basic question suzuki RH

[bazza]

I must say having a ride on Dave Tanners RN400 at CD was a privalage and a ripper.My late mate Barry who had 5 Rh/Rn's Had his RH motor on the work bench with his 360A motor talk about night and day engineering wise, that also went for the forks.The suzuki was agricultural to the Yamaha engineering, from memory not many parts adapted to the TM.

[firko]

Back to the 20 kg question given that factory guys broke a few I would say the main area of weight saving is the frame, the TM was just a TS sans brackets. RH wheels were massively lighter, titanium bolts, alloy brake lever, lighter casings, alloy tank, it all adds up.

Absolutely. TM Suzukis are built on the heavy side because in those early days motocross frame construction wasn't the science it is today so Suzuki played the safe game and made the bikes as sturdy as possible to avoid their products self destructing after a couple of months. They'd learned from the RH program that the super lightweight, thin walled RH frames only lasted half a season so that wouldn't have been good enough for a production machine.

Not Surprisingly the RH and TM design teams had very little interaction and according to DeCoster there was a lot of factory rivalry. The TM design team considered the RH boys elitest and the RH guys considered the TM team below them.
The only time that both worked together was when management insisted that the TM and RH have a passable resemblence to each other for marketing purposes.

The weight thing is the key to it all. My B&S frame is made from extremely thin walled 4130 Chro-Mo tubing, alloy swingarm, has a magnesium RL rear hub (supposedly the same as an RH), did have a sandcast OW Yamaha front hub but I sold it to an OW restorer and it now has a standard YZ250A wheel, lightweight Yamaha YZ250A forks,hollow chro-mo engine mount bolts and axles, plastic tank and the side panels are even held on by zip ties! The Cheney was also very similar but the Cheney frame is noticably heavier than the B&S. As a side point, the RH frame is almost identical to the Cheney after Olle Pederson had taken the Cheney Suzuki that Tom Ledbitter had raced back to Japan for evaluation (ie, copying).
(The B&S at CD6, with the adjustable steering head on full dirt track adjustment, hence the odd stance )
                   
               

[Marc.com]

.The suzuki was agricultural to the Yamaha engineering.

Yep the Suzuki has a much more, just enough to survive the season feel about it. Suzuki is big on stressing cost over zero defects, even today. The Yamahas are much more refined.

I would imagine the RH group at Suzuki and the TM group probably seriously went to different universities, Japanese business centers around which university you graduated from. So whole teams will form around fellow graduates.

[TM BILL]

Hi Johnny, my bike but Mike Feltons job (who has just set up his own VMX business and may produce replica RH frame kits), and I agree he made a superb job. Tank is TM125, seat gap is the same as genuine RH73, there are a few RH bits on it (head, barrel etc), actually off RH75. Rear wheel is RM250 magnesium and that probably gives an idea of where Suzuki saved weight on the RH.

Back to the 20 kg question given that factory guys broke a few I would say the main area of weight saving is the frame, the TM was just a TS sans brackets. RH wheels were massively lighter, titanium bolts, alloy brake lever, lighter casings, alloy tank, it all adds up.

I mean no way was the TM an RH, just some bits can be interchanged, Firko's Cheney or building a lighter frame is the way forward with the TM. But Suzuki knew that, but for a factory that targets a 3 year model run at a production level I would say Suzuki's response was the RM ABC.

Marc your TM GP is a nice looking bike  but i think you will find the TM cases took a bit of machining to accept the RH cylinder Have you ridden it yet , would be keen to know if it steers better than a standard TM 






 

[090]

Oldfart said his rh barrel would not fit his tm250 without a fair bit of modification.

[TM BILL]

Marcs TM GP is probably the nicest (modified TM 250 ) iv'e seen , its a credit to its builder and i would happily have it in my shed but its still a TM 250.
You can dress Susan Boyle in a gym slip but it aint gonna make her Olga Corbett 

I think as a pre 75 race bike your 74 KX 250 would run rings round any TM Mark 

RH models both 74 and 75 are the holy grail for any twin shock Suzuki phile  Unless your names Mr good and you own Joels RH72
As has been said the 74 is a great pre 75 race bike and obviously rarer as less were made, personally i love the look of both the 74 and the 75 and would love to have either in the shed 

Revisuer at the price the blokes asking for the 75 grab it with both hands , if its not for you sell it on

[Marc.com]

You can dress Susan Boyle in a gym slip but it aint gonna make her Olga Corbett 

RH models both 74 and 75 are the holy grail for any twin shock Suzuki phile 

hey Bill, Susan Boyle in gym slip, you sick bastard 

Yeah seriously if I had a lazy 15-20K then I would buy an RH, but alas my bonus will be a little lighter this year. The RH/RN is one of the ultimate in VMX collectibles, buy it you will never loose money.

And yes I think the KX250 will put it to most things in pre 74 racing. 

[oldfart]

Brad, it's still in progress( Gunna Job )    Front stud pattern on TM same as RH but requires a bit of ali added to rear of studs  ( no big deal )
Rear studs need to be removed holes filled and redone around approx 6mm further apart.

This year I'm buying a milling machine which should see further progress
 

[TM BILL]

Hey Marc we should let Mike loose on our KXs  I think with a bit of thought they could be a poor mans RH 

[Marc.com]

Hey Marc we should let Mike loose on our KXs  I think with a bit of thought they could be a poor mans RH 

hey Bill, I have Mike busy most of the time, but you are right I think the KX could be as good as an RH, this comment was also made in VMX magazine, my 250 is basically ready to assemble be interesting to see what it can do.

[firko]

I think youre pretty right about the KX. Even rabid Suzukiphile and RH owner David Tanner prefers his KX over his RH. As good as the RH was, there were a lot of 250s in 1974 that could come close or even top it. Maico, MX Yamaha and TM Suzuki are probably the only '74 250s that aren't really capable in stock trim. My personal pick, the OSSA Phantom was everything a works bike wanted to be in '74. That year was the last bastion of the European domination of motocross and from 1975 on the MX world was totally into 'turning Japanese'.

[Marc.com]

Maico, MX Yamaha and TM Suzuki are probably the only '74 250s that aren't really capable in stock trim.

I mean thats the joy of building the non stock ones Firko, with 20/20 hindsight you can address a lot of weak points. I picked up my MX250 for $600, knew I could get the motor to move from youthful porting experiments on ITs, add a few after market bits and some fork trickery and it may be quite rapid.

the YZ gas tank came about as it is the same stunt as fitting TM125 ones to 250s. Makes the bike feel much smaller/

[mainline]

it may be quite rapid.

did anyone see the first consolation race at the 09 Conondale Nationals?
where a {wait for it} 1973 Yamaha MX250 held off a 81 Maygo 490 for nearly the whole race...
twas one of my favourite moments as a spectator at the Nats     

 

Apparently they're quite rapid out of the box

[Marc.com]

Apparently they're quite rapid out of the box

Yeah but no harm in doing some house keeping with some period performance parts out back and a little monkey magic to the forks. I have done quite a bit with these motors before, other motor mods include porting by me, Webco head, bigger carb, YZ ignition.  Should really haul oats. Plus its cheapo pre 74 bike with an unlimited parts supply, bargain.

[jimson]

Marc what forks are on that TM of yours ? they look like what I have. Have you got a close up pic of the brake stay ? and are the fork tubes machined down at the top? jimson