Eligilibty scrutineer at the Nationals

[211kawasaki]

Nathan

on the MX thing, you would be really suprised just how many radial heads I have seen getting pushed through. Its not a big issue but an example.

On the KX thing, last year there was a 76 KX250 with a modified rear end in pre 75, the 76 KX has different front wheels, forks, triples, frame geo, seat, - I could go on. All good for pre 78 not pre 75.

211

[Rossvickicampbell]

Good idea Dave - gets the arguing out before the day.  I shall line up with my YZB again whilst you check her out 

cheers

Rossco

[facthunt]

What about a 75 TM with the rear end modified to 74 or 75 TM cases in a 74 chassis?
What about MK 8 Pursangs with the rear modified to MK 7?
Is the 1K7 Yamaha front hub ok in pre 75?
Will MXB forks be ok in pre 75?
How to deal with a bike that may have later major components but no id numbers/marks?
What about a bike like that beaut CZ in the current VMX with a new built frame. Would the frame be assumed to be a faithfull repro and would it matter as long as the suspension criteria were met and it looked right?
If a component isn't performance enhancing as such, and looks kinda right but isn't, what happens?

Just a couple of examples. Must be lots more out there.
Good thread.
Cheers.

[LWC82PE]

its very good to see that you will be enforcing the rules Dave T. I like to see that.

[husky61]

Best thread this year.

Thanks dave

[oldfart]

Dave, I am curently building up a Ts/Tm,  using a Ts frame and swing arm 1973 model and using all my 1975 running gear .......what are your thoughts

[Nathan S]

Is the 1K7 Yamaha front hub ok in pre 75?
Will MXB forks be ok in pre 75?

Ah... Excellent questions Kurt!

I had thought that MX-B forks are (visually) identical to YZ-B, and are therefore legal for pre-75?

And the hub thing:
The 322 hub was first fitted to the RT1MX, and was the 'standard fitment' on YZs and MXes right up to 77 models.
1K7 hub first appeared on the IT400C and was fitted to 'everything' for the next seven or so years.
These photos show the only difference between the two types (top photo is the earlier 322 one).
http://i46.photobucket.com/albums/f128/annaandnathan/Bikestuff/Dec11-08003.jpg
http://i46.photobucket.com/albums/f128/annaandnathan/Bikestuff/Dec11-08002.jpg

Does the 1K7 hub classify as a carry-over part? You could easily modify an earlier hub to look like the later one...

[211kawasaki]

MX250B Forks are visualy the same as the YZ A units, from memory the tubes are a tad longer but the same, could be wrong on that one but I wouldnt have a problem with them pre 75.

On the 1k7 you are correct it started with the IT400 from 76 strictly speaking you shoud not be able to use this in pre 75. Im not 100% over every fine detail of every bike, there has to be some responsibility with the rider to make it correct for the period you going to ride it. My question you you is you say that you can easly modify and earlier hub to look like a later, can you do it the other way around?

I know when I restored S Gall's YZA that out of 7-8 hubs  only 2 where acceptable, if there is an arguement that this hub is the same (minor difference) and would allow safer wheels then I suggest that it should be noted to the Commission so it can be considered.

On you other questions, no, you cant modify the frame of a TM,KX, Bully or anything to make a later bike legal pre 75.

Im not even going to go there on the CZ issue and Brads bike, looks great and whereas the USA has very similar rules to us, in fact we have taken many of their leads,  its not for me to comment on that indervidual bike.
 

[211kawasaki]

oldfart

correct me if Im wrong; the later TS stuff differs externaly, such as center port, fins, casting differences in on the clutch side? Doc, your the Guru, what are the differences?

Dave

[Nathan S]

MX250B Forks are visualy the same as the YZ A units, from memory the tubes are a tad longer but the same, could be wrong on that one ...

Yes - the lower legs are the same as YZ250/360A/B and the upper tubes are the same as/very similar to the YZ250/360B. The YZ-B tubes are slightly longer than the YZ-A tubes, although the travel is the same.

On the 1k7 you are correct it started with the IT400 from 76 strictly speaking you shoud not be able to use this in pre 75.
...
 My question you you is you say that you can easly modify and earlier hub to look like a later, can you do it the other way around?

Did you click on my pictures?

The only difference is the 9 small webbs between the spoke holes on the non-brake side - obviously no difference in strength, and (IMHO) insignificant visual difference.
It would be dead-easy to remove them from an early hub, but unrealistically difficult to go the other way.
The value in the later hub is that they're a LOT easier to get, and they're probably marginally lighter.
I guess I was trying to point out that you could legally modify a pre-75-legal hub to be exactly like the later hub, so my reasoning says that the later hub should also be legal for pre-75.

[211kawasaki]

Nathan

if you feel that way put some words to your LCB and state the case. I personaly wouldnt have an issue.

211

[Mark Austin]

Hi Dave,

I have a Bultaco Mk 5 350 that I sometimes race in Dirt Track and MX. It has a later model frontera engine fitted, so has to go into the Pre 78 Open Class. It also has a Mikuni flat slide carby on it (as it was raced in different club classes on the NSW south coast).

Can I run the bike with this set up at the Nationals, or do I have to switch to a round slide Mikuni?

Cheers,
Mark

[211kawasaki]

Mark,
GCRs 18.6.0.4 (b) suggest you take it off.

Looking at it though, this is one rule that has been perhaps left behind, the flat slide was available in 77 and therefore you could argue that as available it should be allowed; but the rules overall ban the use.

I will make this point at the commission meetings in 2 weeks time and ask the LCB 's to consider an amendment that allows flat slides post 75.

Remember; how the system works is the state body, your Historic Committee will be asked if they agree, the Commission has no power to change / alter the rules only on the agreement of your state bodies can this be done.

I guess this is one of the points of this thread. Do others agree that as flat slides (to the best of my knowledge) were available in 77 therefore they should be legal post 75 classes??

Regards
Dave

[Rossvickicampbell]

honest question here Dave - when I was a young fella we could always ride a class up albeit based on size ie 125 in 250s and 250s in 500s or Unlimited.  Why can't I ride my pre 75 in pre 78 as well?   

thanks

Rossco

PS I agree - probably best thread for a while.

[GMC]

So a 75 model can't be modified to be eligble in pre75, fair enough.

But can the 75 model have the shocks laid down further to be more competitive in pre 78, keeping within the 9" travel?