1973 cr250 reed valve mod

[jimg1au]

Another option is to buy a YZ250A reed valve and carb inlet manifold and then machine / fabricate a manifold to bolt the reed valve to the cylinder.
I believe this is the mod Don Jones did to Gary's championship winning CR250...

anyone have any details on this mod as the 1st cr i bought from the usa has this mod(still have bike)
thanks
jim

[09.0]

I just asked the same question regarding a pre '75 Maico that has a reed if it can be legal to race if it was a reed assy off a pre75 bike. The answer was a big NO.

[jimg1au]

i also have a cr250 with a gem reed valve it is pre75 leagle.the po won a lot of titles with it.as long as it is not a v force they are leagle
jim

[jimg1au]

in 1973 don jones made reed valve for cr250 out of yz250a reed blocks and were for sale to the public not long after.
d&h engerneering made reed valves for hodarkas and cz i have 1 for a 400
gem reed valves
all aftermarket parts avalable in 1973/74

[elsie 125]

   you got a reedvalve setup for me and my happy honda Jim

[jimg1au]

not yet pat

[Doc]

A friend has a TM125 with a DT1 reed assembly grafted onto the barrel and he was told it was legal

[firko]

I'll go on record here and say that a Honda Elsinore, Maico, TM125 or anything else in the pre '75 class fitted with a Yamaha DT2, MX250 or related reed block and cage is 100% legal for pre '75. In my 25 years in the vintage MX/DT scene I've seen numerous conversions of that type and I've never seen one excluded because of it. I've also seen a bunch of dodgy conversions that didn't pass muster such as Kevin Hortons CR500 reed equipped Elsinore and other similar conversions. As long as all of the hard parts* used are of pre 1975 origin there's no way it can be knocked back. Furthermore, I believe Boyseen reeds to kosher but doubt a V-Force type reed block to be legal.

I actually built a Yamaha DT250 reed equipped 250 Maico back in the early vintage days. I milled the complete cage from the donor Yamaha cylinder, milled the fins and carb boss from the Maico barrel and TIG welded the reed block in. The cylinder was at Gary Treadwells for him to modify the ports to suit but was lost when his workshop burned down so I never got to see if it worked.

*hard parts= reed block and rubber carby manifold. I asume reed petals and aftermarket cages would be regarded as 'consumables'.

[paul]

thats interesting firko,are v force reeds legal in evo

[firko]

Paul I'm merely guessing. I doubt that a V-Force reed cage would fit the early Yamaha block without a lot of surgery, those early Yamahas have a tiny reed area when compared to what's used today. Even my GEM Hodaka reed block has bigger reeds. Boyseen RAD valve cage for a long forgotten Suzuki 125 model (mid 90's from memory) fitted the stock reed block on my 360 RT2 powered flat tracker (same reed block as the 250). I couldn't find a rule telling me I couldn't do it ...so I did . I've no idea on whether they're OK for Evo or not.

[JohnnyO]

I used a Gem reed valve on my '74 CR250 at the '94 Vintage Nats with no problems. Everybody looked at it but no one said anything negative..

[Lozza]

The V-Force is a conundrum the old GEM and Mossbarger cages were already 4 petal 2 V arrangement exactly as the V force is. Next is the V Force is hardly unobtainium, anyone can buy one and for a reasonable cost. Unlike the old GEM blocks.
I think there should be a clear rule on it and if it were me I see no problem with a V Force, it is just like shocks and ignitions.

[mx250]

I think there should be a clear rule on it and if it were me I see no problem with a V Force, it is just like shocks and ignitions.

+1 .

Just make sure it is not obvious.