Silencers, Exhaust Deflectors & Extensions

Silencers, Exhaust Deflectors and Extension pieces for the majority of popular engines.......

Definitions:

c; is the distance of mounting bolt (centre to centre) (note; 35mm silencers will also fit O.S. and O.S. 'copy' engines that measure 35.5mm)

Bolt: If the silencer 'bolt' size is Mx eg M3 - it means M3 bolts thread into the silencer flange.

Bolt: If 'bolt' size is xmm eg 4mm - it means that there is a hole for a 4mm bolt to go through the silencer flange and (thread) into the engine crankcase

e; total length to end of bolt (inc. locking nut)

Weight is in grams (1oz. = 28.35g)

Measurements are in mm

Standard Silencers

Standard: one expansion chamber with no baffles.

*1 also useful as a small compact stunt silencer for .32-.46 engines.

Quiet Silencers

Quiet: 1 baffle in silencer making it a 2 chamber silencer.

*1 has no baffle but is much quieter than std .10/.15 silencer due to its far larger volume

*2 also fits O.S. 35.5mm engines

Super Quiet Silencers

Super Quiet: 1 baffle (2 chambers, as above) + silencer extension - making silencer larger volume and therefore quieter.

Notes on Super Quiet Silencer

Now this is where it gets clever!! - See diagram for baffle position and baffle options. Spares are fully available; a) front section with exhaust flange, b ) middle extension, c) baffle, d) tail piece, e) assembly bolt, f) pressure nipple g) silencer bolts (2)

This silencer has been designed to allow you great flexibility in set up;
Baffle position A gives you the lowest noise. Position B gives you the best performance (200-300rpm+) but obviously at higher noise. You can open up the baffle holes (by using a pointed noise pair of pliers) for more performance or close them (use a hammer and a piece of dowel on a flat surface) to reduce noise but be careful, closing the baffle holes too far or closing too many will cause the engine to overheat and create engine running problems. If this happens just open out the baffles again until satisfactory running is achieved.

Note C: The silencer (and engine) can be further quietened down by drilling and tapping either a M3 or M4 bolt (a cap head bolt is ideal) through the end of the outlet as close to the end of the outlet as you can. This reduces the outlet area and reduces noise. Again, some care and attention is needed here. Firstly - only drill and tap at 90 degrees to the join line (the part being cast in 2 parts) never through the join line or it will split. Secondly - this will increase ‘back pressure’ to the engine and it the bolt is too big (and reduces the outlet by too much) the engine will over heat (and the needle will become sensitive). Once you are happy with the noise reduction (and performance) of the engine, take the bolt out and re-fit with a permanent heavy thread lock (e.g. Loctite 648) and file down the head of the bolt (optional) so as to improve the appearance of the silencer.

The super quiet silencer (diagram below) assembles with a long bolt that threads into the rear tail piece. This is important the nut at the end is simply a lock nut for the assembly. If you try and tighten the silencer only by using this nut you will strip the threads!! To dis-assemble (in order to position the outlet at the position suited to the model) unlock the lock nut (turn anti-clockwise) - then take assembly bolt out of silencer with the appropriate sized screwdriver. Re-assembly is the opposite - use the right screwdriver to tighten the bolt into the tail piece, then use the lock nut for added strength using a small spanner.

Should either silencer leak, simply dis-assemble, (as above) clean up the components and use high temp silicon or liquid gasket (from a car accessory shop) around all the joints. Re-assemble and clean off the excess silicon.

Questions

Please ring, fax or email for more information or pricing, or if you can't see what you need.
Tel: 01228 712800, Fax: 01228 712800, Email: justengines@enterprise.net