Topic: Phaedrus: CB750 RestoMod - Update: 09/23/21 w/ new video

[MCRider]

I used some Permatex High Tack #80062 I had on the shelf. Gasoline resistant. Heated the female side, got quite a few full turns before the taper stopped it. On to the next thing.

[MCRider]

So, I got the oval pods from bwaller in record time from Canada. They fit perfectly and look sharp. More filter area than the original pods.


I know there is controversy about pods. I'll say i used them very successfully for many years and 10s of thousands of happy miles. I'd been thinking that maybe the difference is that they work better on larger engines. 750+ vs the 500/550s. But more accurately it might be that they work better on something other than the stock carbs. I've never actually used them on stock CB750 carbs, but on the Mikuni smoothbores VM29. Anyway, I'm not anticipating any trouble as this is virtually the same engine I had, just better slicker parts.

The rear brake wasn't adjusting up. I could run the adj nut all the way up, compress the spring, and the pedal still moved too far. An unexpected issue. Remember back, I had the brake "arced" by Racetech, in CA.
http://www.racetech.com/HTML_FILES/BrakeArcing.html
They turned the drum to perfectly round. Then they grind the shoes so they fit in the drum optimally. If you ever checked the stock set up, you'd be surprised how little of the shoes actually touch the drum. I'm expecting this to really improve the rear brake.  Well, I'm guessing they had to grind so much of the shoes off to get the whole shoe to touch the drum, that it's thrown the adjustment out. So I figured that we could rotate the arm on the brake plate a spline or two to get it to adjust up. This isn't as simple as sounds, as the cam on the brake plate is not splined all the way around, There is a part of it that has no splines. This makes it more difficult to just take it off, rotate it, and slide it back on. The spline of the arm hits the flat spot of the cam. Not wanting to force it on, we took the arm and ground down two of the splines with a Dremel. This was easier than we thought to do, and the arm slid easily on in a position that allowed a good adjustment. On to the next thing.

Time to offer up the exhaust pipe. Marshall Deep Tone 4-1. We'd done a lot of work on these years ago. The headers are all individual. They would not gang up and fit into the header. So we ground them like crazy to where they would fit. Now we have the problem of fitting them to the head. They use the stock "spigot and finned clamp" arrangement. But where they fit up to the spigot, the wall of the pipe, which should compress on clamping, is so stout and thick that we had to spread the clamps way far apart.

Then the bolts to draw the clamp down won't line up with the threads. When we did get a clamp to draw down, it was so difficult to compress the pipe, it never got tight against the spigot, and the clamp bolt broke. It may have been crossthreaded, but still it wasn't going to work.

One of the most disappointing things so far.  After struggling with it for 1.5 hours, it was time to call it quits.

While cleaning gutters, I thought of this. I'll cut some more compression relief slots in the header with the trusty Dremel. Then, rather than use the threads in the clamp, I'll drill them out and use a bolt and nut to draw it down. That ought to work.

[Ecosse]

sorry to hear of your header (and drum) woes.

i was under the impression marshall's were good quality. could it be this set got tweaked over the years? i've seen it happen to car headers that have sat and been stored less than carefully.

better luck next weekend.

[MCRider]

sorry to hear of your header (and drum) woes.

i was under the impression marshall's were good quality. could it be this set got tweaked over the years? i've seen it happen to car headers that have sat and been stored less than carefully.

better luck next weekend.

I'd say its real good quality. maybe too good. The metal that needs to be squeezed to clamp on the spigot is so thick, that's the problem. Good thick walls on everything. The megaphone is beautiful and stout. We'll get it done.

As to the headers fitting into the collector, the problem was that the chrome was too thick. I will say there was a fair amount of chickens--t from the welding in the collector that had to be cleared for the headers to slide in. That would be a quality issue I suppose.

[Ecosse]

well, at least the metal and chrome are good quality. that's sorely missing on a lot of products it seems. too bad they can't manage the fitment. one wonders what they have for jigs.

maybe yours is a "friday" pipe?

anyways, it's a heck of a nice looking set of pipes.

[MCRider]

Here's the carrot on the stick. We'll get it on there somehow.

[Ecosse]

a thing of beauty.

i almost hope my mac rots by christmas so i can ask santa for one.

[Old Scrambler]

You could shim the flanges with thin strap or several windings of SS safety wire.

