California Track Bike

[bikingbagga]

Hi Everyone

I live north of Los Angeles and yet I was born & raised in Maghull Merseyside.

I race vintage 2 stroke motorcycles in AHRMA which stands for American Historic Racing Motorcycle Association here in the US and I also ride track days at circuits like Laguna Seca.

The two bikes I have are a 1972 Yamaha Tr3 (Formula 500 class) & a bit of a mongrel I created & built that has all four Japanese manufactures Honda CB175 roller with Yamaha CT1 MX motor with Kawasaki ignition and a Suzuki clutch (GP 200 class)

My next project will be another creation for the Sound of Singles class AHRMA racing.

I bought a 94 Yamaha FZR600 (may have a different name in the UK) and a 87 KX500 2 stroke MX engine. The plan is to transplant the KX500 into the FZR600 with your help and input the vision is to develop a bike that gives me 100HP in a fairly modern road race chassis.

Time frame looking to get this on a track for trials by the end of February 2017. My local track is called Willow Springs which is about an 1-1/2 hrs from my house. In the US that's just around the corner.

Look forward to posting the progress and posing questions to you all

Regards

Rob

[henri]

hi n welcome , turnbridge road maghull was my junior stomping ground .H

[tzsteve]

hi rob

[bikingbagga]

Hi Steve

My plan is to post a specification and information I am gathering to come up with a plan to take a stock KX500 engine that was designed for 65HP and increase it to at least 85 to 100 HP. I would like to stay with the stock bore if possible

I'm assuming the following has to happen

Stroke the crank

Porting

Oversize piston

[Juan]

I'm not entirely sure this was the forum you intended to join but welcome anyway.

Initial thoughts are the KX500 is not really in a very low state of tune from the factory so finding another 30 brake or so could be difficult and certainly pricey if possible.

Secondly, we got the FZR, decent mid-weight bike of the time but not really the lightest rolling chassis either. If you've got it then fair enough but I'd have thought something like a Kwak KR1, Suzi RG/V, Yam TZ/R or Aprilla RS would be a better starting point for what you have in mind.

[tzsteve]

robs a nice bloke. i`know him from the bsso racing i think he already has a fast yam 350 or 500 not sure which.
but a nice bloke who`s nuts about FAST, FAST and FASTER

[bikingbagga]

KX500 aftermarket big bore kits can get you to 130HP granted with all the mods you are looking at $3,500

By removing the 4 stroke engine and replace it with a single cylinder MX engine the total dry weight will be significantly lighter. The FZR400 steel delta box frame with 17" wheels and upgraded suspension should make it a very stable track bike

Everything is always on a budget so my investment so far is $300 for complete bike & $250 for the engine.