Valve Issues! - Ducati.ms

krbreton · Sep 14th, 2011, 6:31 pm

Hi Guys-

Bought an '08 Hyper about 2 months/2000 miles ago. It just went in for 15K service with the local independent (very well respected and recommended) and I just got a call that he's having a local machine shop shave a little off a shim because the exhaust valves are still zero clearance with the smallest available shim. If that doesn't work, next up comes pulling the heads and redoing the valve seats if he can't get clearance, and I'll probably have to do that anyways in another 7500 miles or so. ($2 grand worth of work) LAME!

Has anyone else had this problem? I posted before that I was seeing high temps (~260F) and advice I got here and with other local ducati folks indicated that wasn't too overly high for oil. Could that have been the cause? Running Hot? The mechanic said that the high temps could have been caused by the valve being out of spec and that he thought the lack of valve clearance was most likely a one-off ducati thing (poor QC) and not necessarily related to some kind of abuse/misuse.

Is it possible that the valves were misadjusted previously - would this cause increased wear, or is valve wear relatively constant?

The bike seemed to run fine but I don't really have a comparison. Maybe when I get it back, I'll notice it being more powerful. Maybe not...

Any thoughts? Could really use some information, or at least some sympathy right now.

-Kyle

joelpatrol · Sep 15th, 2011, 6:28 am

Bummer Dude..................That was sympathy.

Dr. John · Sep 15th, 2011, 6:45 am

Hey Kyle,

I don't want to say your mechanic does not know wat he is talking about but "sending a shim to a machinist" kind of sent up a flare. That's not how it's done.

I also have a 08 Hyper as well as a 95 916. The exaust valves were tight at 15000 on the Hyper. It needed a LARGER closing shim. As the closer wears, the clearance on the opener is reduced, putting a smaller opening shim in will ruin the valve, then you will need head work.

Here's a suggestion, call the shop and ask for the opening and closing shim gap. I"ll bet they say "what's a closing shim". Just because you can balance and blueprint a GSXR engine doesn't mean you understand Ducati valve trains.

I may be completely wrong, if so I apologize to your mechanic. I can't see your motor from here, but I have spent a fair amount of time inside these motors-they are different.

I also use an independent shop for stuff I can't or don't want to do, nothing wrong with that. Personally I dislike dealerships, my experiences have been pretty bad as a rule. Just remember the unofficial slogan for our wonderful machines: "Ducati, turning riders into mechanics since 1946".

ducatimike · Sep 15th, 2011, 10:40 am

If the opener rocker clearance is too tight, then the valve has moved up into the head. If it has moved up so far that the smallest shim still leaves interference, then it is possible that the valve seat has worn to the point of needing it reworked. The cause can be do to a number of things, possibly a worn valve guide causing the valve to wiggle around each time it opens and closes. Either the valve has worn or the seat in the head has worn or both.

Closer and Opener valve clearances are independent of each other. Think of it this way. The valve clearances are defined as the gap between the closing rocker and the closing shim and the opening rocker and the opening shim WHEN THE VALVE IS COMPLETELY SHUT. Its difficult to understand that concept cause there is a hair type spring that takes up the closer clearance. So in your mind take out the spring. So you have clearance between both rockers and both shims. Now if you change out the closer shim to decrease or increase the clearance, the valve has not moved. So the opener clearance has not changed. Same thing with the changing an opening shim. A larger opening shim will change the opening rocker clearance, but will not change the closing clearance because the position of the valve has not changed.

