442cc kit changes

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djheard91
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442cc kit changes

Post by djheard91 » Thu Mar 12, 2015 3:09 pm

With my engine in bits and requiring new piston rings, gaskets and a bore honing, I have the option of a 442cc big bore kit. Has anyone completed this change and can they confirm any changes required? I'm wandering if a standard head gasket will do the job or if it needs adjusting? Any advice greatly received.

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Re: 442cc kit changes

Post by Drunkn Munky » Thu Mar 12, 2015 3:29 pm

I would imagine if it does need a different head gasket it will be included in the kit

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Re: 442cc kit changes

Post by Variablevalves suck » Thu Mar 12, 2015 3:52 pm

You have to cut out the head gasket to fit the bore
basically use a hand die grinder of some sort and carefully open it out.

Is it a JE kit or the early FZR 600 59mm kit?

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Re: 442cc kit changes

Post by djheard91 » Thu Mar 12, 2015 4:55 pm

I don't know yet, I was trying to get info on piston ring suppliers on practical sports bike and someone said they had a 442 kit which they couldn't use if I was interested but I'm still waiting to find out more info and a price for it. I just want to know what I'm getting myself into before I buy it.

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Re: 442cc kit changes

Post by Variablevalves suck » Thu Mar 12, 2015 7:12 pm

FZR needs mods to the valve cut-outs, gsxr400racer was using this kit over in the states on a heavily modded gk73a
Last time it was done on this forum the guy (forget name) cut 20 thuo out of the piston and with in the weekend it had smashed a valve.
If this kit carefully measure the old valve to piston clearances and don't go any closer.

If its a JE kit that TTS import its a straight swap after bore and head gasket fit.
People say they are a little heavy but so long as you don't over rev them 140000 they are ok, ive used them and had no problems although I completely rebuilt with new mains etc.

JE kit uses the FZR rings!

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Re: 442cc kit changes

Post by Drunkn Munky » Thu Mar 12, 2015 8:15 pm

An email i had from TTS regarding conversions a while back,

"We do a 429 and 440 rebore options and 490 is a reliner, piston kits are £500 + vat, the liner kit is £500+ vat for the piston kit and £600+ vat for the liners and £500 to fit the liners to a bare case/ head gaskets are £80+ vat each. A rebore is just £160+vat for the 429 and 440 kits"

The above are JE kits

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Re: 442cc kit changes

Post by Variablevalves suck » Thu Mar 12, 2015 9:04 pm

I'd do your own head gasket as TTS only cut, with die grinder, a pattern head gasket.
Needs to be about 0.2/0.4 mm bigger than the bore.

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Re: 442cc kit changes

Post by djheard91 » Thu Mar 12, 2015 10:57 pm

Do you need to adjust the gasket? If the piston doesn't go that high then a standard gasket will not affect anything? My gasket is about 58.4mm diameter and the 442 pistons i believe are 59mm leaving 0.3mm of gasket sat pressed against the head and above the piston. Is machining actually necessary?

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Re: 442cc kit changes

Post by stripes1976 » Fri Mar 13, 2015 7:28 am

Yes machining is required. Without you will create a weak seal and a carbon trap. It will seem ok to start then will cause pre ignition later. The JE Pistons are too heavy and as said previously Rev limit is reduced. As with any engine build multiple assembly and checks have to be completed to ensure no failures. I ran deeper valve pockets than Jay. Biggest gains I found was swapping the crank.

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Re: 442cc kit changes

Post by stripes1976 » Fri Mar 13, 2015 7:29 am

Plastigage is your friend!!!


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