Hi there,

It's Steve Rothwell here from The Two-Stroke Shop in Australia. The thing is, we are chasing parts/info for the NSR500V - as we are trying different needle/jet setups in Keihin FCR 39mm carbs on our twin-cylinder 500cc two-stroke production bike, the RS500GP: http://www.twostrokeshop.com/Aprilia_RS500_2008.htm

We reckon the needle profiles of the NSR500V would be pretty close to what we will end up running ... so we are looking at getting some leaded and/or unleaded needles for the NSR500V - or even if we can get some part numbers, that would be a start. We figure that someone on this 'ere forum will have an NSR500V parts book - hopefully! )


Many thanks,
Steve Rothwell
_________________
The Two-Stroke Shop
www.twostrokeshop.com

9 Compass Close, Edge Hill
Cairns, Queensland 4870
Australia

Tel. (In Australia): 0427 774 285
Tel. (Outside Australia): +61 427 774 285

Steve,

If no one on the forum has this, which will be a pretty rare item, you could try contacting Padgetts Motorcyles in the UK (Dewsbury, West Yorks).

They are an official HRC shop, and their race team used to run the NSR500V. They still have one in their showroom!

http://www.padgetts-motorcycles.co.uk/12997/contacts.htm

By the way, that's one heck of a Engineering project you guys are running
_________________
Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30

Allens might be worth a try:
http://www.allensperformance.co.uk/index.html
Lot of specs and info on their web site.

By the way, that's one heck of a Engineering project you guys are running

Dito what Rich said

Hello Gents,
Thank you kindly for the useful advice, much appreciated.

Update: A member did email through to me a manual for the 2000 model NSR500V - and we are much obliged to him.

The 2000 bike ran unleaded, so now we just need to get the earlier (pre-'9 leaded needle numbers. If anyone out there has the manual for the earlier bike we would surely be most grateful for the info.

Tried calling Padgetts but Clive and Bill are at the Belfast Motorcycle Show, they will be back Tuesday mind.


Gosh you blokes are helpful!



Many thanks,
Steve Rothwell


The Two-Stroke Shop
www.twostrokeshop.com

9 Compass Close, Edge Hill
Cairns, Queensland 4870
Australia

Tel. (In Australia): 0427 774 285
Tel. (Outside Australia): +61 427 774 285
_________________
The Two-Stroke Shop
www.twostrokeshop.com

9 Compass Close, Edge Hill
Cairns, Queensland 4870
Australia

Tel. (In Australia): 0427 774 285
Tel. (Outside Australia): +61 427 774 285

We are a helpful bunch, which is why I said you need to make the engine mount for the NSR, rather then that Aprilia thingy..

Can't wait to see some more video's of the bike running. Sounds like it's getting real close now.

Hehehehe shmokica, Your pointedly pointed point is well taken.

We would love to be able to launch conversion kits for the NSR as well but the amount of R&D involved in the RS conversion - and I'm talking about engineering to beyond OEM standards now - is staggering and took the best part of a year to see through.

Initially we selected the Aprilia RS250 as the most suitable platform purely because it has the strongest chassis of all the 250 reps, and is therefore well up to the job of handling the extra torque and horsepower. And because we like the look of it, and because our wives allowed us to play in the workshop so long seeing as we were working on 'An Italian Exotic' and because we bribed them with Italian handbags and such.

But seriously now - the other big reason for selecting the Aprilia RS250 lies in the fact that the chassis remained unchanged throughout the model run. Therefore we could develop an engine mounting cradle/offset sprocket/modified shock rocker arm & dogbones setup that does duty for all year models. Sweet.


You blokes are the experts on NSRs so tell us, that we may make the first NSR500GP build feasibility exercises:

1): How much does the frame/engine mounting setup vary across the models, from MC11 to MC28? What I'm getting at is that it would be a costly exercise if we had to develop many different NSR conversion kits for the various models, if indeed the frame/engine hookup points varied considerably through the years.

2): How much room is there between the frame rails of the various models? We need to know this to figure out whether our parallel-twin can squeeze up in there ...

3): What is the most popular/respected of the NSR models? Which of the MCs would enthusiasts identify as the best candidate for the conversion?

4): Do any of the NSR frames have internal bracing, i.e. are they up to handling 112HP and 60 lb.ft. of torque?

5): What sort of mods are involved in fitting the HRC RS250R front end into the NSR chassis?


Just a few questions there; I apologise in advance for my lack of familiarity with the breed. I am just looking to get an idea on feasibility of fitting TSS500 power into any of the NSR250 models. Any and all suggestions are most welcome!


Best regards,
Steve
_________________
The Two-Stroke Shop
www.twostrokeshop.com

9 Compass Close, Edge Hill
Cairns, Queensland 4870
Australia

Tel. (In Australia): 0427 774 285
Tel. (Outside Australia): +61 427 774 285

Hi Steve, and welcome!

The MC11 is an NS250R, and a completely different motor design to the NSR250. All the NSR250 motors are based on the same crankcases, but the 1987 MC16 is solid mounted, and in the real world, probably unlikely to be chosen as a candidate for a 500 conversion.

The MC18 Mk1 and Mk2, MC21, and MC28 crankcases are all effectively the same externally, and all interchangeable. That means any NSR from 1988 onwards will accept any other years' motor.

The MC21 and MC28 are the most likely models that would be chosen to modify, as they have the greatest space between the frame rails. I have a couple of frames here and I'll measure one up for you in a moment.

