Penton/Wassel trials

[matt]

I have a 1973 wassel trials fitted with the 125cc Sachs engine. When using in trials the motor is too peaky and will not pick up smoothly off the bottom end. By the time it does pick up traction has been broken.
My question is has anyone got any ideas on how additional flywheel weights could be added? Does anyone know if an after market modification was ever made.
Thanks.

 

[Paul Danik]

Matt  I have both the Wassel and  Saricen trials machines that are 125 Sachs powered.  I know of no flywheel weights that can be added.  What I would check first is to be sure that you have an "A" engine. The A engines have a heavier crank and have more bottom end.  You can tell by checking the engine plate that is located on the top of the ignition cover. If the piston, rings , seals and timing are all OK, the place to work is the carb. I have leaned out the bottom end of my Saricen so that the responce is crisp and clean right off of the bottom.  Work with the needle first.  Then try a smaller main jet if you need to.  The carb is the place to search for a clean responce off the bottom. My Wassel has a cast iron cylinder, it is an early engine, I have put a high compression head on it and that has helped.  My Saricen has an alloy cylinder and head.  Also be sure to apply the throttle slow as to allow the engine to pull smooth.
Good luck, and let me know how it works out.  Paul Danik

 

[matt]

Paul,Thanks for your reply.I can confirm that I have the 125/A engine. I have tried other mods which seems to work. I have replaced the base gasket with one that is 0.25mm thick.(original thickness unknown as it split in two when I seperated the barrel from the crankcases, however it was really substantial, I estimate it to be approx 1mm thick. Can anyone confirm an original thickness)  This has the effect of reducing the exhaust port and transfer port timings, whilst increasing the compression ratio. This definately had the desired effect. I then retarded the ignition progressively to 2.4mm BTDC. The machine is much better for these mods.
Does anyone know of any variable thickness head gaskets, as the one on mine has an aluminium insert in the gasket material.I would like to reduce the squish clearence some more.
I will now try to improve throttle response from the carb. Currently it is fitted with an  original selection of jets as per Clymer manual. These are in a 26mm Bing body.
Can anyone define their carb settings to provide a common platform to work from. Thanks again.

 

[Okie (Dane Marable)]

Hey Matt
I use a colored silicon seal for a base gasket and also used it for a head gasket.  Don't glob it on just a thin coating will do. All so try the ignition at 3mm btdc and use a slow turn throtle assembly.  
See Ya
Okie