16valve adjusters coming loose

[CincinnatiKid]

Checked spark plugs, all is good there. Everything has spark, all plugs are seated about a 1/2 turn past just seated.

bought new exhaust gaskets, installed them onto cylinders 1 and 2 only today, due to time and the fact that the tapping sounds like it’s coming from the bike’s left side. Cylinder 2 looked like it was maybe an exhaust leak culprit. Where the flange seats to the gasket, there was a small band of carbon that maybe said it wasn’t sealing nice...NE side of the flange in the pic. I chased the threads in the head with a tap to make sure I’m not bottoming out there or anything. Reassembled and torqued the flange to the head and slipped the headers onto the flange, and started the bike up.

still tapping just the same.

kinda frustrating.

ive been riding my KTM to work daily since the GS has been in limbo, but I’m thinking about just putting some miles on the GS and see if the tap/tick changes at all.
4B7BC7BD-AFEE-48A6-B135-7527A6E4A554.jpg

[greg78gs750]

is it possible one of the spigots or pipes is out of round or something, causing an exhaust leak? I have no familiarity with the spring-retained pipes, i just know that when mine has leaked it has made a sound real similar.

[GregT]

Try moving the pipes around on their mounts while the engine's idling. I was once summoned urgently to listen to an engine I'd built - "it's making a noise".
My business partner leaned over the bike and the noise stopped....he was leaning on the muffler which stopped the pipe rattling against the frame.

If you had a early FZR1000 or an early Honda V4, I'd suggest a con-rod small end had gone oval, they were known for that. But the GS's don't do that...

[CincinnatiKid]

Try moving the pipes around on their mounts while the engine's idling. I was once summoned urgently to listen to an engine I'd built - "it's making a noise".
My business partner leaned over the bike and the noise stopped....he was leaning on the muffler which stopped the pipe rattling against the frame.

If you had a early FZR1000 or an early Honda V4, I'd suggest a con-rod small end had gone oval, they were known for that. But the GS's don't do that...

I’m in no position to rule anything out @ this point, but the way the sound tracks the RPMs makes me think the source is from inside the engine.

I’m trying to think outside the box here... is there a safe way to “disable” the valves for a cylinder? Either running the adjusters wayyy in to obviously kill compression but also to remove the potential sound source of valve/seat contact or valve/rocker. Just as a diagnostic measure, to listen to the engine for a minute or so. Would it be better or worse to actually remove the adjusters and leave the valves closed?

what about doing it for only half of the valves per cylinder per test? Just one intake and exhaust? Safer? Would it matter?

a friend who own a bike shop in cincinnati said not to do it, but offered no description of what might be problematic.

i don’t want to kill my engine but this lingering issue has me questioning if I even know the 4 strokes of an engine...!

[TeamDar]

Even if you remove the adjustment screws, the rockers themselves will still open the valve part way. However the noise will increase because the cams will be slamming into the rockers.

[GregT]

I’m in no position to rule anything out @ this point, but the way the sound tracks the RPMs makes me think the source is from inside the engine.

I’m trying to think outside the box here... is there a safe way to “disable” the valves for a cylinder? Either running the adjusters wayyy in to obviously kill compression but also to remove the potential sound source of valve/seat contact or valve/rocker. Just as a diagnostic measure, to listen to the engine for a minute or so. Would it be better or worse to actually remove the adjusters and leave the valves closed?

what about doing it for only half of the valves per cylinder per test? Just one intake and exhaust? Safer? Would it matter?

a friend who own a bike shop in cincinnati said not to do it, but offered no description of what might be problematic.

i don’t want to kill my engine but this lingering issue has me questioning if I even know the 4 strokes of an engine...!

Disabling one cylider isn't easy. Yes, you could pull the rockers completely. But to get the engine to run you need the spark for that cylinder to go to earth to complete the loop. Leaving the plug in means a lot of compression drag. Taking it out means you still have to earth the plug.

I'd still be looking at the rockers. Yes, you've looked at the rubbing surfaces - but how are the clearances to the shafts they run on ? Wear here will undoubtedly make a noise. Turn the engine till a valve is closed and try twisting the rocker. There should be very little play if any at all.

[CincinnatiKid]

Well I brought it to a very highly capable Indy speed shop (Fornarelli motorsports, Elgin IL) yesterday morning. They called today and said that the camshafts and the followers need replaced, and that they have run through the hardening on the surfaces. I would like to see the shop take a short video demonstrating the failure point and such, maybe in the future.

Hard to accept that the cams and the followers both/all need to be replaced, perhaps it’s just a point of hygiene that if replacing some, replace all.

It is going to be expensive. Found some sources for new parts, probably close to 1k in parts new.

Anyone sitting on some and willing to make a deal?
saw some camshafts on eBay for like 50-ish shipped, and some for about 200 shipped. Hard to gamble on some as-is pictures only listings like that.

[Rob S.]

Been following your thread since the start. Please remind us of the model by putting it in your signature. (1981 GS1100E)

Thanks.

[Gorminrider]

aha. Dorkburger and GregT had it right. I was afraid so when they posted-it made a lot of sense.

Hard to accept that the cams and the followers both/all need to be replaced,

Yeah, but I guess it's like a chain+sprocket..just replacing the chain won't last if the sprocket is worn.

[GregT]

Megacycle used to offer buildup and refacing service for the followers, I'm sure other companies do too. Cheaper than new.
The cams aren't hardened as such. They're chill cast iron which develops a "skin" of hard material.
If this is worn through, again they can be built up and reground.

You do have options other than new OE.

[CincinnatiKid]

Talked to megacycle. They charge 650 for the pair of camshafts, and each follower at 100/ea.

Ouch. That’s about the cost of new performance parts.

found a complete head on eBay for 350 or so. Probably will buy that....

[CincinnatiKid]

Talked to megacycle. They charge 650 for the pair of camshafts, and each follower at 100/ea.

Ouch. That’s about the cost of new performance parts.

found a complete head on eBay for 350 or so. Probably will buy that....

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F153567629941

its a gamble either way I guess...

[TeamDar]

If you recently rebuilt your top end then you really don’t need another head. All you need is cams and rockers, correct? Let me see what I got. I’ll let you know in the morning. Dar

[CincinnatiKid]

If you recently rebuilt your top end then you really don’t need another head. All you need is cams and rockers, correct? Let me see what I got. I’ll let you know in the morning. Dar

Absolutely correct, but finding the rockers is proving to be a challenge.

thanks for checking, PM me!

[TeamDar]

I’ve got rockers. I’ll pm you with my findings. Dar