Author Topic: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission  (Read 3755 times)

Offline berniebee

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Sorry to hear about your setback.

One cause of the engine hanging at high rpm is too tight valve clearances. Also make sure that there is a bit of free play in the throttle.

Hang in there!

Online Pescatore

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Thanks for the tips, berniebee.
I will check the valves... again.  The cable has about 2mm of free play.

'91 Sessantacinque GT
'80 CM400T
MGNOC Member
Ascolta sempre e solo musica vera
E cerca sempre se puoi di capire

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #32 on: October 20, 2021, 03:23:30 PM »
A month ago I took the bike to a shop regarding the shifting and with a bit of a tweak of the eccentric screw and
a lighter oil (Motul 75W90 gear oil) I am now able to change gears, but not easily.
I have to "flick" up the shifter twice and the next gear will engage.  Also going down, I have to press the shifter twice before I can feel the next gear.
Sometimes I find neutral between 2nd and third gear.
I tightened the clutch cable better and it seems to have helped.
I think I need to play with the eccentric screw some more.

The hung idle problem has gone away.  I guess it was the cracked carb float and it needed to run a bit to clear out carbon build up.
The spark plugs now are dry and gray/brown.  Before the fix, the right one was always black and wet.

I finally measured compression and got 170psi on both sides.  :thumb:

Timing is still a bit shaky.  I hate mechanical points.  I need to look into a Dyna kit.
The rockers also make quite some noise.  I am not sure if it's excessive.  I checked the gaps and still holding
at 0.15/0.2mm on both heads.

The clutch is really touchy.  It has a very short friction zone.  It's taking some time to get used to it.
This bike has one clutch plate, so maybe it's worn out (21k miles).

I went on a 30mile ride a few days ago and  the infamous oil pressure light came on.  It was a hot day with plenty of traffic.
The light first started shimmering at low rpm, then it went solid.  There was plenty of oil in the sump.
I didn't want to risk anything, so I towed the bike home (it's nice to have a brother with a trailer).
The next morning I started it and the light did not come on.  Drove around town for an hour, no light.
A search on this forum found that this is a common problem.  I can't get to the pressure switch without taking the
air box out, so winter project.
I am using ENI i-Sint 10W40.  Looking through a couple manuals, Guzzi recommended 10w40 at one time, then changed to
10W50 (V65 Florida).  I drained a bit of it and added a quart of 20W50 cuz that's what I could find.
I will take that 30 mile ride again and see what happens.

I also found an interesting project to add a pressure gauge. 
https://www.thisoldtractor.com/moto_guzzi_loopframe_oil_pressure_gauge.html
Maybe this winter.
'91 Sessantacinque GT
'80 CM400T
MGNOC Member
Ascolta sempre e solo musica vera
E cerca sempre se puoi di capire

Offline berniebee

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #33 on: October 21, 2021, 12:06:40 PM »

I have to "flick" up the shifter twice and the next gear will engage.  Also going down, I have to press the shifter twice before I can feel the next gear.

I think I need to play with the eccentric screw some more.

The clutch is really touchy.  It has a very short friction zone.  It's taking some time to get used to it.
This bike has one clutch plate, so maybe it's worn out (21k miles).

And now some advice from someone who hasn't completed his Guzzi project yet: :tongue: (But I have worked on many bikes.)

I've read that the Guzzi requires a more deliberate (Which I interpret as slow and firm) foot to shift, than say a Japanese bike of the same era.
Having rebuilt a Guzzi gearbox I know that adjusting the eccentric screw will affect shifting in one direction or the other, but not both at the same time. In other words if the shifting is equally poor going up and down the gears, adjusting the eccentric probably won't help. But if you are going to play with it, turn it only 1/6th of a turn (one bolt flat) at a time and then try riding.

Check that your clutch cable isn't binding. Eliminate any sharp turns and if the cable is strapped/ Tie wrapped/ zip tied to the frame at any point, free the cable completely and see if the clutch action is better. Finally take the cable off, lube it, lube each end barrel where it rubs against the lever. That will probably eliminate the cable as the culprit.  Having said all that, I lubed the old cable on my Guzzi, and it appeared to be free and easy when I had it off the bike. But the clutch lever still required a grip of steel to disengage the clutch. I installed a new cable and the clutch lever force required was reduced by about half. The old clutch cable was binding only when under tension.



Wildgoose Chase Moto Guzzi

Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #33 on: October 21, 2021, 12:06:40 PM »

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #34 on: November 09, 2021, 05:17:40 PM »
Thanks for the tips, berniebee.  I have been riding to figure out the shifting pattern.
First, the gears go in and out no problem when the engine is cold.
Once warmed up this is the sequence I have to do for 3-5th:  lift up to 3rd (feels as if no more gears), very slight tap down (I feel a bit of give), then lift up.
On the second lift up, the gear goes in normally with that glorious clunk sound.
It is not 100% consistent.  Sometimes I do the sequence for 3rd gear, then 4th and 5th go in with first lift.
Other times, all three gears need the sequence.
Going down, I need to pump the lever twice.  The first try feels like no more gears, on the second try it shifts down.

I can't get to the eccentric screw easily and I read on the forum that people cut a wrench to get in there.
I plan on turning it one flat at a time until it's all the way in, but no more than one revolution.  Then unscrewing one flat at a time, no more than one revolution.
I might not get to this until the spring.  It's looking like time to pack it in for winter here in New England.
I know that if I turn it all the way out, it will pull out of the spring and it's game over.  Is there any danger in turning it all the way in?

I sprayed the clutch cable with this lube: https://www.amazon.com/gp/product/B001F2Y25G
Then ran the cable outside as direct as possible.  No change in force.
I put it all back and adjusted the tension at the lever and seemed better now.
I also got used to the short friction zone, so maybe the problem is my hand, not the bike  :laugh:
'91 Sessantacinque GT
'80 CM400T
MGNOC Member
Ascolta sempre e solo musica vera
E cerca sempre se puoi di capire

Offline huub

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #35 on: November 14, 2021, 01:05:09 PM »
sounds like the shift spring is on its way out.
a pretty common fault with these.
the spring is cheap, but unfortunately the box needs to come apart to change it
nice project for the winter....

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #36 on: November 14, 2021, 02:20:54 PM »
I guess I could have a bad one.
The spring broke some time ago, so I started this project.
I had it replaced, the part came from Stein Dinse.
The shifting was bad from the first day I got it running again.

I've read that it could be installed backwards, but I don't think the
shop that did the work would make that mistake.
Perhaps the shop didn't test the shifting after a dry assembly.
And I didn't think of it until I put it all back together.
'91 Sessantacinque GT
'80 CM400T
MGNOC Member
Ascolta sempre e solo musica vera
E cerca sempre se puoi di capire

Online Chuck in Indiana

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Re: Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission
« Reply #37 on: November 16, 2021, 07:39:38 AM »
Quote
Perhaps the shop didn't test the shifting after a dry assembly.
And I didn't think of it until I put it all back together.
Sounds like you will get to do it, now.  :smiley: There is obviously something wrong. Fortunately.. it's a 2 hour job to get to it on the small block.
Chuck in (Elwood) Indiana/sometimes SoCal

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