Edited Date/Time
11/6/2020 8:20pm
I admittedly know next to nothing about vintage bikes. Recently I purchased a DR370. It came from a non Moto company that purchased another company that had it. Needless to say they had zero info about the bike.
After getting it home and cleaning it up I noticed the swingarm was aftermarket. It had a white bros sticker on the side and a profab stamped in it in front of the tire. it also has some unusual blocks with bolts protruding from each side.
The other peculiar thing is the gearing the bike has. A 66 rear and a 15 tooth front sprocket is something I’ve never seen before.
Sorry for rambling but I’m just curious about this mystery bike and interested in what you guys can tell me about it. I appreciate the help.
After getting it home and cleaning it up I noticed the swingarm was aftermarket. It had a white bros sticker on the side and a profab stamped in it in front of the tire. it also has some unusual blocks with bolts protruding from each side.
The other peculiar thing is the gearing the bike has. A 66 rear and a 15 tooth front sprocket is something I’ve never seen before.
Sorry for rambling but I’m just curious about this mystery bike and interested in what you guys can tell me about it. I appreciate the help.
" I like the 16/42 combo when riding distance solo on slab with a 70-75MPH limit. That's not to say that traffic is moving that slow though.
2up, I prefer stock 15/42 sprockets for distance on slab.
For short distances, I prefer 14/42, whether slab or dirt.
DRs making more power up top might be better with 16/42 2up on slab. Pumper carbs may make 15/42 more tolerable in the dirt.
I think a 45T rear would be about perfect for me with my DR's current power delivery. I could easily run up to a 17T up front for solo slab, and down to a 14T up front for gnarly dirt.
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My friend did a ton of work to make his DR500 a big fat mx bike that he does really well on. There's a guy in our local series that races a 370. He also rides it well and beats bikes that you wouldn't think possible
I have 2 Profab DR/SP 370 swingarms too. They are extremely rare. Besides my 2, yours is the only one i have ever seen in the last 20 yrs. One is branded Protec and the other one is White Brothers. The WB has a few slight improvements. The RH side bends in so it can clear the brake cable anchor point/pedal stop? on the frame but they are the same basic dimensions. Protec was probably made 78 and WB one in 80. The pics in this thread are the first time i have seen another one of these arms on a bike and outside of the catalogues. All these swingarms were made by Profab. Al Bakers FMF also sold this swingarm in 1979 too. I have the Protec, White Bros and FMF catalogues that show these swingarms.
Curnutt shocks, too. Very stylish.
Yeah i noticed those too. I would not be surprised if tis bike had a fork kit too, although the thing to do was also fit air caps as well but i don't see any.
I worked at a Suzuki shop in the late seventies and we would ride the DR370s around in the showroom because they would chug along so slow.
Such a strange discovery - Curnutts and a Profab Swingarm, yet it's got the std exhaust on it, and, what looks to be Truly dodgy 'passenger' pegs bolted.
A local Pro here to me , Glen Macquarie, got a ride on a 370 /400 put together by the local, tiny Suzuki shop, Cannel Suzuki. Can't recall if it was shoe horned into a RM400N full chassis, or it had the swingarm and shocks, and bodywork grafted to the main frame.
It was a Trick thing though, that worked Very well !
He really started to do well on it, and, I think he started to get a lot of support, but, tragically, he was killed in a 'coming back from and interstate race' Car crash.
Oh, here's a couple of pictures from two years of the White Bros Fourstroke Nationals, of Koji Matsuda on very trick Floater DRs (400s) - 81/2, and, by the alloy struts, 83 :
And, a Hallman Enqvist / Aberg / Profab ? 370 - from an MXA test. I think Koji may have raced one prior to using the Floaters:
I looked in the old White Brothers catalogue and they were selling Curnutt shocks to go with this swingarm for the 370.
Yes that yellow bike is the Profab kit that Hallman sold. GMC in Australia makes reproduction sof that frame. He copied an original.
Yes, as he did with the Yamaha Abergs.
If I recall correctly, unfortunately, the original frame he took the measurements from / jigged up, was 'out of wack' so his first batch / batches were the same.
Lesson - Always check things!
Does good, nay, Great stuff though, does Geoff.
I've a couple of those little ( the early ones) White Bros Catalogues, somewhere in my Granny Flat 'Library'. Found an '86 MXdN race program in there, a few weeks ago. Had no idea I had it.
Ive got WB catalogues 80, 82, 83, 84, 85 and i've got a few between 86-89 but not sure which ones exactly, maybe i have all of them? Onlu just found 1985 this year. To Jardo, i hope to see your swingarm when its cleaned up. If you need any more WB, Protec, FMF etc DR/SP370 info just pot back here. I have a lot of aftermarket catalogues, magazines and articles and have a very good amount of knowledge on the 70's and 80's stuff. If you want to use and restore those Curnutt shocks reach out to a guy named Scott Tremblay. He worked there back in the day and is the go to guy for anything on those shocks. One other thing, Profab also made a banana style swingarm for the 370 and was sold by Al Bakers FMF but i have never seen one and don't even have a picture of one. They may have made only a handful.
I found this![]()
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