X-Overectomy

[montmil]

Rubi76 got a lengthy timing chain thread going and part of it evolved into a discussion and cussin' of the exhaust headers cross-over connector pipes. Wirespokes coined the term xoverectomy.

This special R65 surgical procedure will begin on the morrow upon my 1983 R65. I believe the crossover pipes can be trimmed to use as patches over the four soon-to-be holes in the header pipes. A bit of TIG welding, some clean up and call it done.

As requested by my deployed Soldier and ersatz owner of the bike, a replica pair of chrome Norton peashooter mufflers, which have the identical header pipe opening as does the R65, will replace the black, LS mufflers currently fitted. Too quiet, son says. From JEGS Performance Parts, one-inch wide, tan heat wrap tape will cover the mottled black paint -and weld patches- now gracing the headers. Once completed, this should be a nice visual with the bike's OEM 501 blue paint.

I know you guys so photos as they come.

Here's the link to the rubi76 thread:
http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1328880748

[tvrla]

Before and after Dyno graphs requested!  

[montmil]

Still raining in Daytona Beach so the 500 has again been delayed. Sunday>Monday late morning>Monday evening. We'll see.

Good time to yank the exhaust off the Mexico Bike and get started on the xoverectomy.

Ah, the joy of anti-sieze; header nuts spun right off sans problems. Oh, and rubi76, the header pipes slipped right out after removing the LS mufflers and assorted clamps. No hammers required. [smiley=wink.gif]

After a dose of 50/50 acetone and brake fluid -the best rust buster I've found, the cross-over pipes came away with just a couple love taps from a dead blow hammer.

The photo shows the cut off x-over stubs and one header after grinding down the welded remains. The header pipes are vintage LS just like the mufflers -except the headers are flecked with rust spots and grungy paint.



The plan is to cut some round discs from 4130, shape them to match the curve of the header pipe and weld 'em in place. Expect to complete the stump grinding mañana and perhaps get a jump on the steel patch cutting. And the beat goes on ...

[MR.E]

local shop did this mod to my bike
I'd be interested to know your thoughts on the difference before & after the mod.

All the best

[Rubi76]

Hi Monte,

Glad to hear that the headers weren't a battle.
I'm sure next time I take them off it will be a little easier.
Very keen to hear if the X-overectomy makes a difference to the performance of the bike. Waiting for spares to arrive so I have time to play.

[Bengt_Phorqs]

What is the specific goal in removing the X-O pipe?  Cosmetics?  Performance?

[Bob_Roller]

Easier to get the exhaust system off .

[Rubi76]

and back on  

[Bob_Roller]

After I got my exhaust system off for the first time, 17 years and 45,000 miles, I got everything  apart  (finally), I applied anti-seize compound to all of the slip joints, and I haven't had a problem removing the exhaust system since .

[tvrla]

After I got my exhaust system off for the first time, 17 years and 45,000 miles, I got everything  apart  (finally), I applied anti-seize compound to all of the slip joints, and I haven't had a problem removing the exhaust system since.

I do the same, but for some reason these dual xovers have been a problem. Especially in comparison to the single xover systems.

Is it possible to separate the two sides when taking them off the bike? I've never been able to, so avoid that job if at all possible. It's one thing to be able to separate them and quite another to get them apart while on the bike.

I'm wondering how much of a difference it makes that you live in a dry climate like Arizona.

[Bob_Roller]

It probably helps, also getting the exhaust system hot enough to evaporate the water that condenses inside of the exhaust system during the warm up of the engine to operating temperature .

My original mufflers on the '81 R65 rusted out due to my 5 mile commute (13 stop lights !!!) to work when I lived in Chicago, the exhaust never got hot enough to get the water out of it .

My '91 Honda Civic CRX Si, still has the original exhaust system on it !!!

[montmil]

What is the specific goal in removing the X-O pipe?  Cosmetics?  Performance?

Yes.

Completed removal of the four x-over stub tubes and shaped three of the four block-off plates. Was 4:55 in the PM and Happy Hour begins at 5:00. Didn't want to miss that so bailed outta the shop.

Plan "A" is to get the last block-off done tomorrow AM and then drop off the goods at my favorite machine and welding shop.

[tvrla]

Are you making them so they fit flush with the surface?

[bruce_launceston]

Although I don't have crossover pipes on my bike I always smear silicone sealant on any slip joints in exhaust systems.
It seems to stop them rusting together and is easy to pull apart when required.

It works a treat on mild steel car exhausts and may keep crud out of the stainless steel systems that shouldn't rust together.

[Barry]

I also use silicone sealant on exhaust joints. When I haven't had any to hand I've also used a thin wrap of PTFE tape at the silencer joints on the bike. It helps to make a good seal and also aids removal. At that point in the exhaust system PTFE easily copes with the temperature.