, dramatically less sometimes)
Ideally, the kits people use for early (pre 95) Honda RS125's would be suitable, (actually designed for 1988 till 2004 Honda CR125's as they are crazy cheap, easily available and a truly well known set up.
My opinion is that you may want to visit a helpful machine shop and take you crank to show them, if you cant find a bike specialist, I suggest someone that does Jetskis would be a good bet, as this boys are VERy experienced in crank rebuilds for high output 2 strokes.
Best of luck, oh and be careful what you read off the net too!
Moped rider
The problem with the old rs and cr rods is that the pins are 22mm and no use for the nsr cranks unless there is serious modifying done .
The pins on the nsr webs are all one piece .
Forum whore
Same same with TZ250s, a shit set up I recon.
Whats stopping someone machining the webs to suit replaceable pins, I have machined several to suit larger pins over the years, is there the possibility of boring the cast pin out/off and machining a slug to suit (what I assume is a smaller pin for the CR/RS rods), meaning you now have a rod set up that can be rebuilt as and when it is needed?
Moped rider
The problem is on the rhs of the crank there is not enough metal around the pin and when a new hole is made for the pin it could split the web .
Rods are not the problem , there are 2 or 3 choices if you are willing to improvise etc , it's the seals that are problems for the early cranks .
Long Haired Yobbo
It's about know I'd be giving up and turning it into a bucket.
I know that sounds like shit stirring but it is seriously a good point in time to pull the plug if it looks like it's going to bleed you real bad.
Heinz Varieties
Forum whore
What about simply machining the new pin smaller (on the ends where it meets the web, not where it runs on the bearing) to suit the existing web size......lots of early 2 strokes did this, (called a stepped pin) and an advantage of this is that they are easier to assemble, as the webs only press on the pin as far as the pin is machined to size, and if that's correct truing it up is way way faster than a conventional (unstepped) pin.
Forum whore
It may be because I'm a thirty something, but writing off 250 jappa 2 strokes is a sin in my book, they are real collectors bikes now, and i think worthy of saving, just so long as you are aware it's for the love that you do it, not profit!
Fair weather rider
I'm certainly not writing this project off! Yeah it's going to be an expensive build, but at the end of it I'll have a like new NSR to enjoy for many years. As for the engine, the crank is really the hardest part to obtain/rebuild. Once thats sorted everything else is pretty easily obtainable.
Oh, and great discussion guys. Lots of good info to take onboard.
Fair weather rider
There's an NSR guy in south africa who was going to rebuild a crank for me. Unfortunately he didn't have enough usable parts to rebuild one in the end. However, he's working on a prototype crank that will accept replacement pins and different rods with a larger big end, so it will be completely rebuildable. Hopefully it works out well in his test bike.
Forum whore
It' only money and you can't take it with you. NSRWorld are idiots. Do you need an English workshop manual?
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