Pinky Twinshock Conversion

[andy m]

Hi, I am toying with the idea of converting my Yamaha Pinky to twinshock. The main reason is so that I can ride some neighbouring club trials in twinshock class. Our club HEREFORDSHIRE CLASSIC TRIALS CLUB runs an a/c mono class but the neighbours dont. Is there anyone out there who has done the same, and if so is it much hassle. I ask because the swingarm doesn't have a lot of meat in it, unlike a box section as on a TLM 200, a mate of mine converted his to twinshock in no time. Thanks.

[martinm]

Can be done, guy called Tim Wheeler down in Bristol area has converted one, looks very thin on the rear subframe where the top shock mounts go.

However, bit against the spirit of the whole twinshock thing. You will find that in the ACU's eyes, the twinshock class is open to "motorcycles originally fitted with twin shock absorbers".

Therefore, why not go the whole hog and get a Scorpa/Rev 3/Sherco/Gasgas etc and convert that.....or sell your Pinky and stick the money towards a Majesty.......or get ultra competetive and buy an SWM

Martin

[woody]

Yes it can be done, as Martin said, Tim Wheeler did it to his, as have a couple of others. But the question is why would you want to..?? You're kidding yourself if you think of it as a twinshock. Even with the mono removed and twinshocks added, it is far superior to any proper twinshock and will p*ss all over them in terms of performance, so could you take any satisfaction in any results you achieved on it against actual twinshocks. Not sure how Herefordshire Classic would look on it either

If the other clubs don't run an air-cooled mono class does it really matter? Just ride the route that suits you. A mono Yam is still good enough to win the hard route in a lot of club trials (please note that's club, not centre or national before anyone jumps in and says that's B*****ks)

As far as the ACU goes, it is only the national ACU Classic championship that has the 'must be twinshock as original manufacture' and 'no disc brake' rules. At club level it's up to individual clubs what they allow, but I'm with Martin - it's not in the spirit of the class. Once a few more people do it where does it stop. Monts, Gassers, Betas, all converted to ride as twinshocks..?

Edited July 28, 2006 by Woody

[scorpa3]

As a regular Clerk of the Course for Statford club trials, you would be more than welcome to come and ride in one of our events on such a bike, however you would not be allowed to enter it as a twin shock.

The class is for bikes originally fitted with twin shocks, so one of these is not allowed.

It seems like a lot of bother to go to just to change class when there are plenty of existing classes you can enter and still be in with a chance of doing well.

[andy m]

I'll get me coat!!!!!!

[pitley]

You are welcome to ride your pinky in the Wye Valley AC classic trial series, we have a class for AC monos... Cheers

[greengrass]

Couldn't agree more with Martin and Woody , its definately against the whole spirit of twinshock trials.

Get yourself over to the Wye Valley Classic Trial on 13th August, Pitley puts on a cracking trial suitable for the classic machines (and classic riders).

[mattylad]

Ohhh please!!! there are quite a few that are not as built

Electronic ignitions in Bultaco, Yamaha

Reed valve engines in Fantics

Cotswolds

Improved rear shocks, head angle changed.

Yam mono wheels forks swingarm in majesty and others for better brakes etc.

I therefore question what is the spirit of twinshock?

It is better to have a prototype or special class where any twinshock whatever its heritage can ride.

I would also add a pre '76 class so the early twinshocks are riding against bikes of the same era.

If not we get into the pre-65 situation where fiddle bikes are the norm.

I am just in the process of modifying a TLM 220 to twinshock as I have a SWM Jumbo which is suppost to be one of the best twinshock and can not get away with the power delivery. I will happily ride in a prototype class against ex-mono Yams, Cotswolds, reed valve fantics etc. The point is to have fun against a comparable bike hence the different classes.

My only specification would be aircooled and fitted with drum brakes.

I think it is important to have this debate now so that the same rules are applied by each club equally and we don't get the same problem as in pre 65 where nowt is standard.

By the way would you allow my ex works Ossa monoshock from 1975 to ride in the twinshock class as it is genuine and totally original to the era??

Edited August 1, 2006 by mattylad

[feetupfun]

My 10 cents worth for what to include in any proposed UK national rules for twinshock trials bikes:

Put an era limit on the bike ie major components of bike must have been manufactured before (say) 1986

Specify which major components are controlled (frame, engine external appearance, forks external appearance)

Specify mechanically operated drum brakes and cable operated clutch

Specify air cooling

Specify twin shocks (not sure about the works OSSA but the idea is to exclude 1985 TY250N Yamaha)

Non controlled mods are things which people fiddled with at the time like tanks, seats, mudguards, shockie mounting location, shockie type, exhaust systems, frame chops (steering angle, wheelbase, tubes removed under engines), fork travel

Bikes should be able to be bitzas as long as the major components were made within the era or are exact replicas.

