Vintage Dirt Bike Q & A

Started off with this basket case.

Progress so far

I aquired these new Ohlin's,there slightly shorter than stock so I've moved the stock swingarm mount slightly forward to retain the correct height.

Motor completly stripped,all new gearbox and main bearings using only high quality bearings.
Luckly gearbox was like new, Big end was trashed, new rod kit fitted using a matched up kit from an RD Yam. 79/80 CR125 kits seem to be unavailable unless you have the crank line bored for a larger big end pin.
Just need to get cylinder replated and a piston.

All stock bolts cleaned up and plated.

Very nice work spannerman.

How did you accomplish this? Did you remove the stock mounting tabs
then fabricate and attach new ones?

Looking forward to seeing the finished product.

dogger

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1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

spannerman, looks like your off to a great start. after seeing pictures of your other 125 i'am shure this one will be awsome. i wish i was that far along. just got my crank back i had the later cr pin installed. so did you powder coat your frame and engine cases. allso what fenders are you going to use? i got a set from vmracingonline, very nice fenders but the red dos'nt mach the stock red on my 79 cr125. but i'am looking at old faded paint i'am not shure how they will look with new paint. i do have a honda xl200r that i painted with dupont red toner only then clear. this is a dead on mach with the fenders. my cr is going to be a rider and vitage racer but its got to look gooood !

Cheers.
Firstly I had to remove all the welded bracketry that had been welded on previously but leaving the origonal rear mounts attached,then I made up new plates which would act as the new slightly forward mounts these are welded to the origonal mounts.

As you can see I've left the origonal mounting hole so I can go back to the stock mounting should I wish.

The frame was blasted back to bare metal then my mate sprayed it for me,its not powder coated.
He used 3020 (I think).
I stripped the motor then removed all the old paint using wire wheel,abrasive paper etc and left the finish slightly keyed up.
I then sprayed it with the high temp paint supplied by Red Rocket racing I think you can get this from VMX racing as well.
Finished off by baking the cases for an hour or so.
Then when cooled I rubbed off the paint from the protuding Honda name with fine grit paper.
Not sure where I'm going to get the plastic's from probably VMX or DC plastic's alot depends on my son's budget as I'm building it for him it will be his first bike .

A simple but effective solution - nicely done.

I also would like to commend you on some first
class welds. Those brackets look like they are
original equipment.

That is going to be a sweet ride when done.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Something I forgot to mention,back in 79 I had a 79 CR125 here in the UK, there was a publication (motocross action I think) giving instructions on how to convert to a 21" front wheel by cut and shutting the top tube to alter the rake to suit.
Back then my Dad made the required jig and carried out that convertion on my bike after which he swopped the jig for some tyres with a local frame builder this guy then carried out these conversions for other 79 CR125 owners.
The irony is is that this bike has had that conversion and as I know of no other person doing that conversion in the UK I can only assume at one point it was on my late fathers jig.
Unfortunatly this one isn't my old bike.
Thought some of you may find that interesting.

Here you go, this is a photo from when your frame was converted 30 years ago, i'm 100% certain its the one because it was the only one which had the swing arm modified too, those shocks had come off my 78 Maico.

Where did you find that bike? I'm pretty sure i had that about 14 years ago but sold it when i cleared out all my 125's. The missing bits would have gone on my 1980's.

have you ever tried the rear holes?
think you´ll get in trouble with the springholder.

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80 CR250Ra
80 CR250Ra
78 CR250R
80 CR80
82 Bultaco Sherpa 340
78 Bultaco Pursang 250 MK12
76 Bultaco Frontera 370 MK10
76 Bultaco Alpina 250
73 Bultaco Lobito 125 MK6
76 Suzuki RM125A
90 Kawasaki KX250