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Maintaining MC18 crank


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FruitLooPs

 
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Maintaining MC18 crank

Sat Aug 30, 2008 11:10 pm » Post: #1 » Download Post

Hey guys, I see for the MC21's the Tyga rebuild kits come with a whole crank as well as the seals etc.

My MC18 has an unknown history, was a race bike so its pretty sure bet its had a thrashing. I've read on another forum there is a source of bearings for the MC18 cranks now.

So what should I do to stop my crank going belly up since finding another would be a nightmare i should think? Its currently fine not making any bottom end noise but i'd be hesitant to take it out racing for too long like that Smile
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dunkenb

 
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1989 Honda NSR250 MC18
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Sun Aug 31, 2008 11:00 am » Post: #2 » Download Post

my 18 r5k has a 21 crank in it, the counter weights have been machined so that it fits in the 18 crank cases( the 21 crank is 3mm bigger). working ok so far done about 600miles on it!
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FruitLooPs

 
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Sun Aug 31, 2008 10:54 pm » Post: #3 » Download Post

Ok cheers for that,

would a solution like that be suitable for the R2J 1988 engines?

Also can someone clarify if you can rebuild an MC18 crank with new bearings and have it pressed apart. Everywhere says no, except the source of bearings comment i wrote in 1st post and an Ebay auction from an ex racer.

And I quote

"honda nsr250 mc18
i have loads of spares from when i used to own them.

people are under the opinion tha you cant split this cranks and that you cant get the bearings,rubbish i rebuilt several cranks for less than £50 all bearings and balancing ect."
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Andy
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Sun Aug 31, 2008 11:18 pm » Post: #4 » Download Post

£50? That's probably why he's had several rebuilt! Rolling Eyes
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FruitLooPs

 
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Mon Sep 01, 2008 1:30 am » Post: #5 » Download Post

So we can surmise it's a load of bollocks, whats the official word on them Andy - non rebuildable, but you can adapt more recent cranks to fit the cases Smile

sounds alright
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fontyyy

 
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Mon Sep 01, 2008 7:14 am » Post: #6 » Download Post

Indeed the official Honda line on all NSR cranks is non rebuildable.

But clearly that's rubbish, anything that's been put togeather can be taken to bits, the problem is aquiring the bearings, the crank is "just" pressed togeather like any other similar two stroke crank.

As for fitting a crank from another NSR, I'm sure with enough machining it's totally viable.
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FruitLooPs

 
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Mon Sep 01, 2008 10:03 pm » Post: #7 » Download Post

I messaged that Ebay fellow, and he got back to me with this:

"yes i used a local crank building company who charged me £15
bearings thought bml (bearing man ltd ),£8 each, and seals from the same company, so yeah it was not expensive"

I think he's in hereford.
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caboking

 
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Mon Sep 01, 2008 10:14 pm » Post: #8 » Download Post

Hi peeps can i just say that i have had my crank for my R5k rebuilt and i have done about 130 miles so far without any problems. I phoned around alot of places and even stan stephens wouldnt touch it but he gave me a number for Chris Appleby, I think he's in essex but cant remember for sure.

Anyways heres his number = 01268 776642

crank cost me £430 all in inc postage and took roughly 10 days from start to finish and turns out he does all stan stephens multi cylinder crank rebuilds so thats all the RGV's TZR's RD's KR1S you get the drift. Very expensive but he knows his stuff and sorted it with out any problems at all, he told me he has done loads of them.

for the £430 it was totally rebuilt with new rods and bigends new center seal and bearing and both outer mains also. Hope this helps
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mike1972

 
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Tue Sep 02, 2008 8:49 pm » Post: #9 » Download Post

i had my ns400 crank rebuilt by sep in kegworth, cost me £330 inc all bearings ,also the shaft welded and re ground where the old bearings had made a groove in the shaft, it was pretty much scrap when i sent it to them , took them 4 weeks to do it , they will rebuild all two stroke cranks
like its been said anything can be rebuilt
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