MNZ requests ProTwin comments

[svr]

IMHO we simply must have a Formula racing class of some description.

BTW, what about this idea of blanking off one cyl of a current 600 to make a 450 triple? Does that fit the rules? Are there still 4 cyls and hence still 600cc even though one is not working? How would that be ruled I wonder?

Enjoy

Steve

Hard to believe it hasnt been done - 90hp R4.5! Just pulling off a plug-cap would make it legal. The 4th `dummy' piston remains as a balancing weight as per supermono.

[FROSTY:Me]

Hard to believe it hasnt been done - 90hp R4.5! Just pulling off a plug-cap would make it legal. The 4th `dummy' piston remains as a balancing weight as per supermono.

Have you tried riding a 600 with a plug cap pulled off?

[svr]

Yep (er not on purpose of course), better than my old kr1 with a yz490 motor!

[Billy]

Yep (er not on purpose of course), better than my old kr1 with a yz490 motor!

Aaah the old 250 proddy days aye.That explains a few things about the speed (or lack there of) of your old proddy bike.Didnt think youd be stupid enough to own up to having one of those!!!

[quallman1234]

Wouldn't you need to take the spark plug out (no compression) completely so petrol wouldn't build up in the top of cylinder and hydra lock it? Or would it just flow out the exhaust valve's

[Burrt Badger]

Wouldnt you remove the rod and piston to reduce drag, Oh and the carb?? Wouldnt be feasible me thinks

[steveyb]

My feeling from an engineering point of view is that one would need to remove the piston and rod from one cyl and replace with a weight of exactly the same mass as that assembly, eg clamped around the crank journal.
Then disable the carb or injector (easy, take off the fuel hose or pull out the power feed) and that 'should' work.
You could take out all the valves to reduce drag and the spark plug too but you would need to replace with seals of some sort so that air and water cannot get it and oil does not come out.

But there will always be a lag when the missing cyl is supposed to fire and doesn't.

Go on ya mugs, give it a go!! But which cylinder do you disable?????

Steve

[svr]

Mechanically I think it would work,
Philosophically I have an issue: There is something deeply wrong with making a bike slower in order to go racing!

[svr]

Aaah the old 250 proddy days aye.That explains a few things about the speed (or lack there of) of your old proddy bike.Didnt think youd be stupid enough to own up to having one of those!!!

Are you referring to my kr-350 Billy?
The 490 was a different animal entirely - 55 hp and 105kg - good in theory but unrideable due to vibration in practice... (KR-1s with balancing shaft removed are pretty bad too - think tz 250G)

Interesting that the guy who built that crf450 road racer told me that it vibrates so bad his arse cant grip the seat so he slides all over the place.
I'm sure an r4.5 would be pretty smooth by comparison.

[oyster]