[MCRider]

You could shim the flanges with thin strap or several windings of SS safety wire.

Thanks, that's "on the list" of fixes now.

[Really?]

Ahhh, Safety Wire Pliers & Safety Wire.  Prolly the only benefit I got out of my expensive A&P license.

[MCRider]

Marshall/Lazer Deep Tone 4-1
Here's a vid:
marshall deeptone

Coincidentally on a SOHC CB750. Unfortunatley there is a lot of raspiness in the recording but you get the idea.

I called the distributor and he said they are discontinued (for the SOHC) but there is one in stock at $489. They actaully had a sale on them for something in the high $200s.  Don't know if the "discontinued" is true. That's what they told me when I bot mine 10 years ago. I'm pretty sure I paid less than $300. Receipts in the shop.
http://forums.sohc4.net/index.php?topic=94794.0
http://www.laser-exhausts.com/cgi-bin/shopper.cgi?preadd=action&key=260256.101113

The distributor in the "Sale" ad is the same one I called today with the $489 price. Probably room to haggle.

I think they are actually street legal sound wise, at least by EU standards. My open pipe days are behind me. Give me a little soul at idle, and on accel, and a quiet sweet spot at highway speeds.

They actually provide dyno sheets for many of their pipes. Most of which are at or better than stock HP. Nothing on the SOHC that I've seen.

[MCRider]

Not an SOHC, but I expect similar:
New exhaust on and done ! JAMA Marshall Deeptone GSX 750 ESD

[MCRider]

Just for fun, here's a 70s GL Cafe with a homemade header and a Marshall can.
GL1000 '76 4-1 exhaust marshall,

[MCRider]

And finally (maybe) a Marshall brochure touting their involvement in Vintage bikes:
http://www.laserexhausts.com/Portals/0/docs/Brochures/JAMA_Originals_Brochure.pdf

[RAFster122s]

Not an SOHC, but I expect similar:
New exhaust on and done ! JAMA Marshall Deeptone GSX 750 ESD

That vid sounds like Chris Dupen ?spelling?, an Australian who is on the VJMC list  and runs netbikes.au
He's a Suzuki lover and rebrieaths life into the older Suzuki bikes.
I didn't open it in YouTube to find out...fwiw...

 

[MCRider]

Not an SOHC, but I expect similar:
New exhaust on and done ! JAMA Marshall Deeptone GSX 750 ESD

That vid sounds like Chris Dupen ?spelling?, an Australian who is on the VJMC list  and runs netbikes.au
He's a Suzuki lover and rebrieaths life into the older Suzuki bikes.
I didn't open it in YouTube to find out...fwiw...

the only identifier is "samtheposter". Nothing else in comments, etc to indicate.

[MCRider]

Rare Saturday night session along with Sunday AM yielded these results.

The Marshall header was simply too stout for the star clamps to tighten them onto the spigots. So I decided to cut additional slots to allow the clamps to tighten down. Cutoff wheels on the Dremel did it.  Stock they came with 3 slits, I added 2 more between each slit for a total of 9 per pipe.

I thought we may have to go to a bolt and nut on the clamps as well. But the original set up , bolt into threaded part of the clamp, was sufficient.

But the ends of the header pipes just wouldn't line up. We struggled with this for quite a while. I was cussing Marshall up and down.


Bruce said, take a breath. Get away from it and come back. Well I hardly had to do that. Once we started to dissect the problem, and stop assuming it was the pipe's fault, we discovered that header #2 was hitting a flange we had welded on the frame to mount the case guards.

Actually, I had a suspicion last week that this may be a problem, but i had pretty well dismissed it by today. And we won't know for absolutely sure that is the problem till we cut off the flange and remount the pipe.

But we mounted all the headers into the collector/muffler without #2, and it seemed to fit properly.

So, works cut out, go buy a sharp hacksaw blade. 

In the meantime, we dropped the bike down onto its wheels, so the centerstand would not interfere with mounting the pipe, and it sure seems low. That 18" front, 17" rear wheel with the low profile tire made a difference, don't know if its a welcome difference or not till I ride it. I can always put a taller shock on it, currently stock length 12 7/8(?). The front wheel is held with one of these trusty wheel chocks, great device.

[Tintop]

The bike is really starting to take shape, looking very sharp.   To bad about the interference issue with the pipe.