[mattylad]

I still favour 3 classes.

pre 76,

original twinshock any year, must be rigidly enforced

prototype anything goes including lightly modified late twinshock.

aircooled and drum brake only.

[woody]

Well I know everyone is different and I am pretty much for the 'each to their own' philosophy when it comes to peoples hobbies, choices etc. but I just can't see the point or desire to convert monos to twinshocks and ride them in a twinshock class when there are plenty of good, reasonably priced twinshock bikes available if it is a twinshock class people want to ride in. Why convert a mono when there are now classes for air-cooled monos, but also, when air-cooled monos are still very competitive against modern bikes in club trials even now. It's not as if there is a shortage of trials for which those bikes are suitable. Chris Myers still rides the Scottish Six Day on his TY Mono and gets a very very respectable result.

If people want to do it and individual clubs allow them to be ridden, either in or outside of twinshock class/awards then that's fine. I just don't understand it. But the twinshock class really came about as a lot of people in the mid 80s were fed up with the direction trials was taking, tight sections, stop, hop trick riding. Then came the stationary balancing which was like watching paint dry. Most trials back then still only had one route and the older twinshocks in particular were unsuitable for modern sections, so fortunately, the ACU introduced the National Pre65 and Twinshock series, supported initially by Sebac. This enabled riders who preferred the old style of no-stop riding to drag out their old bikes, the ones they had an affinity with and rode when new, and ride them competitively again on sections designed for them. It was a fantastic series and very well supported with all manner of bikes being ridden.

Now the key phrase there is 'the bikes people had an affinity with and rode when new'. That was what the spirit of twinshocks was about. Riders who were too old to change to modern technique, or not good enough, or who just didn't want to were able to ride again on the bike they favoured from that era, either one that they rode at the time, or one that they would like to have ridden but never owned, or whatever, but you get the picture. You rode it because you had some sort of affinity with it. Some still owned a twinshock that they rode at the time and competed again on it. The crux of it was you rode a twinshock because you enjoyed that style of riding and the look/character of the bikes.

They weren't perfect though and as far as modifying them is concerned, there was plenty of that going on during their era. Majesty Yams for example came in so many guises. Supported riders bikes had modified steering, suspension, engines whilst some 'over the counter to Joe Bloggs' Majesties just had the basic changes. Most manufacturers or importers were moving rear shocks all over the place, there were aftermarket frame kits, exhaust mods, reed valve conversions were done on Ossas by Keith Horsman for Ossa UK as long ago as 1975, wheels and forks were swopped around etc etc. So there is nothing wrong in modifying them now - up to a point. The difficulty is knowing what that point is, as wherever someone draws a line, someone else will find a way around it. Most competitors in the ACU Classic accept the limit and where to draw the line and are happy to keep it that way - at the moment anyway.

So fitting electronic ignitions, different forks, shocks, altering head angles and rear shock mounts is nothing new. It is still the original twinshock bike and a heavy lump compared to more modern stuff. I've ridden in the National twinshock championship since it began and there are no twinshocks competing in that, at the moment, that are modified to what any of us 'regulars' would call an unreasonable standard. I don't think fitting say a 303 Fantic engine in a 240/300 gives any real advantage, Paioli forks are better for sure, but a significant advantage, no, I don't think so. Electronic ignition doesn't make it go any better, it's just maintenance free and less hassle. Steering angles, shock positioning is just to suit personal taste. I've never heard any of the regulars complain about other competitors carrying out these mods, but none are in favour of disc brakes or converting monos to ride as twinshocks. Ask anyone what they think of Tim Wheeler's conversion to his Yam and they will just say it is done purely to gain an advantage over twinshocks and to win the class in that centre. I haven't met anyone yet who thinks it is acceptable and I know people complain about it to each other but never to the club officials. Bottom line is, they think it is a cheat bike.

If people want to convert monos to twinshocks and ride them in a specials class, I can't see a problem with them having a class of their own. I still don't see the point but as I said earlier, each to their own. The opinion I've voiced here on the subject is obviously my own, but I can also say it is the opinion of a lot of others too. Feetupfun has some good points in his post.

