Yamaico's new el Cheapo Project.

[yamaico]

Bugger you Pete..The contest for the trickest bike in the Kevlar Kompound at CD9 just got seriously interesting! 

I think some of the tackle you're getting ready will set the bar pretty high Mark. We'll have a bunch of Yamahas between us though.

pete dont forget the smaller version we talked about over a sherbit at the auckland speedway!!

Running out of time Mike, but I've still got backup.

totally impressed yet again Pete.
i've been riding a bit of trials this year on my TY175 and have seen quite a few "home specials" in the twin shock class, TS250, later DT175 converted to twinshock, a CT honda AG bike thing to name a few. the port specs on that thing of yours will be pretty close to TY specs as is. a 22mm carby would be nice
but you do realise you'll need to make 3 pipes as the first 2 will be crap
great idea

The pipe is the biggest worry Mick. No-one seems to have any idea how a trials pipe actually works. Not really sure what to do at this stage, so I'll push on with the rest of it, and leave the pipe until last.

[Flatout]

I've logged in..so how come I cant see any of these photos..

[EML]

My thoughts are that the pipe will work pretty well as it is. And it looks ok for the era.
Having said that, the Villiers/Bantam I rode at the Nats(MX) was set up for trials and has a straight pipe into the front half of a hotdog muffler that is then weld into the second half which seems to be turned around (reveresed) Works ok too. 

[bazza]

Petes pipes are a work of art

[vandy010]

Trials pipes
not that i'd know but i'd go for a long header section, long divergent cone, belly section optional with a strongly tapered baffle cone.
plenty of tourque but not much over rev.
maybe a smallish stinger diameter?
something like that for a starting point.
an upcoming project for me is to put a DT100 motor into a TY175 roller which will need a pipe also,
so i'll be watching with interest Pete.

[Mick D]

Once again you're putting the rest of us to shame Pete, good work.

Yeah, that's exactly what I was thinking too Steve

but on the other hand I love seeing the ongoing productions of Pete's art work

[yamaico]

Trials pipes
not that i'd know but i'd go for a long header section, long divergent cone, belly section optional with a strongly tapered baffle cone.
plenty of tourque but not much over rev.
maybe a smallish stinger diameter?
something like that for a starting point.
an upcoming project for me is to put a DT100 motor into a TY175 roller which will need a pipe also,
so i'll be watching with interest Pete.

My thoughts are that the pipe will work pretty well as it is. And it looks ok for the era.
Having said that, the Villiers/Bantam I rode at the Nats(MX) was set up for trials and has a straight pipe into the front half of a hotdog muffler that is then weld into the second half which seems to be turned around (reveresed) Works ok too. 

Now I'm confused. I can't use the standard pipe as it is rusted out, but I could model it off it, or the TY pipe, or just start from scratch with something like Vandy says. Have to give it some more thought...

Got some work done over the weekend. Made up the rear shock mounts and tacked them in place. Made up the footrest brackets and rear brake pedal and rod. Dropped the springs out of the forks so I can see how much clearance I've got for the pipe, which turned out to be plenty. The kickstarter is a bit of a problem, even a TY one won't clear the brake pedal so I'll probably use the original and position it forward and kick onto the footest, a la Bultaco.



Also cut about 25mm out of the tank width and made up a base for it and tacked it in place. Machined up the filler neck to suit a TY style filler cap and welded it in.



Not sure what the tank will look like, but I'll know when I mock the bike up.

Vandy, if you get some time would you be able to measure the offset in your MX125 forks for me? Thanks. You need to start thinking about a colour scheme for this one too

[vandy010]

Vandy, You need to start thinking about a colour scheme for this one too

easy Pete,
TY250D Blue
i'll measure the triples tomorrow and put it up here but it's possible it's pretty close to what the CT3 would be.

[EML]

I was looking at my Ossa Explorer pipe yesterday and as was said in the thread above, there isn't much 'expansion box' about them, just more like a couple of bits of pipe with a square-ish 'box' in the middle. Then a muffler banged on the end! Not sure how they make power out of them at all.

