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81 gs1100e, a top end rebuild story

CincinnatiKid

CincinnatiKid

Forum Mentor
it's time for a rebuild. Not sure what happened, but I will find out here soon.

Took the bike to the track, had a great day, bike was running really great, until I lost a oil cooler hose, the engine oil spilled onto the track, and my engine, and my rear tire, and I went down.
rebuilt the bike, started it up, heard a weird noise on the left side of the engine while trying to get it timed, but it disappeared on it's own. checked behind the alternator cover. nothing amiss.
once the bike was ready to ride for a shakedown, I was hearing a sound that sounded a lot like brake pad/rotor drag, but it was coming from the left side of the engine. kind of like a sliding sound... weird. engine ran fine, but the sound was there and it was RPM dependent.

rode it to work yesterday and got downtown and saw that the crankcase breather was puffing smoke heavily. this happened in winter 2017, I had to put a top end on it then. engine still ran fine, started easily, idled ok without having to adjust any settings from track day. got it home, didn't run it hard.

compression test results tell the tale:
1 -120
2 - 80
3 - 105
4 - 110

got the boroscope out and shot some video from inside the cylinders. i'll post a YouTube video of that in a little while. piston 2 crown has some damage for sure.

for now, i'm looking at parts.
probably an 1134 kit, +2mm pistons (about 6-700)
slotted cams because why not ((about 120)
will check integrity on rocker pads
put new valve springs in last rebuilt (gsxr springs as recommended by the shop)
hopefully valves and seats look okay
 
very curious as to what the mode of failure was, more info will come when the engine is opened up.

after the crash @ the track, my ignition cover was broke, the dyna pickups were broke, and the bolt holding that assembly to the crank was bent pretty bad. I was initially worried that there was crank damage, but a new bolt into the crank spun true and concentric. so I felt better about there being no crank damage. no oil has seeped from the right side crank seal. or anywhere else.

I can't see a way that a pretty mild crash (in the grass... no plastic parts broke) could have caused physical trauma into the piston/cylinder. it does seem like it was pieces of broken ring marks in the top of the cylinder. something was in the combustion chamber. tbd. check video for details.

I thought maybe there was something to the oil spraying all over the front of the engine on the 2&3 cylinders, maybe quenching the heat from them while the piston stayed hot, as hot as it's ever been run (15 minutes into a track session, pulling about 8k or so down the straight). a heat mismatch perhaps caused distortion and problems between cylinder wall and piston??
 
Heat mismatch seems not to probable. Did the kill switch kill eng. immediately or did it lay on the side idling for a bit ?
 
Here’s the inspection video. My wife helped me cut it together and she lightened the mood with her sound effects library.

re:running, I think it ran on the ground for a bit, not too long tho…. Less that 20 seconds??
 
Might be, as the bike flipped you off it over-revved for high and just long enough to stress a piston or cause a valve / piston interface.
 
IMO you're going to have to lift the head to see where the debris came from and how much damage it's done

If it was just in one cylinder I'd guess a brass screw has come from somewhere along the inlet tract - but it's in three cylinders...
 
Engine is out and has been brought into the basement for further inspection and disassembly.

i wonder what sort of brass screws could have gone missing?? Air cleaners were intact, carburetors seem complete and functioning regularly. I’m very anxious to break into the top end tonight (hopefully).
 
progress is static since getting the GS engine to the basement. I acquired a proper bike for the track, (2009 zx6r) and have spent the evenings after work changing tires.

i'm at work and since I cant wrench I can ONLINE SHOP!!
I don't want to purchase anything until I get the head removed from the GS motor, but i've sorted out a small shopping/wish list:

piston kit w/head gasket K1133 $700
machining $400
air cleaners 005-121 $66
cam chain BF05MUx120 $90
cam chain tensioner rail TGS1100 $75
valve stem seals 99201 $37
hardened clutch hub nut SHN1150 $35
​oil pan gasket EC007 $6

about 1400 total. 1100 for the piston kit and machining, and about 300 for the extra stuff.
these are from the APE parts store

Air cleaners, clutch hub nut, and cam chain tensioner rail are kind of "why not" impulse buys. air cleaners have been on there since I got the bike 8 years ago. clutch hub nut, i've seen people mention as a potential weak point. expensive for a nut, but also kind of "why not". replacing cam chain seems prudent, and might as well refresh the slider also. won't purchase until inspection happens, but maybe some of you have some more insight.
 
OK now lets get one thing straight..... I think this motor is more Fkedup than it's worth.

