Sessantacinque GT rehab (V65 GT), frame crabbing, gear box, transmission

[berniebee]

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!

[Pescatore]

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

[Pescatore]

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. 

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.

[berniebee]

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: (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.

[Pescatore]

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 

[huub]

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....

[Pescatore]

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.

[Chuck in Indiana]

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.  There is obviously something wrong. Fortunately.. it's a 2 hour job to get to it on the small block.

[Pescatore]

I finally resigned to the fact that I can't fix the shifting problem
from the outside. So I crabbed the frame again.
It was painful to do, thinking about all the care I took to
reassemble it.
On the bright side, I couldn't believe how filthy it was after
a few hundred miles on dry roads last summer.
I wish the rear fender went down below the swing arm.
All clean again.

[Pescatore]

With the gear box on the bench I confirmed the same shifting issues: it went into 1st and 2nd, then to get to 3rd I had to shift up,
tap down a bit and then up again.
I adjusted the cam screw a bit, but the pattern was not changing, nor improving.
I decided to take advantage of this great forum and contacted Scout63 for advice.  He was extremely generous in lending his time, his knowledge,
his shop, his tools, his grease, his mineral spirits, a ham and cheese snack and most importantly his confidence.  He didn't show hesitation in opening
the box and, like a kid wanting to learn to ride a bike but afraid to fall, I inhaled all the confidence and dove in.
Look at these beautiful trees with flowers on them!

   


But I am getting ahead of myself.
I am also grateful for many posts I found on this forum.  Just search for "gear box" many stories came up from others who repaired their gear box.
There is also a write-up by Nick Webb referenced in many posts and here it is again:
https://www.thisoldtractor.com/guzzitech.dk/gb_en_complex-technical_gearbox-repair-breva-750-pictures.htm
Nick refers to a Wildgoose post where all the work was also discussed among two other folks who had similar problems.  Unfortunately that
post was deleted.  I am not able to track down Nick for questions, but Muzz is on this forum (thank you Muzz).
As well as factory training videos:
http://thisoldtractor.com/moto_guzzi_technical_training_videos_eng.html
Also, while this other write-up is for big blocks, many tips and ideas can be leveraged, so thank you John Noble for this:
https://www.thisoldtractor.com/guzzitech.dk/gb_en_complex-technical_gearbox-rebuilding-pictures.htm

In the process of researching and opening the box we realized that, even though special tools are useful, there are ways around it.  That was one
of the obstacles I was creating in my head.  A pneumatic or electric impact wrench will do, if you can accept a compromise in re-assembly (read on).
With an impact wrench, you don't need to undo the nut on the input shaft.  This is the dreaded 10Kgm torqued nut, in the middle of the picture.



The only reason for removing that nut, barring any bearing or seal damage, is so that you can use the shaft and its gear to hold the lay shaft, under
the clutch housing.  That would be using the gear on the right side of the picture below to mesh with the lay shaft gear on the left.  Then, you need the special
spline shaft holder tool to undo the nut on the lay shaft.  Even though I saw the videos and did plenty of reading, it didn't click until I did this work.
I guess I am not the sharpest tool in the shed.




So, the first step in opening the box is to remove all the allen screws on the inside of the clutch cover and pop it off.
BTW, the picture above shows the clutch push rod. I put that in later and it should be removed before you start opening the box.

The next step is to take that impact wrench and unscrew the nut on the lay shaft.  Remember to pry open the punch in the lip of the nut!
Here is a zoom in:




   ...more to come.

[Pescatore]

Looking around the box, I found these two interesting stamps.  I guess the box was cast in 1983?
I cannot make out what the other stamp says.




The next step is to remove the vent because it has a detente pin that slides into slots on the fork drum to stop it at the right position (see top of drum below).
I added a banjo to the vent to route any overflow into a bottle next to the battery.  You don't have to remove the neutral switch.
Next, undo all the allen screws at the back of the gear box.  The housing comes off with a few taps. This is another view of the guts:




When I first opened the box, the gear selector was in a position similar to below:



After a few hours of shifting gears and observing how it works, I realized that the shifter was returning to a bad position.
Except for 1st, neutral and 5th, both teeth are supposed to touch a pin of the drum.  For neutral, the first drum pin should be in between the teeth.
In 1st, the inner tooth should be touching the first pin and in 5th the outer tooth should be touching the last pin.
This is neutral position, also noted by the two round cutouts on the bottom plate of the drum lined up with the shifter teeth:



The cutouts (easier seen on next picture) should allow you to remove the drum without removing the shifter.