Concerning modifying a shim thickness: Shims are initially made on a turning center. They are cut with a single point tool or final cut with a ground tool with the shape of the internal geometry (7 mm closer shim). So it is possible to chuck it up on a lathe and remove material from the face of the shim to make it smaller. Now, the old ducati shims were fairly soft and it was easy to machine off material. Around 2007 when Ducati came out with the 1098, they changed the material in the shims to a Bearing Steel, which is much harder than the older shims. You can still cut them on a lathe, but it is more difficult. My shims are even harder, being A2 tool steel, and the only way to cut the shim down on a lathe is to use a carbide tool and remove very little material at each pass. Even then the tool with wear out very quickly. A better way to remove material is to grind them or lap them. 300 grit paper on a flat surface followed up by 600 grit to polish the surface is what I use to remove a few thousanths of an inch if necessary. I also have a lapping machine which I use to lap quantities of shims at one time when the thickness is out of spec. Removal of material can be done without changing the hardness of the shims, cause they are hardened through, not case hardened.

Mike

hyperdookie · Sep 15th, 2011, 12:25 pm

Since you're in Fremont, I assume your bike is in capable hands at Nichols? If not, it should be.Welcome to Nichols Service Shop

krbreton · Sep 15th, 2011, 3:39 pm

Hi Guys-

Thanks for all of the information.

@joelpatrol - Thanks, I needed that

@Dr John - This man is very well respected specifically as a ducati mechanic. I will double check with him on the clearances - I assume that this was probably the opener shim, but I'm not sure - getting the news that you're going to have to spend a lot of money on a recently acquired bike shuts down some of your listening capability.

@ducatimike - Yep, I think you've nailed it pretty well. All of that to say that the heads are going to have to come off. I realize that the shaved shim will only delay the inevitable. The mechanic said that will only take a couple of thou off the shim. If he can't get the clearance he needs with minimal shaving, it's new seat time...

@hyperdookie - Yep, It's in with Jim Davis (Advanced Cycle), the old head mechanic for Nichols.

Thanks again guys,

-Kyle

hyperdookie · Sep 15th, 2011, 3:51 pm

That sucks. Unfortunately you have the bike being diagnosed by a guy very qualified to give you such bad news.

I guess the good news is he's also very qualified to repair it.

Dr. John · Sep 15th, 2011, 5:16 pm

Sorry to hear that Kyle. For your sake I was hoping it was the mechanic's fault.

Sounds like the bike is in good hands so if there is a bright side, just think about how sweet it will run after a couple thousand dollars of love is laid on it.

Be glad you caught it now, you were on your way to major engine failure.

Ain't bikes fun?

krbreton · Sep 15th, 2011, 5:28 pm

Quote:

Originally Posted by hyperdookie

That sucks. Unfortunately you have the bike being diagnosed by a guy very qualified to give you such bad news.

I guess the good news is he's also very qualified to repair it.

Quote:

Originally Posted by Dr. John

Sorry to hear that Kyle. For your sake I was hoping it was the mechanic's fault.

Sounds like the bike is in good hands so if there is a bright side, just think about how sweet it will run after a couple thousand dollars of love is laid on it.

Be glad you caught it now, you were on your way to major engine failure.

Ain't bikes fun?

True enough, gentlemen and thanks for the support. I'm hoping the shim shaving works this time, to spread out to the upcoming burden a little bit but I s'pose the Hyper's have been so reliable, someone had to take one for the team to perpetuate the ducati reliability statistics

krbreton · Sep 16th, 2011, 11:10 am

Just to close up - Well, I have my bike back

Jim's pretty amazing. He managed to make it work (and get within factory specs) with just a little off the shim. And for all of that extra hassle, he didn't even charge me extra. I'm sure he lost some time on this but he definitely earned himself a customer for life (plus he'll have all the fun of removing the heads in another 5-7k miles.)

Amazing difference. The bottom end is much smoother (still a ducati, though). The midrange power is significantly increased, and I haven't had a chance to go wind it out but the whole engine feels better (probably because the valves are actually working now). The temperature is much lower now.

As I was coming home, I let the clutch out too fast in second gear, only to find the front wheel coming up. Crazy Awesome!

Looking forward to enjoying the bike for a while, and it's nice to have the forewarning about the big repair - I can start shuffling pennies aside now.

Thanks to everyone here for your explanations and help...

-Kyle