Author Topic: 79 CR250 Front End Conversion  (Read 72617 times)

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Offline FourstrokeForever

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Re: 79 CR250 Front End Conversion
« Reply #120 on: July 06, 2014, 12:16:46 pm »
Reading and participating on this forum does have benefits.  I don't get upset b what others may say, unless it get personnel.  Some of the things it has done is make me consider the term OEM.

Original Equipment Manufacturer (OEM).  So if considering this correctly IMO any replacement parts should only come from the original manufacturer of the part.  So Maico forks should only be replaced by Maico, showa by showa, kayaba by kayaba etc, clearly this is not practical.  So in my opinion the word OEM should go, but I believe it should be replaced by components must come from EVO legal bikes (or something like that).  However there also needs to be provision for replica parts and for the purpose of safety improved parts (approved by MA). 

Something everyone needs to be aware of.  Any submissions to the MA Board RE the proposed rule changes are only likely to stop the introduction of the change/s not change it to something different.  Classic/Post Classic MX and DT are only a small part of what MA administers.  The Board have the minutes from every other commission to consider and probably other matters.  I believe they do want to change the way things have been done, but change will take time.

When the time is right I will put a submission in, but I will keep it simple and short.  It may be too late to go back to what many believe EVO should be, but hopefully we can stop it becoming UK and Dutch Twin Shock.

Kevin

I'm with you Kevin.
All the arguing (and it has been polite for a change  :) ) is just semantics really. It appears that the '82, '83 Showa forks have been on the start line in Evolution class bikes for any number of years with no problems so why tighten the rules now? Yes, Evo post classic racing is relatively new to me, even though I grew up with and rode the bikes back in the day. I was a late starter to VMX after years of chasing my dreams on moderns. However, I have always loved the bikes from my youth and always will. I have been racing pre75 for a few years now even though I have had my Evo CR (RC replica) for around 5 years just sitting in the shed. Some could say that I have a vested interest in amending the current rules, but don't we all in one way or another? The way I see it, the more vintage mx bikes out of sheds and onto start lines, the better.
 There does seem to be some ambiguity in the rules. So I will attempt to propose a draft of what COULD clarify rules for the class in an attempt to avoid the UK and Dutch retro twinshock HOTRODS.

1) Frame must be of ORIGINAL Manufacture twin shock design. Yamaha non linkage "monoshock" design is allowed. After market twin shock era frames are allowed.
1b) NO re-engineering of linkage design frames converted to twin rear shocks in an attempt to comply are allowed.

2) Any fork, to a maximum of 43mm stanchion is allowed.
2a) Forks must be of ORIGINAL manufacture drum brake design.
2b) NO re-engineering of disc brake design forks in an attempt to comply are allowed.

3) Brakes must be drum type, front and rear. No disc brakes.

4) Any Engine MUST be Aircooled and be from an original twin shock motocross/enduro frame motor cycle. Engines from Yamaha non linkage "monoshock" motocross/enduro frame motorcycles are allowed.
4b) Engines can be of Four or Two stroke design.

5) Replica after market swing arms are allowed.
 
6) Handle bars must be 7/8th cross bar design fitted with a protection pad.
6a) NO fat bar design handle bar is allowed.

7) Footpegs must be of the folding type with a self returning mechanism.

8) A chain guide/guard must be utilised and be no more than 30mm from the lowest point of the rear drive sprocket.

9) All motorcycles must have an effective muffler/silencer fitted.

That's it. Any comments are welcome but please, lets not turn any debate/discussion into a slanging match. I want to keep this all positive and attempt to make the rules as clear as possible for the betterment of the class.

Cheers
Mark
Arrogance.....A way of life for the those that having nothing further to learn.

Offline Rossvickicampbell

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Re: 79 CR250 Front End Conversion
« Reply #121 on: July 06, 2014, 12:31:39 pm »
Guys - I am just sitting back and watching this - way outside my field of expertise - but Mark - weren't the later model Fox Forx 44mm - so careful with the 43mm ruling?
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline Mick D

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Re: 79 CR250 Front End Conversion
« Reply #122 on: July 06, 2014, 12:41:28 pm »
Yes they are.
Its great to see somebody put forward their side with style and class. (talking about you TBM)
« Last Edit: July 06, 2014, 01:21:07 pm by Mick D »
"light weight, and it works great"  :)

Offline FourstrokeForever

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Re: 79 CR250 Front End Conversion
« Reply #123 on: July 06, 2014, 01:30:00 pm »
Guys - I am just sitting back and watching this - way outside my field of expertise - but Mark - weren't the later model Fox Forx 44mm - so careful with the 43mm ruling?

Thanks Ross. I'm unfamiliar with stanchion sizes of the Fox Factory Forx. Are they (the model you write of) designed for a drum brake set up? Amending to 44mm stanchions won't be a problem IF the fox fork is for drum brake. I'd hate to leave them out of the equation.

Yes they are.
Its great to see somebody put forward their side with style and class. (talking about you TBM)

Thanks Mick. I do have my good days  ;D
Arrogance.....A way of life for the those that having nothing further to learn.

