X-Overectomy

[montmil]

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

Nope. I would only undertake that chore if the headers were to be re-chromed. The ones I'm working with are old, black-painted headers off an LS.

What I did was to begin with some .070 steel, then work it over some heavy pipe to achieve a close approximation on the header's o.d.
   Trim, grind and sand the patch into a semi-circular shape that overlaps the holes in the header pipes by approx 1/8 - 3/16-inch. Take the patch piece back to the header and continue encouraging the metal to lay properly over the hole. Each patch is ever so slightly different as the bends in each header are different due to the fore n' aft offset of the cylinders. The header tubes also do a little angled kick up at the muffler end. Guess where the aft cross-over holes are? A bit tricky, those two.

Will try to post a couple photos later today showing the pipe patches.

And, as mentioned in the first post, SFC Miller digs the tan-color header wrap so the block offs will not be evident. Need to do some clean up and rust proofing after the welding. Will refit the LS mufflers until the shiny ones arrive.

[tvrla]

Ok, I get it. The repairs won't be visible, so no need to be seamless.

I've always used antiseize on the exhaust junctions - never thought of silicone. Or PTFE. Interesting ideas...

[montmil]

This is the way the headers went to the machine shop Wednesday afternoon for welding. Should be ready by Friday afternoon. Chatted with the owner but figure someone else will do the torch work; that's why I break it down for them Barney-style -to insure which bit goes where.

Weekend will be used to do any needed dressing of the welds, prep the pipes and shoot 'em with some high-temperature disc brake caliper paint. Want to refit the headers and mufflers and ride the bike for a couple days to cure the paint. I had previously used the VHT-branded caliper paint on a pair of dulled LS mufflers. While sorta dry, the paint was "pebbly" looking but after a few hours of ride time, the paint actually smoothed out.

FedEx says the heat wrap tape will arrive tomorrow. Coming together...

[montmil]

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.

More's the pity that the factory lads didn't think of something similar as our freshly built bikes rolled down the assembly lines three decades ago.

'alf a mo'... Perhaps they did, considering all the used and new exhaust components Airhead owners seem to consume.

$$$ & £££  [smiley=bmw_smiley.gif] tweek tweek

[Rubi76]

Looking good there Monte ,

Can't wait to see the finished product and results.

[Rob Valdez 79 R65]

That is impressive work Monte!

We can wait for Darryl Richman to chime in here, but I'm pretty sure the Type 247 in 1970 (69?) was the first BMW to have the cross over.  At least that is what I found looking at pictures of their early sport models.

I think the first one was added to increase torque, and the 2nd one was a similar modification, which on the R65 happened when the fresh air pulse plumbing was introduced to the U.S., along with the Nikasil cylinders and larger valves and lower compression ratio.  I could be wrong about the compression ratio, but the early models were 9.2/1.
I know from my early driving record that they were plenty hot when they were fresh ... and I weighed 50 pounds less!  

Bottom line is we have first hand testimony that the bike will run ( ) without them, so what the heck?

Myself, I have a brand new set of single-cross over OEM headers, so I won't be cutting them up anytime soon!  If I had doubles I would be welding the rear ones up in a heartbeat!

[montmil]

Header pipes are done and neatly welded. Metal prep happening right now before shooting some hi-temp paint this weekend.

Planning to install the pipes along with the soon-to-be-replaced LS mufflers, then put some miles on the bike next week to cure the VHT paint. Wrap 'em by, hopefully, mid-week as the new Norton Peashooters are due 05-08 March.

I'll add a couple progress snaps this weekend.

And here they are:


Block off plates welded. Clean up and metal prep started.


Getting rid of old paint and rust areas. These LS headers were never chrome.


Shot some VHT rattle can high-temp paint and put the headers in the solar paint booth dryer. Maybe the paint will be cured enough to refit the headers by Sunday afternoon, then slip on the LS mufflers and do the final paint heat cure before beginning the wrap exercise.

Ready to get the Norton muffs in the shop.

[montmil]

It was Monday afternoon before I could get to the R65's headers. W-a-y many honey-do and momma-do errands, plus some yard work as an early Spring has arrived. It's 77[size=12][ch730][/size]F and sunny right now. Grass and weeds competing for my time.