Hi Vicky.
I've been very interested as it's a progression path from Streetstock (1 path, the other is 125GP)
As an engineer I've been involved in prep of these bikes and have to read/interpretet the rules for people many times as a result.
1) In Canterbury we gave it a really good promo to get it started at club level and was instantly in good numbers as a result. In the last few months quite a few more have joined, 4 of them 16 years old so all good.
What was missing was effective promo to get clubs / riders underway so there was enough for a good national champs.
Mag articles etc are free and work well, but this wasn't done. Not too late, get busy.
And yes, "instant classes" can be made, Tim Gibbes proved it in his "Suzuki Series" in the early 90's. That's my first suggestion,
stimulate industry interest and promote the class.
2) The rules need 10 units sold per year of the model. That excludes the older ones, which obviously are not sold new any more.
The wording needs to be changed to read "in the year it was sold". And no, that's not obvious, overseas there are series that specificaly exclude obsolete models. The manufacturers demand it that way.
3) The fuss about tyres. The rules are clear. If it's a road legal fitment it's OK, if it's not it's not. Simple. It's written. But what is road legal? According to the LTSA there are very few restrictions but for circumference /diameter which must be within 5% of the manufactures original specification. Outside that, no WOF, no pro twin eligibility. Did anyone do the sums on the super big tyres fitted to Karl Morgan's bike? Even though they were grossly overwidth, and hugely outside the TYRE manufacturers recommendations, they were still within the 5% dia, so ultimately were road and pro twin legal.
4) Slotting the cam sprockets is fine, that's just a method of adjusting the engine optimum timing within the engine manufacturers
specs (like altering mixture) It's still a standard engine.
5) Drive sprockets can be changed, but not the chain. Plenty of proddy people go from 525 down to 520, plus ditch the "O"ring
chains. This was common at last nationals, but not allowed under the rules. The rules are at fault, the chain should be "open"
6) "The following items must be removed or altered"
Why alter or remove the chain guard? Headlight, rear light, blinkers, horn, licence bracket MUST be removed. This should be in the "may" category. It's realistic that people could ride their bike to the track, race and go home. Removal of these items only makes it go slower, so why is it mandatory to remove them?
7) Items not allowed. This means transponders can't be used. They're not originally fitted, plus they log data. Double no no. Of course they should be OK, so this needs noting as an exception.
8) I can't find it, but in the rulebook is an age reference. The wording is wrong, from memory there are two age groups. 20 years old. Over 20. So is a 19, 18, 17, 16, 15 year old is excluded??!! A typo for sure, but needs fixing.
9) Bigger picture. The class needs a manual. Look at the fine job Karl Morgan / Ray Clee did. Good ring, good spannering.
Get these guys to sit down and write it all up. Then the new riders with little experience and support will have something to keep them safe, save them money and effectively become great riders. Having coaching courses is Ok, but is short sighted as it only gives out fish. The "manuals" way provides the fishing rods. This way the whole future, North Cape to Bluff is covered. This is the right use of SPARC money. 5k would do it.

That's it.
Thanks

[Shaun]

Hard to believe it hasnt been done - 90hp R4.5! Just pulling off a plug-cap would make it legal. The 4th `dummy' piston remains as a balancing weight as per supermono.

I can believe it has never been done as THE RULES DO NOT ALLOW FOR IT

[scracha]

BUT, cost must NEVER be a part of writing Formula-based rules, that is for the other classes. If cost reduction is a part of your decision process then you should be deciding to be in another class (now that we have the Pro Twin class)

Cost is always an issue, no matter how much money you have. For example, there's "cost restriction" measures in Motogp and World Superbike so why should a national championship in a tiny wee speck of a country be any different?

This is a small country with very small numbers involved in motorcycle road racing and very little in the way of return for riders, pit crew, sponsors, investors & manufacturers. Keeping costs below "astronomical" (i.e. just "very expensive") is the only way to increase interest and participation in the sport.

[Deano]

I just commented about making the rules, whatever they may be as I am not involved directly in the class other than trying to sort out a protest at NZSBK Rd 1 this year as riders representative, unambiguous so there is no room for interpretation.

e.g. the tyre rule; Either say what tyres are allowed specifically, or say it is open. No ambiguity then.

Cheers

Steve

So was Karl Morgan's 'oversized' rear tyre the reason for the protest ?

Has there been a determination on this yet ?

[steveyb]

So was Karl Morgan's 'oversized' rear tyre the reason for the protest ?

Has there been a determination on this yet ?

The protest made at Rd 1 of NZSBK had several points in it.
Determinations were made on most if not all of the points at the time.
As the riders representative for that meeting only I am not in a position to be able to pass further comment.
Further explanation should be sought from an official MNZ representative.

Cheers

Steve

[johnsv650]

hi steve,
the protest had two points to it, did you know that it was extended at levels and more imformation given and decision was given at invercargil, can you tell me did you get the extra information or any information after ruapuna from mnz and as the rule reads, the riders rep and the club rep vote and mnz rep only gets if a deciding vote is needed , did this happen after timaru.... ???