Costin - YZR500 1990 Rainey bike

[Ax-Racing]

Engine is amazing too
great machine Mick !!!!

[Ronnie]

Someone over here must have lots of money to spare! What's their plans for it? Expebsive toy for a track bike. It wiuld be some road going machine as well.

[RC45]

RZ500 cylinders with a stage 3 tune. 3ma SP heads which are sadly no longer available form Yamaha. I had a mate look long and far in Japan to find these. They fit almost perfectly with the stud holes and cylinder bore lining up perfectly. I had to weld a little material on the inlet side to match the cylinder and also had to grind away some of the material surrounding the water jackets to match the flow of the cylinders. Not to difficult just time consuming.

The bike is for a customer in the UK. You pommies certainly love your 2 strokes!!

Not sure on the weight but it is very light. I made the frame and swing arm with slightly thinner material than normal because it has internal bulkheads and is heat treated after welding. I made a lot of parts out of titanium and magnesium so I am hoping for around the 130kg mark.

Cheers
Mick

Sounds great. What bits did you machine from magnesium? I was hoping to try triple clamps, rear sets, wheel spacers and even fork legs - but I wasn't sure if civilian sourced magnesium billet stock was strong enough to do the job. I imagined the factory used forged magnesium for their odds and ends.

I already have magnesium wheels, brake calipers and throttle and a myriad Ti fasteners and rear brake rotor.

I imagine the Ti exhausts you have welded up also account for a substantial weight savings. HAs the bike got Ti axles as well?

[Tommy36]

This bike is stunning!! Great work as usual. My bike is on its way to the painter any day now. Thanks again Mick for fullfilling my 500cc dream.

//Tommy

[Mick C]

Top triple and footpeg brackets are AZ31B magnesium. The oil pump cover is cast in magnesium in a similar casting grade. I am not sure of what grade magnesium Yamaha would have used but I have some original YZR triples and footpeg brackets and they are machined from billet magnesium and not forged.

You will be okay making your parts out of AZ31B but I wouldnt make wheel spacers out of it. It isnt that hard and will scratch easily from sliding an axle in and out, loading up the spacer may also cause the thin walls to buckle. Most YZR's that I have seen use alloy for the wheel spacers and have them anosided light blue, red or a beige/gold colour.

Its got Ti axles which are a nightmare to bore out. The pipes are steel as I dont think they used Ti pipes in 1990?!?!?!?

The guy who bought the bike is planning on just a ride/track day bike and no street use.

And Tommy I have seen pics of your bike and it is looking great. Cant wait to see it finished!

Cheers
Mick

[Ronnie]

Must be great to have that sort of spare cash to get one built!

What happened to the NSR500 you building with the RD500cc up to 750cc Stan Stephens engine? Heard nothing more about it.

[alexander]

nice replica.

[aaronmvrider]

very tasty...

[racer38]

Great work Mick, but what's the paddlock thought the rear brake disc for?????

[Mick C]

Sorry guys went away for a few days...

The NSR is at rolling chassis stage with engine and bodywork fitted. Just waiting on a few things from the owner and Ill be putting a seperate post up with that build . Stan reckons 150HP will easily be achievable so need to start looking for someone who can ride it better than me....

Paddlock is just me being paranoid...

Im back at factory on Wed and Ill post some updated pics of the exhaust and new radiator mounts. Hope to start it next week.

I bought some rollers recently cause my spine is starting to curve to the left with all the pushing, jumping on then off and pushing again

Cheers
Mick

[hybrid]

Looks great Mick... gotta come see you for some of those fairing clips soon!

I'm away for a week from this weekend, but I'll organise to come visit some time after that if it's OK.

[Ronnie]

Great to hear about the NSR coming along. Be good to have a separate build for it. Is it still a 750cc and has the engine been running yet?

[Mick C]

Anytime Jeff, just drop me an email first to make sure im there...

The NSR is using 4 x RZ350 cyls and Stan bored them out so I thinks its about 770 or close to it. I havent had it running yet. To be honest I havent really had a good look at it as Im trying to get rid of the back log beforehand. Its been engraved with HRC on the heads and ignition cover so it certainly looks the part


Cheers
Mick

[RC45]

Mick, if you still get around to visiting here please drop me a PM. I think the answer to my current dilemma is going to be one of your frames.

Does anyone know if the phone/email at the Costin Engineering website is still good?

Thanks,

Paul

[RC45]

No luck getting hold of Mr Costin. Either by phone or email, hope he is still in business.