Snapped Piston Rings and Head Bolt

[HeadSmess]

and then...once an engines assembled, dont be tempted to turn it over until the start up...

ok, ok, its more important with castiron bores, but its still a good habit. why?

all them "sharp" edges in the cylinder wall are needed for the initial "bedding" of the rings. (if you couldnt see the honing marks, it would be smooth, polished, not sharp...glazed even)

sealing is created by combustion pressure behind the ring forcing it out into the cylinder wall. not the "spring" of the ring itself.

the initial startup and run should be full load, full throttle...maximum pressure on the ring. THEN you back off and take it easy until all the bearing surfaces wear in...

gotta trust your work to avoid the temptation. but on these things...who cares? lol

 

[Dave C]

I'm going to add a few things to the other suggestions. Biggest problem besides blowby from your broken rings is the ends can score the cylinder wall. If you see scraches in the cylinder wall take it to a motorcycle shop and have it *lightly* honed. This is NOT boreing it out, just making a clean surface to seat the new rings.

Now, really, there can also be a big problem running the motor with 3 studs. Not only is there burnt oil all over the place but quite possibily there will be what is called "torching". This is when the hot exaust gasses actually tunnel or burn a grove in the cylinder head or jug then your looking at new parts, especially if it's the jug.

Now, as to installation of the new studs. I'm sure as in most towns you can find a place that sells used tools. That would be your best bet to find a beam-type torque wrench, the clicker type I don't trust with such low torques. Get a 3/8", not the 1/2 " type.

For assembly I use Permatex Copper Spray-A-Gasket for the head gasket. Spray it on both sides of the head gasket and let it dry to tacky then install. For proper torqueing you should use a Moly Disulfide lube. I use CR Sta-Lube. Grease the threads and washer with the grease. This insures the torques are as close to the same on all the studs.

Torqueing: Looking down on the front of the motor start with the stud closest to the exaust port, torque to 2 1/2 pounds. Then do the other front stud. Now, go across the motor, not to the stud next to the one you just did. Then to the last stud. You have just done a "Z" shaped pattern and all are torqued to 2 1/2 lbs. of torque. Next series of torques move your starting point to what was the second stud in the first go around and repeat the pattern, torqueing to 5 lbs. this time. Keep this up shifting your starting point each time and going up 2 1/2 lbs. every time until you reach the desired 12 1/2 lbs. of torque. Do not just zip the torques right up to 12 1/2 lbs., you'll be very unhappy with the results(like having to do it all over again with a new head gasket)

 

[echelonunit37]

I bought and installed the parts. I'm running at 35-40 mph again. The motor sounds and idles so much better. The MB king of Oceanside is back!

 

[a/c man]

Glad you're back in the game man.
Re-check those head bolts after riding it for awhile.
Wait until it's cooled down first.

Good luck....,
TIM

 

[echelonunit37]

Checked the head bolts and torqued them back up. Everything is running strong and smooth.

On another note, I've got some serious flames shooting out of the exhaust. Running lean, I know. But it was pretty cool to see. It was a nice blue yellow mix. Every time I throttled down.

 

[echelonunit37]

For anyone who cares: here's a video of the rides I took with my friends around town BEFORE the repairs. I'll post a video of the AFTER soon.

http://www.youtube.com/watch?v=grLD6DYKC9A

 

[GearNut]

Nice movie.

 

[echelonunit37]

Heres video two... no audio but you can see the difference in performance. It powers up hills like a champ.

http://www.youtube.com/watch?v=OJs5IOvT9ds

 

[GearNut]

Very nice movie as well! What is the band/ song that you used in it? I like the tune.

 

[echelonunit37]

Dayvan Cowboy by Boards of Canada. Amazing song.