!977 Sachs 175 Stuck Crank?

[vitaminT]

I've got a 175 Sachs engine that has a stuck crank. Does anyone have any ideas? The gears shift freely and the clutch gear is loose. The bearings look good behind the crank gear and under the blue seal behind the motoplat. The case splits horizontal. I have never seen this before. Is there any thing else I can do to free this crank? Is there something I should look out for before splitting the case? Any help would be greatly appreciated.
Thank All!
Vance

[Speedy]

quote:Originally posted by vitaminT

I've got a 175 Sachs engine that has a stuck crank. Does anyone have any ideas? The gears shift freely and the clutch gear is loose. The bearings look good behind the crank gear and under the blue seal behind the motoplat. The case splits horizontal. I have never seen this before. Is there any thing else I can do to free this crank? Is there something I should look out for before splitting the case? Any help would be greatly appreciated.
Thank All!
Vance

Do you mean the connecting rod will not turn?
Did you take the cylinder off to check the rod goes back and fort?
How do you now the bearing behind the blue crankseal is fine?Did you take the seal out to look?
Did you open the ignition cover to check the flywheel?
We need more infos before we  can help you.
Cheers,Speeedy------>>>>>>>SACHS HORICONTAL SPLIT SPECIALIST.-->>>>>>>>

Helmut Clasen
162 Hillcrest Ave
L9H 4Y3
Dundas Ontario Canada
Ph.905-627-5349
[email protected]
http://speedy_c.tripod.com

[vitaminT]

The piston was stuck in the cylinder. The bike was sitting for quite some time. Once I pulled the head and put some penatrating oil down the cylinder . I tapped the piston and it came loose . I pulled the jug. I opended up both side covers to find a nice clean clutch a gear shifting mech. but the motoplat side was very rusty. I removed the motoplat and the blue seal. Looking into the ignition side bearing they look good. Looking into the gear side crank bearing they look good also.Is there anything that can come loose behind the crank that can jam it? Does the case spit for inspection without removing the clutch and crank gear? Any suggestions!

[Kip Kern]

I just rebuilt an engine that had the same problem.  It turned out to be moisture in the crank area caused the magnesium case internal to corrode and swell to the point of binding the crank from turning.  This engine looked very good on the outside but was full of corrosion on the inside.  I would be very cautious when buying a KTM engine unless it turns free and you have inspected the ignition area and crank area as these are the two biggest places for corrosion.  I have also found it in the transmission enclosure where the clutch cover mates up with the left case, bottom area.  Needless to say, I will be bringing my KTM tools to Mid Ohio when shopping for used engines!  The majority of time, if a engine has moisture damage in the ignition area, it will most likely have damage in the crank area.  

[Kip Kern]

I was talking KTM engine but there are magnesium Sachs engines out there too.  Also, check the M20 bearings, attached to the crank, for corrosion.  Good Luck

[Speedy]

quote:Originally posted by vitaminT

I've got a 175 Sachs engine that has a stuck crank. Does anyone have any ideas? The gears shift freely and the clutch gear is loose. The bearings look good behind the crank gear and under the blue seal behind the motoplat. The case splits horizontal. I have never seen this before. Is there any thing else I can do to free this crank? Is there something I should look out for before splitting the case? Any help would be greatly appreciated.
Thank All!
Vance

After you have removed the flywheel,stator and mounting plate you can lay the engine upside down,remove all 8 mm SW 13 nuts and washers and tap the lower engine case off the upper part.Crankshaft and all transm.shafts are then visible.It looks like you have to do a toatal rebuild on that engine so clutch and shifter system has to come out too.I suggest to be safe,take everything apart(very simple)inspect,clean,replace(whatever)and rebuild complete.Any try on an older engine to bypas will bite you later.
Cheers,Speedy---->>>>>>>

Helmut Clasen
162 Hillcrest Ave
L9H 4Y3
Dundas Ontario Canada
Ph.905-627-5349
[email protected]
http://speedy_c.tripod.com