Gasket tickness

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David Lahey
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Re: Gasket tickness

Postby David Lahey » Thu Oct 06, 2011 10:32 pm

I can't recognise one single part on that bike that originated from a TY250 twinshock


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Re: Gasket tickness

Postby Bully fanatic » Thu Oct 06, 2011 11:58 pm

What about the front mudflap David it looks like it could be of an early TY. :D :D . Graham.



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Re: Gasket tickness

Postby Guy53 » Fri Oct 07, 2011 1:41 am

I think David, that your mind is close, the colour of the Yamaha logo look the same as the 76 model , Hi Hi, seriously my point is not that we should all '' transform '' our TY's into whatever that bike is, but what's the problem with making the ride fun espacialy for a non championship seeker like me, by '' preparing '' our bike so it will be pleasant to ride, I'm not the kind of rider that take my bike out of the shed 10 min before a comp. I enjoy fussing aroun the thing ( but not on the look ) . Also, the more I think about the restricted exhaust the more I think your right. I know that you can '' calculate '' a pipe, it would be fun to have one calculated for a std TY 250.

Guy



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Re: Gasket tickness

Postby FM350 » Fri Oct 07, 2011 5:54 am

Jon V8 wrote:FM, I guess you mean this bike;
TY250.jpg

I really fail to see how this bike is accepted in the Sammy series,its just not in the spirit of twinshock trials.Chris Koch would most likely still win on a bog standard whatever.Using bikes like that just winds up other riders who use appropriate kit.



Chris's bike complies fully with the ACU rules relating to the TS class, which require that the frame was originally built as a TS, with no modified mono's allowed. Jon Bliss who built the bike contacted the ACU to confirm these details before he started on the project.

However in terms of function the almost stock 300 Fantic pictured behind Chris's bike is every bit as good, and probably better in events where power is an advantage.

Bikes that are genuinely not in the "spirit" of competing in classic trials, are the modern day British specials, which are ridden in the "P65" class, and are actually far superior to anything vaguely reassembling an authentic older machine, and certainly provide their riders with a big advantage.



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Re: Gasket tickness

Postby FM350 » Fri Oct 07, 2011 6:05 am

Guy53 wrote:I think David, that your mind is close, the colour of the Yamaha logo look the same as the 76 model , Hi Hi, seriously my point is not that we should all '' transform '' our TY's into whatever that bike is, but what's the problem with making the ride fun espacialy for a non championship seeker like me, by '' preparing '' our bike so it will be pleasant to ride, I'm not the kind of rider that take my bike out of the shed 10 min before a comp. I enjoy fussing aroun the thing ( but not on the look ) . Also, the more I think about the restricted exhaust the more I think your right. I know that you can '' calculate '' a pipe, it would be fun to have one calculated for a std TY 250.

Guy



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. Link this to something like a modified YZ125 back box, and you have an exhaust which will in conjunction with some changes to the intake system, and alterations to the porting and squish, totally transform the lack lustre stock TY250. In terms of the work involved though, if you can do it yourself the cost will be very little, as the only new parts needed will be a flat slide carb, a few gaskets, and material to make the exhaust.



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Re: Gasket tickness

Postby David Lahey » Fri Oct 07, 2011 7:34 am

FM350 wrote:Chris's bike complies fully with the ACU rules relating to the TS class, which require that the frame was originally built as a TS, with no modified mono's allowed. Jon Bliss who built the bike contacted the ACU to confirm these details before he started on the project.

Where some cunfusion enters the discussion is that while the UK ACU rules may allow for recent manufacture of a bike frame for Twinshock class, here in Australia, for Twinshock class there is a major items manufacturing date cutoff of 1987. I realise the motor and wheels on that Bliss bike are pre-87 but the frame is obviously not pre-87.


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Re: Gasket tickness

Postby Guy53 » Fri Oct 07, 2011 9:41 am

FM, what do you mean by passive silencing element, I don't think you are tinking '' stuffing '' like material. Please explain I am as bloqed as my TY pipe.

