KDX-CR125 Hybrid

[Buddha#81]

Two different mates had the two major components in their sheds doing stuff all. I haven't had a dirtbike for ten years or so. Recently I brought a XR600RE cheap but the more it stared at me in the shed the more I knew it was planning to kill me. So the 600's gone and this is in its place.

1988 CR125 rolling chassis and a 1987-88 KDX200C2 engine.

started by stripping the CR down and have slotted the KDX in. next will be to cut all the cr engine mounts and weld new ones.

This is going to take a while and will be a work in progress, more as funds become avaliable. Its going to need tyres, chains and sprockets, fork seals, wheel bearings. But for now I'm working on getting the engine mounted in the frame.

Any good ideas on what chains and sprockets, tryes etc to run where to get them from. I don't want to blow the budget but I do want reasonable quality. The bike hopefully will come up "tidy" with a full ground uprebuild (bearings seals etc) the motor is in good nick, but I'll probally throw a piston and ring at it.

[cheese]

Should be an interesting bike.

I'd just run what ever is standard sprokets for a KDX and that should be enough for you. Is it going to have a 19inch rear wheel? just go for a MH3 if it is. Best tyre for your money.

[theblacksmith]

It will be a fast Honda.lol.

[cheese]

Oh and you can bore those Air cooled KDX's out to a 250 quite easily. My brother had one back in teh day and it was fucking quick.

[B0000M]

upload a picture of yourself in your red and white striped apron!

[scott411]

interesting Conversion, KDX's run 13-47 gearing std but i think they run better with 13-49,
88 CR125 would still have a 18" rear wheel i believe, will not make much difference if they do not,

are you building the exspansion chamber yourself? that will be th e toughest job,

i have seen a few KDX200 motors in KX125 chassis's, but never one in a CR Chassis,

[Ktmboy]

I had a KDX200/KX125 conversion once and what a beast. Should be interesting having this motor in a CR frame as Scott said.

Green mixed with Red usually makes Orange...correct.

[krad_nz]

Damn, I would love to do that conversion.
Where does one get a kx125 front end from these days?

Or do you just put the engine into a kx125?

[cheese]

From what I've heard you can do either. Check out Ebay for forks and shit. you need the tripple clamps and brakes too I think???

[barty5]

lateral thinking out side the box anything can happen i put together an 83 tt600 with as set of uSD forks from a KX250 bout years back had the have the steering head center machined down to suit the frame but bike handled real well.

[tommorth]

there are a few ally framed cr/kdx conversions floating around on the us forums and step by steps to the kx/kdx hybrid I think the kdx motor will bolt straight into a 90 or 91 kx125 theres an article in a old adb about one

should be a cool bike once its finised dont hold back on the updates

[kezzafish]

upload a picture of yourself in your red and white striped apron!

ha haaaaa, awesome. "the southern slasher"
What a job, onya for giving it a hoon

I believe red and green would make browny orange (a shit KTM)

[F5 Dave]

yeah before you go too crazy I'd scope out the airbox & pipe. Without a robust setup of both it won't last in the dirt.

240 big bores apparently vibrated to a bitch.

Check the carb, a mate's old round slide KDX carb had ovalised the emulsion tube slightly (wear from needle) & ran dreadfully until it was replaced.

JT sprockets are a fair & economical brand any shop should get. o-ring chain at a minimum. DID or decent Japanese brand chain, forget anything remotely Italian.

[LittleJohn]

Wicked little project. Will make a fun bike once it is completed.

[barty5]

heres a pic of my TT600/KX250 front end i built bout 5 years back.

[Buddha#81]

Well it a step closer to being realised, yesterday I got the chamber, so I hooked up the electrics and fitted the pipe (fits well, the mounts will need changing, as will the L/H downtube) and second kick it started and ran nicely. Next weekend I'm going to pull the front end out and strap it down to the welding bench and frabricate the engine mounts.

Thanks for the info on gearing etc, where's the best place to go for chain, sprockets, seat cover etc.

As F5 Dave has said the exhaust and airbox are going to be an issue, the airbox mainly due to the carb opening facing the rear shock.

As for the "apron" comment Boom, I take it you mean I'm a butcher? If so, saving the frame and motor from collecting dust in sheds and doing something different, sorry for that but some seem to be taking some interest in what I'm doing.

[cheese]

Ha ha he is just having a joke with you.

Always thought is would be funny to fit a KDX motor to a scooter. or a KX85 motor....

[F5 Dave]

Charmans in Onekawa will likely do a seatcover if specified the year & model, else any other decent upholster chap, but they would need the seat would need experience with dirtbikes. The rest I guess you're asking the local shops. Look up KDX gearing, ahh heck, you'll be wanting a 13T KDX front sprocket, if JT part 569. Then you, - -- oh hold on, Scott has looked this up before.
CR for years used a 210 part rear sprocket. Can get them in wide range of teeth.

