Author Topic: Convert exhaust crossover installation, and general Tonti exhaust  (Read 308 times)

Offline brider

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Hoping some of the known Convert owners chime in (Charlie? Yoo Hoo!). I just bought a new replacement exhaust crossover from MG for my Cal II Auto, and it looks like I'm going to have to pound a VERY flat section into the actual crossover pipe to get it to clear the ATF return line (unique part of the Automatic system) banjo-bolt at the bottom of the bellhousing. I do not recall if the original crossover had a flattened area from the factory, but I suspect it didn't, as I recall adding the "flat" when I re-installed the exhaust after the head work I did a few years ago.

However, I can't see how it was EVER installed WITHOUT the flat, as that banjo bolt looks like it wants to rest right in the center of the crossover cross-section.

Are there any Convert (or Cal II auto) owners out there that can look underneath and see what the relationship between that banjo bolt and the crossover pipe is?

If I allow the new crossover to have a very incomplete overlap with the headers, I might be able to install the crossover behind the banjo, probably just touching it.  I suspect this is how the crossover was installed originally. This would leave an ugly gap between the front end of the crossover and the full-section of the header (header is tapered down for ~1 1/2" at the end for crossover to slip over), where the crossover should be jammed right up to. I could cover this exposed section with the clamp, but that's really kind of half-_ssed.

Exhaust installation in general: I really don't like the Tonti 3-piece exhaust (header-crossover-muffler) that involves 3 pieces of bent tubing that hopes all the manufacturing tolerances go the right way so everything lines up and you don't have to preload the header/head interface and produce leaks or worse. What I was hoping was to snug the headers up with new seals and easily slide the crossover into place with no excessive out-of-position preloading of the headers, and the same with the follow-on mufflers. We'll see if that ultimately happens. If anyone has any suggestions, please LMK.
'85 Cal II Auto
'86 LM IV (sold)
'71 Ambo project
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300

Offline Cal3Me

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #1 on: April 25, 2021, 09:35:15 PM »
my 1980 Convert X-over is forward of that banjo bolt but right next to it barely room for a socket. Stock headers and mufflers also..
TMS

Offline Bulldog9

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #2 on: April 26, 2021, 06:50:20 AM »
My 76 Convert has a full exhaust system from a Bassa. The crossover is behind the banjo and if I recall has a section that is flattened. Unfortunately I just took it out of my garage and put it in the storage unit to make room for some servicing on the 1200 sport. If I can I'll try and swing by on my way home from work today and take some pictures.
The Living: 1976 Convert, 2007 GRiSO, 2016 Stornello #742, 2008 1200 Sport
The Departed: 2017 MGX, 2014 Norge GT,  In Stasis: 1978 XS750, XS1100SF (134K miles and going)

Offline chuck peterson

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #3 on: April 26, 2021, 07:09:54 AM »
If I remember....

That return fitting below the TC can be installed 2 ways. Flipping it over, then spinning it 90 degrees, or 180, or 270, ...? and redirecting the hoses “might”solve your problem of clearance to the crossover. It was close but not hitting. 1/4-1/2”

Its a tight fit. The header gasket can be reused if you stay w the torque spec. You’ll want the exhaust assembled but hung loose everywhere before snugging it up slowly. I slather anti-sneeze on the slip fit header pieces so that it drools out the first time you heat it all up. You’ll be rewarded the next time you have to take it apart.

If I remember...

There is a slight bend in the crossover. Lay it flat on the floor...flip it over...different? That might have been later...or sport models. You’re also on a cal2, that might be a different part number than v1000.?

Got photos?
"I'd like to thank all my friends who have kept my Guzzi's going, but mostly...TOMB."
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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #3 on: April 26, 2021, 07:09:54 AM »

Online Antietam Classic Cycle

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #4 on: April 26, 2021, 07:12:05 AM »
Yes, clearance at that banjo banjo bolt is very tight and I've had to resort to making a "divot" in the crossover. A pair of aftermarket headpipes made the situation even worse - they were nearly an inch too short and the crossover barely slipped onto them.

Charlie
A hard-nosed bloke that tells grieving widows their late husband's bike isn't worth much.

