Author Topic: Convert pressure-side guage ideas  (Read 2691 times)

Offline brider

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Convert pressure-side guage ideas
« on: March 22, 2025, 09:39:59 PM »
Been a while since I saw a Convert technical topic, so why not? I ranted about this same bike maybe a year ago, but after cooling off and re-re-re-considering a swap to a 5-sp or just selling it as a "project", I figure I'd re-hash it first.

My beloved Cal 2 Auto has been parked since the TC began to "slip" right after a long trip, 2 (3?) yrs ago. So now, to try to begin diagnosing the slip, I'd like to find an in-line or flow-thru pressure guage I can plumb into the pressure-side line coming off the pump and entering the TC.

This has been discussed on these pages before, and I WAS in e-mail comms with Rodekyl, a Convert guru, but I lost some relevant e-mails and I can't find related threads thru searching here. I know there are some smart folks here who know a thing or two about hydraulics or system monitoring or stuff like that, so I'm appealing to anyone who is familiar with small, low-pressure guages.

Circuit #1 in this diagram is the line I'm talking about, I think it's the only one under serious pressure, and at that it's something under 30 psi:





Some backstory: After the long trip, which included a trip up Mt. Washington in NH (a TRUE test of a Convert drive system), the TC began to slip about a week after I got home. Familiar with this routine (4th time with this bike), THIS time I went thru a lengthy process of replacing the pump with a good replacement and honing the internal surfaces so that they spun like a wrist pin, and had a special hex key ground to a tighter fit than stock to minimize slop on that connection. Put it all back together......and it still slipped same as before.

No burning smelling of the ATF, can detect some flow movement in the tank itself with the bike on the centerstand. The bike WILL move under it's own power down the road, but there is very limited horsepower at the rear wheel. So the first thing I want to do before dismantling anything else is to check the pressure out of the pump.

I can't envision any reason WHY the pump would not be producing enough pressure, but I have to know, and it might help to know that pressure under drive conditions rather than just with my foot on the brake.

I think RK mentioned the hoses as a possible culprit, like somehow being plugged or collapsed, and mentioning that the banjo ends are removable and all the hoses can just be replaced with good-quality aftermarket hose & clamps, given the low pressure. Might do that just for the heck of it, wouldn't that be a scream if that fixed the problem?
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

Online Antietam Classic Cycle

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Re: Convert pressure-side guage ideas
« Reply #1 on: March 22, 2025, 10:04:24 PM »
If the hoses are over 10 years old, they should be replaced. It's common to cut the alloy crimps off, remove the old hose and reuse the end fittings to make new hoses.
https://www.thisoldtractor.com/moto_guzzi_tonti_i-convert_replacement_oil_lines.html

Did you ever check the pressure relief valve built into the timing cover at the pump?

The gauge doesn't have to be anything fancy, I used an oil pressure test kit from Harbor Freight to check the pressure on one Convert I owned.
Charlie

Offline brider

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Re: Convert pressure-side guage ideas
« Reply #2 on: March 23, 2025, 10:44:16 AM »
Thanks for the tip about the HF oil pressure testor, I'll look into that. The relief-valve parts were replaced as part of the replacement timing cover I installed, just a ball & spring, I guess if the pressure-test comes in low I can suspect a fatigued spring? I don't recall measuring it's free length.
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

Offline MattP

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Re: Convert pressure-side guage ideas
« Reply #3 on: March 23, 2025, 11:40:35 AM »
Look the only thing the oil pump dos ,in a convert system is to cool the oil. The converter allways slips and generates heat.that is the reason for the pump of course it oils the bushings ect. You probubly have s cracked converter .if you had 100 or more psi  realy just blow seals .think about it the system could not be more simple,oil dos not compres. If the pump was the problem the converter would overheat burn the oil. Not your ishue

Offline brider

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Re: Convert pressure-side guage ideas
« Reply #4 on: March 23, 2025, 12:29:32 PM »
I have used those PEX clamps many times in my house plumbing, never thought to use them for Convert hoses, might experiment to see how it works. As far as the pump; there's pressure, and there's flow. Either one could affect supply to the TC. It's not impossible, but I think it unlikely the TC itself is bad. If it were cracked, where would the leakage go? I have always wondered about that scavenge hose at the bottom of the TC housing, what is it scavenging, and how does it get pumped back up to the tank?
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

Online bigbikerrick

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Re: Convert pressure-side guage ideas
« Reply #5 on: March 23, 2025, 02:15:17 PM »
Those "pex" type clamps along with the hoses Charlie recommended from mc master carr should make for a clean installation. Theres not all that much pressure in those lines. a simple pressure gauge in line #1 will give you useful  information as to whats going on.
good luck
Rick.
"You meet the most interesting people on a Guzzi"

Offline MattP

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Re: Convert pressure-side guage ideas
« Reply #6 on: March 23, 2025, 02:41:13 PM »
it is not burning the atf theirfor the pump is working nothing to do with bad lines, change them if you want but that is not your problm . something is wrong with the tourkconverter

Online bigbikerrick

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Re: Convert pressure-side guage ideas
« Reply #7 on: March 23, 2025, 03:36:35 PM »
it is not burning the atf theirfor the pump is working nothing to do with bad lines, change them if you want but that is not your problm . something is wrong with the tourkconverter

How about the "O" rings that seal the TC , where the pressurized ATF comes in from the pump? I think if those are leaking, it would cause slippage,and some fluid would appear in the drain hose at the bottom of the tc.
Rick.
"You meet the most interesting people on a Guzzi"

Offline brider

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Re: Convert pressure-side guage ideas
« Reply #8 on: March 23, 2025, 03:48:31 PM »
I DID find a previous e-mail of a discussion I had with RK about those o-rings. His sentiment was that they were not likely the cause of slippage, even if they WERE leaking. I'm trying to remember now where in the drive system that shaft even is.
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

Offline MattP

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Re: Convert pressure-side guage ideas
« Reply #9 on: March 23, 2025, 09:05:48 PM »
The hex shaft is in the timing cover, under the oil pump.not the problem to fix it  replace converter or not

Offline Don G

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Re: Convert pressure-side guage ideas
« Reply #10 on: March 23, 2025, 09:33:18 PM »
Is your clutch hooking up? Perhaps you have slippage there, check if the clutch cable has free play, you can also back off the adjuster on the pull rod and see if that cheers it up.   DonG

Offline brider

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Re: Convert pressure-side guage ideas
« Reply #11 on: March 23, 2025, 09:43:04 PM »
Sorry, I was talking about the shaft in the bellhousing with the o-rimgs. I am WELL aquainted with the hex shaft.

I do not suspect the clutch yet. Lots of lever free play, clutch operates like it always has, for the seldom times I use it. Like I said, this is my.4th episode with the TC slip, and I'm 100% positive that's what this is.
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

Offline brider

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Re: Convert pressure-side guage ideas
« Reply #12 on: March 23, 2025, 09:46:50 PM »
I've had a side conversation with RK and he sketched out an analogue/elec guage setup I'm going to try along with the new hoses.
'85 Cal II Auto
'71 Ambo project
'02 GasGas EC300
'07 Norge
'05 KTM 950 Adventure
Wish'd I'd never sold:
'72 Red Eldo
'74 White Eldo LAPD
'77 Convert with DB bags
'06 Gas Gas EC300
'86 LM IV

 

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