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Over revved '80 1000 SP... What Is Likely Damaged?

K

K2Guzzi

Just got it firing!
Joined
Aug 14, 2019
Messages
15
Location
Chicago
Ran out of gas doing 80 and had trouble flipping petcock on right side. Bike died so pulled over to left to restart after flipping to reserve.

Pulled in clutch, thumbed starter, didn't hear it start and when I hit the gas didn't get acceleration. Downshifted nothing. Dropped two gears (maybe 3) and popped clutch while doing about 50...

Bang! Pulled in clutch and upshifted twice and entered back on the highway with my exit being next.

Pull off and come to stop light bike dies. Hmm? Didn't do anything. Go to start it and it starts but dies right away. Hmm? Start it again but give it gas and it sounds metallic so kill and push 100 feet to fire department parking lot.

Get off bike... and see I left a trail of oil into the lot. Could get bike to start but had to give gas to run. Put in gear but felt like running on one cylinder. Was tempted to limp home but didn't want to amplify cool guy damage... so trailered. Left oil in trailer.


Diagnosis:

Popped heads off... don't see tell tail sign of piston and valve touching on either side. Very disappointing. Push rods look fine but will pull out and roll on flat surface. Think that would mean the penalty isn't the cheap, easy fix of valve, o-rings, and gaskets. Maybe should have started bike and pulled one spark plug and then other to determine side of damage? Was worried about amplifying.


Was going to drop pan and look for evidence of damage.


Some of you gentlemen have more miles on one Guzzi... than most riders do on all their bikes... so if you haven't done this stupidity... you may have helped someone who has.


Bike: 1980 1000SP with 46,000 miles

It had been mostly sitting for 20 years since mechanic was paid $350 to fix charging issue... didn't deliver...he was adamant he did. Fixed it myself year before while also doing starter relay rewire and just replaced the clutch two months before. Put ~1,000 miles on it while making it into a cafe race racer before stupidity occurred.

Many thanks for constructive directions. Have picture so pistons and cylinder head/valves.
 
Can you let us know where the trail of oil was coming from? The factory red line on these bikes is very conservative and these engines can do about a thousand RPM above the factory red line for short periods without damage. Let us know if a push rod or rods were bent. Hopefully that is the extend of damage, but the oil trail is a bit of a puzzle if you didn't hole the block. Also with 46K miles, she probably needs a timing chain anyway. Do use an updated chain tensioner (see MG Cycle) if you replace the chain.
 
Could just be a bad rear main seal, all of a sudden alot of crankcase pressure. I can't see the over rev. At 80mph tack on my SP1 said 4500rpm even 3 gears wouldn't be over 9K rpm.
 
john zibell - "Can you let us know where the trail of oil was coming from?" - Looks like the overflow tube.

"Let us know if a push rod or rods were bent." - Will do.

"Also with 46K miles, she probably needs a timing chain anyway. Do use an updated chain tensioner (see MG Cycle) if you replace the chain." - Thanks for heads up and recommendation.

This cold weather has been motivational for garage work. Will try to get in there this afternoon.
 
V700Steve -

Wish it was that easy and cheap as I know how to strip and crab the bike... but that sound was metal. Don't think even if a quart of oil was spit out that kind of friction would occur... but that is only a guess.

Obviously don't know how high the RPMs went as I was watching traffic... but definitely way past 6k.

I may have also blow the main seals... which would just add to the headache... but when you are too nonchalant about something... you invite problems.

Clutch doesn't seem affected so not sure if that indicates anything about rear main seal.

Hopefully I get in and drop the pan and get more direction.

Thank you.
 
K2, Engine oil can't get to the clutch, but gear box oil can. The flywheel shields the clutch components.

Please keep us posted on what you see as you investigate.
 
If you accidentally over-revved an older Guzzi, the intake would float and kiss the exhaust valve, which being hot, would tweak and cause the engine to run on one. Bike will not idle on one. Makes it real hard to start too. Have to chuck the valve in a grinder to see the bend, usually. Since you have the heads off, pour some solvent in to the ex port and see which valve is leaking. Hope this helps. Been there, done that! A new set of valve springs properly shimmed will minimize future issues.
 
Alright! Weather was bad and lined up to stay bad so got out of Dodge.

Today dropped oil pan and examined bottom of engine. Kickstand and left side frame were covered in oil. Noticed front of oil pan are covered in oil. See a little oil puddle under alternator. Guessing this indicates front oil seal blew.

Rear of oil pan was not covered in oil so assuming/hoping rear oil seal didn't blow.

Was shocked that only a quart of oil or so drained out! knew I left a serious trail and even some in the trailer.

After pan was removed I reached up and grabbed one conrod(throttle side) end and tried to wiggle it. Bingo! That horrendous, loose sound when engine was running was replicated! Grabbed other one conrod end and it was tight.



Ok! Found main problem... blown conrod bearing and likely the front engine seal.