Online fotoguzzi

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #5 on: April 26, 2021, 07:26:17 AM »
I "think" on my EVert project I just eliminated the crossover with 2 sections of stainless pipe.
I've got a set of EV headers I'd sell reasonable if they would make a difference but I doubt they would.
MINNEAPOLIS, MN

Offline brider

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #6 on: April 26, 2021, 07:43:26 AM »
Thanks, all. I DO have a dim memory now of observing that tight clearance with the crossover pipe forward of the banjo......so I can try again by assembling the crossover to the loose headers, THEN trying to cinch down the headers; but I sense this might drive a mis-alignment at the header/head interface, which I DON'T want.

If this new crossover wasn't so shiny and quality-looking I'd consider the straight-stainless connector method, but there IS a slight bend in the crossover flow-pipe sections, so "straight" introduces other problems.

'85 Cal II Auto
'86 LM IV (sold)
'71 Ambo project
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300

Offline brider

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #7 on: April 27, 2021, 03:58:19 PM »
UPDATE:

I tried assembling the crossover into the headers, tapped as snugly as I could, THEN fitting the whole contraption up with the headers inserted into the heads. Major PIA, still wouldn't clear the banjo bolt. So I went back and did it the correct way again (headers first, then X-over), but THIS time I just let the headers king of hang there with the top header bolt kind of snug, so I'd get some "swing" clearance.

Slipped the X-over snug to the proper overlap on the headers, and here's what it looks like. This is the right header slipped into the X-over:





This is looking underneath to where the X-over strikes the banjo bolt. The blue dashed line is the bellhousing outline, the green dashed circle is where the X-over WANTS to be:





On a 5-sp the X-over pathway is a great location, but on a Convert it's the exact WRONG location. At least on my bike. Kind of frustrating (Guzzi content) that Guzzi didn't produce a different P/N X-over for Converts. Looks like I'm going to have to get the big hammer and pound that thing almost flat, and hope I don't crack it. As you can see, I already started.

Forgot to add: In the bottom pic, the headers are still hanging by the top studs. Tightening the bottom studs draws the X-over straight up hard into the banjo bolt. Grrrrrr
« Last Edit: April 27, 2021, 04:06:43 PM by brider »
'85 Cal II Auto
'86 LM IV (sold)
'71 Ambo project
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300

Online TOMB

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #8 on: April 28, 2021, 06:41:49 PM »
The  pictures relate to my 1976 convert the bottom pipe on my bike was flipped over so it would run forward and not follow the top of the crossover so it goes forward from the bolt towards the bellhousing makes a 90-degree turn and runs in front of the crossover pipe and then goes up and over the rubber part goes up and over the crossover on the left side and it clears up by three quarters of an inch I left it this way because there's less Heat going into the pipe except for where it crosses at three quarters of an inch and then it goes to the take pictures attached







I realize these pictures may not be clear to you and you may have to enlarge them to get a better picture but as I said before where the banjo is under the transmission type goes forward towards the left side of the bike and the rubber hose that goes over the crossover book clears about three quarters of an inch and this was the only place it gets any direct heat is where it crosses over on the left side of the of the x over  where  the rubber hose goes over with three quarters of an inch hope this is helpful

Late addition. My x over does not have any flat. Spots for clearance

TOMB
« Last Edit: April 28, 2021, 06:50:24 PM by TOMB »
TOMB

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1972 Eldorado new to me so "0" miles so far
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1978 G5 170000 MILES
1973 V7 SPORT 25000 MILES
1973 ELDORADO 300000+ MILES
1980 CX100 50 MILES
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Offline brider

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Re: Convert exhaust crossover installation, and general Tonti exhaust
« Reply #9 on: April 28, 2021, 08:53:10 PM »
Thanks, TOMB. Your opening sentence and first 2 pics baffle me, but the 3rd pic looks like mine, I think, except I don't have that oil-filter-looking thing, and my crossover pipe bangs against the bolt. Yours has an enviable amount of clearance. No amount of routing changes would change that clearance.

I pounded a flat in mine and now it clears by ~.10".

I've been to Newington many times, both my boys played hockey at the twin rinks there a bunch of times.
'85 Cal II Auto
'86 LM IV (sold)
'71 Ambo project
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300

 

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