Gasket tickness

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FM350
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Re: Gasket tickness

Postby FM350 » Sat Oct 08, 2011 5:33 am

The Chris Koch TY isnt comparable to a £10K modern day "P65"........................but like the "P65" bikes it uses many recently made major parts so should be running in a "specials" class rather than as a twinshock.

However pretty much all of the bikes being used by serious contenders in the Normandale Brit Championship series, are running things like modern front forks, and later motors from mono-shock machines, so we have a situation very much like "P65", where anything vaguely authentic is at a distinct disadvantage.

Riding and competing on older bikes would I think be a lot more popular, with some sensible rules on machine eligibility, and recognising the rather obvious fact that an old Bultaco or Ossa isnt comparable to a money no object Fantic or TLR, and to introduce a specific P78 class which would allow owners of the older bikes to compete against others on the same type of machinery.



JC1
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Re: Gasket tickness

Postby JC1 » Tue Oct 11, 2011 8:44 am

FM350 wrote:

To make a working front pipe for a TY you simply need to use as large a volume as you can fit in the available space, and design it so the front 75% of the pipe contains a passive silencing element, and the rear part is an empty area to allow gases to expand.



Can you post some pics of your own TY's with modified front-box please.


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Guy53
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Re: Gasket tickness

Postby Guy53 » Tue Oct 11, 2011 8:29 pm

That would be usefull, and I was thinking about a DT 360 front pipe, but maybe I not going in the right direction.

Guy



FM350
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Re: Gasket tickness

Postby FM350 » Wed Oct 12, 2011 9:20 am

Not owned a TY for more than 20 years, but the principle of making an exhaust which will improve any 2T bike with a very poor OE system fitted is the same for any older trials machine.

The TY system can be made using a pair of rollers and forming sections of 1.5mm aluminum, along similar lines to the extrusions used on the WES systems, but much larger, with 75% of the internal area being a passive silencer, and 25% expansion area. However while an exhaust such as this will certainly improve performance, other alterations will also be needed for the best possible results.

Here in the UK there is no real point in this type of work though, as Fantic 200 and 240 are both relatively easy to find, and work better than the TY even if it has been heavily modified. Have ridden a TY fitted with a modified 240cc Blaster motor though, and that seems very good, and probably less costly than modifying a stock TY with big bore kits, electronic ignitions, £2k frame kit etc etc etc!



JC1
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Re: Gasket tickness

Postby JC1 » Sat Oct 15, 2011 10:21 am

FM350 wrote: but much larger, with 75% of the internal area being a passive silencer, and 25% expansion area.


Do you mean like a Fantic system?


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FM350
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Re: Gasket tickness

Postby FM350 » Sun Oct 16, 2011 3:42 am

Unless you are pretty good at sheet metal work, it would probably be a good idea to try and get hold of an exhaust system from something like a 305 Fantic, and modify it to fit your TY. Someone I know tried this on a Bultaco, and it made a really big difference with the bike performing far better than with the dreadful OE system.




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