A forum for owners of Yamaha TTR250 trail and enduro bikes!

Yamaha come up short on Auto gearbox's not much with them maybe bits from a Grizzly Quad I don't know about the older models 2 wheel drive the new ones seem to have the xt top end but the motor bottom cases are way off the xt and 4 wheel drive as well.

Pug

-- Edited by pug on Friday 24th of August 2018 11:46:57 AM

Agree pretty standard set up 

Just came across these photos in my library and they are of the same go kart I reckon 

clever person out there somewhere do or can we find out who

If that Kart is the Ebay one from Derbyshire, then I believe the following to be the old Ebay descriptive text.

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This is a very rare opportunity to buy one of these Kart packages, I doubt you'll see another for sale, especially with two spare engines what have been stripped down for parts when it was purchased!---

 

More pictures of the spares will be added when I get time to get them all out for a picture, there's lots, you won't be disappointed

 

Very well looked after kart package!

 

Yamaha Built and designed the Twin Cam FK250 kart engine years ago for a kart series Overseas, They where never produced for the English market, It was based on the TTR 250 engine, but has had the gearbox removed and casting Changed by Yamaha to make a kart engine, With a Heavy duty Centrifugal Clutch

 

Very expensive new, this kart package with spares would be over 10k

 

An amazing amount of spares is also included, Two more FK250 engines where purchased just to be stripped down for parts, So you could probs build another Engine up out of the spares nearly with a bit of work!, Also the brilliant thing of the engine being based on a TTR is that you are able to get spares from motorcycle shops!

 

You can't compare the build quality of this engine the likes of Bilands etc, The performance of the motor would kill one,

And the engineering is in a different League, It's Over engineered, Its manufactured and designed by Yamaha, so imagine how much money, testing and time have been thrown at these engines, No need to be sticking tape around the cheap cam belt covers up like biland to stop stones getting in the poor designed plastic covers 😂, This engine has a timing chain and is Leagues ahead,

This doesn't run the little poxy 219pitch chains either, these engines run the stronger 428 Pitch!

 

The engine what's fitted has had lots of development work and is far off a standard FK250 Yamaha, Standard they produced around 30HP as a 250cc, But this engine has had a special big bore kit made to make it a 400cc, The cams have been tuned by Newman Racecams, due to there being a massive amount of low down power from the 400cc, Newman managed to alter the cam to Also make more top end, But don't worry It nearly wheelies out the corners still LOL

 

ICATUSA Spark Plug booster fitted, works fantastically, Was around 200 Dollars new,

 

Big 40mm Mikuni Carb, Many different carbs have been tried and this one suited the engine great, brilliant throttle response, Been Jetted to suit

 

RamAir Air Filter

 

4S Breather System

 

Quality Carbon Fibre Shorty Exhaust end can, Comes with baffle, sounds mega! Lovely sound, like a 450 crosser

 

I will also include a GSXR silencer

 

Made 41HP on the dyno with a big restrictive GSXR silencer

 

It's got a built in Rev limiter!

 

I have had Aixros XR50, KFs, SA250, etc and none of them pull out the corners like this! Amazing for twisty tracks, It's a lovely package to drive

 

It's not really a heavy kart either, it's surprisingly light even though it looks bulky, it's not much different to an Aixro package!

 

It's electric start on the Button!

 

Birel Motorsport Chassis just been Power-coated in Red, Lovey finish and not been used since

 

Front and rear Freeline Brake system, Brilliant stopping power and a nice lightweight setup!

 

Adjustable brake bias

 

All Freeline Bearing carriers, Pedals etc

 

Wild kart Rear Hubs

 

Brand New Tillett Seat

 

Angled Steering Boss

 

6" Superkart Wheels, Wider and bigger tyres then your normal 5inch kart wheels, I used these for more traction!, Currently has Dunlops fitted, can supply the kart with a set of 6" wheels shown or a set of Freeline 5" Magnesium wheels

 

I have spare engine sprockets, Rear

Sprockets, Chains,

 

I also have a few chassis spares what will be included

 

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My thoughts again:

The Yamaha FK250 engine is an exceedingly rare bird because it was a preemptive response to the rumored elimination of 2 stroke classes due in 2004. A ban that never came. That means there are only few lucky survivors.

Wow! Stroked 315 big bore I guess? If his claim of 400cc is to be believed.

"No simple big bore..." Agreed! I suspect his dreams-reality interface is congested!

Our 350 TTRs are 86mm pistons running standard stroke (59.6mm) but the largest piston using the standard barrel is Thumper Racing's 325 (closer to 315cc) 82mm (probably similar to the piston in your spare engine) There were a few comments about stroking them when I was building them but it was more than I could be bothered with. I achieved what I set out to do. Someone else can do the next stage (I would like to see fuel injection before a long stroke which I think would spoil the nature of the bike.)

mossproof wrote:

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"No simple big bore..." Agreed! I suspect his dreams-reality interface is congested!

Our 350 TTRs are 86mm pistons running standard stroke (59.6mm) but the largest piston using the standard barrel is Thumper Racing's 325 (closer to 315cc) 82mm (probably similar to the piston in your spare engine) There were a few comments about stroking them when I was building them but it was more than I could be bothered with. I achieved what I set out to do. Someone else can do the next stage (I would like to see fuel injection before a long stroke which I think would spoil the nature of the bike.)

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 Yeah, about that FI. So all this FK stuff got me thinking. I have a third semi complete bottom. So I got a fresh paint stir stick, it is almost exactly 3mm thick, I then used it as a gage to see if I could work it down behind the piston and get an idea of clearance between the crank and third/fourth gears on the cluster. Guess what, it fit with clearance to spare. This means a 66mm stroke might be possible for the TTR form factor. So my idea was that if a 67.2mm stroke is possible, then you could trick the TTR into thinking it was an SR400 (87mm×67.2mm bore and stroke), then you simply just run the SR wiring, TCI, fuel pump, and throttle body....all that efi engineering  already taken care of by Mr Yamaha.  I know some may think, why bother, just go buy a proper bike? Well where are you Going to find a 400cc, E start, 4valve, air cooled, play bike motor, in a lightweight ultracompact modern TTR engine form factor? Good luck with that mission