Legal for Pre 82?

[Triplenut]

I'm building a sort of next generation XS850 pre 82 ( Some pics in my albums) and was curious whether a single shock conversion using period parts would be legal? .
I've converted it to chain drive so I need a new swingarm arm anyway.
I thought a pre 82 era yamaha monoshock swingarm( shock under fuel tank one) off an IT/TZ or LC350 might be the go.
I see guys racing pre 82 with all sorts of modern forks( incl USD) and other bits that appear to be illeagal under the word of the rules and no one seems to worry.
Would I have a problem in pre 82 or would I have to run in pre 89?

Appreciate any thoughts

Cheers
Red

[98tls]

Nice,no idea on the rules but if its a go then post up pics eh,ive a 750 in bits/boxes awaiting time and a lotto win,that and a Z650.

[Kickaha]

I'm building a sort of next generation XS850 pre 82 ( Some pics in my albums) and was curious whether a single shock conversion using period parts would be legal? .

IF you only ever race in the SI it "possibly" wouldn't be a problem, if you ever intend to do any events run by the Post Classic Association up North I would check with them first


I've converted it to chain drive so I need a new swingarm arm anyway.

How'd you do that? I've always thought a "Rodney Gray XS1100 replica" would be a good one to build


I see guys racing pre 82 with all sorts of modern forks( incl USD) and other bits that appear to be illeagal under the word of the rules and no one seems to worry.

They shouldn't be, and they wouldn't be allowed up North, it's a bit more lax down here but USD fitted bikes shouldn't be allowed in pre82

[suzuki21]

Depends where you race. I got pulled up because my GS1000R F1 replica had a 1981 GSX750 motor and not a GS1000. Thats what happens when a $800 Bernard built motor passes an Auckland member's bike with a $18k motor on the back straight at Puke. I couldnt be bothered with the political bullshit after that so I chucked it in. Had no problems Manfield through to Invercargill - even comments about what a good job I done building it.

[RDjase]

Depends where you race. I got pulled up because my GS1000R F1 replica had a 1981 GSX750 motor and not a GS1000. Thats what happens when a $800 Bernard built motor passes an Auckland member's bike with a $18k motor on the back straight at Puke. I couldnt be bothered with the political bullshit after that so I chucked it in. Had no problems Manfield through to Invercargill - even comments about what a good job I done building it.

The GSX engine is legal tho....................

Did they officially protest? It would have cost them $50 and egg on there face if they did !

Vic Club winter series starts in a few weeks and come and do the BRM/Pacific series later in the year, be great to have more pre 82's

[sinfull]

The GSX engine is legal tho....................

Did they officially protest? It would have cost them $50 and egg on there face if they did !

Vic Club winter series starts in a few weeks and come and do the BRM/Pacific series later in the year, be great to have more pre 82's
Build my norton up for me Jase and i'll come race in pre82 :)

[froggyfrenchman]

Build my norton up for me Jase and i'll come race in pre82 :)

Sell the snorton and buy a period Triumph. How dare you defect to the wrong side of the fence like that!

[sinfull]

Sell the snorton and buy a period Triumph. How dare you defect to the wrong side of the fence like that!
Still BEARS bro lol
Now i got me a norton, i think it may be up to the kids as to what happens to it when i'm gone mate !

[roogazza]

[QUOTE=Kickaha
How'd you do that? I've always thought a "Rodney Gray XS1100 replica" would be a good one to build
[/QUOTE]

This was Greg Pretty's in 1980 (well, Mal Pitman's really) just after it had been built and was being tested in Adelaide.
There are some clever buggers around.

[froggyfrenchman]

Still BEARS bro lol
Now i got me a norton, i think it may be up to the kids as to what happens to it when i'm gone mate !
Will let you off the hook. I do have a soft spot for them.

Will be interesting to see the outcome of this thread though. As a mate has just gotten his hands on a dirty old GS1000
It has had a power of modificatioins done...
Oversize carbs
S model head
Yoshi cams
Converted to CDI (off a 1980 model)
17" rear
19" front
Progressive fork spirngs
Braided lines
Monoshock conversion - we dont know what the rear is off, someone thought it might be rf900 but thats just a guess.
What class would this be legal in guys? The bike started out life as a '78 model.


