Topic: Installing Busso Pipes

[ZTatZAU]

I hate to even post my Busso exhaust questions with others here still waiting for their no-stamp pipes.  But I was fortunate to have received my Busso pipes in one of the first batches shipped back in February and I'm getting close to installing the new exhaust.  My best "hopes and good luck wishes" go out to everyone who's still waiting!

In any case, I bought my K1 750 new in 1971 and by 1973 had swapped the wimpy OEM 300 pipes for a much cooler and louder set of 4 into 2 collectors.      So while I took a set off 50+ years ago, this will be the first time I've ever installed a set of "stock" CB750 pipes; let alone a set of Bussos which may present their own fitment issues.
 
First off, it seems each side should be started with the fitment of the inboard pipe (#2 or #3), followed by the outboard pipe (#1 or #4).  Is this correct?  Any tips or suggestions appreciated.

I've searched the forum and Youtube but most of what I found had more to do with ditching 4 into 4 systems to install aftermarket 4 into 1 systems.  From what I have found, I'm considering coating the inside of the new pipes/mufflers (?) with the Eastwood Ceramic kit and drilling the drain holes that Busso skipped.

My questions, for those who do this sort of thing regularly...

Any general recommendations (for or against) the Eastwood ceramic coating?

With a 24" Eastwood extension sprayer, do you coat the entire inside of the pipe and muffler with the ceramic coating?  From both ends with baffles removed?  Or just the muffler end?

Do you complete all test fitting and any required modifications before coating the pipes with the Eastwood ceramic kit?  Or coat the pipes straight away and have at installing them.  (The thinking being, once you've got a pipe modified and/or massaged into place, you may not wish to remove it to do it again?)

Will one kit do four pipes/mufflers ?

Busso specific questions...

First thing I noticed when I laid out the Busso pipes, was the difference in the exposed length of inner pipe at the clamping (cylinder) end of the pipes...



Is there any reason the two inboard pipes should extend farther (5 mm) than the two outboard pipes?  Or is this early indication that my Busso pipes will require modifications to install?

I was also surprised at how large the rear muffler mounting holes (sleeves) were in comparison to the stock oem mounting bolts (18mm vs 14 mm).  Were the sleeves in the Honda mufflers this large?

Is there something other than the configuration of the passenger peg mounting plates that helps to center everything up on that stock mounting bolt?

I did notice a small crescent shaped (locator?) attachment plate on the inboard side of my passenger peg mounting plates.  Is this what I remember reading somewhere about having to grind out a notch on the Busso pipes?

Any and all replies, advice, suggestions are appreciated!
ZT

[Don R]

 I started the Eastwoods pipe coating deal. I spray through both ends, tape the opposite end well because it sprays a lot of paint, you will paint your shoes and the floor. Then, tape off the open end. I rotate the pipe a lot to be sure everything gets coated especially in the baffle end. I open an end, pour out any excess paint and leave it open to dry. I like to prop up the pipe and heat it from the end with my heat gun to cure it after drying a day or two. Lastly, I drill out the drain holes.
 My installation experience is from 3 sets of Yamiya and one set of cmsnl 341 pipes. Dry fit everything first before tightening any bolts. They all fit well but I have had to cushion a pipe with a towel and tap the engine end with a rubber mallet to encourage the flange end to fit up to the engine end after putting in the peg bolt. None of them has turned blue at the engine end.

[ZTatZAU]

I started the Eastwoods pipe coating deal. I spray through both ends, tape the opposite end well because it sprays a lot of paint, you will paint your shoes and the floor. Then, tape off the open end. I rotate the pipe a lot to be sure everything gets coated especially in the baffle end. I open an end, pour out any excess paint and leave it open to dry. I like to prop up the pipe and heat it from the end with my heat gun to cure it after drying a day or two. Lastly, I drill out the drain holes.
 My installation experience is from 3 sets of Yamiya and one set of cmsnl 341 pipes. Dry fit everything first before tightening any bolts. They all fit well but I have had to cushion a pipe with a towel and tap the engine end with a rubber mallet to encourage the flange end to fit up to the engine end after putting in the peg bolt. None of them has turned blue at the engine end.

