YamaSuki XT 250 Z Supercharged Project

[Prichard XT]

as most riders I love me first bike but knowing that I was doing me DAS test this year (Now Passed)

I started to think what bike to get next and almost brought a 95' ZX400 that fell through

then decided to look in to what engine I could change for my XT 125

250 seemed a reasonable upgrade

about a Year ago I payed for an engine for mine and a friends project which ended up going back to a 125

That will do It came off a Suzuki GZ 250 (marauder)

not the most powerful engine but its already double a stock XT's BHP on a heavier bike

so iv started to buy the electrics

came with A 34mm CV carb iv restored and boxed

spec is a Single AC 249cc SOHC 4V Twin exhaust ports

so it has a chance of being modified

while sat there looking at the engine then the manual then the engine over and over

I noticed the cam runs a duplex cam chain and on the head cover on the side

there is a cap centered with the end of the cam shaft (chain side)

im thinking damn that's strong enough and so perfectly positioned . . . SUPERCHARGER

so il remove the cap have the cam remade with higher lift an added output shaft to run the SC system

add a oil seal ring where the cap used to be correct to the output

then figure out the correct RPM Ratio for the compressor to reach the correct Psi via 2 cam belt setup

this will not be easy a lot of trial and error

but when it works damn it will be a one of a kind

im hoping it will take less than 3 months so progress may seem slow

any pointers welcome and il try to keep this updated

[Ttaskmaster]

Well beyond my spannering know-how, but intriguing stuff to follow!!

Have you spoken with the insurance guys about how this will affect the premium, or anything?

[Prichard XT]

iv been checking on comparison but wont get quoted

il try when its done and dyno tested or give them the stock BHP and add that its been super charged

im not a 100% but il try anything this principle of a supercharged engine is way easyer than turboing to me and is more efficient and cooler

but its getting it to run at the right ratio increasing RPM from head to compressor and getting it a good PSI and being well balanced which will be the hardest so the XT don't just vibrate to pieces

[Prichard XT]

hahaha iv just realised is im going to be super charging this im gonna need a BOV/dump valve

but first things first get the engine in and running just waiting till Friday so I can buy the cdi and coil

[tritowns]

you don't usually use a dump valve with a super charger... do you by chance mean turbo chrager?

[Prichard XT]

Turbo is exhaust driven Supercharger Is engine driven but it will need some sort of pressure release system between charger and engine BOV seems to fit that purpose

I have been on hold on this project due to unforeseen circumstance

But went and had a look at the 250 yesterday and it should be in the bike running Stock in a month or 2

then il start on the charger

[wild foamy]

When i looked into 'charging the FUCR i was planning to have a poppet valve in the plenum to vent any excess, a quick google search should turn up some solutions.

[Prichard XT]

Where Can I Find a Plenum Small Enough To Fit 32 - 36 mm Intake,

Would A BOV Not Do The Job Then From Experience

I Want IT Runing Around The 12 PSI Force And Drop The Compression Ratio To 7 : 1

Finally Started striping Down The 250 To Respray And Modify Found Out It Runs A Mitsubishi Electrical System

Il Have A Few Pictures Soon Now Its Been Moved To Our Workshop I Can Crack On

[wild foamy]

make your own pressure box/plenum?

[Prichard XT]

time to do some reading up I think

I assumed Bov Would Do The Trick As There Easyer To Adjust and do the same job

Got Any Links To Suggest