OzVMX Forum
Clubroom => Bike Talk => Topic started by: albrid-3 on May 20, 2009, 06:58:56 pm
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Could someone be able to tell me, What is the differents in a 73 MODEL CR frame and a 73 MODEL HONDA MT frame other than mounting luggs. the reason why is that l am thinking about using either frame to put a xl 350 engine in it.
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apart from different lugs here and there and the rear guard loop I thinkthe mt is steel and the cr is chrome moly
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Is a whole MT frame chrome-moly or just part of it.
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Dave,
I'd be almost certain the whole MT frame is mild steel. The CR frame was said to be cro-mo back in the day, but its doubtful that its hi grade stuff. Japanese steel was low grade stuff.
The MT frame is a little heavier & the rear of the backbone extends further down under the front of the seat (like TS250 or DT1/2/3 frames) before it meets the uprights from the swingarm pivot area (to give clearance for the up-pipe).
That maybe just what you need to clear the intake if yr going to use a side-port XL engine.
MT frames are also easier to find.
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The MT frame is a little heavier
Dave....JCs right about the differences between the two with the exception that the MT frame is a lot heavier. The geometry is the same so using the MT for a special would work except that there is a shitload of fabrication to fit the lumpy XL engine in the frame. My mate Eds bike looks stock but the amount of work involved was extensive. I know, I did some of the welding. The Elsinore's less than perfect geometry doesn't lend itself to the swap either, you'd be better off finding a Husky MJ frame or even better, a Rickman Montesa roller. I had a look at a Rickman Monty/XL350 conversion a few weeks ago and it looked like something the Rickmans would have built themselves.
(http://img.villagephotos.com/p/2005-8/1062154/phippsy2.JPG)
(http://img.villagephotos.com/p/2005-8/1062154/phippsy.JPG)
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I tho't there was only about 3.5kg diff in MT/CR frames. Still, thats enough. Perhaps wouldn't be much gain over std Xl frame.
Rob Tumes loves the handling of his stock-framed Yoshimura 305 once it got some decent suspension. Came w'in a wisker of winning the Nat title on it in WA against big-bore CCM's
Agree that XL into Husky frame would be one of the easiest. Husky has a deep engine bay, but the MJ/MK frames aren't exactly light either.
I have a pic of a Rickman produced frame w XL engine. Will have to try & scan it & post it here.
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number 31 honda, Egars bike, it would be very light to ride.
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number 31 honda, Egars bike, it would be very light to ride
Edgar wishes that was true. In reality, the bike is a pig to ride. The power over torques the chassis causing all sorts of weirdness. The Elsinore/XL swap is one of those that just plain doesn't work. Nearly everyone I've spoken to who's done this swap has been disapointed with the result. Too much work for too little gain.
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Yes l will agree with you mark, Elsinore / xl that is out
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Dave, re the xl/mt/cr dont bother. The 2 stroke frames are too flimsy. I have looked at and raced against all types of xl's in all types of frames. The maico or husky is the best handler but I just used a std 350 frame, 250 swingarm,cr 250 forks, & koni shocks. I put a lot of effort into the getting the suspension working with the bike and it is more than competitive. I am not riding it at the moment because the camshaft broke in half and I am in love with a certain Bultaco. I dont know yet if I will make it to Campbletown as am having a lot of trouble finding a suitable piston for the Bulty but if I do I we can talk xl's ( & bultaco's). Tony
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Thanks tony for that info, see you at campbelltown. l have just received my xl 350 engine, frame will be nexted.
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but I just used a std 350 frame, 250 swingarm
Tony, Just reading this bit.....is that a typo, or do have a secret? :)
Only ask 'cos everyone seems to suggest going the other way round.
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I am letting go of some secrets here. xl 250 swingarm gets it shorter in the wheelbase = easier to turn. Everyone rides different but this works well for me
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Hows the old bugger getting along Tony? Is he back on board a bike yet or is that wishful thinking? Give him my regards.
I'm glad we agree on the Elsinore 4 stroke swap. I don't think Dave believed me when I told him Eds bike is a pig. It twists like a cheap coat hanger when you dial the horsepower on. The material the CR is made from is shitty enough so the MT must be bloody awful. ;D
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G day Mark, Edgars bike looks fantastic but I have followed it enough times to know it is not the greatest on the track.Dad is coming along great, he is making plans to ride again and has worked out how we can lift him onto a bike. But under no circumstances are we to tell mum. I have entered for the Nats and he is coming with me so you can catch up with him there.
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Tony, when you say to use the xl 350 frame, put a 250 swingarm into it, do you mean cr swingarm or xl 250 s/arm, Mark hi, l do listen and l take it on board, as l listen to tony, and every body else, then l work out what l can find to build up , but if it gets to hard for me , l change my mind, and try something else. We all bounce off each other experiences and expertise. Tony which model bultaco are you enjoying , is it a 360 cheers david#46
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for sale 1973 cr 125 frame with 73 xl 250 fitted
and painted red as seen cruising the pits at cd6
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So that was a CR125 frame w the XL250 engine!