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Discussion Starter · #1 ·
as you may or may not know, the heads on my knuck were converted for dual carbs, with panhead style exhaust ports by Pete Hill back in the day. i'm having a hard time getting a good seal around the pipes at the top where they slide onto the exhaust ports.

i've got the big, thick, heavy duty style clamps, but can't seem to get a good seal.

what have some of you guys who have ridden pans for a while done to get a good seal?

thanks!
-dan
 

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Cut slots into the the pipes (where the clamps cover) so that when you tighten they don't deform.
 

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You may also use a beer can shim (strip of Al cut from a can the width and circumference of the spigot) under the pipe, split as described above to pack the joint.
 

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And as a last resort, High temp RTV, Black, not the Orange!!

Other wise they all leak........Roach.
 

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No, but that will work, the orange RTV looks like a back yard mech did it, the black makes it look more pro....
 

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Number one way to get a good seal?

Set up your other mounts properly. Bend tabs as needed, use spacers/washers as needed to get the exhaust positioned perfectly at the head junction. Use good fasteners and keep 'em tight. You can tighten the clamps better this way and you're not loading up the exhaust ports which can break them off.

After that, the other things that have been mentioned apply.

Jason
 

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Discussion Starter · #8 ·
thanks for the ideas, guys. everything lines up perfect and there's no strain on anything, but i just can't seem to get a good seal. think i'll try a combination of the aluminum strips with a bit of high temp rtv and see if that won't take care of it.

i know a lot of them just leak, but it's giving me a backfire that i wanna control. maybe i'm just being too anal, but hey, why not huh?

and yes, i know that a backfire can be caused by an excessively lean or rich state, etc., and i *am* trying to work out the optimal jetting, but at this point it's really looking like it's the exhaust, too.

at the least i wanna eliminate the exhaust as one potential cause.

thanks for all the replies guys, they all helped out.

-dan
 

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It is a sloppy setup with those pipes just sliding into the head. I also use the orange sillycone. After a few miles (500 to 1000) it seems like enough carbon builds up to seal them.
A buddy of mine who is a better mechanic than me uses an exhaust pipe expanding tool a bit at a time untill the fit is right.
I always figured you do not want them too tight because the pipes might expand and crack the port. My 61 has true dual exhausts with no crossover and you have to raise the motor or the head to get the rear pipe on there...a nightmare.
D
 

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I think a cracked spigot is more likely to result from over tightening a clamp on a poorly fitted pipe or a misaligned system than expanding pipe due to heat. If you think about it. Maybe.
 

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I went to STD heads that have the standard STD 3 bolt flange, but I still use the Ultra High Temp Copper RTV.

If it's fitting tight but not sealing, I'd think the RTV would work better since there is no room for a shim.

I'd cut the slots in the pipe, smear some Ultra High Temp Copper RTV (or black) on there, clamp it down and let it sit overnight, then start it up and see if you have any leaks. Then you can get rid of the excess RTV that oozed out.

The Orange/Red never bothered me, I'm always able to trim the excess off, so it doesn't look gobbed up, just a nice clean Orange/red line around my exhaust. I prefer the Orange/red over the black, because if it does have a small leak in it, I can see the black exhaust on it, and re-seal it if need be

Sixball
 
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