I'm also aware that my Majesty has been called a cheat bike but the last thing I am is dishonest and the mods were carried out to personalise the bike, not create a fiddle one. There is nothing hidden and it is what I'd have done to one at the time if I'd been able to but I didn't have the facilities so it was easier to buy something that suited me better. But I always wanted one and now I've got one I did what I would have done then. Quicker steering, longer swingarm, electronic ignition, better forks, different exhaust. Yes I used a Yam mono swingarm shortened but that was because I wanted a box section one (as I hate the original one's shape) I can't make one myself but have got just enough ability to shorten the mono one to fit. It's no advantage coming from a mono, it's still just two sticks of metal to the back wheel and the shock position is unaltered, it's just 1 and a half inches longer than sandard. The 'works' Majesties had revavled forks as TY forks are useless, under sprung and under damped. Again, I didn't have the expertise to revavle mine, tried and failed, so was going to fit a pair of marzocchis (Fantic, Armstrong etc) but I had some mono forks. They are no better than marzocchis but look nicer and have the neater mudguard brace, so I used them instead. I couln't get the original Majesty or Fantic type wheels to fit so had to use the mono wheels. Braking performance is no better than the standard wheels and I'd never use them again on anything else as you can't get spokes anymore.

In terms of fiddle performance - Different people have ridden it. One didn't like the steering, one didn't like the front weight bias, another hated the motor, some like most of it but not everything. The point here is no-one has jumped off it and said - it's too good, it's a fiddle bike not in the spirit of it. And that is my point. It's still a big heavy lump of a twinshock, just tweaked to suit me. A mono Yam with twinshocks will murder it.

I couldn't agree more with your suggestion Mattylad, that there should be a class for pre76 twinshocks (or maybe pre75) I would love to see this introduced in the ACU Classic but it would need 2 routes also, something the series needs right now anyway. I don't see a problem with a specials class for the converted monos either, other than the number of classes we'll end up with but the ACU might. As regards the mono Ossa I can't see how they can be excluded from the twinshock class as, like you say, that was their era and they were the bikes they were ridden against. I don't think they were actually that much better anyway. They should qualify purely on the basis that they were fitted with twin shock absorbers as original manufacture anyway. They were converted here in the UK......

PS Mattylad - do you want to sell your SWM as I know someone who may be interested. He was looking at the one on ebay a few months back and was interested but was involved in a house move then. Wasn't yours was it?

[mattylad]

Woody thank you for the considered reply.

I think our opinions differ somewhat in execution but not real substance.

Firstly in Europe we do not have air cooled mono class so that is a non-starter for me.

The problem with allowing obviously modified bikes is that it starts a ball rolling which is difficult to stop.

Just look at pre-65 to see what I mean 5-6000 pounds Ariel and v. expensive cubs.

For me forks do give a significant advantage when they work properly as you say the 250 Yam ones don't (which is one of the reasons I am selling mine and converting the TLM).

For me the biggest problem with genuine twinshocks is the speed of the power delivery, I swap from a modern two stroke and mistime everything so I want a similar response. Maybe I should buy an early Fantic.

As I am over 40 and I am not a pot hunter I just want to ride round enjoying watching others on bikes from my era. I love Hondas and have 4 two strokes and 2 four strokes so for me the solution is easy. It is also a question of personlisation but from a different starting point.

Up to a point many of the mods do make original bikes much better, that is why I think a specials class is necessary as people with original bikes dragged out of the garage will be put off competing. Exactly as has happened in pre 65. Here we have a guy who has got a 250 Yam twinshock down to 82kg....and obviously spent a fortune. My TLM is just as good and costs 500 pounds.

Obviously there is no perfect solution but if thinking converges a good and most importantly, a workable solution can be found.

Woody sorry the SWM is not for sale as I may need it if the TLM is banned!!!

[andy m]

I have got a Gas Gas JT 250 chassis I was going to fit a TLR 200 motor in to ride in a/c mono class. That was until I rode a Scorpa 125 and went and bought one. Its air cooled its mono but there are still people who have a whinge........... until they see me perform. Then they are not too bothered.

[mikedabike]

Bo Drinker, If you wanna do it go for it (physics and mechanics allowing).

Reckon it's more important to have a bit of fun than get caught up in the rules and regulations thing. How many older bikes do you reckon are "out of the box"? OK there are things that some folks disagree with but, I'm with Darwin....Things evolve!

....... Not sure how Herefordshire Classic would look on it either

Pretty sure they won't mind!!

[andy m]

Thanks Mike, Ill be trying a standard pinky out the t*****r has bought and decide from there, as mine is 270cc and a bit sharp for a ***t rider like myself. PS hows the Hereford/cotswold/TY/ coming on. YOU KNOW YOU WILL BE FROWNED UPON BY CERTAIN PEOPLE. Its not the way it left the factory, blah blah blah acu blah blah