This is second gear.  Note how the teeth are touching the pins.  I could hear a click when both teeth snap onto the pins of the drum, ready to move to the next gear.



BTW: I had to keep spinning the shafts to get the forks to move.

After a few more hours and just about giving up, I tried different positions of the eccentric screw, one flat at a time.  I marked the nut where I started.
On the fourth try, I started getting repeatable shifting and the snappy sound of the teeth grabbing the next pin of the drum.
Did I fix it?  I don't know for sure.  The real test will be when I run it at speed.

[Pescatore]

After much thinking and recurring bad dreams, I decided to check if shifting works while the gears spin.
I attached a drill to the lay shaft and spun it slowly.
Only three gears were engaging, WT...???




I turned the eccentric screw again and got to a position where all the gears clicked in. The downshifting is especially smooth and I can even find neutral.
I was turning the screw by one nut face at a a time, like I read online.
That was too much. It needed to be in between.  Seems too finicky,  but it works.
Time to reassemble everything. If it doesn't shift once installed and warmed up, hopefully the screw will be the answer.

I still have to figure out how to properly torque the big nuts.

[Canuck750]

Great work! impressed with your dedication to sorting it out. I have never seen the model you are working on, its an attractive bike.

I find transmissions, especialy getting the shift to smoothly function up and down a real challenge. I have had more than one transmission out and stripped several times before I understood it and sorted it.

[Pescatore]

Thank you, Canuck! 

[Muzz]

Never thought of doing it like that.

[Pescatore]

Hey, Muzz.  That came to me in a dream, after pinching my fingers in the gears many times.

I gave up on tightening the nuts my self.  I did not have a solid way of holding the gear box while working the wrenches.
I even bought the special tools from the dealer ($160 for both) and I could not hold the box steady in a vise.  I was afraid to break it or scratch it.
If I had a welder, I might have built the jig to put the box in a vise, but I had lost my patience.  I wanted to ride the bike.
So I went to a Guzzi dealer near me.  I gave them new nuts, gaskets and the whole assembly.  They had it together in less than an hour... and another $150 
I reassembled the bike a couple weeks ago.  Shifting gears on the kick stand seemed to work.

Scout63 helped me build the confidence to do this work myself.   A heat gun worked wonders to extract the bearings from the gear box.
We took the gear trees out and cleaned them.  We put it all back together without really finding anything wrong.
The eccentric screw was not set properly, but I don't think I would have gotten it to work without seeing what's going on inside the box.

I've been riding for a week now and all the gears are working.  I do hit a neutral sometimes, but I think I need to rotate the shift level one notch to make it easier on my foot.
The downshifting is kind of hard.  I need to push down with my foot more than I expect.  I might have to play with the screw some more.

Here it is now with new windshield and LED lights.




After a 120 mile ride last week, I discovered one of the front forks has a slight oil leak.  Here we go again.

[CharlieW]

Hello Pescatore
 I talked with you at NH Rally a little bit.
 Fabulous job on your Dads Bike. After all that work it is Your Bike now.
 I learned so much from the Wild Goose Guys, I dont think I could do what you accomplished .
 Nice to meet you and look forward to meeting you again.
 Great Story
 CharlieW

[Pescatore]

Hi Charlie, thanks for the nice comment.
I hope this helps someone else with a small block engine.
I am cautiously optimistic about going far places with this bike.  I will try to make it to more rallies.
Nice to meet you and thanks for posting pictures.

[Pescatore]

I put on about 500 miles this past summer, so I decided to give it a clean before storing for winter.
I realized there is a film of oil on the left side of the bike, from the carbs all the way to the swing arm.  The right side is fairly clean.
After some poking I realized the left side head gasket is leaking just a smidge.
Looks like I'll be taking off the left head, probably both heads.  And the left fork is also leaking.
The replacement parts arrived, so looks like I'll be freezing my butt in the garage this winter.

[Scout63]

Welcome to the unheated garage club...