Offline FourstrokeForever

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Re: 79 CR250 Front End Conversion
« Reply #124 on: July 06, 2014, 01:34:33 pm »
Here a couple of tweaks that Mick D has suggested. Highlighted in RED I think they should be included. Thanks Mick.

1) Frame must be of ORIGINAL Manufacture twin shock design. Yamaha non linkage "monoshock" design is allowed. After market twin shock Replica era frames are allowed.
1b) NO re-engineering of linkage design frames converted to twin rear shocks in an attempt to comply are allowed.

2) Any fork, to a maximum of 43mm stanchion is allowed.
2a) Forks must be of ORIGINAL manufacture drum brake design.
2b) NO re-engineering of disc brake design forks in an attempt to comply are allowed.

3) Brakes must be drum type, front and rear. No disc brakes.

4) Any Engine MUST be Aircooled and be from an original twin shock motocross/enduro frame motor cycle. Engines from Yamaha non linkage "monoshock" motocross/enduro frame motorcycles are allowed.
4b) Engines can be of Four or Two stroke design.

5) Replica after market swing arms are allowed.
 
6) Handle bars must be 7/8th cross bar design fitted with a protection pad.
6a) NO fat bar design handle bar is allowed.

7) Footpegs must be of the folding type with a self returning mechanism.

8) A chain guide/guard must be utilised and cover the point of chain return onto the rear drive sprocket.

9) All motorcycles must have an effective muffler/silencer fitted.
« Last Edit: July 06, 2014, 01:38:58 pm by TBM »
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Offline Ted

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Re: 79 CR250 Front End Conversion
« Reply #125 on: July 06, 2014, 02:42:08 pm »
Ok now you've done that adjoin a bleeding heart note remonstrating the handling deficiencies of shitbox twin shock Hondas, highlighting the fact that it's not fair that a Yamaha can have a bigger fork and also add that if they don't see things your way you will continue to leave your bike parked and just look at it.

Send it to your SCB and wait till August to see how you go. Good luck.
81 YZ 465 H   77 RM 125 B

Offline evo550

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Re: 79 CR250 Front End Conversion
« Reply #126 on: July 06, 2014, 03:17:39 pm »
This question requires a YES or No response, from the people who interpret the rule as being able to use major components from later model drum brake bikes (in this instance forks)

Can I use 1984 KTM 495 upside down forks on my RM 250 T in the Evo class ?

Thanks.

Offline Canam370

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Re: 79 CR250 Front End Conversion
« Reply #127 on: July 06, 2014, 03:36:34 pm »
Guys - I am just sitting back and watching this - way outside my field of expertise - but Mark - weren't the later model Fox Forx 44mm - so careful with the 43mm ruling?

Thanks Ross. I'm unfamiliar with stanchion sizes of the Fox Factory Forx. Are they (the model you write of) designed for a drum brake set up? Amending to 44mm stanchions won't be a problem IF the fox fork is for drum brake. I'd hate to leave them out of the equation.

Yes they are.
Its great to see somebody put forward their side with style and class. (talking about you TBM)

Thanks Mick. I do have my good days  ;D

Yep, 44mm for Fox forks. As far as I know they were only available to suit drum brake wheels.
WANTED. Canams;all models,complete or parts.SWM stuff too!

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Offline JohnnyO

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Re: 79 CR250 Front End Conversion
« Reply #128 on: July 06, 2014, 03:40:07 pm »
This question requires a YES or No response, from the people who interpret the rule as being able to use major components from later model drum brake bikes (in this instance forks)

Can I use 1984 KTM 495 upside down forks on my RM 250 T in the Evo class ?

Thanks.
Stupid question.. No

Offline bigk

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Re: 79 CR250 Front End Conversion
« Reply #129 on: July 06, 2014, 03:44:49 pm »
The answer to you EVO550 is a no as they are inverted forks not conventional, even though they are drum brake. The sticklers for this are just doing it because they can, it makes no sense at all to "fostering" the sport of VMX racing & will most certainly discourage new participants. As for the Dutch twinshock frankenbike scenario, well that goes against the "spirit" of VMX racing so therefore no fear of that happening. Good thing I'm not a scrutineer, I would decline any bike fitted with tapered bars, black modern rims & gobs of CNC machined billet alloy. Much more of a travesty to vintage bikes than 30 year old conventional forks. The point is moot anyway, it's been proven they are good to go and DT even said so before last years nats so why are these guys so bent up about it? Someone should build a horror of a bike within the current rules & turn up with it to see how they like that, I'm sure the squeals would still come. An example would be a '79 Honda chassis, 1984 Husky 500 engine, '81 YZ465 43mm forks & twin shoe brake with the latest greatest 150 click adjustable rebound/compression shocks, billet alloy everything, Pro taper bars, etc, etc. It's all legal but would be a horrific mismatch and what do you have in the end? A lot worse of a creation than a pair of '82 Honda forks in an '80 model Honda. Please let common sense prevail on this matter.
K

Offline evo550

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Re: 79 CR250 Front End Conversion
« Reply #130 on: July 06, 2014, 04:24:26 pm »
This question requires a YES or No response, from the people who interpret the rule as being able to use major components from later model drum brake bikes (in this instance forks)

Can I use 1984 KTM 495 upside down forks on my RM 250 T in the Evo class ?

