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Moto Guzzi 850 T 5 Rotor issue

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
16
Location
Croatia
Hi guys,
I have 2 alternators damaged by rotor. Is it possible that shaft on which rotor is screwed has some free play?
I try to move it by my hand, and I think I can feel something like 1mm free move.
I ordered a new stator and rotor but afraid that it could happen again. Is it possible to test it somehow?
1668032871619 1668032893713
 

V700Steve

GT Reference
GT di Razza Pura
Joined
Dec 8, 2008
Messages
1,334
Location
Atlanta area, GA
That would be the crankshaft. For in frame check you would have to pull starter off & measure the ring gear back and forth movement.
New main bearings are available. I'd get the service manual which is just a supplement to the SP/G5 1000cc book.
How many miles on the T5?
 

john zibell

Moderator
Staff member
GT di Razza Pura
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Oct 28, 2008
Messages
9,037
Location
Huntsville, AL
The front main can be replaced without removing the engine. It would be a good opportunity to replace the chain and install a bow type chain adjuster.

1668041118349
 

Moto-Uno

High Miler
Joined
Aug 7, 2016
Messages
618
Location
Burnaby,B.C
If you can actually feel 1 mm ,up and down on the crank , you definitely have a problem . The crank
fit in the front support bearing is less than .005" or less than a tenth of what you feel . Hard to tell from
your picture of the rotor about the actual contact . Peter
 

V700Steve

GT Reference
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Messages
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Atlanta area, GA
I thought of for & aft play cause I never seen a front main loose enough to do as he's saying. That would make a deep noise, I would think.
Maybe the tapered end is bent, that I have seen. Had to check mine after the wreck.
 

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
16
Location
Croatia
If you can actually feel 1 mm ,up and down on the crank , you definitely have a problem . The crank
fit in the front support bearing is less than .005" or less than a tenth of what you feel . Hard to tell from
your picture of the rotor about the actual contact

That would be the crankshaft. For in frame check you would have to pull starter off & measure the ring gear back and forth movement.
New main bearings are available. I'd get the service manual which is just a supplement to the SP/G5 1000cc book.
How many miles on the T5?
Hi Steve,
It is more than 100000km. I was afraid of that news, before one month my red lamp of ignition went on a dash, I opened an alternator cover and saw that alternator and stator had contact, bought a new alternator rode it for few km red light still on opened an alternator cover the new alternator again damaged. Is it possible in any combinations that rotor bit maybe over shaped? I bought a new set rotor and alternator but afraid to place to the bike until I rule out the camshaft free movement....How I think that it has free movement I just move rotor with my hand, maybe I move whole bike and it looks like it has movement...I mean I hope all this just to rule out crankshaft :) What is the right procedure to test this? Bike can start but how to test it?
 

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
16
Location
Croatia
I thought of for & aft play cause I never seen a front main loose enough to do as he's saying. That would make a deep noise, I would think.
Maybe the tapered end is bent, that I have seen. Had to check mine after the wreck.

You think tapered end is where rotor screws on crankshaft? I am still having trouble getting stator from rotor waiting for that special tool , a screw.
 

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
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Location
Croatia
1668076611237
Some more pics and video, appreciate all the help!
 

Attachments

  • VID-20221110-WA0005.zip
    2.7 MB · Views: 5

john zibell

Moderator
Staff member
GT di Razza Pura
Joined
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Messages
9,037
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Huntsville, AL
I think this is the link to follow John?
If you read the banners at the top of the pages, external links are prohibited and I have removed the link. I looked at it and it doesn't tell you how to replace the front main. If you get the service manual for the bike that would be best. I'll briefly give the steps for you here but I'll skip alternator removal since you already have it off.

1. Support the bike by blocking the engine at the oil pan.
2. Remove one exhaust header so you can remove the through bolt at the front engine cover.
3. remove through bolt at the front cover.
4. Remove front engine cover.
5. Align timing marks on the cam gear and crank gear.
6. Remove cam gear, crank gear, and oil pump gear together with the timing chain. Remove old timing chain adjuster.
7. Remove front main.

Assemble in reverse order with new gasket, timing chain, and timing chain adjuster.
 

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
16
Location
Croatia
If you read the banners at the top of the pages, external links are prohibited and I have removed the link. I looked at it and it doesn't tell you how to replace the front main. If you get the service manual for the bike that would be best. I'll briefly give the steps for you here but I'll skip alternator removal since you already have it off.

1. Support the bike by blocking the engine at the oil pan.
2. Remove one exhaust header so you can remove the through bolt at the front engine cover.
3. remove through bolt at the front cover.
4. Remove front engine cover.
5. Align timing marks on the cam gear and crank gear.
6. Remove cam gear, crank gear, and oil pump gear together with the timing chain. Remove old timing chain adjuster.
7. Remove front main.

Assemble in reverse order with new gasket, timing chain, and timing chain adjuster.
Hi John,
Thanks
I tried to look for the front main bearing but on site you can order same part with extension from 0.2 to 0.6mm not sure which one to pick? And what it is about? You maybe know better? 1668097195517
 

john zibell

Moderator
Staff member
GT di Razza Pura
Joined
Oct 28, 2008
Messages
9,037
Location
Huntsville, AL
You have to measure the crankshaft to determine if you need an oversized bearing. Usually oversize bearings are used when the crankshaft is turned on a lathe to smooth it out. Dimensions of the crankshaft and bearings should be in the service manual.
 

motomatt

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Joined
Nov 11, 2022
Messages
7
Location
Portland
Hi Runner, sorry you are having problems with your bike. It sounds like the front main bearing is worn out. It will be very difficult to accurately measure the crankshaft front journal diameter with the crankshaft still in the bike. Too difficult to get in there with a micrometer. With that much wear on the front, it would be prudent to measure all of the crankshaft diameters anyway.
 

Runner130

Just got it firing!
Joined
Jan 4, 2022
Messages
16
Location
Croatia
Hi Runner, sorry you are having problems with your bike. It sounds like the front main bearing is worn out. It will be very difficult to accurately measure the crankshaft front journal diameter with the crankshaft still in the bike. Too difficult to get in there with a micrometer. With that much wear on the front, it would be prudent to measure all of the crankshaft diameters
Not sure what to do? Would really avoid to have to open the engine
 

scottmastrocinque

GT Godfather!
GT di Razza Pura
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Jun 26, 2011
Messages
3,678
Location
Findlay, Ohio
Not sure what to do? Would really avoid to have to open the engine

The most important thing about motorcycle maintenance and repair, is to be honest with yourself about your true skills and tools.

I’ve been watching this thread and honestly, this clearly appears to me to be outside your abilities.

You have a motorcycle with 100,000+ km on her.

Your crankshaft is seriously worn and you have destroyed 2 rotors/stators. The video you posted, the rotor is jumping all over the place. The crankshaft is shot.

I know you are seriously fighting this but…

Time for a tear down and rebuild. This is the cold, hard, truth.
 
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