same guy who built Chris Koch's twin shock legal bike , still interested !

ty mono forks seem to be the safe bet from the owners who have fitted

them !

Still no concrete ideas on any twin shock guidelines/rules ! how about

pre75 original

pre85 original

twin shock evo e.g. new frame kits/mono sourced parts/one off specials with

air-cooled motor and drum brakes !

original class means just that , how it left the factory to exclude ,

cables, handlebars/controls, electrical systems, tyres and rims!

Anyone else got any idea's !

Suggestion.

If folk want a set of rules, then arrange a seminar/meeting for all those intrested with the Trials and Enduro Committee up at ACU HQ. Its the only way forward.

This needs to be done sooner than later, else we will end up in the same cart as Pre65.

majestyman340,

I'll post a few shots of Trevors's frame and final build tomorrow.

Tony

I have seen pics of the chassis already, but not the final build.................looking forward to seeing pics, thanks.

Last time i saw a picture of Trevor Kemps Majesty it had mono forks fitted.............................

Funny old life init...

Trevor I think is based in the US where he takes part in ITSA events, which have a specific class for evo type twinshocks with later parts fitted. Spoke to UK based chassis builders who made his one off frame yesterday, and apparently its quite a bit different to the original item.

Michael I am enough of a perfectionist to have done that sort of experiment you described with moving the pieces of lead around to see if it was noticable.

I had solid aluminium handlebars on a standard TY250 twinshock and thought it was not quite as nice in some types of turns as my other TY250s which had tubular aluminium handlebars - particularly turns where rapid bar movement was required. My experiment was to swap the bars between the bikes so a different TY250 had the solid bars. Both sets of bars had the same shape and were the same width. No change to tyre pressures or fuel tank contents or anything else except the handlebars.

Yes it made the previously very "nice" steering TY250 noticably harder work to do turns that alternated quickly from one extreme of steering angle to the other. Since then I have been an advocate for minimising mass in the steering particularly at the ends of the bars and the wheel rims/tyres.

I find the steering geometry of both my standard TY250s and my Godden Majesty to be quite wonderful compared with the other twinshocks I use in competition (OSSA MAR, KT250, Cota 348) for the type of riding we do here which is dry, tight and with plenty of traction. I suspect that if we rode mainly wet, mossy boulder strewn creek beds, that other bikes like the later model Sherpas might be just as as good or even better. I find Sherpa T steering to be as sublimely pleasurable in those conditions as the Yamaha 250s are sublimely pleasurable in the opposite conditions.

For people with TY twinshocks, did you know that the D model TY250 rims are lighter than the A and B model rims and so provide slightly less moment of inertia as Michael has explained. Not sure about C model rims.

This weekend I will be mostly riding my 1968 Sherpa complete with chopper head angle and thoroughly enjoying riding it too - providing it doesn't break down, first time out on the road on it. Ah, but it will have modern footrests fitted so I've entered the specials class..

Woody

I have an early type M49 (M49-00100) and am considering relocating the footpegs to make it a bit easier on the body to ride. I'm guessing from your remark about your bike having to be entered in the specials class because it has modern footpegs that you have also moved the footpegs. If you have, please advise what you did with the footpeg location and the footbrake arrangement and what you think of the changes.

Thanks

David Lahey

Woody

I have an early type M49 (M49-00100) and am considering relocating the footpegs to make it a bit easier on the body to ride. I'm guessing from your remark about your bike having to be entered in the specials class because it has modern footpegs that you have also moved the footpegs. If you have, please advise what you did with the footpeg location and the footbrake arrangement and what you think of the changes.

Thanks

David Lahey

Yes, I've lowered them about level with the bottom frame tubes and set them back but only slightly

I made new footrest hanger plates (ie; the ones that bolt on) and then welded another piece at the bottom of each at 90 degrees to the hangers to get the rests as low as possible. I couldn't get them low enouh on the original hangers. This gives an L shape - or reversed L on the other side of the bike. I then attached the new footrest brackets at the bottom of the L (eg; on the toes if you imagine the L as an ankle and foot) I had to space the piece I welded on out from the frame so it didn't foul the frame downtube which sits out further than the original footrest hanger.

The rear brake I've left as I can still reach it ok but as I hardly ever use it it's not a problem. The original brake pedal is a hideous concoction to look at anyway so I was going to replace it with a later alloy one anyway if I can get hold of one.

The bike is now much more comfortable to ride with the lowered pegs. Once I've had a couple more rides on it to satisfy myself they are ok I'll remake the brackets neater. Can't post photos unfortunately but I can email you some if you need.

Thanks Woody

I reckon I know what you mean about the L brackets. I'll ask you again in a while when you are happy with the location then I'll make nice looking brackets using what you reckon is the best position. I'm pretty keen to get rid of the original brake pedal too. It really is a monstrosity and reminds me of what was on 1960s Japanese commuter bikes.

David

Majestyman,

Here are the pics. 2 frames made one for Mark Kemp and this one (still in the raw) for Bob Ginder of BJ Racing.

Bob's Frame

Mark's bike in finished state 30lbs lighter!

Different bash plate and exhaust routing

.....and with ITSA rules for Modern Classic Twinshock

Drum Brakes

TwinShock

Air Cooled Engine

Tony

Any idea what sort of price the one in the raw cost to have made over there. (the frame)

The other is a beauty, though not quite finished. Can't see a kickstart???

Oh look at those forks, what ever you do don't mention the forks, I did once but I think I got away with it.

Edited March 8, 200818 yr by bo drinker

bo drinker,

I guess he saved a couple of lbs by not having the kicker! These frames were made by a friend of Mark Kemp in the UK by the same company that does Valentino's race frames........ the price may not be available to mortals!

The forks of course come from "another" Yam but are acceptable under our ITSA rules.

Tony

Majestyman,

Here are the pics. 2 frames made one for Mark Kemp and this one (still in the raw) for Bob Ginder of BJ Racing.

Bob's Frame

Mark's bike in finished state 30lbs lighter!

Different bash plate and exhaust routing

.....and with ITSA rules for Modern Classic Twinshock

Drum Brakes

TwinShock

Air Cooled Engine

Tony

Thats lovely............wonder why they didnt modernise the geometry of the chassis tested in Classic Dirt Bike, in the same way as this one?

Any idea what sort of price the one in the raw cost to have made over there. (the frame)

The other is a beauty, though not quite finished. Can't see a kickstart???

Oh look at those forks, what ever you do don't mention the forks, I did once but I think I got away with it.

ITSA in the US has a specific class for twinshock bikes with non standard modern parts fitted................

bo drinker,

I guess he saved a couple of lbs by not having the kicker! These frames were made by a friend of Mark Kemp in the UK by the same company that does Valentino's race frames........ the price may not be available to mortals!

The forks of course come from "another" Yam but are acceptable under our ITSA rules.

Tony

Is this the same Mark Kemp that used to run BVM Moto in the UK?

Buy run it into a wall i did not mean at 40 MPH ! BUT just enough to open up a gap

it the top tube, after you have cut it

Reading the posts maybe it only needs, must be aircooled motor, adding

to the championship regs already in place !

That should at least stop any future 4RT twinshock worries !