& some 520 chain, how long depends on mounting, could easily be 116 links or over.

[cheese]

Charmans in Onekawa will likely do a seatcover if specified the year & model, else any other decent upholster chap, but they would need the seat would need experience with dirtbikes.

Ha ha my dad is mate with them. Dad is a local upholsterer in Napier too.

[F5 Dave]

They've been supplying bike shops for years, think they have a website, erm hold on, try this;

http://www.charmans.co.nz/products-&-services/motorbikes.html

[jt119]

did this out of bordom went well took for nights and a mate thats good with a weilder

[Buddha#81]

I spent yesterday with a grinder and welder. The frames now modded for the KDX engine and pipe, the twin down tubes have bee modded to a single to suit the angled exhaust port. the frame is going to work tomorrow for a good wash and some red paint and it will be sweet. The Swing arm will make the trip too, it needs some minor machining to fit.

LET THE BUILD BEGIN!

[Buddha#81]

.......AND BEGIN IT HAS

More progress today, frame and swingarm cleaned. Swingarm machined to fit. Got home and put a coat of paint on the frame and started assembly. Also fitted new wheel bearing to the wheels which have had a wash.

[cheese]

Ha ha good one hondazaki CDX!! LOL

[Buddha#81]

.....and a bit more progress, front end in with new steering head bearings and the forks stripped, flushed and new seals fitted.

[barty5]

This is going to take a while and will be a work in progress, more as funds become avaliable.

remember the 1st post another week and youll be telling us youve worn out the first set of tyres and motor needs a rebuild at the rate your going. Keep it up

[Buddha#81]

This is going to take a while and will be a work in progress, more as funds become avaliable.

remember the 1st post another week and youll be telling us youve worn out the first set of tyres and motor needs a rebuild at the rate your going. Keep it up

Dont worry Barty, the hard stuffs comming up like the air box........and expensive stuff like tyres, handlebars, piston and rings, seat cover etc, so the stuff you mentioned is all ready rooted. I'm just getting into it because the motovation is there.

I've also got a front end swap on my Bucket going on in the other corner that needs finishing!

[camchain]

Rate of progress is impressive. RE airbox: I'm currently figuring out some tweaks to my KTM gap infested, dirt gathering airbox. I made up a pre-filter support frame out of fibreglass.

Seems to me if you get stuck you could make a whole airbox out of fibreglass. Not too vulnerable in middle of frame and shouldn't crack if decent rubber grommets used to mount. You could make your shape to mould onto out of a big chunk of polystyrene. Easy and quick to carve. Fair it up with some masking tape. No part lines needed as you can chop polystyrene out afterwards. I've recently been told you can get the goo (from as yet undiscovered location) to possibly make your own flexible shapes for a connector boot to your carb.

[B0000M]

As for the "apron" comment Boom, I take it you mean I'm a butcher? If so, saving the frame and motor from collecting dust in sheds and doing something different, sorry for that but some seem to be taking some interest in what I'm doing.

sorry , wasnt being negative, i reckon this is a brilliant idea. im following this thread closely! but still, you need to be a bit of a butcher to even come up with the idea of building a frankenstein! hopefully it all comes together without too much trouble

[F5 Dave]

I made an airbox for my 500 with polystyrene & covered it with instant plaster from a tube so it didn't desolve. Use epoxy resin. Then cut a hole for a std rubber peice, much easier.

By that I mean for my 35mm carb mouth I found GS1000 airbox rubber worked, but depends on space, may need to get an old curved one from a dirtbike. Soak in almost boiling water to soften if need be. Cut hole too small & work way up so it just goes in hole with medium amount of swearing.

[Buddha#81]

Not got much done of late. I got another project out of the way and I'll get back to this, this week.

Anyone got or knows where I can get a front brake caliper from? it appears to be the same as the mid to late 80's XR stuff too? Mine is well beyond economic repair.

[cheese]

Try Econo honda.

[CRF119]

Thats differnt i had a 1991 RM125 Frame with a XR200 motor in it for my first good bike before the 4 stroke mxers came out.

[Buddha#81]

Try Econo honda.

No go at Econo Honda......Anywhere else? There must be tons of wrecked mid 80's hondas around and the front brake caliper all canny be rooted, just need to find one.

[CRF119]

Farm and trail in TA may be a good place to look i got lots of bits from there

[honda_power]

Farm and trail in TA may be a good place to look i got lots of bits from there

i think they closed down? i could be wrong though

[barty5]

seeing your doing a hybrid you could use this
http://www.trademe.co.nz/Browse/Listing.aspx?id=203022322

throw in a bit of KTM in the mix

[Buddha#81]

Due to a lack of time and a change in jobs the Hybrid is never going to get finished. Its here http://www.trademe.co.nz/Browse/Listing.aspx?id=213863470&ed=true if anyones keen on finishing it.

Ive got a DRZ400 on the way so not alls lost.