Guy



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Re: Gasket tickness

Postby FM350 » Fri Oct 07, 2011 5:31 pm

David Lahey wrote:
FM350 wrote:Chris's bike complies fully with the ACU rules relating to the TS class, which require that the frame was originally built as a TS, with no modified mono's allowed. Jon Bliss who built the bike contacted the ACU to confirm these details before he started on the project.

Where some cunfusion enters the discussion is that while the UK ACU rules may allow for recent manufacture of a bike frame for Twinshock class, here in Australia, for Twinshock class there is a major items manufacturing date cutoff of 1987. I realise the motor and wheels on that Bliss bike are pre-87 but the frame is obviously not pre-87.


Here in the UK you can buy brand new £2k twin-shock and "P65" frames, so I guess the ACU had to OK the use of recently made frames on older bikes? None of these is as good as the Jon Bliss TY frame though, and personally I feel that anything with major parts from a later period should run in a "specials" class.

Costs in the UK are already completely out of hand in the "P65" class, with people spending up to £10K on building Brit "Specials" which are allowed by organisers to run as "P65's". The same thing to starting to happen with twin-shock, with the appearance of £7k TY Yams, and cobbled up bitsa RS Honda's built with TLR parts.

In terms of competitiveness though a well built stock 240 or 200 Fantic is far better than the top dollar TY's or RS Honda's, so hopefully TS wont go down the pan in the same way as "P65" has here.



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Re: Gasket tickness

Postby FM350 » Fri Oct 07, 2011 5:37 pm

Guy53 wrote:FM, what do you mean by passive silencing element, I don't think you are tinking '' stuffing '' like material. Please explain I am as bloqed as my TY pipe.

Guy



Passive silencing is generally glass wool type packing around a perforated core, and active is an arrangement of steel tubes, baffles etc, which work by reversing flow of exhaust gases. Passive silencers work better for serious competition, but do tend to get clogged pretty quickly on TS bikes, as many owners still seem to insist on using too much oil in the petroil mix.



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Re: Gasket tickness

Postby Jon V8 » Fri Oct 07, 2011 11:14 pm

FM350 wrote:
David Lahey wrote:
FM350 wrote:Chris's bike complies fully with the ACU rules relating to the TS class, which require that the frame was originally built as a TS, with no modified mono's allowed. Jon Bliss who built the bike contacted the ACU to confirm these details before he started on the project.

Where some cunfusion enters the discussion is that while the UK ACU rules may allow for recent manufacture of a bike frame for Twinshock class, here in Australia, for Twinshock class there is a major items manufacturing date cutoff of 1987. I realise the motor and wheels on that Bliss bike are pre-87 but the frame is obviously not pre-87.


Here in the UK you can buy brand new £2k twin-shock and "P65" frames, so I guess the ACU had to OK the use of recently made frames on older bikes? None of these is as good as the Jon Bliss TY frame though, and personally I feel that anything with major parts from a later period should run in a "specials" class.

Costs in the UK are already completely out of hand in the "P65" class, with people spending up to £10K on building Brit "Specials" which are allowed by organisers to run as "P65's". The same thing to starting to happen with twin-shock, with the appearance of £7k TY Yams, and cobbled up bitsa RS Honda's built with TLR parts.

In terms of competitiveness though a well built stock 240 or 200 Fantic is far better than the top dollar TY's or RS Honda's, so hopefully TS wont go down the pan in the same way as "P65" has here.

I am confused as to what your stance is - first off you make the point that tricked up bikes like Chris Koch's are needed to compete at the upper levels of TS in the UK. Now you are saying that bikes with major parts from a later period should run in a specials class?
Maybe the odd bike does change hands for 7-10k,but these are the exception,and at club level there are still lenty of people like me riding round on old sheds enjoying every moment.Even if I wanted to upgrade my Ariel it need not cost that much; http://www.ebay.co.uk/itm/Ariel-HT-Tria ... 1c1f667b43
I think there will always be people willing to part with big cash,whatever sport they take part in.I would spend a bit more if my kids were not still at school etc, but I still admire people like Steve Allen who has won the Sammy series for the last few years on a '51 Matchless rigid - its only mods are modern tyres and footrests.




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