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Discussion Starter #1
I started a post on compression ratio but couldn't edit the title so I'm starting a new thread to get maximum view. Sorry for the double post.

From the other thread:

"1098 started to run a like crap. It was a little over due to valve service. It had a inconsistent idle when cold which got better after it warmed up, but not perfect. Then I was riding around one day and it really started to run like crap. I would go full throttle and it would pull like it had 50hp. It had trouble doing 70mph on the highway. I limped it home, did the valve adjustment, new belts, new spark plugs, new fuel filter and it fired right up, idled perfect. However, the lack of power still persists. I'm going to test the compression. What specs should I be looking for?

Also, any ideas what would cause the power issue?"

Today:

So I removed the plugs and to do a compression test. I have the fitting with the right threads but the neck of the fitting is too wide to fit. Has anyone ran into this issue? Is there a solution?

Second, while I had to the plugs out I noticed the one for the horizontal cylinder looked brand new and the vertical looks use (Pics attached). I've only ridden the bike a couple miles since all the maintrnance but I don't think any used plugs should look like this. I held my hand over the plug holes and cranked the motor and both cylinders is pumping air out. Then I connected the plugs to the coil and held it close to ground and both plugs are firing. This leads me to believe I have a fuel issue on the horizontal. I'd like to access both injectors and see if they're spraying. What's the best way to remove the horizontal injector?

Any other ideas on my issue?


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We had similar symptoms on my '07 1098S earlier this year. I took it to an independent motorcycle shop, owner also owns a couple of Ducati's.

He checked it out and with nothing showing the cause of the issue, swapped his personal 1098 fuel tank for mine. Bike then ran great on the dyno.

So I bought a used fuel pump off eBay, installed that with a new internal fuel filter and it's been good since.
 

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You are on the right path. Yes, I have a dozen compression tester adapters and some have proven too fat. I have made special ones because with a Hemispherical head, often what's available can't reach into the treads and be snugged up. You have to either buy something that works or silver solder some pieces together to get what you need. Stick to your guns and do the compression test first.

That said, you verified sparks, so you have a fuel problem on the new looking plug cylinder. It wouldn't be a tank/pump.filter issues because that would affect both.

You can start the process of swapping pieces between the cylinders to try to identify the problem item. I suggest you make a log of ever step and label each component when you take it off. It can be a good idea to identify that a signal is being sent to the problem cylinder from the ECU before you go through any changes. I would think that a duty cycle indicator would work at the connector but I haven't had a reason to try that on a Ducati myself.
 

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Discussion Starter #4
You are on the right path. Yes, I have a dozen compression tester adapters and some have proven too fat. I have made special ones because with a Hemispherical head, often what's available can't reach into the treads and be snugged up. You have to either buy something that works or silver solder some pieces together to get what you need. Stick to your guns and do the compression test first.

That said, you verified sparks, so you have a fuel problem on the new looking plug cylinder. It wouldn't be a tank/pump.filter issues because that would affect both.

You can start the process of swapping pieces between the cylinders to try to identify the problem item. I suggest you make a log of ever step and label each component when you take it off. It can be a good idea to identify that a signal is being sent to the problem cylinder from the ECU before you go through any changes. I would think that a duty cycle indicator would work at the connector but I haven't had a reason to try that on a Ducati myself.
Where can I get narrower compression tester adapters that you have? I'll try swapping injectors first to see if it works out before doing the fancy duty cycle test.
 

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Compression test is the last thing you need to worry about. Your issues lay elsewhere and like I've said soooo many times, diagnosis over the internet on problems of this nature are such a waste of time. If you haven't an understanding of diagnostic procedure, send the bike to someone who has.
 
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