NSR MC-21 seized

[wtf?]

gidday lads, just seized my NSR.

i have started pulling it to bits and found that where the gearbox normally holds 700cc of gear oil, mine had approx 1500cc, most of which was motul 2stroke synthetic. if its filling up the gearcase then im guessing its not going to the carbs/crankcase, hence the seizure. (there was still plenty left in the oil tank)

is this a known prob, and can i expect to be doing more than pistons/rings/gudgeons/small and big end bearings/crankshaft bearings and recoating the bores? these seem to be the obvious bits to me or should i start looking for another motor?

if you know a bit about these motors/where to get spares your comment would be appreciated,

thanks
richard

[Mr. Peanut]

Yeah, its the seal in the oil pump. Quite prone to failure. If you're having trouble finding parts let me know.

(Pray that your crank is OK ;) they are not rebuildable)

[nsrpaul]

peanut has it in one!!!! gota glue that seal in

[bumsex]

nsr cranks are rebuildable. Rick Porter will do the work (for a price) and bearings are available: I got two sets (for my mc18) from a guy in aus. He has gaskets etc too.

[wtf?]

thanks lads,

hey bumsex, id be grateful if you could post the contact details of those guys you mention in your post

[Crasherfromwayback]

(Pray that your crank is OK ;) they are not rebuildable)

Like bumsex says...they (and all two stroke cranks for that matter) are rebuildable. That's how the build them in the first place.....they're pressed together as they use one piece roller bearings as big ends etc...well lotsa pieces if you count the rollers! It's just that some dirty brands won't sell you the pieces seperately and expect you to rush off and buy a new crank assembly. Most 250 twins use similar crank bits to 125 mx bike cranks of the same family....in race bike applications like my old RS 250 Honda, they also don't belive anyone other than 'their guys' are capable of truing a crank to good enough tolerances for high rpm racing applications.....again...utter crap!:scooter:

[bumsex]

if you go to the website www.nsr-world.com and look in the classified section he has an ad there. He is not cheap but if you try honda dealers and they tell you that that part is unavailable try him. His name is dietmar shulz and is very good to deal with.
He has his own centre crank seals made especially cos I don't think that even he can get them. (they are good)

Do you need a new crank?
Sorry, I don't have his contact details at hand

[wtf?]

thanks alot. havent had a chance to see the crank yet, havin a big roster at work. im familiar with that site, so will check it out.


thanks again

[Mr. Peanut]

Yeah, Koyo bearings I think. Rarer than Hens teeth, (Honda doesn't stock cranks or bearings and I've cross searched for compatible parts.) If you can find em let me know (would really like some bearings!!)
I can get a crank for about $1200.

And good luck ;)

[vamr]

You probably have identified the cause of the seizure of your engine but just incase others looking for the cause of the effect here is a site that may help.

Piston Diagnosis guide (http://www.smellofdeath.com/lloydy/piston_diag_guide.htm)

[Tim 39]

Theres an NSR on trademe at the moment with spare bearings with it, it's becoming quite common to lunch the crank in them due to the age of them

[wtf?]

thanks tim, have already been talkin to that guy.