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 Post subject: Engine life
PostPosted: Thu Jul 23, 2009 5:36 am 
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Joined: Sun Aug 13, 2006 9:00 pm
Posts: 22
Location: Austria / Hong Kong
I'm currently looking at buying a NS400R, but I wonder at how many km these engines need a rebuild.

Do any of you guys ahve experience with this and are parts for the engine, e.g. pistons still available?

Any info would be highly appreciated.

rgds rd_waeldar


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 Post subject: life of the engine
PostPosted: Fri Jul 24, 2009 8:31 pm 
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Joined: Wed Nov 16, 2005 7:49 pm
Posts: 395
I have two of them and I think they are great bikes, but there are no more crank kits available, no rods, maybe pistons. I had an engine that needed a rod. I try to get a crank kit from Japan not available any more. Karl from RG500.com found a use engine from Japan. They are fairly cheap and he did a reseal and I'm fine with it. They are great bikes.


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 Post subject: Re: life of the engine
PostPosted: Sat Jul 25, 2009 12:07 am 
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Joined: Fri Oct 28, 2005 10:53 am
Posts: 1308
Location: Temecula, CA - USA
giron wrote:
.... but there are no more crank kits available, no rods, maybe pistons.

Gus....?? :cool:


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 Post subject:
PostPosted: Sat Aug 08, 2009 9:20 pm 
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just for the heck of it how many were made and are they as popular as the RZ or more, I was a Yamaha guy forever I know Mark at GP Customs has a motor on the bench I believe


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 Post subject: NS400r
PostPosted: Tue Aug 18, 2009 6:57 pm 
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Gus, I was bench racing one time with Ken Smith. He said that the NS400R sat in showrooms brand new up to 1981 because no one wanted them. I can find out the total production numbers if you still need them.


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 Post subject:
PostPosted: Sat Aug 22, 2009 8:37 pm 
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yea I was wondering their numbers compared to the RZ/RD 500's


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 Post subject: NS400r
PostPosted: Thu Sep 10, 2009 3:32 pm 
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Gus, I would say less NS400R than the RZ500. You can still get parts for RZ, RZV, RD500, but the NS400R good luck. They're still great bikes :)


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 Post subject: NS400R
PostPosted: Thu Dec 02, 2010 8:09 am 
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Joined: Fri Oct 29, 2010 5:43 pm
Posts: 73
Giron I surely agree in that :grin:

I have several NS400R's, they rides great and are nimble and have very good build quality. Std engine will put out around 52 RWHP, but still it is pretty fast. Do some minor changes on airbox, carbjetting and gut the pipes and change for modern silencers, you get around 60-62 RWHP. No it is a flyer, revs to 10500 rpm and weigths in at around 153 kg dry. You save over 10 kg of weigth by doing the pipe gutting.
If you are planning an engine rebuild, go for race tuned ports, new squish, O-ring heads, big carbs/reeds and Jollymoto pipes. This mods bins the ATAC, but you now have 80-85 RWHP.

The engine is rather good, and the Nicasil coated cylinders wear very well. On my racebike they have in fact survived several crank/piston failures, without damage.

The culprit of this engine is the heavy, not properly balanced flywheel. This cause the left main bearing to come loose on the web, and soon all the mains will be spinning on the inner rings. This can be overcomed by machining a ligther flywheel to fit.

Racer

_________________
ESW Rotax 250 racer, Kawasaki S2 350,
Yamaha RZV500R, Honda VFR400R. NSU Prima D 150 cc 1957


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