Exhaust pipe heat wrap / lagging?

Does anyone have experience of how motorcycle exhaust pipes cope with exhaust heat wrap over a period of years?

I have read some negative feedback from race car owners who use it on manifolds and headers to reduce under-bonnet temperature. Some damage was reported as a result of accelerated corrosion. I have a stainless high-level exhaust on my G50 and I have used heat wrap for a few seasons to stop the pipe burning through my leathers. There is a heat shield but it is ineffective. This season, I wrapped the header from the cylinder head about 2 feet along the pipe in an attempt to reduce heat in this area because the header curves quite tightly around the left side of the cylinder head and partially masks the fins from the airflow.

Could a thin stainless steel header become brittle as a result of the higher temperature inside the lagging?

Here's the stuff I use: http://www.demon-tweeks.co.uk/Search.do ... =heat+wrap

I would be grateful for some advice on this. I can take some pics if needed.

Dave

I have had some funky patterns on stainless pipes from wrap. Welds using other filler rod had a tendency to rust a little. I broke one mount and re-welded thicker larger contact and had no more problems. Was the break caused by the metal getting brittle from higher heat range in the pipes due to wrap? I don`t know. Probably had more to do with a 625cc single cylinder Vibrator doing extended runs near redline.

willh said:

I have had some funky patterns on stainless pipes from wrap. Welds using other filler rod had a tendency to rust a little. I broke one mount and re-welded thicker larger contact and had no more problems. Was the break caused by the metal getting brittle from higher heat range in the pipes due to wrap? I don`t know. Probably had more to do with a 625cc single cylinder Vibrator doing extended runs near redline.

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Thanks for that, Will. Yes, I guess it's difficult to know if the break happened from vibration or otherwise. The G50 exhaust is held on by springs at the header and by two 'cotton reel' type rubber mounts at the silencer, so it should isolate some of the vibes. BTW, what engine did you have that was 625 cc?

2003 KTM 640 Supermoto, it had wrap on the pipes for a few years. Only removed for weld-up and then re-wrapped. Made service, carb adjustment, etc., easier as you wouldn't leave skin attached to hot high pipes. Also safer with my kids running around or going for the odd ride. Ti end pipe never got too hot as long as the packing was in good shape.

With wrap fitted to a thin gauge stainless pipe, it will be running red hot at sustained higher engine speeds, and not sure this is a god thing? Best way to get over this problem is a composite heat shield, made to fit leaving 4-5mm air gap, with reflective heat shield on the inside surface.

Carbonfibre said:

With wrap fitted to a thin gauge stainless pipe, it will be running red hot at sustained higher engine speeds, and not sure this is a god thing? Best way to get over this problem is a composite heat shield, made to fit leaving 4-5mm air gap, with reflective heat shield on the inside surface.

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There's not enough room for a heat shield around the cylinder head area.