Vintage Dirt Bike Q & A

Hi everyone, I'm new to this great site, and hoping to get some advice.

Like many others who rode dirt bikes when they were younger I’m now in my 40’s and not greatly impressed by the looks of the new bikes. As a teenager in the 70’s the Honda works bikes are still the epitome of dirt bikes for me. I’ve still my Dec ‘77 copy of Motorcyclist magazine with their “Dream Christmas” colour spread - and it features Tommy Croft’s works Honda “trench digger” RC500 - beautiful.

Any way, I’ve decided to try to build a replica (in appearance more than technical specs) of that bike, and after a fair bit of internet research (the MXworksbike.com site is great) think that the best bet is probably to start with an ‘83 CR480, and modify it to suit. The monoshock would have to go for a start, and then replace the tank with a CR250 version, new plastics etc, plus enlarge the top of the tank as they did on the works bikes. And a fair bit of other work to make it look right. And of course I’m not working with a huge budget (not alone there!).

If you have time could you help me out with a couple of questions?

How does the above sound? Any better/other ideas I should look at?
Can you suggest a good source for the rear shocks (any style eg. Fox would suit me OK)?
Where could I find the correct paint codes for that deep red paint?
Can you recommend some engine mods to improve ridability? My riding is all trail riding (I never had the chance to race MX when I was a kid - lived too far from any tracks or clubs) and I’d like to get a more even powerband and more bottom end.

First -start looking for the right project bike!
Many thanks for your time.

Cheers,

Neil.

Back a couple of years a guy turned up at the Vintage Iron World Championships with this bike or a 1978 version. The donor bike was a 1979 CR250R. Into this frame he transplanted the red 1981 CR450R engine. He also brought across the Prolink swing arm. The linkage stuff was removed and he added twin shock mounts for Fox Shox. The air box was painted gloss red. It looked very clean. Fox Shox come up for sale on eBay and I know someone who would rebuild them perfectly. If you used a CR480R engine you would not need to mod it, but could add a flywheel weight, and/or use a hand-built Pro-Form pipe for that works look. There has been much debate over what is a true match for Tahitian Red. I have three suggested paint codes that I can share with you when you are ready.

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Thanks redrocket190,

The '83 CR480 option seems a bit easier to me - then I have the better forks (am Iright here), plus no problems with the engine swap, just cosmetics. I'm not about to race so originality is not an issue.

A few more questions if you don't mind:
Are the Boyesen Power Pro reeds worth having?
Waht about a different carb for more low end?
Where would I get a hand-built Pro-Form pipe (eBay?)?

Thanks for the offer of the paint codes. Once I find a donor bike I will let you know. I had a peek at your bike on the Thumpertalk site - wow! Looks great and the specifications list had me drooling.

Thanks again,

Cheers,

Neil.

http://www.pro-formracing.com/ for the pipe and silencer. The stock 38mm round slide is plenty good once you get the jetting sorted. Run VP C-12 mixed 50/50 with pump gas and it helps with starting and runs cleaner. I run Boyesen Pro reeds in my 250 and have a Moto Tassarini reed valve in the 480. The best reason for after-market reeds is you don't want a steel reed going through your engine, but both are better performers than stock whether you get the fiber or carbon fiber reeds. I would have thought that converting a ProLink frame to twin shock was more challenging than welding up a swing arm. I did remember that the donor 250 frame was a 1980 not a 1978/1979 because you need a twin cradle frame to accommodate the center port exhaust on the 450/480 engine.

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Hi Michael,

Thanks for the reply. I am very happy to be guided by your helpful comments. I will look at the cr250 transplant as you suggest, and start looking for those Moto Tassarini reeds.

Many thanks again,

Cheers,

Neil.

You want a V-Force 2 (V2M05) or a V-Force 3 (V305A). These are for a 1986-2001 CR250R, but drop right into the 1983 CR480R and the 1978-1980 CR250R. Occasionally NOS parts come up on e-Bay.

http://www.oldmx.com/index.htm Check this out. Not only these folks at least in your hemisphere, but this was the only site where I saw pictures of the RC conversion I raced against at Glen Helen in CA. Maybe you can get access to those photos?

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Thanks Michael,

With your help I now have a good shopping list.
I emailed the author of the site you suggested a few weeks ago but haven't had a reply so far. I'm hoping its still active. We do have a reasoably healthy vintage mx scene here but my '83 XR350 would be a real handful (mint though it is!).

I read in this forum that Red Racer are no longer in business.
Is there another retailer of the plastics (eg. side panels, tanks, guards) etc that they had?

Thanks again.

Cheers,

Neil.

For plastics google "Vintage Iron", "Vintage Elsinores" and or check out "DC Plastics" on eBay (the US site). And yes Red Racer is very much out business.

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Hi Michael,

The DC plastics site looks good - thanks for the tip.

On your advice I compared the '83CR480 frame and the '80 CR250 frame - I now see why you suggeest using the 250 bike and doing an engine swap.

Geoff from the oldmx.com site also contacted me with some information - thanks to both of you.

Cheers,

Neil.