[MCRider]

The bike is really starting to take shape, looking very sharp.   To bad about the interference issue with the pipe.

Thanks! One step at a time, but each step seems to have a twist.

[Tintop]

The bike is really starting to take shape, looking very sharp.   To bad about the interference issue with the pipe.

Thanks! One step at a time, but each step seems to have a twist.

+1...boy, I understand that.

[CBJoe]

Hey Ron...Looking good! 

So you're gonna have to cut that mounting tab off?   Isn't it needed for the Case Guards?  Or did I miss an earlier post 

Cheers, Joe

[MCRider]

Hey Ron...Looking good! 

So you're gonna have to cut that mounting tab off?   Isn't it needed for the Case Guards?  Or did I miss an earlier post 

Cheers, Joe

Thanks.
Yeah the tab comes off. First Phaedrus had the 2 point guards. I always wanted the 3 point guards, so i found a set. The third center mount was originally a U bolt affair. To clean it up, I had it changed to a tab with a corresponding tab on the frame, much cleaner than a U bolt that was reminiscent of a muffler clamp. So its the third tab that's coming off. The guard will mount perfectly well with the remaining 2 points, like all 2 point guards do.  If I weren't speaking about it now, no one would ever know.

You can see the 3 point guard in the 1st picture back. The 3rd center point will simply touch the frame. At least until Phaedrus III in 2035.   

Goes to show when you go to cutting and welding on the frame, mock ups are necessary, and even with that you can miss something.

I gussetted the rear of the frame above where the battery box went. Had to hold my breath that the air cleaners would fit. They did.   

[MCRider]

Today's priority was, get the pipe mounted. AS discussed last week, the center mount of the case guards, interferes the the #2 header. So, it has to come off the frame.

The corrresponding tab on the guard itself also has to come off.

Nothing like a new sharp hack saw blade.

Finished the process with the angle grinder.


That allowed the #2 pipe to swing into place, along with all the others. Amazingly the collector slipped onto all 4 headers and with taps from the rubber mallet, it all went home. Remember though that way back in the beginning we had to spend several hours with the collector. It was full of weld bird sh-t, which we tapped out with a small chisel. Then to finish prep we used a small 3 stone hone in the collector to get it to where the pipes would sink in all the way.

I may have some ground clearance problems, but I'll worry with that after its running. Some taller shocks will help offset the low profile 17" tire.


The case guard on the left side becomes a 2 point mount with a third "touchpoint". I may be happier with this anyway. There was a thread on case guards this week, where i relayed my several experiences where case guards saved me. The 2 points tend to fold back against the alt cover. But in so doing they absorb energy, then completely protects the alt cover from damage. The 3 point mount would transfer all the energy from the fall into the frame, and i wasn't too comfortable with that.

Also in the "identify these headers" thread i discussed the old pipes and what the gimmicks to each were. One was that a pipe would have the headers enter the collector in the firing order to create a "swirly" effect. Some did and some didn't and I never saw dyno run proof of the efficacy of this gimmick. Sounded good. Another was the "equal length header". The Triple A in my avatar was such a pipe. The CycleX pipe is such a pipe and uses it in their advertising. It generally involved extra bends to make it happen. I didn't think the Marshall was that way, I just thought they were wiggly for effect.

Upon closer inspection, the Marshall uses both of these gimmicks. The headers enter the collector in the firing order. Looking at the collector from the front, the top rt is #1, bot rt is #2, bot left is #4, and top lft is #3; AND they are equal length. 27" measured on the outside of each bend. They also came with a certificate from the European guys saying the muffler was street legal. This last point is probably the most important to me. I think the "deep tone" was used to achieve this. Even though I appreciate performance, there is no proof that the swirl and the equal length actually adds any. But for me being quiet does make a difference. It will still be louder than stock. And lighter.

With the holiday weekend, I hope to get in an extra shop day or too.

[Retro Rocket]

I may have some ground clearance problems,

Yep, i would be trying to get that pipe fixed higher up....

[MCRider]

I may have some ground clearance problems,

Yep, i would be trying to get that pipe fixed higher up....

My picture makes it look a little lower than actually, bad angle. Look at reply #1961, that's how it really is. Some taller shocks will fix it. The ones I have are the stock 12 7/8 in. I can tell the reduction in wheel/tire size from stock is the problem. It's a bear to get on the center stand.