77 Convert and compression results

[Irishflyer]

Well, my 77 Convert (53,000 miles) I acquired as a non runner, that had been in storage for over 10 years, has compression test results I didn't particularly like..lol.  I initially checked compression at about 60/70 psi. (L/R)  Adjusted valves, and let some Marvel Hail Mary juice soak in each cylinder for a week.  Came back today, didnt change much (75/80) I squirted a bit of oil in each, which brought it up to 100/90 psi. 
  Before I really sink a lot of money into it, does this seem like an engine with some sticky rings, and will 90 psi be enough to support it running long enough for the rings to possibly un-gunk themselves?  Or with what I've done, am I looking at just plain old wore out rings? 
  Ive never even ridden a Convert, so not sure if I would want one or not.  I know there are some Convert champions on here, so I welcome input!..:-)

[Antietam Classic Cycle]

Are you holding the throttle wide open during your compression test? Good battery cranking as fast as possible? Good quality tester or cheap Harbor Freight? The extension hose on the latter expands and gives false readings. A leakdown test will tell you more.

But try this: turn the engine so that the pistons are at BDC or close, remove the rocker arms, using a brass drift and hammer, "bump" the valves open several times. This will help dislodge any chunks of carbon and hopefully help the valves seat/seal better.

[Irishflyer]

Carbs are removed at this point, so plenty of air getting in..:-)  Using group 34 car battery to spin engine.  My compression gauge is a Bosch unit I've had for a while.  I can try to bump the valves as you describe.  Finding top dead center sucks on a Convert, turning rear wheel doesn't seem to do much.  If that doesn't help, then a leakdown is in order.  Just sucks because I was wanting to be riding it by now, but the weather has been too hot and humid to do much in the garage.  Today is pretty decent.  Well, until the low psi numbers...lol. 

Thanks for the suggestion!

[Antietam Classic Cycle]

You're not going to turn the engine over with the rear wheel on a Convert. Remove the alternator cover, remove the plugs and then use the alternator bolt to turn the engine. I rarely do it any other way even on manual transmission Guzzis.

It's a 42 year old motorcycle that has been in storage for ten years. Who knows how it was treated prior to being put away. One should expect to have to do quite a bit of work to any motorcycle (Guzzi or otherwise) under these circumstances. 

[Irishflyer]

Yeah, it was running and the guy put it in storage.  He opened the tops of the carbs (mistake), and the gas tank (also a mistake, nice rust coating).  I always consider it could have been thoroughly worn out before I got it.  If it looks too bad, might consider parting it out.  Im not seeing that Converts bring that much money online, especially non runners such as mine. 

[gearman]

What Charlie said. The low compression coming up with oil indicates stuck rings. Put the carbs on and get it running. Converts have cast iron cyl. liners and are very durable. Let us know what happens.  Cheers

[Irishflyer]

Is the 80-90 psi good enough for starting and running, albeit poorly?

[gearman]

Is the 80-90 psi good enough for starting and running, albeit poorly?

   I think so.

[s1120]

What Charlie said. The low compression coming up with oil indicates stuck rings. Put the carbs on and get it running. Converts have cast iron cyl. liners and are very durable. Let us know what happens.  Cheers

I gotta say that I agree with this. being it has cast iron cyls.. You got some oil in there all ready, and that will start freeing things.. Get her running, get a little heat into it, with some fresh oil and check again.  Might be flat worn out... but might be just all gummed up from sitting, and might come back.

[John A]

Its worth a try , wont hurt anything

[Yeahoo Whoyah]

Ive never even ridden a Convert, so not sure if I would want one or not.  I know there are some Convert champions on here, so I welcome input!..:-)

Follow Charlie and others advise and try to get your Convert running before parting it out, or at least that's what I'd do.  If you're able to ride it then you're in for a laugh, Converts bring grins :) 
I love to take mine for errands. It'll hold 4-bags of groceries easily since its still got all the period touring equipment.  Onward!


 

[Gusable]

Another use of kroil.  Drown those pistons in kroil for 3-4 days and then retest “ the oil that creeps”. It’ll get in there. I’d turn it over by hand on day2

[brider]

Since the carbs are already off, and to accomplish Charlie's valve-tap procedure you'll have to remove the rockers, and since rings gaskets and cyl-stud O-rings are cheap, you might actually save time by just pulling the cylinders and replacing the rings. At 45k, all the cyl stud O-rings on mine were just like plastic and didn't seal anything, oil leaks everywhere.

