General Category > General Discussion

V7 II Broke Down, Metal Flakes in Crankcase = Poops.

(1/19) > >>

Dirk_S:
Last Saturday I was riding home from Maine with my 275 lb friend in my 200 lb sidecar. We did a good bit of secondary highways, not going any faster than 65mph. Sometimes there were some long uphills, but I didnít usually go over 60 mph up them. Kept the rig between 4500-7000 rpm. Then I got a low oil light and heard a slight but peculiar, metal tinging sound. Pulled over right away. Dipstick read bottom line. Thankfully had some reserve oil in a 1L bottle, and poured it in. Started up and on our way. Within 1 mile, the metal chatter  got a little louder. Sounded like it was on the right side, but wasnít positive since the sidecar might be amplifying and ricocheting the sound. Within 2 miles, the bike shut down on me. Next day, I trailered it home.

Compression test on both cylinders read 180 psi both sides.

Leakdown test today:
Left side = at 75 psi, the cylinder read only 1 psi lost in the cylinder.
Right side = different storyóat 75 psi, the cylinder read 63 psi for a 15% loss. I heard air coming out of the engine oil filler hole as well as through the throttle body. Intake leak, it seems?

I checked my valve clearances on the right sideó still reading 0.15mm intake, 0.20mm exhaust, just as it did when I set them 2000 miles ago.

I pulled off the cylinder head. Guess Iíve been running pretty rich:







Dropped the sump. Uh oh. Lots of metal flakes, both gray and copper/bronze colored:







Drained the gearbox, minor metal amount, tiny granules, and not a lot, I think itís normal.

Decided to go ahead and remove the cylinder and piston. Cylinders didnít appear to really have any scoring. But the piston connect rod does move a few mm, maybe 5mm, up and down the crank shaft. Should it shift along the shaft at all? Saw some metal flakes sticking around inside the crankcase as well. Guess weíre gonna have a drop-down, clean-up job.

Thoughts? Main bearings look like they might be gray? Wondering whatís the copper color from?

Potentially important note: 3000 miles ago I replaced the clutch with the help of a custom bike builder, neither of us ever had a Guzzi motor opened up in front of our eyes before, but he had auto mechanic experience, and once he saw it looked like an auto style block/clutch, he was game to help. Since replacing the clutch, pushrod, thrust bearing, and oil seal back then, Iíve never once felt the need to adjust the clutch, so my limited knowledge feels somewhat confident that the clutch replacement may not be the causeÖI hope.

I really wish I had a mechanic for a friend at this point.

chuck peterson:
Ouch

Sorry for your lossÖthat seems pretty destructive

On the bright side weíre getting tons of used V7ís coming up for sale used

Buy a motor and slap it in? Iím not sure rebuilding would be cost effectiveÖIíd hate to see just the parts cost to repair

jacksonracingcomau:

--- Quote from: chuck peterson on September 11, 2022, 04:15:36 AM ---Ouch

Sorry for your lossÖthat seems pretty destructive

On the bright side weíre getting tons of used V7ís coming up for sale used

Buy a motor and slap it in? Iím not sure rebuilding would be cost effectiveÖIíd hate to see just the parts cost to repair

--- End quote ---
:thumb:
Fixing motors that have run dry of oil always involves more than just the big end thatís knocking
You also get plenty of spares to use or help others with
V7 850 motor might come up cheap

Dirk_S:
Iím willing to bet that I didnít do a good enough job keeping up on the oil, especially considering that I ride in all conditions, more aggressive terrain, and now have a Sidecar attached. I was told by my nearest dealer a couple years ago that I should split my fluid replacement intervals in half.

I donít mind doing this work if I have to and IF itís doable. No garage, so yeah, Iíd be bringing it in onto the kitchen table. BUT, seeing that Iíve never done this before, I know Iíll need to be aware of steps that need to be super precise. I imagine balancing the crankshaft is no easy job.  And making sure that every single metal flake is out of the crank case so as not to impede oil passage. My 300,000+ mile, former warranty service associate at a BMW dealership friend told me that the balancing and bathing to get all the debris out are not great kitchen table jobs.

Unfortunately, a lot of those V7 IIs have the undersized crankshaft, which makes the point moot, I imagine.

moto-uno:
  Not too sure I understand your phrasing about 'moving up and down the crankshaft' ? Is this front to back or
up and down ? The latter is really bad !  Peter

Navigation

[0] Message Index

[#] Next page

Go to full version