The 88/89 MC18 and 90~ MC21/28 frames are based on the HRC RS250 NF5 frames of similar years. The casting isn't as heavy on the MC21/28 as it is on the RS, but the MC18 is pretty close. The MC18 is about 40mm narrower than the MC21 frame though. The front engine mounts on MC18 HRC frame were braced like the RS, but the mounts on the HRC frame for the MC21 are not, as the main frame extrusions are stiffer than the MC18. Again, the increased stiffness making the MC21/MC28 a better candidate for modification.

The RS250 front end fits the NSR very easily. It just needs a custom stem. I have a 1991 USD HRC NF5 front-end on mine now, and previously a 1990 RWU NF5 front-end on it. Both work exceptionally well on the NSR, and will fit right across the model range. NF5 RWU forks will slot right into NSR triples (both 41mm) if you don't want to use the alloy RS lower and also wish to keep the ignition switch in the OEM position. HRC magnesium Magtek wheels are pretty much interchangeable with NSR wheels across the entire range of both models. Even the RS Pro-Arm wheels from 1999 will fit the MC28, although they have to run backwards!

The MC21 Gull-Arm will certainly handle as much power as an Aprilia swingarm. Have a word with Matt at TYGA about the MC28 Pro-Arm, as to whether it's viable to run 100hp+ through one. He used to race a 75hp+ Pro-Arm'd NSR, so can speak from experience. The RS Pro-Arm is back-to-front, so it can't be substituted with a standard one.

As for choosing the Aprilia RS over the NSR, well you have one positive factor correct... junking that awful bloody Suzuki boat anchor of a motor! Preferring the looks though, is "in the eyes of the beholder"! The early "Romboni" ones, yeah, I can see it, but the later jelly mould ones?! Pig ugly!

I'll go grab a tape measure a moment, and let you know how wide the frames are.
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Andy.
NSR-WORLD.COM

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send me an engine and i will see if it fits mate
_________________
ive seen more tarts than mr kipling

Approximate dimensions, given the awkward position and the amount of other parts the frame is under!



MC21 & MC28:
Distance between frame rails: 260mm
Distance between lower rear engine mounts: 170mm
Distance between front engine mounts: 220mm
Distance between lower rear mount and front mount: 310
Distance between swingarm pivot and front mount: 340mm
Distance between front brace and rear brace/top rear mount: 335mm

The MC16 frame that's hanging up is 220mm wide between spars, and I am pretty sure the MC18 is the same as that.

Plenty of room for a nice compact modern V4/500!

Something that may be of interest too:

Martin77's NSR350D


_________________
Andy.
NSR-WORLD.COM

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Wow Andy, Thank you kindly for the avalanche of most welcome info! The best news is that our cylinder assy is only 223mm wide, so it will fit between the MC21 & MC28 frame spars with about a hand width either side! I was surprised there's so much room in there for what is a frame for a v-twin mill.

And given the YPVS lump has already been inserted into the NSR chassis, it won't be revolutionary engineering to do it again. Actually the YPVS motor is wider across the pots than the TSS, because of the jutting-out of the PV boss on the left cylinder.


Looks like a bit of rear shock linkage surgery might be required to the NSR in order to fit in the 123mm diameter belly of our 500 pipes.


Oh and I take the point that the jelly-mould RS bodywork is definitely 'approval subject to taste' - but the RS frame and swinger are pure muscular sculpture at its finest. It's a sin to cover it up with fairings I reckon, and at least one RS500 - mine - will be built as a naked bike. I want to cope an eyeful of the swoopy lines of the frame, and to see the bonkers engine. Inboard oil tank and rad reservoir ... lovely.

Agreed - the RGV motor is a proper rotter. Can't throw them out of the RS frames quickly enough. Our customers are certainly glad to see the back of them!


Oh just one thing, in case it's of interest to chaps on the forum, we have a friend over in Japan that orders parts direct from HRC for us (he's been away the last week, hence our original post on here) - mostly we buy new HRC RS250R forks - typically the 2002-on 43mm forks rather than the earlier 41mm forks. We do have a spare pair of new 43mm stanchions with fork bottoms/full damping mechanism, and fitted with bushes, seals etc if anyone's interested.

Many thanks,
Steve
_________________
The Two-Stroke Shop
www.twostrokeshop.com

9 Compass Close, Edge Hill
Cairns, Queensland 4870
Australia

Tel. (In Australia): 0427 774 285
Tel. (Outside Australia): +61 427 774 285

Steve, if you are interested in possibly becomming a Supporting Vendor and can offer a small discount for Titanium Members on parts, then I can set that up for you.

Offers (such as the forks for example) would be made through the Members Area as we don't allow commercial advertising (as we don't charge!), but we would include a banner link for you as we do Redline, TYGA, Race Lubricants etc. The guys in Australia and NZ are looking for somewhere/someone reliable in your neck of the woods for parts!

As for the shock linkage, that's always been a slight bugbear. Martin77 makes his own hydro-formed pipes so worked round it (I imagine his pipes are a little smaller OD for the 350 anyway), but the HRC pipes and some aftermarket pipes had a little "ding" in them to clear the linkage. It's long been accepted that a little modification may be needed to NSR bodywork to clear decent sized pipes though. The MC18 HRC linkage uses a narrow dog bone and "kinked" link plate on one side, which helps give about 20mm of extra clearance.
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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