Thanks.
Stupid question.. No

Stupid question...Why?
No...Why?
I just applied the same reasoning you do by using forks from a drum braked, air cooled, linkage bike. Plus not to mention the reasoning of no performance gain, some would even argue even worse performance than a set on 1984 43mm Yamaha forks..
So why No?

Offline marshallmech

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Re: 79 CR250 Front End Conversion
« Reply #131 on: July 06, 2014, 05:00:40 pm »
Here a couple of tweaks that Mick D has suggested. Highlighted in RED I think they should be included. Thanks Mick.

1) Frame must be of ORIGINAL Manufacture twin shock design. Yamaha non linkage "monoshock" design is allowed. After market twin shock Replica era frames are allowed.
1b) NO re-engineering of linkage design frames converted to twin rear shocks in an attempt to comply are allowed.

2) Any fork, to a maximum of 43mm stanchion is allowed.
2a) Forks must be of ORIGINAL manufacture drum brake design.
2b) NO re-engineering of disc brake design forks in an attempt to comply are allowed.

3) Brakes must be drum type, front and rear. No disc brakes.

4) Any Engine MUST be Aircooled and be from an original twin shock motocross/enduro frame motor cycle. Engines from Yamaha non linkage "monoshock" motocross/enduro frame motorcycles are allowed.
4b) Engines can be of Four or Two stroke design.

5) Replica after market swing arms are allowed.
 
6) Handle bars must be 7/8th cross bar design fitted with a protection pad.
6a) NO fat bar design handle bar is allowed.

7) Footpegs must be of the folding type with a self returning mechanism.

8) A chain guide/guard must be utilised and cover the point of chain return onto the rear drive sprocket.

9) All motorcycles must have an effective muffler/silencer fitted.
Now here is a  black and white set of rules that all can understand and not read between the lines with as the current ones do!!
I'm not against the bigger forks I'm against the way the current rules  are so undefinable and to be able to be read different ways and that's why this discussion has come about.
Andy Viper #70
Honda CR125 RB
Honda CR125RC
Honda CR125RA
Honda CR250RZ
Honda Z50A

Offline Ted

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Re: 79 CR250 Front End Conversion
« Reply #132 on: July 06, 2014, 05:07:27 pm »
This question requires a YES or No response, from the people who interpret the rule as being able to use major components from later model drum brake bikes (in this instance forks)

Can I use 1984 KTM 495 upside down forks on my RM 250 T in the Evo class ?

Thanks.
Stupid question.. No


With the proposed rule change you can use right way up, upside down or diagonally opposed forks if you wish, as long as it came out with a drum brake fitted, irrespective of its linkage rear and water cooled motor if it has one. But why would you bother when you can use 2014 48mm upside down forks. These proposed rule changes will allow that.
81 YZ 465 H   77 RM 125 B

Offline JohnnyO

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Re: 79 CR250 Front End Conversion
« Reply #133 on: July 06, 2014, 05:42:12 pm »
This question requires a YES or No response, from the people who interpret the rule as being able to use major components from later model drum brake bikes (in this instance forks)

Can I use 1984 KTM 495 upside down forks on my RM 250 T in the Evo class ?

Thanks.
Stupid question.. No

Stupid question...Why?
No...Why?
I just applied the same reasoning you do by using forks from a drum braked, air cooled, linkage bike. Plus not to mention the reasoning of no performance gain, some would even argue even worse performance than a set on 1984 43mm Yamaha forks..
So why No?
Evo bikes have always had to have conventional forks, you know that...

Offline JohnnyO

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Re: 79 CR250 Front End Conversion
« Reply #134 on: July 06, 2014, 05:44:05 pm »
The answer to you EVO550 is a no as they are inverted forks not conventional, even though they are drum brake. The sticklers for this are just doing it because they can, it makes no sense at all to "fostering" the sport of VMX racing & will most certainly discourage new participants. As for the Dutch twinshock frankenbike scenario, well that goes against the "spirit" of VMX racing so therefore no fear of that happening. Good thing I'm not a scrutineer, I would decline any bike fitted with tapered bars, black modern rims & gobs of CNC machined billet alloy. Much more of a travesty to vintage bikes than 30 year old conventional forks. The point is moot anyway, it's been proven they are good to go and DT even said so before last years nats so why are these guys so bent up about it? Someone should build a horror of a bike within the current rules & turn up with it to see how they like that, I'm sure the squeals would still come. An example would be a '79 Honda chassis, 1984 Husky 500 engine, '81 YZ465 43mm forks & twin shoe brake with the latest greatest 150 click adjustable rebound/compression shocks, billet alloy everything, Pro taper bars, etc, etc. It's all legal but would be a horrific mismatch and what do you have in the end? A lot worse of a creation than a pair of '82 Honda forks in an '80 model Honda. Please let common sense prevail on this matter.
K
I'm hearin ya K!