Simons for pre 78?

[Noel]

easier to change the class to pre 77 and let the bikes in question run with evo ,,

as far as I know accepted method for rear is to remove one shock and measure axle to fixed point on bike vertically above axle with rear wheel off ground then compress and measure distance between same 2 points

[Nathan S]

Is it the vertical movement of the axle, or do we include the extra distance of the arc?
European or African swallow?

[Noel]

Nathan,
you and I had to sit around while they sorted a protest that we weren't involved in ,
Just trying to help out here

Personally I prefer African swallows

Noel

[TM BILL]

This has gone off track a little  but

My problem is that an official from Qld, Michael Bamford aka Jikov made a statement on this forum

 "If you are thinking of entering on a Pre 78 bike  that has more than 9 inch suspension ( for the Aus Nats at Qld Motopark) , make sure you bring a comfy chair , you won't be protested , because you won't be riding"

Then when asked to clarify the best he can do is add a sarcastic comment  

Personally i could spend 5k shipping bikes from NZ plus all the other cost to come to the nats , only to be tripped up buy some power mad officials formula dreamed up in his own head . There needs to be full disclosure and clarity pre event .

These pre 78 rules are ambigous at best, yet an official with a lot of experience starts waving his dick in the air but has fork all to back it up with when challenged  

I dont know if Michael has an official role at the nats or not   but going by his statement i can only assume he does .

This is not a personal witch hunt , but if you are going to be an official at events then act like one FFS . How can anybody take officials seriously when they spout off crap that when challenged they have no rebuttle .

This is  a serious issue that Michael has raised , if he cant answer it can someone else please do so, then we are not left hanging till the event when the great formula is unleashed and all is revealed .

[motomaniac]

there's no specified way to measure the suspension travel

To be very boring about it, there needs to be a specified load for the travel measurement.
A standard rubber bump stop will compress fairly easily to about half it's original length, then it gets radically stiffer. By the time it's down to around a third of its original length, it's damn near solid - and flexy old 1970s frames and swingarms will be giving more "travel" than the shock absorbers.
Foam rubber bumpstops typically give more useable travel relative to their free length (the exact amount varies considerably, depending on the design and material used) but are also typically longer...

Thats bullshit , how can you assume a specified load ?Every rider will put their bike under different loads on the track and it is not allways that the fastest will inflict the greatest load. What is a standard rubber bump stop? Bump stops on fox airs and fox mono airs are 6mm and compress about 1 mm if you are lucky.Alonger bump stop on  anarrower shaft might compres abit more.Fox twin clickers for single shock bikes are about 12mm thick ,have much more load at full compression than any nonlinkage bike and still dont compress to half their thickness.The foam bumpstops compress to about 2/3 to 1/2 ,anymore and they would be destroyed after one long moto.


If they have any noticable amount of movement they need to be replaced, you might as well count loose swingarm and rearwheel bearings free play as travel if you are going to count that.

[Marc.com]

as far as I know accepted method for rear is to remove one shock and measure axle to fixed point on bike vertically above axle with rear wheel off ground then compress and measure distance between same 2 points

I don't know Noel might work with the twin shocks in outer Pomgolia but taking the shock off a YZ will be a challenge.

[Nathan S]

Thats bullshit , how can you assume a specified load ?Every rider will put their bike under different loads on the track and it is not allways that the fastest will inflict the greatest load. What is a standard rubber bump stop? Bump stops on fox airs and fox mono airs are 6mm and compress about 1 mm if you are lucky.Alonger bump stop on  anarrower shaft might compres abit more.Fox twin clickers for single shock bikes are about 12mm thick ,have much more load at full compression than any nonlinkage bike and still dont compress to half their thickness.The foam bumpstops compress to about 2/3 to 1/2 ,anymore and they would be destroyed after one long moto.


If they have any noticable amount of movement they need to be replaced, you might as well count loose swingarm and rearwheel bearings free play as travel if you are going to count that.

Don't look now, but you're agreeing with the point I was making.

