Engine sizes are available in, 400cc, 421cc, and 443cc sizes.

Featuring cast aluminum cylinders, the Cub use's Banshee pistons, and cylinder head.

The 400cc use your standard ypvs crank your reed blocks and inlets and a banshee head no casing mods at all. The Larger engines require head mods to a standard banshee head. The 421cc needs a 4mm biger stroker crank, wich means a crank case modification, not a big one like the 10mm and 16mm ones. Only a litle machining to the top part of the case to accept the larger sleve area.The 443cc needs a 7mm crank and a little macheening to make it fit. All the cranks run standard ceals The kits will run with your standard carbs, but to get the best out of them You will need atlest 28/30mm carbs for the , 400cc TZR250 or KR1 carbs would be ok and 34mm for the 421cc, 443cc TZ carbs would be best. Carb kits can be purchaced.

((( CHEETAH KITS )))

The cylinders can be or race ported .

Barrel studs and head bols all in clooded in kits

The heads are can be standard or modifyed for the biger 421cc and 442cc barrels or for a stage IV head with interchangable domes.

Top end gasket set and O rings allso inclooded in kits

Pistons and rings are the very best "Weisco prolite pistons"

4mm stroker Cranks for the 421cc and 7mm crank for the 442cc

This is a ProSeries stage IV head only avalible for standard Banshee barrels but becides the extra 4 bolts on the out side its the same top view of the head described above.And is simuler to the one you get in the kit with chanable domes.All stage 4 heads come with interchangable domes in 15-22 cc, for the 68mm bore size we cary 17-21cc some of the pics for the cheetah show the old heads that did not have interchangable domes all new cheetah heads have seperate domes.

With the Cad-Cam Sure-Flow design, water flows over every millimeter of the cooling system, dissipating heat with an efficient flow as well as increased water volume. There are a lot of heads on the market that offer the ability to change domes, and thus compression, but aren't you looking for better cooling and increased reliability as well? With an O-ring head water flow will enter the head and follow the path of least resistance- In one side & out the other, across the top of the head (the factory Yamaha head uses the head gasket to divert the flow). Unless the flow is diverted (forced down the cylinders), the head may be cool, but Your cylinders are running way too hot.

 

 



WHY WON'T ANY OTHER HEAD MANUFACTURER SHOW THE INSIDE OF THE DOME IN THEIR ADVERTISEMENTS?
Look closely. With the Sure-Flow technology the head fins(1) divert water around and through the dome fins(2), then force water down the cylinder.(3) When a given volume of water is leaving the head (4), it has dissipated the heat across the entire surface of the head, the domes, and most importantly- Your cylinders. The interchangeable domes already have the Trinity Stage IV head mod incorporated into the dome design, correcting the bowl shape, and squish band angle, to optimize the burn rate, and thus give you increased Horsepower & Reliability.

You can get Keihin 28mm PWK carbs to feed every last bit of power into your new gig bore valve engine. The PWK kit comes dynamically tuned for the kit to 650ft MSL at standard pressure & temp. The kit is laced with stainless steel braided throttle cables with plastic coating to prevent fraying and splitting. Outerwear-wrapped K+N filters and a selection of jets are included. Compared to the C.V. system, this dual kit gives up some power on the bottom end for a larger gain on the top. Compared to the dual 35mm system, this 33mm kit gains power on the bottom end with less gain on the top.

400cc kit ** ( uses stock crank )
485cc kit ** ( uses 4mm crank )
535cc kit ** ( uses 10mm crank )
610cc kit ** ( uses 16mm crank )


The Cheetah powervalve engines you will find a huge increase in power across the entire power range and a smooth power delivery due to the powervalves. Available in many sizes ranging between 400cc and 610cc,

Featuring such items as cast aluminum cylinders, billet aluminum powervalves, Wiseco pistons, a custom Cometic gasket set, o-ring heads, and a custom crankshaft*, the Cheetah motor kit will unleash power like like nothing else in your valve.

Custom cylinder porting is £280

400cc engine kit uses stock crankshaft, all larger sizes require stroker crankshafts (included with Cheetah kit).

The stud extenders go on the back of the cyls on the studs to make them longer because the back of the cheetah and cub cyls are thicker and larger. The ,535cc and 610cc require the crank mods shown further below. The new 485cc uses a 4mm crank and only needs the top cacing matching to the barrels.

Theys are Big Bore kit for the YPVS motor only
They will fit both the 350 YPVS and the RZ250 YPVS
I am doing 7 kits. 3 CUB kits and 4 CHEETAH kits ,The cheetha's have a powervalve the cubs do not . Theys kits provide you with a huge increase in power across the entire power range!
((( CUB KITS )))
Theys 2 pic's are of the cub barrels click on ether one and they will give you a blow up of them, for a better look.
Both the tuned standaed banchee head and the stroker crank have blow ups click on them to see.
Click on the pics to see a blow up of whats in the big bore kits.
The price
(The 610 is just to big for the powervalvs so the price of the valves have been deducted for the 610 kit as it simply dos'nt have them)

The kits are

400cc / 485cc / 535cc / 610cc

Due to the flutuating exchange rate Prices are P.O.A

 

EXTRA MODS for even more power
Click on the pic for a blow up
All cheetah's have mashened barrels and use O rings, just like the TZ's. With the power theys put out they would blow a head gasket. Click pic for blow up
The Cheetah Powervalve system does not work like the one on your valve It has no servo controle box or cables . It works of exhourst presher. Baskikley the more you rev the more presher you make as the exhourst expels the gasses and this pushes up the gate.
All the kits require H/D plates and springs with 3 TZ 750 springs, as they put out to much power for a standard clutch to cope with. Theys are £58.
To give you a better idea what is involved in modifing your crank cases for the biger stroker cranks i have put up 3 blowups from this link .As you can see in the very big cranks like this 16mm 610cc casings you have to rezin up the casings first befor you get your enginear to do the job. I can suply the number of people who can do the mod if you dont know anyone your self.
The stage IV head has a blow up click to view.
Click for a blow up image
: You will have to add post to any order :
You can get a stage IV head for the cub aswell if your feeling flush.

BHP figures will vary quite a bit depending on weather they are race ported or standard and weather they have case porting as well. The last 421 cc cheetah on the dyno made 110 hp to the rear wheel this was a full race ported with case porting as well, a standard 421 will make 80-100 hp


A 400 cc cheetah on the dyno made about 105hp with extra porting. A standard 400 will make 70-80 hp.

A 535cc with extra porting will make about 125 hp

A 610cc will make about 145 hp

Theys are very reliable kits. I know of one in a banchee, fully race tuned that has been raced every weekend for the past 18 months and has nothing done to it at all, it gust keeps on going. Theys babys get thrashed aswell .

The total kit prices include: all the woshers, bolts, gaskets, crank, pistons, head, head domes, Powervalve systems, Everything you will need to fit to make the bike go very fast in deed.