Thanks Don!  I appreciate your input and good luck with your no-stamp pipes!
ZT

[Don R]

  The day those pipes appear at my door I'll go to the riverboat and throw a hundred at the blackjack table.

[ZTatZAU]

Well then, let me ask this...

How do the measurements in my photo above, (20-25 mm), compare with the exposed length of inner pipe on a set of OEM Honda HM300 pipes?  The after-market pipes I took off, just clamped around the outside of the Honda spigots.  Nothing went inside the spigot.

Before I start cutting & fitting anything, I'm trying to figure out how far into the exhaust port 'spigot' - the inner exhaust pipe should be, (or need to be), when the outer belled clamping section of the exhaust pipe bottoms out on the 'spigot's' flange?  Assuming the outside ever does bottom out?

Can I get some help on this?

  The day those pipes appear at my door I'll go to the riverboat and throw a hundred at the blackjack table.

I'm rootin' for ya' Don!

[Lucien Harpress]

Can't speak for inlet lengths, but I can off a bit of wisdom for installing stock pipes.

Right side is easy.  Pipe 3 first, then pipe 4- 3 sits kind of under 4, so that one needs to go on first.

Left side is a bit tricky.  As with the right side, the inner pipe needs to go on first, so pipe 2.  However, the side stand is slipped in between the pipes, so 2 has to go under the side stand, while 1 has to go over.  On top of that, the shape of the pipes prevents you from installing 2 with the bike on the center stand, BUT because the bumper for the center stand is on pipe 2, you kind of have to half-drop the center stand (while the bike is on the side stand) and fish pipe 2 over it, while keeping it under the side stand.

Pipe 1, by comparison, is a piece of cake. 

[ZTatZAU]

Can't speak for inlet lengths, but I can off a bit of wisdom for installing stock pipes.

Right side is easy.  Pipe 3 first, then pipe 4- 3 sits kind of under 4, so that one needs to go on first.

Left side is a bit tricky.  As with the right side, the inner pipe needs to go on first, so pipe 2.  However, the side stand is slipped in between the pipes, so 2 has to go under the side stand, while 1 has to go over.  On top of that, the shape of the pipes prevents you from installing 2 with the bike on the center stand, BUT because the bumper for the center stand is on pipe 2, you kind of have to half-drop the center stand (while the bike is on the side stand) and fish pipe 2 over it, while keeping it under the side stand.

Pipe 1, by comparison, is a piece of cake.

Thanks Lucien!  That helps a lot!

Assuming there's no problem installing the side stand after the pipes are on, I think the bike is in the perfect state to start installing the pipes.



Side stand is off... center stand is propped down, and hopefully out of the way.  I've been focused on the left side; but will heed your advice and get some practice on the right side first.

I'm hoping I won't need to trim any of the outer slotted bells on the new pipes but do think I should trim the longer of the inner pipes (#2 & #3) at least down from 25mm to 20mm to match pipes #1 & #4... maybe more???

There's a small ridge inside the exhaust spigots, about even with the base of spigot's outer flange and where the outer slotted bell should wind up when the pipe is successfully driven home.  (I think!)

It's another 30mm or so to the inner gasket at the far end of the spigot pipe.  So how far should the inner pipe extend into the spigots?  OR how far should the inner pipes extend beyond the belled out slotted sections?

The pipes I've tried to insert so far, #2 & #1, were very tight going into the spigots so it's definitely going to be somewhat of a wrestling match to get the belled out sections all the way up against the spigot flanges.  So, I'm thinking the shorter the better on the inner pipes extending beyond the bell... as long as they're not too short!

