Race engines and F3 engines

[Mori Man]

Over the years I have bought a fair stack of ZX lumps from the ZX-4 ~ M6

Some have been described as ex-race F3 engines but once opened they were just normal SP motors prepared for racing with lockwire , thermostat removed , SP cams dialed in and the occasional starter motor blank.

Recently I bought another SP motor described as being used in races and was started up before removing from bike for storage. Sellers photos didn't make it look pretty and neither do mine lol

Generator cover is plain so a sure sign it's a J1 or J2 , however it has stubs for FCRs and even the F3 J1 used CVKs with bellmouths and airplate , startor motor is removed and has the kit blank plug fitted , generator cover off and no flywheel or windings and the kit plug for the electrical lead exit fitted even the sprocket cover has been modified.

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Inlet tracts and exhaust ports have been polished and block still has F3 manifolds bolted into it ( I have an F3 system so know what it and the springs look like )

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Cam cover off reveals it has F3 cams installed too ( I have a set I can compare against )

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Pulsar cover off to spin the cams around to check lobes reveals a kit rotor

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It also has J stamped on the block

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Plugs out and some old school Champion race plugs in there:

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Just keeps getting better

So this is the first motor I have seen to have been so far fully tricked out for racing , I suspect when I remove the head it will have had the F3 modifications done to the cylinder walls and head , with the rotor drilled I wouldn't be surprised if the crankhas also been balanced and I can check if it has an F3 gearbox as I have one of them in the store already.

I am all for stripping it down and fully overhauling but another part of me is " buggar that! " - fit nicer casings, bung my race generator into it , check the clearances and get it into a bike and try it out and power check it. Then at some point in the future once I've built the F3 motor I have all the parts for, replace with it and then go through this one like a dose of salts - will report back on my final decision

Anyhoo, delighted with my purchase what a result - only taken 6yrs to get an actual F3 engine or from a racer running at a professional level.

[R P Corse]

Massive über huge spunkerage over that engine! Lol

Lucky bugger mate, would love one of those motors!

[AFM327]

Mori, what are you using for a race generator? BDK makes one but they're very expensive. I've thought about seeing what kawi dirt bike generators might work. Any specs on teh f3 motor you could share? I'm getting ready to send out a couple cranks for balancing. Still contemplating a bit of lightening too.

[Mori Man]

Mori, what are you using for a race generator? BDK makes one but they're very expensive. I've thought about seeing what kawi dirt bike generators might work. Any specs on teh f3 motor you could share? I'm getting ready to send out a couple cranks for balancing. Still contemplating a bit of lightening too.

It's a generator kit that was made for the ZRX but I have a casing for the ZXR modified for it. I checked through the Fiche's here available for the dirt bikes to see if I could find it but to no avail

When I find the instructions for it again I am going to send a copy to fella at NEN ( he does the 441 billet kit ) and let him make contact with the company and see if he can source and make up a new kit.

I am reluctant to do any more work on the F3 engine other than a service as this has come from a tuning house or KRT and I don't want to undo their work lol Once I get my next motor built I will have had this one on the dyno so will know what it is pumping out for a comparison.

If your getting SP cranks done just have them dynamically balanced , they are already 500g lighter than a standard crank - if you have them knife edged and dressed your tickover will likely be around 3K rpm and on track you want to keep above 7K at all times. I have a dynamically balanced SP crank for my motor build - a couple of drill holes and it was done !! But does show they are pretty good out of the factory to begin with Standard crank will benefit from weight reduction // knife edging.

Will be a few weeks before I have the F3 motor in a bike so much on just now but have picked up the service kit for it and new inlet stubs for the FCRs.

[AFM327]

I found a company in the UK that makes generators that was willing to make a race genny. Only problem was that they needed a bottom end to work with and I'm in the US. I think that something could be made to work with a dirt bike or atv setup but it would be a trial and error thing. Wonder if this would fit? http://www.ebay.com/itm/Kawasaki-Mojave ... b6&vxp=mtr

[Mori Man]

That stator is $345 new here ! Search my posts you will see the kit I have and the size of it.

[AFM327]

Just saw it on the face book page, do I need to give up my firstborn? I need two of them Interested in a Marvic mag wheel with galfer rotors?

[supercool7712]

hi guys,
any one know where i can get a race ignition rotor? or have the part number? email, girvan.1967@hotmail.com
best regards
paul