Sorry for the hijack Triplenut,
just thought the question is so similar to your own that I would throw it out there

[codgyoleracer]

Depends where you race. I got pulled up because my GS1000R F1 replica had a 1981 GSX750 motor and not a GS1000. Thats what happens when a $800 Bernard built motor passes an Auckland member's bike with a $18k motor on the back straight at Puke. I couldnt be bothered with the political bullshit after that so I chucked it in. Had no problems Manfield through to Invercargill - even comments about what a good job I done building it.

Haha , thats pretty funny. had a mate that was told he couldnt race is pre82 in the pre89 class , cos it didnt qualify .................. ??, howz that work ?. (might be because he was beating all the pre89 guys........)

[worm13]

Haha , thats pretty funny. had a mate that was told he couldnt race is pre82 in the pre89 class , cos it didnt qualify .................. ??, howz that work ?. (might be because he was beating all the pre89 guys........)

hmmm well chris sales seems to beat everyone on his pre82 XR.... its gotta be big buzz beating 89jnr and snr bikes on a pre 82 jnr bike.
if you ever lost triplenut, The guys at nzpcra are pretty good and can help ya understand or clarify any problems or questions.

[malcy25]

Try reading the MNZ rule book http://www.motorcyclingnz.co.nz/download/2010_MoMS_Chapter_25_Road_Racing_Post_Classic.pdf, is all laid out there.

But to ensure understanding....here's a cut and past of the relevant stuff in this instance.

25.4 Pre 82 Class Specifications
25.4.1 Exceptions
Water cooled engines and mono shock rear suspensions, unless fitted as original
equipment, are prohibited.
25.4.4 Forks
Upside down forks are prohibited. Forks must be period items. Internal spring and
valving modifications are permitted.

Monoshock conversions have been done, BUT only where it was actually done in period. ie Harris built lots of monoshock conversions for TZ750s in the mid 70's where the swing arm was changed with a monoshock one. Onus of proof is on the rider. Do your homework first to show it was done on the bike you want to ride and then talk to the NZPCRA tech guys and it may well be okay, but randomly converting a bike won't cut it.

Talking to the right people and gaining approval first stops elevated blood pressure later...

Dodgy / illegal parts only piss other riders off big time and are just a lack of respect to all other entrants who have made the effort. Protests do happen when guys take the piss and why should the Postie classes be any different to adherence to rules as any other class?

Froggy Frenchman: Eligible class for the GS1000 With the RF900 monoshock Swing arm in the back? Reading the rules above....Clubmans.

[Triplenut]

Cheers Gents, appreciate the feedback.
My racing budget is pretty limited so aren't likely to race in the North for a while, would be keen to to do Wanganui and Paeroa one day though, got the street racing bug.

Rules are pretty clear I guess, I need to prove it was done in the period.
I'm not so anal that I'd protest, i get beaten by skill not machinery:laugh:

I have pics of a German XS 750 superbike that was single shocked and chain driven, so it has been done. What I don't know for sure is what year it was, I've been told it was raced 79-83 looks like I'll need to get some proof to go forward.

A Bob Gray or Pitman yamaha XS11 replica would be COOL.
The chain drive I have was actually built for an XS1100, the middle gear box set up is essentially the same for 750/850 triples and fitted straight on with just a bit of case trimming.
You could build your own chaindrive using the output shaft from the middle gear box.

Cheers
Red

[Peter Smith]

The post classic rules are there to keep the bikes true to the period of racing.
Just because you see a bike racing doesn't mean that it is legit.
E.g. At Paeroa this year there was a Kawasaki ZX10 with upside down forks that finished 2nd.
This is a no no, but in the spirit of the event no one protested.
If someone had he would have been excluded from the results.
A lot depends on the type of event, everyone want to encourage the class to grow, but it pays to check out modifications before they gets protested.

[malcy25]

Cheers Gents, appreciate the feedback.
My racing budget is pretty limited so aren't likely to race in the North for a while, would be keen to to do Wanganui and Paeroa one day though, got the street racing bug.

Rules are pretty clear I guess, I need to prove it was done in the period.
I'm not so anal that I'd protest, i get beaten by skill not machinery:laugh:

I have pics of a German XS 750 superbike that was single shocked and chain driven, so it has been done. What I don't know for sure is what year it was, I've been told it was raced 79-83 looks like I'll need to get some proof to go forward.

A Bob Gray or Pitman yamaha XS11 replica would be COOL.
The chain drive I have was actually built for an XS1100, the middle gear box set up is essentially the same for 750/850 triples and fitted straight on with just a bit of case trimming.
You could build your own chaindrive using the output shaft from the middle gear box.