Any suggestions?  ZT

[BenelliSEI]

I never get HM300’s tight enough for the split pipes to bottom on the spigot flange. I’ll look at my K1 tomorrow but from memory they are usually about a 1/4” off. They must go deep enough for the slits to be fully over the spigots, or you will get noisy leaks. Focus on getting the pipes on far enough that the rear footpeg bolts line up correctly with the frame, slide those bolts in place and then make sure the front end is stuffed back far enough to leave no openings in the splits.

I have no idea how well those will fit. My experience with two sets of new HM300’s was very good. Yamiyas were also excellent. Those varying lengths at the spigot end suggests you may have some trimming to do. The BUSSO pipes I fitted to my Benelli SEI ended up fitting well, but I did spend a few days tweaking them into place. If you think four are tough, imagine six!

[newday777]

The key to the lengths is the fitting of the passenger peg bolts. You want the bolt holes to line up correctly. That is the determining lengths of the spigot fitment. Each pipe was welded different so you will have to do your own measurements and cut lengths. Don't assume someone else can tell you the fitting lengths. Busso didn't have good quality control of the welded lengths. We may even have been sent their seconds......

[ZTatZAU]

Thanks John!  I always appreciate your thoughtful replies!

And the same to you too Stu!
IIRC you got two sets of the no stamp Bussos.  Have you installed either set yet?  If so, did you have any Busso specific fitment issues?

I am making progress and will update shortly... likely with more questions.  But I am feeling pretty good.

ZT

[BenelliSEI]

Go slow and think it through. If you think you need to make a cut, sleep on it and look again tomorrow.

[newday777]

I kept 1 set and sold the other to cover the expenses to a guy in Brazil that David said wanted a set.
I haven't put my set on yet, I did try them on a 76 I have on the lift and saw they will need trimming. I put them back in the boxes.

[ZTatZAU]

Go slow and think it through. If you think you need to make a cut, sleep on it and look again tomorrow.

Ha Ha!  I've been thinking this through for months John!

As is often the case, I got tied up last night with other things but I think my first Busso test fit went pretty well.



I haven't yet cut anything off the pipes; though I did revisit cleaning out the inside of the exhaust port spigots again.  It's still a tight fit but with a little WD40, much easier to get the pipes all the way on and off.

With all the bells up against, (or within1-2mm of) the exhaust port flanges, the rear muffler mounting holes are close enough to insert a 3/8" bolt all the way through the two muffler sleeves and the frame hole.

The left side is very close and I'm tempted to clamp down tight on the front of the pipe and bend, pry, or whatever it takes to get the stock bolt through the rear holes.  Then again, perhaps not?

 See the pix below... I hope they show enough detail to offer your suggestions.

LEFT SIDE



The right side rear muffler holes seem to be a little farther off, and may require some trimming.  Again, your suggestions are much appreciated.

RIGHT SIDE


Before I start bending, prying, or cutting, I think I'm going to more carefully fit each individual pipe, one at a time, to confirm what each pipe needs or doesn't need.  When I'm happy with that, I'll try one last full mock up with all four pipes before drilling drain holes and coating the inside of the pipes.

FYI,  I don't know if the mounting sleeves in the Bussos are the same as OEM Honda pipes but I've found a short piece of 1/2" (emt) electrical conduit fits very nicely through the Busso mounting sleeves which provides a good hand hold for the rear of the pipes.

ZT

[newday777]

Do not tighten the front until you get the peg bolts in through the mount holes so you can confirm it is correct.

[ZTatZAU]

Do not tighten the front until you get the peg bolts in through the mount holes so you can confirm it is correct.

Got it!  Thanks Stu!

Once each individual pipe fits correctly, can then join the two mufflers with 1/2" emt through the mounting sleeves, install the equalizer tube, and rotate the two pipes up together to go onto the spigots simultaneously?

Or would that be too easy?
ZT

[newday777]

Maybe, Maybe Not.
I wouldn't guarantee with anything that Busso made at this point in the game.

[BenelliSEI]

From memory, I had one set of Yamiya exhaust where the link pipe at the back just refused to line up.i ground the faces of the mounting tubes, where they tightened up together, at slightly offsetting angles. When I tightened the foot peg bolt they rotated against each other just enough to line up……

[Tracksnblades1]

Do not tighten the front until you get the peg bolts in through the mount holes so you can confirm it is correct.