Did you ever try to see if it would fire with the carbs on? If you're just focusing on the compression but have not had the fuel system or ignition operational, then pulling the cyls to ensure that your rings are top-notch might be a SMALL percentage of the time you may have to spend on the other systems.

But using Kroil/Marvel Mystery and other methods sure can't hurt, and may get you up to compression #'s that should allow it to at least fire.

You guessed right, there are a lot of Convert devotees on this forum, and they are a very under-rated and unique bike. We keep hoping that alone will make us all rich when their value skyrockets in 100 yrs!

[chuck peterson]

The first one I found was leaking from every seal until I could get to it. Started, ran, and never stopped for a decade while I slowly and methodically replaced every single system over another 100k...thank god for Guzziology! I was a complete rookie...it refused to die so I learned a hell of a lot...Keep putting it together like its gonna live again..

Or sell it. You be you.

Id bet the psi will come up when it's starts being run...also getting the same numbers on both sides is a good sign...I can remember only one guzzi in 25 years that bled oil into the Pistons and cylinders blowing smoke out the back

[Irishflyer]

Got the carbs put back together, have a air filter manifold on its way, along with a few odds and ends.  It will live again.  I was looking it over, and yeah, even if I had to pull the cylinder heads, I forget its air cooled, and pretty damn simple.  I will try to see what 90 psi gets me as far as running.  I believe the electrical parts are ok.  Soon find out.  I am closer to getting it running that I thought.  (I know that brought some raised eyebrows and laughter...lol).  I do have a copy of Guzziology, and the Haynes manual, and I used to build Boss Hoss motorcycles, so just have to get back into the swing of things again. 
  On another note, how much play should there be in the driveline when I spin the back wheel?  There seems to be a bit of a clunk when changing directions.  I checked the ATF fluid in the drive reservoir itself, and didn't smell burned. 

[chuck peterson]

Ooooooohhhhhh I've heard that before....might be time to check the universal joint between swingarm and trans...should be no play..some play between rear wheel and rear drive forward and back taking up the slack in the driveline but if it turns into light medium resistance, then loose suddenly,  it might be the needle bearings in the ujoint about to give up...will also show up as unusual vibrations while under way...replacements available for the unusual convert one piece ujoint/driveshaft with 20 teeth, vs the 2 part 5 speeds ujoint/drive

[chuck peterson]

My inclination is if you have fresh looking not burned aft, don't change it...something about the newer aft  fluids not pushing the torque converter as well as the older less slippery fluids...I've lost track of that topic....

[Antietam Classic Cycle]

On another note, how much play should there be in the driveline when I spin the back wheel?  There seems to be a bit of a clunk when changing directions.  I checked the ATF fluid in the drive reservoir itself, and didn't smell burned.

Since there is no direct mechanical connection between the rear wheel and engine, it can be very difficult to tell what is actually "play" and what is normal movement. The clunk when you change directions may be nothing more than slack being taken up between the shift dogs and gear.

Dexron III/Mercon ATF works perfectly well in my in my Convert and is readily available at any auto parts retailer. I would definitely look at the condition of the fluid hoses - if they're the originals, then it's time to replace them. If any shows signs of deterioration, then it's time to replace them. No need to buy complete lines - cut the crimps off, remove the old hose, replace with new hose and proper clamps.
http://thisoldtractor.com/moto_guzzi_tonti_i-convert_replacement_oil_lines.html

[brider]

There seems to be a bit of a clunk when changing directions.

The Automatics are eeeeaaaaasy on u-joints, but they can wear. investigating that very same clunk on my Cal2 Auto last winter (same driveline as Convert) with 45k miles, the u-joint was like new, zero play, but the driveshaft coupler was severely worn where it mates with splined tail-end of the driveshaft. At that time the couplers were un-obtainium, but as soon as they became available again Charlie was nice enough to post the MGcycle link:

https://wildguzzi.com/forum/index.php?topic=100958.0;topicseen

Took care of a HUGE portion of my own "clunk". The rest is internal to the tranny.

[Irishflyer]

I am going to put the bike up for sale, I am over my head with time, and Im not 20 anymore, I have missed two riding seasons already, and I just dont have the time for it anymore.  I will be asking $1300.  I will post in  sales section.  I appreciate the help!