For the conrod I need bearings for both and new bolts and nuts. Anything else?

For replacing the cylinder heads need the gasket and 4 o-rings for each side. Anything else?

Is changing the front seal complicated? Any special tools needed?

What else is the standard to change when doing this?

What else is a good idea to change?

I know timing chain should be checked and possibly changed and a new tensioner should be installed.



How priorities have changed! Sizing up second bike... since I hope to get back to riding a ton (~20,000 miles a year)... and a top consideration is what can do high mileage besides be fun and have personality... but not be a license incinerator.

Thank you for your help! Hopefully I can put on another 48,000 miles before having to do this much work again.
 
Once you get the connecting rod off, check the crankshaft for damage. A grind and undersized inserts may be in your future.
 
John,

Oh! Yeah! I was going to remove it... but then figured it was best to remove and replace at the same time when possible. It makes it easier.

The only metal I found in the pan was a thin flat piece that had one side bent up. Since it was malleable I figured it was the bearing... but it could be a shaving from the crank shaft.

Ugh! Thought the worst news was over!

Thank you for the heads up!
 
gyrotex,

I missed your response. Thank you! Should I pull the valves apart to check that they are straight or will the liquid be good enough?

IMG 8316 IMG 8327
 
John,

Alright.

Picture of the sheared off metal piece. Under closer inspection it does look like the con rod bearing.

The dipstick from the oil cap was in there but no other chunks. Dipstick must have broke off sometime in month after oil change.

IMG 8746 IMG 8750 IMG 8748
 
Oil puddle under alternator I believe indicates front main seal was blown. (Drips on ground are from oil pan removal. IMG 8757 IMG 8751 IMG 8758 )

That would explain why the front of engine below it is covered with oil and lower left side. I thought/was hoping it was spray from over flow from crazy pressure... though at 50 mph few things spray forward.

It is that con rod with blown bearing. Throttle side.
 
Looking at the picture with the oil filter, I would recommend a complete tear down and flush of all the oil passages. That would include flushing our the crank shaft. I know you don't want to hear this, bur you have quite a bit of contamination. To clean out the crank shaft the plug must be removed and a new one inserted an peened. Also it would be helpful to get a picture of the crankshaft with the connecting rods removed.
 
Thank you John for your opinion.

I popped off the conrods as I couldn't remove the damaged bearing without loosening up other one. I was amazed at how well that bearing works! Wow! Rotated smooth as butter but didn't want to pop off. Think oil added adhesion.

The crank shaft does not feel like it has any gouges. My plan is to do the old 400-600 grit sandpaper with wd-40 using a shoestring or cloth to polish the crank.

I measured the crank diameter at 43 to 43.5 mm to see which bearings I need to order but don't understand the translation. There are four options: standard, 0,762 mm, 0,508 mm, and 0,254 mm.

I would think that is thicker than standard since obviously if the shaft gets ground down a thicker bearing would compensate without having to change the connecting rod.

Getting closer!

Ok! So far parts list:

- 4 - bearing halve (size to be determined).
- 2 - cylinder head gaskets.
- 16 - 9 x 2 o-rings (says 12 in parts catalog?) for 4 cylinder studs on both sides.
- 4 - 20,42 x 2,62 o-rings for 2 short cylinder studs on both sides (on oil plugs each side).
- 4 - connecting rod bolts.
- 4 - connecting rod nuts.
- 1 - front main seal gasket 28 x 38 x 7.

Recommended:

- 1- cam chain.
- 1 - tensioner.
- 1 - front cover gasket.
- complete tear down of engine.


Flushing the oil passages needs to be done. Best fluid for this?


Thank you as always!
 

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My documentation shows the crank pin should be 44.013 to 44.033 Your 0.5mm difference in measurements is a bit out of round and you need it to be round. So, remove the crank and have it properly ground to a size for the next oversize bearing. I suggest you contact Harper's Moto Guzzi and have them do the machine work and supply you with the correct oversize bearing inserts.
 
If you pull the crank & have it ground it will be round again, like John say's. Auto Machine out in St Charles, IL can do it. They did my cranks for me. They are the best in area. I went to school w/one of the owners. They did all my work from my shop in Kingston,IL. You could also call Joe W (GuzziDoctor) up on northside to see about a machine shop in the city.
 
Hmm? I better better get a digital micrometer so I can get the most accurate reading. My 10 cent analog tool obviously will not give me the accuracy I need. I just gave a range because it was just over 44.

What is the proper way to get an accurate reading?

Guessing take three or four readings... quarter turn of crank... take the readings again in the same areas... and do it until until all four sides are done? Then do it all again to double check.

I was getting the same reading then after twenty or so measurements I may have gotten sloppy. Again... cheap measuring tool which obviously lacks the accuracy.

Thank you for the guidance on who to use for the crank.

Warmer weather is coming in a week or two... so it would be nice to get the heart surgery done. The best way to social distance!
 
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