Costin - NSR500 1994 Doohan bike

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Mick C
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Costin - NSR500 1994 Doohan bike

#1 Post by Mick C » Thu Oct 15, 2015 6:07 am

Hi Guys,
While im waiting on a replacement piston for the Rainey bike im back into this replica of Doohans 1994 NSR500. It uses the RZ500 engine as a base so even though its a Honda replica I still reckon it belongs on this board.... Stan worked his magic on the engine and has fitted 4 x RZ350 barrels which he has tuned to F3 spec. Heads were cut in half and welded up. Dual manifolds are used so only using 2 Carbs from an NSR250GP bike. The engine came to me with no powervalves but the customer really wants them so I have had to put them back in. Ill be posting more pics up in the next few days as its about 75% finished...

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Cheers
Mick

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Ax-Racing
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Re: Costin - NSR500 1994 Doohan bike

#2 Post by Ax-Racing » Thu Oct 15, 2015 7:48 am

interesting project, Mick

could you tell something more about crankshaft ?
Alex

Mick C
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Re: Costin - NSR500 1994 Doohan bike

#3 Post by Mick C » Thu Oct 15, 2015 8:49 am

Hi Alex,

I haven't pulled the engine apart yet as im still building the pipes and finishing off the electricals. Once their all done I will strip the engine, fit the new shaft and dry clutch and put it all back together. Ill have a good look over everything then. Cant wait to ride it though, the Rainey bike was fast enough, cant imagine what this will be like..

Cheers
Mick

vin97
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Re: Costin - NSR500 1994 Doohan bike

#4 Post by vin97 » Thu Oct 15, 2015 12:46 pm

that looks interesting

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Speed Freak
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Re: Costin - NSR500 1994 Doohan bike

#5 Post by Speed Freak » Thu Oct 15, 2015 1:45 pm

Interesting engine.

There will be ~150HP+
Is the RD500 gearbox ok for this power?
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

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nzminis
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Re: Costin - NSR500 1994 Doohan bike

#6 Post by nzminis » Thu Oct 15, 2015 3:12 pm

that motor is crying out for fuel injection

looks real nice :)

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WVWRZ500N
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Re: Costin - NSR500 1994 Doohan bike

#7 Post by WVWRZ500N » Thu Oct 15, 2015 3:37 pm

I've stated this on multiple accounts, good luck tuning it with a single carb feeding two cylinders. Oh it'll run but never to it's designed level of performance. Each cylinder demand is drastically different when getting it dialed down properly.

Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net" onclick="window.open(this.href);return false;
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com
Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

Mick C
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Re: Costin - NSR500 1994 Doohan bike

#8 Post by Mick C » Thu Oct 15, 2015 4:58 pm

Not sure what the end HP will be. If it makes 150 then that would be great but I think 130-140 is maybe more realistic. Stan has done a heap of RZ350 tuning over the years with very good results so heres hoping. I think gearbox will be fine.

As far as 2 into 4 carbs go, this will be the first time I have used it on one of my bikes. Stan has done it a few times and has had good results. So I guess the verdicts out till its up and running. Only bad thing so far with the carb setup is that its closer to the front wheel than id like so may need a little re-working..

I built a 535cc cylinder RZ350 a few years ago and that was the fastest 2 stroke I have ever ridden on the road (and the scariest)!!! Im hoping this scares the crap out of me even more!!!!!! :grin: :grin: :grin:

Also this one is going to the UK as well...bloody pommies...

Cheers
Mick

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Smoker
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Re: Costin - NSR500 1994 Doohan bike

#9 Post by Smoker » Thu Oct 15, 2015 7:17 pm

Thank you for your part in this awesome project.

Very inspirational for small-time builders like me. :smt006

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Re: Costin - NSR500 1994 Doohan bike

#10 Post by Rufus » Fri Oct 16, 2015 2:17 am

Smoker wrote:Thank you for your part in this awesome project.

Very inspirational for small-time builders like me. :smt006
Smoker, your work is so very far from small time....time limited maybe but that appears to be the end of it.

Mick C
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Re: Costin - NSR500 1994 Doohan bike

#11 Post by Mick C » Fri Oct 16, 2015 6:51 pm

Hey Smoker, lovin your streetfighter. especially the titanium...keep it up

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Re: Costin - NSR500 1994 Doohan bike

#12 Post by Mick C » Fri Oct 16, 2015 7:49 pm

This is the frame for the engine....

I have made it as close to the original as I could...only major limiting factor when building a replica frame like this is the mounting points of the engine. Obviously the RZ500 motor has completely different mounting points compared to the NSR500 motor. The front engine hangers are noticeable smaller. the spars have an additional fold in them to get them wider (coming from the pivot plate) for the extra width of the NSR500 engine. This worked out good because the RZ350 cyls and heads are a lot longer and I needed the extra width for clearance....

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Cheers
Mick

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hybrid
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Re: Costin - NSR500 1994 Doohan bike

#13 Post by hybrid » Fri Oct 16, 2015 10:12 pm

Looks great Mick.
Very interested in what's involved in fitting those 350 cylinders and heads. If I ever have issues with my cylinders I would love to move to RZ cylinders, even if just to future proof the engine a bit.
The RZ500 is 50mm stroke normally, and RZ is 54mm stroke, so I wonder how he overcame that. He's used spacers too, so maybe a longer rod in there.
I can't imagine the 350 crank could be used out of the box.

And whoever asked about the gearbox. It should be more than enough to handle the power.
Aren't they pretty much the same as one of the 1000cc bikes?

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Re: Costin - NSR500 1994 Doohan bike

#14 Post by jackson.40 » Sat Oct 17, 2015 8:01 am

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racer38
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Re: Costin - NSR500 1994 Doohan bike

#15 Post by racer38 » Sat Oct 17, 2015 2:04 pm

Looking like it's going to be an awesome replica, if the Rainey bike's anything to go by. As a lover of all things Honda GP (own 2 NSR250s & 2 RS250s) can't wait to see how it turns out. Shame they never made a V4 replica. Good luck!

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