Optional Alloy Arm for pre'78 RM's

[DR]

I don't want to clutter the Nats thread or cause a ruckus with this trivial crap but the parts book listings for the optional alloy arm is not proof enough according to MA (beats me why not when it was listed as far back as April 1976 ) Technically, you should also be allowed the use the frame mounted torque arm and go full floating if you wish also as this floating system was around many many years before 1978. Below it appears on the DT1 yamaha in 1968. Kawasaki also used the floating brake setup pre'75 on the F11 trailies.




 

Here's 'some' examples of of the proof of the RM setup I've collected to back my 'ludicrous' statements..


A. Gunter Adelaide 1977 RM250B with optional alloy arm and floating rear brake.


This ad appeared for the whole world to see in Trail and Track's February 1976 issue



I have other 'proof' of the alloy arms' existence pre'78 though I'm keeping some of it up my sleeve since I seemed to be the only one who really cared to research the facts

[JohnnyO]

Doc along with you i know the alloy arm was available and used in '77. A friend of mine bought one for his RM125b in '77 from Phil Thew and it came painted black.
I've also got the parts book printed in late '76 with the alloy arm listed but it appears the 'Einsteins' at MA know more than all of us.
I'm running a DG alloy arm on my RM250b.. so what's the difference between using that and the genuine suzuki item?

[cyclegod]

I'm running a DG alloy arm on my RM250b.. so what's the difference between using that and the genuine suzuki item?

The difference will be if you finish in front of someone who isn't using one 

[E74]

Hey DOc, I will sell you a Pro-Fab one for $500 or a Thor one for $600 and you won't have to worry about it any more

[JohnnyO]

I'm running a DG alloy arm on my RM250b.. so what's the difference between using that and the genuine suzuki item?

The difference will be if you finish in front of someone who isn't using one 

I won an Aussie title last year with it on and no one said a word.
I was ready with all the proof of availability just in case.

[monaro308]

This is a silly question as i do not race and never have (apart from karting for 13 yrs)why was the cut-offs selected at pre 78,etc etc and not decades and half decades ie pre70,75,80,85?
I'd like to see a break down of major bike changes of different manufacturers at year 70,75,80,85 i'm not brave enough to even attempt what little i know in say changes between the KX,CR,YZ,RM80-500@1980

I occassionally look up the swingarm issue (RM B,C )on US sites and come up blank alot...i'm just curious about it as much as the next bloke.

[DR]

Hey DOc, I will sell you a Pro-Fab one for $500 or a Thor one for $600 and you won't have to worry about it any more

Jesus wept E74! $500! that's more than I pay for a whole bike! better check the shock positioning before you say no worries

Johnny, yup..and just between you and me I'm sure that arm was the reason you won

CG..the difference is the DG item was splashed all over glossy mags whereas if you wanted to see the 'genuine' article you had to snuff out the spare parts dude and steal 'the then' sacred parts books

Mario, there are numerous reasons behind the cutoff dates I'm not now, nor was I ever disputing any of the logic behind such decisions/rules as they do make perfectly good sense but somewhere along the track things got a little distorted and my original question was seen to be taken as bending the rules

     

[bigk]

I've got am RM with one of those arms in it, I guess if I ever wanted to go to the Nats with it I'd be wasting my time then, coz it's obviously up for protest. Who in their right mind could be bothered with the eligibilty BS? I can't even take my bog stock '77 CR390 Husky without limiting the travel for christ's sake! I used to be shit until I realised I could buy trophies, maybe the protesters don't know you can buy them.
Cheers,
K

[PERM250]

hey chris yes i think you are  100% right .and if you stay at this you will be found to be correct.may be noel harker can shine some light on this or even gunter himself? i know that this must be starting to get under your skin ?

[LWC82PE]

I have a few questions.

Doc is your alloy swing arm off a 78 model or is it actually the optional 76/77 swingarm? If its truely a 76/77 optional arm then i dont think you have anything to worry about as long as these were available for purchase FOR the 76/77 models before 31 dec 77 and it cant be an alloy 78 swingarm bought in late 77.

Is the optional alloy swingarm that was listed as being available for purchase in 76/77 for the 76/77 models differnt to what was listed for the 78?

The way i see it to be legal you would to have the optional 76/77 swing arm and it couldnt be off a 78

[JohnnyO]

Leith the difference between the optional '77 alloy arm and the standard '78 arm is the brake stay rod bracket is welded to the '77 arm and the '78 was a floating rear brake with the bracket welded to the frame.

[LWC82PE]

ok so as long as its a 77 then thats ok. I dont think you should be allowed to add the tab onto a 78 arm (to make it appear that its a 77) and then claim that its a 77. That wouldnt be within the spirit of the rules. Dont know if anyone could really prove it though unless there is welding experts on hand that can pick out the original suzuki welds from new fresh ones. Im sure people have done this to 78 arms and gotten away with it though.

[Lozza]

Doc if you feel so strong about it, take your proof to Dave Tanner and he takes it up with the commission. There is a clear procedure for this and forum posting isn't one of them. First is parts books are not considered as proof of eligability, because they could well be listed but in suppliments and to be supplied on a need to know basis.As was the case in prodution road racing where 'kit' parts leaked out to certain riders.Even if you had the part numbers the distributor would kindly say that that part number does not exist when you put an order in.
An aftermarket arm isn't an issue as that would be fairly easy to show the item being available and raced within the period.   

[oldfart]

What's so mad about this whole saga is that it is perfectly legal to run a 77 B option arm with the brake tab on arm   FULL STOP .  Pictures of race bikes and Suzuki promotional brochures clearly indicate it  back in the day.

BUT here is the flip side the rule makers can't seem to bring it to themself that a B model had an optional alloy swing arm.

The down side is that you will have the shady likes that will modify a C arm to make it a B arm.

Hence the relunctancy. 

[DR]

Suzuki offered 'kit' or 'optional' parts for many models so why is this part any different? The bottom photo of the black arm is indeed the real deal purchased for a bike way back in 1977 If this swingarm is not permitted and the '78 model arm is infact a direct copy (which it is) then riddle me this..

how/why is it possible that the RM125C engine in it's entirety is 100%  pre'78 legal when infact the 2 do share 'some' differences and 1 is quite obviously built well after the stipulated cutoff? I thought build dates meant little to nothing if the part remains unchanged as a carry over or flow on You can use the front wheel from a C and it's legal even though it's from '78..it's the same deal! Remember the optional swingarm was available 2 models prior to the designated '78 C model so which is actually a copy of which? In this case the egg definitely happened along well before the contentious chicken as the part was hatched/derived from something that already existed 2 years prior. There is no need to bother Commissioner Dave with this crap as proof is all that's needed and that proof exists

Something else I'd like to ask, what if one fitted a '73 F11 wheel complete with floating brakes and simply welded a mount to the frame to suit the torque arm? Is this also not legal even though all the parts are more than 100% eligible? If not, why not? You can fit a 4 banger into a chassis that originally housed a 2 smoker so where lies the difference if it's only an optical thing?