Xover Shims

[Allan1956]

Hi All,

Well I got myself a set of Aaron's shims for the LeMans through Todd Haven. Nicely machined etc. Thanks Aaron.

 

Anyway, a couple of questons.

After taking out the factory "gaskets" from the xover I spread the pipes in the headers and then put the shims and crossovers on. Tightened up. When started there is a small amount of exhaust gas coming out from where the xover meets the headers. I guess this is just where metal and metal meet (some gas getting past the 2 parts of the shims where they meet). Tightened further when the xovers/headers were hot but still small amount escaping.

 

Questons-

1. Is this small amount leaking ok (but if so isn't that the same as the factory gasket "blowing out" in part)?

 

2. When I put my exhaust pipes back together after I have had them off I smear or place silicon gel on the pipes that join and at the joints to stop any small leaks (and to stop "popping" when you back off the accelerator). Should I just pull the xover joints apart and place silicon inside between the xover/shims/header pipes to solve this leak?

 

Any hints,

Thanks, Allan

[Keith Foster]

Snip

Questons-

1. Is this small amount leaking ok (but if so isn't that the same as the factory gasket "blowing out" in part)?

 

2. Snip - Should I just pull the xover joints apart and place silicon inside between the xover/shims/header pipes to solve this leak?

 

Any hints,

Thanks, Allan

I have a set of these from Aaron installed, for a year and a half now I think. I do have a small spot where exhaust seeps out, on the left hand connection. Over time it has left a brown discoloration spot the size of...of..of... a couple of postage stamps. The other side is leak free and the cross over pipe itself remains secure. The seep isn't enough of a bother for me to pull it all apart and try to eliminate it...YMMV. This isn't the same as the factory gasket blowing out as this left a loose/woobly/rattly crossover when it got bad. I don't think the Aaron shimset could ever get that bad.

 

I suspose you could pull it back apart to smear around some hi temp silicone, its your call as to how bad it is and how much it bothers you. But I can't see that it would cause any problem beyond cosmetic.

[sctt2525]

I've had mine off & on a few times since installing the shims and have found that these small leaks usually occur when one of the two "slots" in the shims are aligned with one of the three "slots" in the header pipe. I usually just take the whole thing back apart and start over keeping an eye on this.

Hope this helps.

 

Scott

[Greg Field]

I installed mine early this morning and had some problems. There was no way to make them fit if I followed the instructions and put the long side toward the crossover because there was insufficient flex in the system, such that I would've had to bend the pipes to get them back in the exhaust ports, putting stress that I think would have led to cracking.

 

SO, I turned the shims around. This gave more lattitude in positioning the joint between header pipe and crossover. Still, it was very tough to get the headers seated in the exhaust ports without putting undue stress on the headers. They're on, now, and my lefty leaks a little, too. I'll have to look at it again tomorrow.

 

Overall, nice parts. My difficulties I attribute more to production variation from Aprilia-Guzzi, rather than a fault with the shims.

[todd haven]

My difficulties I attribute more to production variation from Aprilia-Guzzi,

 

Get outta town!!