I have previously worked extensively with fiberglas and carbon fiber materials. Without proper safety precautions, the flotsam and jetsam from this stuff can be bad for your health. So... Eye protection, dust mask and doubled-up gloves.

Twenty-five feet of 1-inch wide fiberglas header wrap went into a bucket of water. The header was clamped in a vise between semi-rigid plastic jaws. Stainless steel zip ties prepped for both ends of the wrap.

The instructions with the wrap encouraged using a 1/2" overlap if the product was to be used on a motorcycle or ATV. Vibration, they said. A chart accompanied the instructions and provided estimates of how many feet of wrap would be needed for specific pipe diameters. I read everything. The last line stated, "If using a 1/2" overlap, disregard the chart." Great.
   I decided to cut the fifty-foot roll in half. For one header, I used slightly more than 23 feet.

Patience is required for a nice job. Wrapping the pipes while they are off the bike makes the job so much easier; you can put the Mk1 eyeball on a 360[ch730] scan mode and keep overlaps and visual line ups nice and tidy. BTW, I did this first pipe twice.



Look, Ma! No crossover pipes. And what a pleasure it was refitting the exhaust system.



In case you're asking yourself, "How do he unscrew the exhaust nuts to get the header pipes off?"
Pull the muffler as usual. Loosen and remove the rear header clamp. You can easily do this as there is no longer a cross-over pipe. Then, while loosening the butterfly nut, jiggle the header pipe and simply work it forward at the same rate as you remove the nut. Cake.



Using the 1-inch width tape and employing the recommended 1/2" overlap provides a consistent finished diameter for the header pipe. That was one of my goals with this project. I also wanted to eliminate the funky x-overs for easier service work and get away from so much visual 'black' color down by the waterline.
   The soon-to-arrive chrome Norton mufflers will replace the black LS muffs and will definitely add some needed bling while the tan header wrap material pops nicely with the BMW 501 blue.

Left side happens tomorrow. Now where the heck are those peashooters?  

[tvrla]

This may be a stupid question, but I'm curious what's to be gained from wrapping the headers besides hiding the patch. I know the temp in an automotive engine bay can be reduced doing this. And supposedly a HP gain can be realized, I sort of recall that.

But beyond that it makes no sense to me.

[Barry]

There is a theoretical improvemnt in effeciency due to increased exhaust gas temperature and velociity. It should look to the engine like the mixture has been richened very slightly but I've never seen it quantified on a dyno or described as detectable by the butt of the pants version.

[montmil]

This may be a stupid question, but I'm curious what's to be gained from wrapping the headers besides hiding the patch. I know the temp in an automotive engine bay can be reduced doing this. And supposedly a HP gain can be realized, I sort of recall that.

But beyond that it makes no sense to me.

Whoa up. Did I miss the memo? Since when does a hobby have to make sense?  

For the '83, it's all cosmetic. Performance has never been mentioned, at least by me, as a consideration.

Since purchased, the exhaust headers and crossover tubes have been a visual blight on the scooter. Buying new headers is out of the question. Too danged expensive and in a few months, they would look just like the original chrome headers on my '81... blued and pebble pitted.

Now that "makes no sense to me."

[craig@pmpress.org]

Let's see a pic of the full bike to see how the wrapped pipes look!

[montmil]

Let's see a pic of the full bike to see how the wrapped pipes look!

You'll have to wait until the Norton Peashooter mufflers arrive sometime this week.

[tvrla]

For the '83, it's all cosmetic. Performance has never been mentioned, at least by me, as a consideration.

Ok, I was wondering if that was the case. Mystery solved!

It's all a style thing.

[montmil]

Still waiting on the Norton Peashooters mufflers to arrive but I went ahead and re-fitted the LS cans this afternoon. Was kinda interested in how the bike would perform sans balance pipes..

For those amongst us who have an interest in the potential performance changes wrought by the crossover balance pipe removals, I contracted with a local shop to get a definitive answer.

Not being able to find a local motorcycle dynometer, I contracted with a bike performance shop to run some operational tests, ie: horsepower, torque, carburetor tune - the whole enchilada. The shop's performance tuning expert is nicknamed Dino Butt. I thought it was just a misspelled word on his business card. He related that he could determine no changes of torque or horsepower, either with or without the balance pipes. I hope this answers all the questions and concerns. The test was kinda pricey; cost me six double cheeseburgers.

The only photo I could get of DINO Butt