help! 01 ducati 748 insane idle at hot

2978 Views 4 Replies 4 Participants Last post by speedn.j, Mar 17, 2015

james198989

Discussion Starter · Feb 6, 2015

Hello everyone. Need some help repairing the problem with my 01 ducati 748. I had ridden the bike for some time before the issues started. I have been able to determine exactly how/when the problem happens but I have no idea on what to do/get to fix. I will try to be as detailed as possible. When cool the bike starts and idles fine. The bike runs great until warm. At just over 180 degrees all hell breaks loose. The bike starts idling high, 3-4 k high. As it gets hotter it idles even higher. At about 190 ish the bike damn near bounces itself off the rev limiter. Now here's the kicker. If I just turn it on in neutral, let it hit operating and just idle it doesn't do it. But once I click it into gear within a minute the rpms shoot up. It accelerates out of control. It literally revs itself in gear (which is terrifying I might add). Long story short when hot it revs through the roof. It doesn't do it if I let it get hot in neutral but does when I put it in gear. If I warm it and ride it once it reaches hot it revs high. Even if I put it in neutral. Here's what I know. The idle switch is pulled completely out. The bikes fan works without a problem. The coolant is full and clean. The throttle operates smoothly. Literally the most confusing problem I have ever came across with any bike.
1. When hot while riding it revs high
2. When warmed in nuetral and staying in neutral its fine
3. When put into gear for the first time after warning it revs high.
4. The higher the temp The higher the ROMs
5. Fans work coolants full
6. Idle switch fully pulled out

Any and all help would be much appreciated. If you have any questions please ask. Thank you guys in advance for any help.

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Tuned

· #2 · Feb 6, 2015

Welcome to the forum!

So… the only thing that can truly raise the RPM's like that is the addition of air into the throttle bodies. My guess is, the link between the two throttle plates has failed. There is a plastic receiving assembly on the rear throttle body which cracks over time. I bet that throttle plate is opening up on its own as the bike vibrates whilst riding. This is why in the garage it only happens when it's in gear, by simply touching the bike to get it into gear, you disrupt the throttle plate enough to open it up. It's literally vibrating open on it's own.

I'd pop the tank off and play with the throttle body. Ya know, open it up, wiggle the throttle plates, things like that. I'm sure the issue will be very easy to find once you get in there.

Here is the kicker… it doesn't happen when the bike is on the kickstand leaned over because there is just enough friction to keep the plate from opening on it's own.

How about them apples?

Just a guess… but it seems to go along with your description pretty well.

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james198989

Discussion Starter · #3 · Feb 6, 2015

Sounds like a reasonable possibility. The minute its warm enough to ride/cold enough to make it to the shop. I will tear it apart. Thank you for giving me a possibility. Its much appreciated.

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serious black

· #4 · Feb 9, 2015

Agree on air leak. Check if one of the small screws that block the holes for throttle synchronizing hasn't fallen out. Also check the manifold nuts as it is not unknown for them to loosen.

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speedn.j

· #5 · Mar 17, 2015

Mine kinda had a problem like that. I had to lube the throttle linkages. They were sticking

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