Costin - NSR500 1994 Doohan bike

[Mick C]

HI Guys,

Been a while. Theres been a small delay with the dry clutch kit, which has worked out good in that it gave me a bit of time to make a completely new pattern for the dry clutch cover...the existing pattern was an original RZ500 cover just cut and shut, welded and slightly increased in size. It worked fine but I was just never happy with it so I made this one....it is at the foundry now so I should have a prototype cast in the next day or so..





Cheers
Mick

[PilotMarky]

Man, I want one of these!!!!

[Ax-Racing]

great idea Mick

[Mick C]

Hi Guys,

Just picked up the aluminium castings...really happy with them. Ill machine them up when I get the dry clutch kit.

Im going to send the pattern off and get one made in magnesium. I prefer the darker look than the lighter aluminium plus Honda always used mag for their clutch covers...

Cheers
Mick

[Smoker]

I'm really amazed, because I've rarely seen this kind of one-off work - and I've seen a lot of custom bike builds!

Could you give any info about what it takes to make the pattern and final part, and also why you chose this method over CNC machining the part from billet stock?

Thanks for inspiring me to get off my ass and do more work!

[Vin]

Great job Mick

A lot of effort mate but going that extra yard makes massive differences in the end to the over all look, I'm looking forward to seeing the end result

[Mick C]

It was an easy choice to use a casting because its what the V4 500's used for covers...also I actually enjoy making patterns. I don't have a CNC machine and I really hate out sourcing parts because in the past I never get back what I need.

I didn't take any pics while I made the pattern. Its fairly simple just very time consuming, especially getting a perfectly smooth finish.

The base is basically a 4mm clutch cover gasket cut with a jigsaw out of MDF. It is about 1.5% bigger than the original to allow for shrinkage during casting. There are a heap of 10mm dowels which I nail into the base which will be where the mounting bolts go through. There are 2 larger dowels for the locating dowels. Then a piece of 2mm MDF sheet which is cut to the shape of the face of the cover is nailed to the top of the dowels. The sides of the cover is filled using timber for the straight edges or O temper aluminium for the edges with radius. The aluminium is much easier to curve and bend to shape. These pieces are glued in using PVA glue. The 2 boses for the cranks are machined on the lathe out of solid bar on a 2 degree taper. they are 2mm thick. these are capped with 2mm MDF glued. The boss for the oil filler is just 20mm dowel cut on an angel of about 45 degrees and glued in place. The real time consuming part is using filler to get it all smooth and make sure that EVERY corner has a generous radius and all the sides and vertical surface's have to have a taper which helps when the pattern is pulled out of the sand. I would guess the basic shape took about 1 week to make but I probabally spent another 3-4 weeks filling, sanding, filling , sanding etc to get the draw and radius right and getting it smooth.

Next time I make a pattern Ill take some pics which will make it easier to understand...

Cheers
Mick

[Smoker]

HOLY SHIT!!!

Incredibly fantastic fabrication.

You should have a You Tube Channel, or a website where people can watch you make stuff. There can be big money in that. Thanks very much for sharing!

[skunkworks]

man mick you sir are an artist...cheers

[Mick C]

Finally finished the long term NSR500...its on the slow boat to the UK.
Theres a few more pics of my web site and facebook

https://costinmotorcycleengineering.com.au/" onclick="window.open(this.href);return false;
https://www.facebook.com/Costin-Motorcy ... =bookmarks" onclick="window.open(this.href);return false;

Cheers
Mick

[Mick C]

Thanks Steve for the headsup on the picture hosting site...heaps easy

[Mick C]

Few more pics...

[RC45]

Very nice.

Is this the 700+cc RZ engined NSR replica?

If so, how does the over sized RZ motor run?

[Mick C]

yes mate, its the RZ350 cylinder bike...ive had it running quite a bit, although Ive only ridden up an down the local street. We need new manifolds which angle the carbs off about 45 degrees to either side to give a little more clearance for front wheel. The wheelbase is the same as Doohans so I don't want to alter that otherwise we loose the authentic look of the bike. Changing the manifold will give us all the clearance we need. That will be done once the bikes in the UK..

It runs quite well and revs really crisp...the lowers seem to run a little richer than the tops but that's only an observation from a short amount of running the bike.
When its being tested ill make sure to post results cause the 1 into 2 seems to have a lot of interest

Cheers
Mick

[RC45]

Is this with the shared manifold, 1 carb between upper and lower cylinder pair?

If so, lowers running richer makes sense, I believe Bill Wilson may have raised the point of gravity favoring the lower cylinder with more fuel.