I broke into it last night, took a lot of photos. I'll host them up in Google photos here in a bit.
Top ring on Cyl 4 and Cyl 2 were broken to pieces. Pieces from Cyl2 migrated into the chamber and caused the physical trauma to the piston and underside of the head.
Oil starvation and excessive heat seems to done a number on the camshafts from the crash incident... they look pretty hurt in the chromed hardening surfaces. ditto on the rocker pads.

I haven't checked the valve/seat condition. nothing looks too bad from the valve-closed resting arrangement, but I assume there's some damage to cylinder 2 valves and/or seats.

adding a couple hundred for some presumed valve work to the costs listed above, it's looking like $1500 in engine work. which of course begs the question.... how much could a used 11E motor cost? decidedly less.

so who's holding an engine? you see my budget. I'm willing to pay a fair price and even a $50 finders fee for a referral to someone who's got the goods.
 
Nessism used to have a good 1100 engine under his bench I think... no idea if he still has it.
 
Does this warrant a new thread?
Questions about clutch part wear…

I got a 83 1100 motor in October. Top end claimed to be good and tested and proven. TBD… but the engine was missing peripherals.. stator&cover, starter, ignition, clutch&cover…
so I’m pulling my motor apart to harvest good parts and list the others for sale. Lmk if anyone has parts needs/wants. 1981 gs1100e

anyways I took my clutch out and noticed the back side of my clutch hub/basket/gear looked pretty hurt. Not sure how clean the factory welding job on it was, but mine looks more like English manufacturing than Japanese manufacturing.. can anyone offer a second opinion? Is this worthy of service in the 83 motor?
Im curious about the welding and grinding. I don’t see any wear marks that indicate any rotational wear…
 

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I’ll add that the engagement part of the gear (some call those parts “teeth” LOL) looks great (from a very preliminary inspection). Nothing jumped out as a problem.

Also about the Clutch Hub Nut… I have seen that APE offers a billet clutch hub nut for $36 that claims to be better than the OEM nut. It claims that the OEM is soft and will back itself off the threads on the shaft. I’m going to replace the Nut for this reassembly but does popular opinion say that the go-fast part is necessary? An OEM nut cost $3…
 

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CincinnatiKid said:
Does this warrant a new thread?
Questions about clutch part wear…

anyways I took my clutch out and noticed the back side of my clutch hub/basket/gear looked pretty hurt. Not sure how clean the factory welding job on it was, but mine looks more like English manufacturing than Japanese manufacturing.. can anyone offer a second opinion? Is this worthy of service in the 83 motor?
Im curious about the welding and grinding. I don’t see any wear marks that indicate any rotational wear…
Click to expand...

You should probably start a thread in the Projects forum

The clutch hubs are well known to come loose. The welds means someone has fixed that issue so, no, it's not factory.

The nut? Well, if you're not going to race the 1100 some blue Loctite and the stock nut should suffice
 
I see, I was assuming that it was welded from the factory. It’s never given me trouble yet, so I will carry on with it as is.

And thanks, I think the OEM nut and the loctite will sort me out just fine. My days of pushing this bike to any type of limit are done. Probably.

If a moderator wants to move this thread, that’s fine with me. I probably don’t have the determination to continue updating at checkpoints. I’ll assemble the motor, put it back into the bike and hopefully it will be drama free.
 
I don't think nobody's mentioned the locking washer for this nut, and don't know if yours still had one when you took it apart, it goes under the nut, then is "bent up against the flat edges" of the nut so it shouldn't be able to back off... "Proper torque", Loctite, locking washer, My opinion you should be good to go.
 
Certainly. Every manual always specs to replace that folding lock washer upon disassembly across any bike I’ve ever wrenched. I’ve always reused them to no detriment.

thankfully, that past-service-limit lock washer was there, it was the only thing holding the nut from backing off completely. New ones are on order for the clutch and the front sprocket.
 
Back in the days the ape nut was the thing,the OEM nut had a tendency to back off even with the locking tab. I would consider it cheap insurance. Looks like the someone welded the rivets, they would work them selfs loose and rattle everything. The OEM backing plate is a little thin if you are beating on it on the track they flex and loosen up. The APE plate is a good upgrade if you are going back to the track.

Looks like you might have starved the engine of oil, the piston ring looks like it seized or caught something and peeled up, that's why you have 80 psi and oil use. How bad are the cylinder walls, i suspect scoring, which will need as bore out, the one cam lobe also looks grooved.

good luck getting it back on the road.
 
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