[howard]

Do any of you boffins know what is the best exhaust system for a 32A Villiers trials engine and where to get one? Is a true silencer better than an expansion box? What sort of packing is best? Does length matter!!!??
Thanks in anticipation.

[bigshineybike]

Howard, I started a thread like this in pre 65 section
http://www.trialscentral.com/forums/index....showtopic=24592

I havent taken the advice given yet, but have spoken to greeves about an off the shelf item from their cataloge at around £90
I would though like to understand the ins and outs before choosing as there are several approaches to the final choice.

I am not so bothered about origionality so much as reliable and within what I can afford or make myself.

[pgc40]

I have experimented with various exhausts for my 32A Villiers Greeves as I have the same problem trying to find a replacement silencer here in the USA. I found that without an expansion chamber the bike ran flat as a fart. No power band. My original tin exhaust can was so loud (even with new wadding)that it deafened me and everyone within a 2 mile radius and was annoying to ride see ...... http://greevesmotorc...s.blogspot.com/

I have therefore decided to put on a NOS pipe designed for an early 70's Yamaha enduro (DT250)and fabricate a new header pipe. I will post some photos once I have finished it next week.

To make matters worse, here in the US there are noise regs for offroad bikes (below 98 dbs)and I have to fit a spark arrester to prevent wildfires. I would be interested to find out what solution you came up with together with a photo.

Cheers,

PS Villiers Services do not stock anything to fit.

[htrdoug]

pgc40, on 23 October 2010 - 05:56 AM, said:

I have experimented with various exhausts for my 32A Villiers Greeves as I have the same problem trying to find a replacement silencer here in the USA. I found that without an expansion chamber the bike ran flat as a fart. No power band. My original tin exhaust can was so loud (even with new wadding)that it deafened me and everyone within a 2 mile radius and was annoying to ride see ...... http://greevesmotorc...s.blogspot.com/

I have therefore decided to put on a NOS pipe designed for an early 70's Yamaha enduro (DT250)and fabricate a new header pipe. I will post some photos once I have finished it next week.

To make matters worse, here in the US there are noise regs for offroad bikes (below 98 dbs)and I have to fit a spark arrester to prevent wildfires. I would be interested to find out what solution you came up with together with a photo.

Cheers,

PS Villiers Services do not stock anything to fit.

Looks like your present exhaust would not have any significant back pressure,Stinger(tailpipe)is far bigger than even a 500cc two stroke would need.When I was a kid we'd yank the baffles out of our trailbikes and have dad weld a washer with a 3/4" hole at the end of the exhaust,they'd run fine(not better than originally baffled,just louder!)If you want to keep the cool old Greeves look install a J.C.Whitney baffle into the tailpipe and experiment with different size washers to adjust the back pressure,be cautioned that if it starts to run great with alot of top end zap it may overheat the piston and kill it.


I'm no two-stroke exhaust expert as far as design engineering but I'd try gutting that muffler into a open chamber and then integrating a conventional two stroke silencer core inside a big tailpipe for a vintage look.
JCW has these specifically for two-strokes(made by pertronix)1 1/2" outside diameter


Conventional Expansion Chambers are not necessary,and might be counterproductive as they are tuned to specific power ranges,personally,when I rode Harescrambles the only time I noticed and power loss from a dented pipe was when I mashed my KTM headpipe down to a half-inch wide against the ignition cover

[htrdoug]

Also,if I ever get a bike with earl's forks I want to add slotted axle mounts and snail cams to them so I can adjust the trail until steering's perfect.(surely someone's done that already though)

This post has been edited by htrdoug: 23 October 2010 - 01:08 PM