[Suzukal]

Hi Nathan S …

1: I never said you had any thing to do with the protest.
2: my bike sat higher as it has new firmer springs not the sacked out stockers.
3: an appeal would have cost $750 … way over priced.
4: the triple clamp was the source of protest as was the air caps. (that’s what it states on the paperwork)
5: My bike would have been ignored if I didn’t finish 3rd.
6: I’m not complaining three years later, I simply stating a fact, no matter whether the item is performance based (eg: motor/ suspension), visual appearance ( eg: wrong back ground/wrong font), big, small, whatever, people at a national event will protest.
I have yet to hear of any protests at local events.
This thread started off about trying to find out about Simon forks in pre 78, then sort of got miss directed to the titles, protests and measuring points.
"If you are thinking of entering on a Pre 78 bike  that has more than 9 inch suspension ( for the Aus Nats at Qld Motopark) , make sure you bring a comfy chair , you won't be protested , because you won't be riding" end quote .
Simple, if you don’t like the rules, get together and have them changed, but if you like them, fine, run 9" or put those spacers in.

[Marc.com]

Is it true they are giving out protest vouchers as prizes this year

[Simo63]

So I  have just read most of this thread because I am considering entering the pre '78 Nationals this year on my 77 YZ250 but if I'm reading right I can't in it's stock standard form?  I actually have to limit the original suspension travel to 9 inches !!!

Is that right?  Is there someone that can give me a definitive answer here?  Someone I can call or that can check the bike before I go to anymore trouble and expense preparing it for the event?

I must be wrong .. that can't be right can it?

Yes the YZD had more than 9" in fact the list is shorter to find 77 models that didn't have 10'

I've got to say I'm fuggin shattered.  I thought I would be able to ride my stock friggin standard (ooh except for my new dead sexy PFR pipe) 1977 YZ250D at this event and as it's only a couple of hours away I was really looking forward to it.  It would have been my first (and maybe only??) Nationals but now it seems I shouldn't even bother showing up unless I bring a comfy farken chair!!!!

Oh hang on .. I can spend more money and limit the bikes standard, showroom travel to under 9 inches .... I wouldn't have a clue how many inches it has standard ..... and nobody can decide exactly how is that is measured??

FOR SALE YZ250D ... race ready stocker but only good enough to ride in the Evo class apparently .....

Signed
Disillusioned 

[motomaniac]

So I  have just read most of this thread because I am considering entering the pre '78 Nationals this year on my 77 YZ250 but if I'm reading right I can't in it's stock standard form?  I actually have to limit the original suspension travel to 9 inches !!!

Is that right?  Is there someone that can give me a definitive answer here?  Someone I can call or that can check the bike before I go to anymore trouble and expense preparing it for the event?

I must be wrong .. that can't be right can it?

Yes the YZD had more than 9" in fact the list is shorter to find 77 models that didn't have 10'

I've got to say I'm fuggin shattered.  I thought I would be able to ride my stock friggin standard (ooh except for my new dead sexy PFR pipe) 1977 YZ250D at this event and as it's only a couple of hours away I was really looking forward to it.  It would have been my first (and maybe only??) Nationals but now it seems I shouldn't even bother showing up unless I bring a comfy farken chair!!!!

Oh hang on .. I can spend more money and limit the bikes standard, showroom travel to under 9 inches .... I wouldn't have a clue how many inches it has standard ..... and nobody can decide exactly how is that is measured??

FOR SALE YZ250D ... race ready stocker but only good enough to ride in the Evo class apparently .....

Signed
Disillusioned 

As already mentioned ,measured by the sales brochure they are 250mm each end, just take out 21mm each way.Atleast you are lowering the bike evenly at both end.Try taking 10-20mm out of the forks and see how she goes down fast straights

[motomaniac]

Don't look now, but you're agreeing with the point I was making.
[/quote]

Don't look now but I didnt agree with anything that you said.
To measure travel under a specified load is a waste of time. If you are setting up something new for rear suspension you need to install the shock minus the spring and bump stop to check clearance's at full travel , although its not so necessary with a rubber bump stop on non linkaged bikes as they don't compress that much.
To consider movement or addition travel from older style rubber bushes in shock eyelets is just stupid, they also hardly move .If they do they should be replaced as its uncontrolled(undampened )travel and will make your bike handle like shit similar to uncontrolled movement in loose wheel and arm bearings.

