GT80

[Broadsta]

What i want 2 no is, which class canu race these things in? ive seen plenty of 80cc bikes in these posts but never at any race meetings.

[Noel]

Hi ,
My understanding is that only juniors would be allowed to race them.
for a senior's bike it needs to have a minimum wheel diameter of 17 inches and
a minimum capacity of 100 cc.
I'm happy to be corrected by someone who knows for sure.
Noel

[caps 999]

front or rear wheel cause i just got a yz100j front wheel19" rear 16" and i want to hopfully race it

[caps 999]

sorry i just realised it runs a 21 and 18 setup

[Doc]

There was a guy at the vintage nats racing an XR75 and from memory I believe it had stock sized wheels..this bike was taken out to about 150cc I believe but it's still an XR75 regardless. It dusted off many full sized bikes and was quite rapid. I don't recall seeing anything in the rule book that states you can't ride an 80 mini.  My assumption is that the powers that be think we are too big for mini's and why would anyone disadvantage themselves by riding such hence no mention of them in the rule book. What they don't realize is I and maybe some others personally weigh and measure the same as I did at 15 and my '77 RM80 still suits me down to the ground (if only it had a 400 motor)

[Noel]

Hi Doc,
I spoke to that guy at the Nats and he confessed to there being a
gray area as to how  diameter is measured
"with or without the tire "?
You are right I have not seen it written any where only   "heard" the parameters
Cheers
Noel

[Doc]

g'day Noel, yeah mate I really was impressed with that little XR. I've just been scouring the rule book for reference to such but found nothing. I also went back through the program from the event and the guys name is Les Barfoot , apparently this bike was only out to about 100cc. The pic below is the bike and rider at the said event. 

[caps 999]

i had a 140cc xr75 awsome little bike it ran a alpha romeo car piston and the crank was out of a xl175  which was litend and machined to fit a far as i know back then  could have raced it this was around late 2006

[DJRacing]

Geez Caps how long did it take ya to find out that a Alfa piston would do the job?

[Tim754]

Just sussed out the rule book and cannot find this wheel size stuff(*). I say go for it but beware! you ...will ....be passed by a lot of punters so race with care and up to your machines and your limitations.   Tim754
(*) Somebody may have seen the reference, please post the item and sub item numbers for all if they exist.

[caps 999]

i actually got the piston from a guy that had done one befor i had to machine valve pockets and get a custom sleve fabricated and drill the centre cases but man did it fly

[Broadsta]

Soooo what u guys r sayn is that imay b able 2 race this bike  but in what class 125s? And Tim idont think being passed will b a problem cos this thing aint no stocko, it goes like a cut snake.

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[Doc]

Broadsta, if your thinking of running the 80cc in the 125 class you will be passed 
As quick as a worked vintage 80cc may feel it would still be very hard pressed to keep up with a full size bike on a full sized track.

[Tim754]

Assuming it is a pre75. Models (367 /374 ? ) You may race in 125, All powers, your age group races, and maybe others.   Nice Little YZ80 Sidecar piccie is yours?, Back to the your MX 80 ,  You can fit the 5 speed box out of an early C./D YZ80 straight into your MX/GT80 cases as a unit. Done it before ...twice, The MX shafts are the same items except that they only 4 gears and a blanked out spot!  Tim

[Doc]

  now Tim, just to be argumentative, whilst perusing the the rule bible I did notice something. The gearbox 'must' retain the correct amount of ratios as per manufacture thus making a 5 speed GT only eligable in pre78  not that I think anyone would care unless they have a can of whip ass opened on them by a GT80