That’s interesting..

I was taught just the opposite back in the sidewinder and 2 bolt flange type 4/1 days…🤔

With the reasoning you wanted the lead pipes square against the copper crush washers, so you didn’t have to overtighten them to prevent leaks... Then if there was any foot peg hole misalignment you could modify it or force the alignment and let the heat cycles train the weld distortion to the correct position…?  Not that it ever did,,much..

[newday777]

Do not tighten the front until you get the peg bolts in through the mount holes so you can confirm it is correct.

That’s interesting..

I was taught just the opposite back in the sidewinder and 2 bolt flange type 4/1 days…🤔

With the reasoning you wanted the lead pipes square against the copper crush washers, so you didn’t have to overtighten them to prevent leaks... Then if there was any foot peg hole misalignment you could modify it or force the alignment and let the heat cycles train the weld distortion to the correct position…?  Not that it ever did,,much..

You aren't talking about the same thing.  Totally different arrangements.

[Tracksnblades1]

I think we are..

Sidewinders had spigots others  had two bolt flanges..

The pipes or pipes either lined up when tightening the spigots or the flanges with the rear mounting holes side to side or they didn’t.
At least the spigots would allow a little forward and backward adjustment.. unless of the Busso are different.

[newday777]

Nope

[Don R]

 I remember running a drill bit through a set of Yamiya pipes at the peg bolt hole to ream all three tubes to match up.
 My newest yamiya pipes had a tube that went inside of the balance pipes. I believe it was there to force me to line those up before tightening the other bolts. I tried to do that on a set of CMSNL 341's but the tube wanted to drop into the muffler.

[BenelliSEI]

I remember running a drill bit through a set of Yamiya pipes at the peg bolt hole to ream all three tubes to match up.
 My newest yamiya pipes had a tube that went inside of the balance pipes. I believe it was there to force me to line those up before tightening the other bolts. I tried to do that on a set of CMSNL 341's but the tube wanted to drop into the muffler.

I’ve got a set of +5 year old Yamiya “no number” pipes to install on the Sandcast. Will report on the fit soon…..

[Rookster]

Do not tighten the front until you get the peg bolts in through the mount holes so you can confirm it is correct.

Got it!  Thanks Stu!

Once each individual pipe fits correctly, can then join the two mufflers with 1/2" emt through the mounting sleeves, install the equalizer tube, and rotate the two pipes up together to go onto the spigots simultaneously?

Or would that be too easy?
ZT

You will never get the passenger peg bolt to fit unless each pipe is already pushed into the spigots.  I don't think there is a way to line everything else up and then slide the head pipes on.  There's just too many variables and the pipes have to fit around the frame in a specific way.  You could do this with a 4 into 1 or 2 but not with the 4 individual pipes.

Every time I read about the Busso pipes I am thankful that I didn't get in on the deal.  I had just paid over double for a set of Yamiya no number pipes when the original Busso deal was announced on FB.  I was very close to cancelling my Yamiya order.  So glad I didn't. Good luck with the install.

Scott

[HondaMan]

Hmm...some of this #2 pipe discussion sounds like the 2008 set (I think it was 2008) that I got: since the #2 mold was reportedly 'broken and scrapped' somewhere along the way, the OEM bend of that pipe due to the sidestand fitment was "lost", it was said. Accordingly, the #2 muffler mount was 'off' by 2mm at the footpeg: I got a LARGE drill in the end, after clamping, wiring, and skyhooking the left-side pipes into position, and slightly off-drilled the footpeg's hole thru that muffler to get it to mount up (I didn't modify the bike, just the pipe). It also needed a thick washer, custom-ground to be an egg-shape, in between it and the #1 muffler at that mount, and the cross-connect rubber hose at the back has always slightly leaked carbon ever since because it is offset by the thickness of that washer.

They sure look nice, though.