[Simo63]

As already mentioned ,measured by the sales brochure they are 250mm each end, just take out 21mm each way.Atleast you are lowering the bike evenly at both end.Try taking 10-20mm out of the forks and see how she goes down fast straights

Right .. thanks for clearing that up motormaniac.  I honestly didn't know how much travel it had.  I purchased the bike last year because I wanted a pre 78 bike that I could run in the pre 78 class  .... I though that was what I had.  Not a pre 78 bike that had to be modified to 76 standards to be eligible to run in pre 78.  Lol, how stupid does that sound .. or am I the only one that finds that freakin ridicuous??

Easier to just not bother to be honest.  Got plenty of other competing priorities and this sort of crap just takes the fun out of it for me.  Couldn't be bothered with any such rubbish .. spent too many years (a long time ago now so I do have th erose coloured glasses firmly fitted) racing post classic road bikes to even bother going down that path.  At least with road racing in post classic, classic, period 5 etc all you had to do is prove the technology was "of the day" and you were right to run it.  Sometimes not as simple as I make that sound but you get the drift.  Certainly if the bike was factory stock (as is my YZ) then you had absolutely no problems.

In fact one of the reasons I liked VMX is that there was, to my knowledge at the time, none of that sort of crap.  But I guess all that shows is my ignorance and that I need to do more research.  Nah I won't be bothered ... I've got Jikov's and Lucien's message loud and clear.  Thanks.

[09.0]

Well the same crap rule has been there since the beginning. Nothing new here. Yet all this bitching on the forum and around the camp fires. If you don't like it, do something about it or suck it up. Yes it is a crap rule.
Dave Tanner told me how to measure the rear when I asked. Take one shock off and take the spring off the other. On the stand a fixed point at the rear of the bike to the centre of axle . Drop on the ground and re measure. Work out the difference. Its been a while but I'm pretty sure that is how it's done. I would also go from the rear of the swingarm and see what you come up with being the furthest point.
There was a Husky checked at scrutineering in Broadford .
There was also a yz250D at Conondale that ran 2nd in stock trim. No protest.
For me, if you turn up with a stock suspended bike they would/ should turn a blind eye. BUT! If you turn up with a bike that has been modified with later model parts or worse ( it happened at Conondale ) a thinly disguised later model bike then you SHOULD be jumped on.

[Nathan S]

Don't look now but I didnt agree with anything that you said.
To measure travel under a specified load is a waste of time. If you are setting up something new for rear suspension you need to install the shock minus the spring and bump stop to check clearance's at full travel , although its not so necessary with a rubber bump stop on non linkaged bikes as they don't compress that much.
To consider movement or addition travel from older style rubber bushes in shock eyelets is just stupid, thye alos hardly move .If they do they should be replaced as its uncontrlled(undampened )travel and will make your bike handle like shit similar to uncontrolled movement in loose wheel and arm bearings.

You're trying too hard to disagree, and you're missing the point.

Let's go with the old theory of taking a spring off and measuring the travel. Seems easy and will give a clear-cut answer, right?

What happens when the shock hits the bump-rubber as you compress the shock?
Do you stop trying to compress it and take the measurement then? If so, every cheating prick will fit 3" long "bump stops" made out of airfilter foam and score a stack of additional travel without breaking the rules...
Or do you stop when the bump rubber is fully compressed? How much load does it take to "fully compress" a bit of rubber? Just the weight of the bike? Or five big blokes?

What if the rider claims that the spring is what limits travel? Obviously it would be a bad set-up, but how do you prove whether a spring gets coil bound (particularly a fork spring)?

What about the forks with a top-out spring in them? Do you extend the forks to completely flatted the top-out spring and then completely compress them? (FWIW, that's how Yamaha measured the travel of the DT200R forks, even though you'd never access the extra ~20mm of travel from the top-out springs being fully compressed...).

My basic point is that without a published way to measure travel, scrutineers would be mad (and doomed to failure) if they tried to reject a bike for having less than an inch too much travel, particularly in the rear.