Ace UCE project.

[ace.cafe]

I'm 100% positive I've narrowed down the louder valve train noise I thought I was hearing. It's the louder clicking you hear when you first start it up cold, it eventually stops when the engine warms. The decompressor? It's not stopping, or closing, or whatever it does when the engine warms. I'm sure of it after listening to it today, that's the clicking I hear, constantly now. It might explain why the exhasust sounds weird to me as well. Is there anything I can do to check this out, or should I just take it to the dealer for inspection? I don't mind pulling a case cover or two. Is there anything electrical, or is it strictly mechanical in nature?

As I understand that decompressor, it is rpm actuated.
I don't know the rpm, though.
What I know is that it works on a centrifugal actuator with a spring, which causes a little "hump" to come up thru the cam lobe when the rpms are below a certain amount, and that lifts the exhaust valve as the cam goes around, and releases the compression in the cylinder.
At a certain rpm, it is supposed to be retracted by the flyweight system inside the cam, and not work again until the rpms drop.
So, I suspect you might be able to get rid of that issue by increasing the idle speed rpm.
If that doesn't work, then it might be sticking.

[Ducati Scotty]

I believe it's 250RPM.  They tend to stick open for a bit when it's cold.

Scott

[Arizoni]

I seem to recall reading somewhere the lift off speed was 700 rpm but whatever it is it is less than the idle speed.

I also noticed that when the oil is cold the auto decompression would tend to "hang up" and cause a loud clicking.
Revving the engine just a little always got the things attention and it would stop causing the loud clicks.

IMO, if riding the motorcycle doesn't make it quit a visit to the shop should be made.

Riding the bike with the exhaust valve hanging open for any distance can burn the exhaust valve and the valve seat.

[Ducati Scotty]

Maybe it was 750RPM.

[Hobbydad]

Yeah, that's what it is. It's either stuck or broken, I'll take it in and have them look at it tomorrow. Now that I know what it is, I don't think it was the rev limiter that made it burp & stall, it was this. I distinctly remember when it did it in 4th and stalled, I had just hit 65mph. I've been up to 70 in 4th a few times, it wasn't the limiter. I was really hoping to avoid not having the bike to any length of time, but if it needs work so be it, it's for the best.

[gremlin]

That's not far from where I spent my youth ..... I lived on Vassar&Glendale (near Harvard) .....   I come back every five years or so ~ maybe someday I'll come home for good.

Jim in Minneapolis ....

Hobbydad, you're in Toledo, Ohio? Meet your newest stalker I live in the Old South End behind the zoo.

[iron.head]

not sure if this will be of any help though!

[Ice]

Hi iron.head and welcome aboard.

[gremlin]

cool photos, what caused the abnormal wear ?  do both engines have approx the same history ?

not sure if this will be of any help though!

[ace.cafe]

That photo of the piston is showing that there was some grit of some kind in the oil that was on the bore, which scored the thrust face of the skirt.

[ace.cafe]

I had a long meeting with the guys at Mondello's yesterday.
A variety of approaches were discussed, and I gave them a pretty good budget to do their development experiments with. My instructions were to get the best bang for the buck that they could get, and I didn't limit what they could do with it. Whatever would give the most, is the instruction, as long as it wouldn't put the final price out of range of the buyers.

I also stipulated that I'd like to be able to offer at least 2 "stages" of performance, so that people on a budget with modest performance improvements wouldn't be forced into a high price option.

One  of the biggest things to come out of the meeting was that they think they may be able to get enough flow improvement out of the exhaust port without moving it around, or enlarging it beyond what the stock pipe can take. This is still a conjecture, but they stated that they might be able to do that. It that turns out to be the case, it could save considerable money from not having to buy the aftermarket exhaust pipe. I think the telephone pole muffler will still have to go, in any case, though.
I always try to keep the costs down by any means possible, as long as I can deliver what's needed in the overall package.

So, we'll have to wait a while, to give these guys some time to work on the development processes. They have the green light and a budget, and if I have to increase the budget along the way, I will do that if it means getting a better result.

[Ducati Scotty]

Good news so far then   I'm glad to hear that there might be an option that retains the stock header which really helps keep cost down.

Scott

[Arizoni]

Ace:
Being the lazy sort of guy I am, I will ask you a question.

Does the O2 sensor protrude very far into the gas path?

It's pretty obvious that the area where the O2 sensor is located gets much hotter than the exhaust pipe shortly upstream or downstream so I was thinking it might be quite a severe obstruction.

If it is, perhaps adding a spacer between the O2 sensor and the bung to move the tip back out of the way could improve the exhaust discharge a bit?

[ace.cafe]

Ace:
Being the lazy sort of guy I am, I will ask you a question.

Does the O2 sensor protrude very far into the gas path?

It's pretty obvious that the area where the O2 sensor is located gets much hotter than the exhaust pipe shortly upstream or downstream so I was thinking it might be quite a severe obstruction.

If it is, perhaps adding a spacer between the O2 sensor and the bung to move the tip back out of the way could improve the exhaust discharge a bit?

Arizoni,
My current answer is "I don't know".
I don't have the pipe here to put on the flow bench.
I suppose that is something that I'll have to measure.

However, moving the O2 sensor back out with a spacer WILL affect its readings. It is very sensitive to position.

[GreenRE]

I had a long meeting with the guys at Mondello's yesterday.
A variety of approaches were discussed, and I gave them a pretty good budget to do their development experiments with. My instructions were to get the best bang for the buck that they could get, and I didn't limit what they could do with it. Whatever would give the most, is the instruction, as long as it wouldn't put the final price out of range of the buyers.

I also stipulated that I'd like to be able to offer at least 2 "stages" of performance, so that people on a budget with modest performance improvements wouldn't be forced into a high price option.

One  of the biggest things to come out of the meeting was that they think they may be able to get enough flow improvement out of the exhaust port without moving it around, or enlarging it beyond what the stock pipe can take. This is still a conjecture, but they stated that they might be able to do that. It that turns out to be the case, it could save considerable money from not having to buy the aftermarket exhaust pipe. I think the telephone pole muffler will still have to go, in any case, though.
I always try to keep the costs down by any means possible, as long as I can deliver what's needed in the overall package.

So, we'll have to wait a while, to give these guys some time to work on the development processes. They have the green light and a budget, and if I have to increase the budget along the way, I will do that if it means getting a better result.

Awesome Ace !

If you could have one of each on the shelf to do an exchange/swap it would put F5's on the road much quicker.