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Thread: interesting experience with exhaust wrap

  1. #1

    interesting experience with exhaust wrap

    My header pipes are probably the most unattractive part of my bike, slightly pitted and old, but overall solid. They just look silly with new chrome dunstall replicas and an otherwise clean bike. I figured I'd go the cheap route in "hiding" their appearance with exhaust wrap, it would look good with the rest of the bike as it has a giuliari sport seat and a cafe treatment. I have heard of the benefits of wrap from old VW guys that swear by them in reducing engine compartment temps but considered them useless in a boxer powered bike because cooling is almost a non-issue while running, the choice was purely aesthetic.

    I wrapped them tightly, but left about 1/8th inch of space where the crossover tube meets the j-pipes, just couldn't get it covered and it wasn't noticeable unless really looking for it. Took it for a ride, bike ran normal, carbs were in tune, synced correctly, valve adjustment was flawless (I know because I had just done it and rechecked it the next day after this incident) and everything was going great. This ride was during the daytime and I wasn't paying particular attention to my header pipes. Took it for another ride on my way to work (before the sun came up) and noticed the header pipes were glowing red in that 1/8th of bare metal I could see, nothing could be determined past the wrap. This was on the highway, once I was on back roads they looked fine. This was also only about 5 minutes into the ride.

    Assuming this was merely a lean condition I enrichened the mixture and tried again later, same results. I then enrichened it to the point at which the idle was pretty poor and again had the same results. At this point I took the wrapping off so I was back down to bare metal, based on the markings on the inside of the wrap, it appeared that the only "red hot" areas of the headers were in the bend immediately exiting the cylinder head. I left the pipes bare, and leaned out the carbs back to their original, "normal" mixture and went for a ride and the pipes were fine, no glowing whatsoever.

    Now, the bike ran normal with the wrapping on and if there hadn't been that small space of bare metal showing I would be none the wiser to any change in my header pipes, but since I don't want them possibly welding themselves to the head or weakening them any further, I'm leaving the wrap off.

    Anyone have a similar experience? On a positive note, it seems to have cleaned some of the surface rust off the header pipes
    // 1975 BMW R90/6 (cafe'd) // 1957 BMW R60 (in pieces) // 1967 Aermacchi/H-D Sprint 250 SS (custom special) // 1967 Moto Guzzi V700 (current restoration)

    http://symphonyofshrapnel.blogspot.com

  2. #2
    Yarddog
    Guest
    I understand that wrapped pipes do make bikes run lean, and that was only from reading a tech article in one of my Harley mags a couple of days ago... I'm not a fan at all of wrapping pipes, for the same reason you describe...it just cannot be good for the pipes, or the engine, for heat not to escape...what I did with my own exhaust when I redid my bike, because they looked funky, too, and I didn't want to spend the money to rechrome them, is that I sand blasted them and painted them with House of Kolor High Heat Black...very expensive material, over seventy bucks a quart, my price, for the paint, but also a very high quality paint...no problems since, and they look great, a year and a half later...

    Were I you, I'd consider this option, but for SURE I'd unwrap those pipes... there will be others who disagree with that, but for just appearance reasons? Naw, there are better options, in my opinion...

  3. #3
    They're definitely staying off, probably will go the paint route as well.
    // 1975 BMW R90/6 (cafe'd) // 1957 BMW R60 (in pieces) // 1967 Aermacchi/H-D Sprint 250 SS (custom special) // 1967 Moto Guzzi V700 (current restoration)

    http://symphonyofshrapnel.blogspot.com

  4. #4
    Registered User lmo1131's Avatar
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    I went the "Hi-Heat" paint route myself. It's was a rattle-can product and has held up surprisingly well. They are starting, after a year, to look a little ratty and I was considering going the "wrap" route ... but now, I don't think so. I think I'll just reshoot them.

    I still have the cans at the shop; I'll get the brand name. It was nothing too fancy, I'm sure I bought it at the local Ace hardware.

    Another possibility mentioned by the local powder-coat guy was a high temp material that he has ... looks much thicker than spray-paint. He says he's painted a number of headers. I'll check.
    "It is what you discover, after you know it all, that counts." _ John Wooden
    Lew Morris
    1973 R75/5 - original owner
    1963 Dnepr

  5. #5
    Yarddog
    Guest
    Lew, so far, I really like that House of Kolor product...no need so far for recoating however you do need HVLP gear to apply it rather than rattle cans...the paint in rattle cans, as you know, is exceedingly thin, to allow it to get thru the nozzles, whereby HVLP gear can be applied much more heavily...

  6. #6
    keelerb
    Guest
    Quote Originally Posted by Yarddog View Post
    just cannot be good for the pipes, or the engine, for heat not to escape...
    Quite true, but the pipes are made to take it and wrapping an exhaust properly takes heat out of the engine....which generally is a good thing.

  7. #7
    tricyclerob
    Guest
    I've been curious about exhaust wrap for some time. Has anyone tried it with cylinder head temperature gages and was a lower head temperature realized?
    rj

  8. #8
    Quote Originally Posted by BrianK View Post
    Quite true, but the pipes are made to take it and wrapping an exhaust properly takes heat out of the engine....which generally is a good thing.
    that's the theory and I believe it to be true, however I'm not sure how the temperature is being raised in the cylinder head and can't seem to find any info online. In fact, all I could find online relating to temperature are reducing engine compartment temps by insulating the pipes. This insulation of the pipes could be what was causing the glow as it stopped glowing once I got off the highway.

    I'm still leaving them off, in my case it served only an aesthetic purpose and one not worth having my pipe weld itself to the head... I would like to see some real research/testing done on this though, but fwiw, I was looking at vintage BMW racing bikes in "Mick Walker's German Racing Motorcycles" and I don't see any with their pipes wrapped
    // 1975 BMW R90/6 (cafe'd) // 1957 BMW R60 (in pieces) // 1967 Aermacchi/H-D Sprint 250 SS (custom special) // 1967 Moto Guzzi V700 (current restoration)

    http://symphonyofshrapnel.blogspot.com

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