[vandy010]

Here's some 30mm Yammie triple info Pete.
i do have some spares depending, so let me know which set~up you like and i may be able to help.
Note:- "old" AG175 is the good old Orange tank we all knew as kids
         "new" AG175 is the later blue model with leading axle forks and laid down shocks.

also, i found this in my computer.it may help, even if it is from a modern trials bike.
 just disreguard my spelling mistakes

[firko]

I was looking at my Ossa Explorer pipe yesterday and as was said in the thread above, there isn't much 'expansion box' about them, just more like a couple of bits of pipe with a square-ish 'box' in the middle. Then a muffler banged on the end! Not sure how they make power out of them at all.

Ditto my hand made Maico trials bike. There doesn't seem to be a lot of science in the exhaust design but the bike performs really well in trials situations so the original builder must have done some form of exhaust research. I had a bit of a look through A. Graham Bells 'Performance Tuning in Theory and Practice' bible and there's not a mention of trials exhaust design.


Pete..As far as the colour scheme goes, I reckon the original Yamaha design would look cool. I've got half a litre of original Candy Apple Tangerine Yamaha paint left over from the DT1 from Hell that I'll give you when you come up to get the DT2MX. You can buy the CT3 stripe kits from Speed and Sport on eBay http://www.ebay.com/itm/YAMAHA-AT3-CT3-TANK-COVER-DECAL-GRAPHIC-KIT-LIKE-NOS-/360222833737?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item53def43c49

[firko]

I've just pulled my garden shed apart looking for the swingarm off the DT1 from Hell when I came across a silencer/pipe mid section from a Honda TL125 that I'll gladly donate Pete. I know it's off a 4 stroke but you never know with these things. I also found the Telesco shocks I'd promised Jerry for his Pomeroy replica but still no swingarm

[EML]

According to those figures the AG175 should steer just like an MX124---yep, they got that right---they both steer like crap

[yamaico]

I was looking at my Ossa Explorer pipe yesterday and as was said in the thread above, there isn't much 'expansion box' about them, just more like a couple of bits of pipe with a square-ish 'box' in the middle. Then a muffler banged on the end! Not sure how they make power out of them at all.

This is what is confusing - doesn't seem to be a lot of science. or we're missing something.

Here's some 30mm Yammie triple info Pete.
i do have some spares depending, so let me know which set~up you like and i may be able to help.
Note:- "old" AG175 is the good old Orange tank we all knew as kids
         "new" AG175 is the later blue model with leading axle forks and laid down shocks.

Thanks very much Mick, you went to a lot of trouble there - much appreciated. The CT triples are about 48mm offset so a set with 60mm offset would be good. The MX125 ones are the go as they are aluminium. There's a set on ebay for about $85 to my door from the US, which isn't too bad.
With regards to the pipe, I guess I'll go with something similar to that Beta one. It would be nice to apply some science, but in the absence of that, I might see if I can patch the original CT pipe up so at least I can have baseline to start with, otherwise I'll never really know.
TY 250 blue, or Mark's kind offer of original paint? Both good ideas, but as I am absolutely hopeless with colour schemes, I'll let that sit for a little while.

I was looking at my Ossa Explorer pipe yesterday and as was said in the thread above, there isn't much 'expansion box' about them, just more like a couple of bits of pipe with a square-ish 'box' in the middle. Then a muffler banged on the end! Not sure how they make power out of them at all.

Ditto my hand made Maico trials bike. There doesn't seem to be a lot of science in the exhaust design but the bike performs really well in trials situations so the original builder must have done some form of exhaust research. I had a bit of a look through A. Graham Bells 'Performance

I've been through it too Mark. The principles could be applied, but I think it might be rather long, which I guess isn't a problem. I can curve down to the swingarm from the tank as the little CT frame has a single backbone, which leaves enough room either side.

[Freakshow]