Crafting a kr250a1 motor into a dirtbike frame ???

[hybrid]

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[Azza1980]

Hi guys got some picks up on photo bucket at if people want to see just serch Aaron19806

[Jeram]

just get the IMG codes from photobucket (on the right hand side next to the particular photo) and paste them into the reply box. then the photos magically appear

[Azza1980]

This week I had a go at hydroforming a test pipe with my gerni supriseingly it worked and well this one I just made straight to have a go and lern something in the process what I learnt was if I dollied the sides bofore I welded it up so there was a radius at the join it realy helped get a true circle also use thin mild steel like 1.2mm and most inportenty bleed all the air out first unless you want a bomb in your shed because the air will compress and water doesent so at some point it will blow to bits if there is air traped

[Azza1980]

Ok I have a delemer with fiting a airbox on this bike well one that is a big as the kr motor used as standard I no on four strokes air box volume and volocity stack lenth are very importent for tuneing power at certin rpm ranges my question is are 2t engines as fussy about these things I was thinking I might just make a small plenem chamber just above the carbs like 1L and then run two rubber flexy hozes from there to behind the radiator shrouds what do you guys think.

[hybrid]

Neither of mine run airboxes, but they definitely help.
It will even help if you can just provide air to the carbs without the turbulence of air rushing around when the bike is moving. So a smaller airbox will probably be better than none at all, provided it's not restrictive.

[Azza1980]

I think the box would be about 1.5L with two pod filters inside and a few 40mm flex hoses going up to somewhere that wont suck wat er in thanks for the help it never herts to have a second opinion on these things

[azwood80]

Hi guys still building the bike got it almost ready to fire up engine is all mounted pipes all done wireing works just odds and ends left i will let you know how
she goes real soon

[JonW]

Cool, do some video!

[2TInstitute]

Suppose I'll know where to get a cheap kr engine soon

[hybrid]

Sooo.... you don't approve of this mating of bits then Lozza?

[azwood80]

Lol i thort some die hard kr fans may not aprove of cross bleeding of the two makes of bike oh well you cant make everybody happy a guess.i naw have the bike running wireing was a pain to minimise to its bare bones without all the on road stuff but got it done just need to join the stingers to thr muffler and make some sort of air box.but the motor is a nice fit in the bike hope the 14/50 gearing is ok with the 19in wheel if not i may drop a few teeth on the front.

[azwood80]

I spent today finishing up lots of little things l gave the like radiator pipework and gave the motor a service new plugs and g earbox oil hope the oil is ok i used motul trans oil 10w40 ester based and for the premix motul moto mix 100 i think its semi synthetic what sort of oils are you guys running in the kr,s i read somewhere that the cluches dont like full synthetic.

[Jeram]

Lol i thort some die hard kr fans may not aprove of cross bleeding of the two makes of bike oh well you cant make everybody happy a guess..

i think its more that it will make the same power as a late model MX125 but heavier

But if you can get it to work, than hats off to you

but at the end of they day, if you like it, that all you need!

[azwood80]

I plan to test her out today i will put t he go-pro on and put it on you tube i will see what happends it may be awsome it may be shit either way its onley cost $1000 to build so i can live with that.