Cheers
Red

Interesting photos. Swing arm is TZ500. The photo is post 1983 as it looks like RZ350 frontwheel in the bike next to it....

I saw 2 Chain drive XS1100's in Aussie this year and the boys were well barred up about them.

[codgyoleracer]

The post classic rules are there to keep the bikes true to the period of racing.
Just because you see a bike racing doesn't mean that it is legit.
E.g. At Paeroa this year there was a Kawasaki ZX10 with upside down forks that finished 2nd.
This is a no no, but in the spirit of the event no one protested.
If someone had he would have been excluded from the results.
A lot depends on the type of event, everyone want to encourage the class to grow, but it pays to check out modifications before they gets protested.

Hi Pete, rode the GW01 for the first time the other day....... OMG, heavy, slushy, wobbly lethargic, - and thats just the positive comments.......... :-)

[worm13]

Hi Pete, rode the GW01 for the first time the other day....... OMG, heavy, slushy, wobbly lethargic, - and thats just the positive comments.......... :-)

The Joys of being a chubby chaser..... :laugh:

[Peter Smith]

Hi Pete, rode the GW01 for the first time the other day....... OMG, heavy, slushy, wobbly lethargic, - and thats just the positive comments.......... :-)
Are you doing the Vic series? Mossy needs to be kept honest. (and I can check out your lap times):shifty:

[Triplenut]

Try reading the MNZ rule book http://www.motorcyclingnz.co.nz/download/2010_MoMS_Chapter_25_Road_Racing_Post_Classic.pdf, is all laid out there.

But to ensure understanding....here's a cut and past of the relevant stuff in this instance.

25.4 Pre 82 Class Specifications
25.4.1 Exceptions
Water cooled engines and mono shock rear suspensions, unless fitted as original
equipment, are prohibited.
25.4.4 Forks
Upside down forks are prohibited. Forks must be period items. Internal spring and
valving modifications are permitted.

Monoshock conversions have been done, BUT only where it was actually done in period. ie Harris built lots of monoshock conversions for TZ750s in the mid 70's where the swing arm was changed with a monoshock one. Onus of proof is on the rider. Do your homework first to show it was done on the bike you want to ride and then talk to the NZPCRA tech guys and it may well be okay, but randomly converting a bike won't cut it.

Talking to the right people and gaining approval first stops elevated blood pressure later...

Dodgy / illegal parts only piss other riders off big time and are just a lack of respect to all other entrants who have made the effort. Protests do happen when guys take the piss and why should the Postie classes be any different to adherence to rules as any other class?

Froggy Frenchman: Eligible class for the GS1000 With the RF900 monoshock Swing arm in the back? Reading the rules above....Clubmans.

Been doing a bit more research on this as suggested.
Through the German triples website have managed to find an email address for the current owner of the red xs750 racer, still waiting to hear but sounds like it was build pre 82.

Also found the pic below which is of an xs750 that was raced in the 1978 Bol D'or 24 hour race. It has a moto martin cantilever monoshock frame and chain drive. 884cc tuned by a guy called Knut Briel.
Hopefully this will be sufficient evidence for the powers that be to rule my little project a goer.
Fingers crossed

cheers
Red

[malcy25]

Been doing a bit more research on this as suggested.
Through the German triples website have managed to find an email address for the current owner of the red xs750 racer, still waiting to hear but sounds like it was build pre 82.

Also found the pic below which is of an xs750 that was raced in the 1978 Bol D'or 24 hour race. It has a moto martin cantilever monoshock frame and chain drive. 884cc tuned by a guy called Knut Briel.
Hopefully this will be sufficient evidence for the powers that be to rule my little project a goer.
Fingers crossed

cheers
Red

Red, I suggest strongly you still read the MNZ rule book, as it still must replicate what was done. ie original or Replica Motomartin frame, yeah, okay if it can be dated with authority. Tossing in a random monoshock conversion on a stocker, nah again, uness you can prove with authority it was done with that swing arm or what you are replicating.

[Triplenut]

Have read rules and understand and agree completely.
A replica frame will be required, my original concept is a dead duck... for pre 82 at least.
I have found a british 'Bike" magazine from 1980 with an article that details the moto martin chain drive conversion kit. It also details the frame kits they made for various jap multis of the time XS11, CB900, Z900 etc.
They didn't list an XS triple frame but I have found out they did build 5-6 for customers on request as kits, mainly endurance racers but also one for the IOM .
Trying to get details and proof.

Cheers
Red