Hitchcocks Forum

I fancy doing a Custom job on an old 350 Bullet and looking at the 'net for ideas I often see the exhausts wrapped for the first 20". Apart from making the bike look like Nora Batty, what's all that about???

Mainly cosmetic, to cover up the bluing.

A bit like the chequered go faster tape that used to adorn knackered old cars one time

Reminiscent of an inadequate repair on a drainpipe.



Helps to retain heat to aid exhaust port valve seat burn.

Don't mock it - go faster tape can add at least 10mph to your top speed.

An old timer in "The Trade" told me a good tune up trick was to oil the throttle cable (youngsters never did this!) and put a slick of silicon polish on the saddle, after the service the young customer would swear the engine revved better and was so fast he slid off the seat!


REgards, Mark

Seems to be a fashion in India. Only seen it done back in the day to protect off-road trials bikes from inevitable dings. It hides dented pipes and may reduce noise. Re the trials bikes though, they got soaking wet and the pipes went rusty under the wrap.

http://www.thermalvelocity.co.uk/page.asp?id=distrib

What the exhaust wrap really does is prevent your exhaust tubes to cool down. Therefore an exaust system equiped with the right set of wrap will keep the exhaust gases of your engine at a high temperature. Maintaining the exhaust gases at higher temperatures increases performance on several levels
When traveling at a higher speed in your wrapped exhaust system, the gases will increase the scavenging effect and improve the performance of the intake and exhaust systems as a whole. The exhaust gases are therefore removed faster from your motorcycle or car exhaust system when hot.

Exhaust wrap also improves the performance of the engine in general. Once again, the hot exhaust gases will be expulsed more quickly, leaving room for purer air in the combustion chamber. This will increase the quality of the air-fuel mixture and then improving the engine's performance.

I think the earlier replies are correct. Jeff I think as an ex trials rider the reason for the wrap is to prevent burns in the inevitable spills. Papasmurf just a sales spiel I'm afraid, as the gas cools it shrinks and increases the scavenge effect.

Revband, from a non partisan source:-


http://www.allaboutbikes.com/feature-ar ... haust-wrap
The Benefits
All of the benefits of exhaust wrap revolve around the material’s heat-controlling properties. The most obvious benefit is that fact that less radiant heat makes it to the rider’s legs or the bikes components and body-work. The wrap serves as a thermal blanket that directs more of the heat out of the exhaust outlet rather than the sides of the pipe.

Though external heat control is the primary benefit, there is also a potential performance benefit. Hotter exhaust gasses (as created by the insulation of the wrap) are less dense. Thus, the exhaust “scavenging” can be more effective. In effect, intake and exhaust gasses are pulled more quickly through the engine which increases performance.