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224917


When I was a kid, I saw Monster 900 on the cover of some motorcycle enthusiast magazine and it was love at first sight. The big monster has been my dreambike since I realized I wanted a motorcycle, and about a week ago I took the first step towards making that dream a reality

I just got my hands on a project bike, but I may have bitten off more than I can chew. It has a fair share of problems (been scouring the web to try and diagnose the issue, but so far I haven't had much luck pinpointing the issue) -

First, the good -
Bike is almost immaculate cosmetically
Lowish mileage (13k)
Electrical seems fine at first glance, cable routing looks good, no DIY jank as far as I can tell
New tires (nice)

From the mouth of the previous owner (discussing the previous previous owner) the fuel line blew, unsure of whether it was a clog or what - the guy pulled the fuel filter and completely bypassed it which sets off all sorts of red flags in my book.

He also swapped out stock for K&N air filter and sloppily cut the lid of the airbox down.
224915

Bike has some sort of aftermarket carbon exhaust, not sure what the brand is as they all look fairly similar. The bike itself has some unfortunate (maybe minor, maybe major) issues that prevent it from getting on the road

___
SYMPTOMS

- Low idle, doesn't take throttle well

- Low compression (makes 125-118, spec is 131-160)

- Inconsistent idle (it jumps from 1k - 1.5k - 1k)

- Backfiring out of front end, shop said it seemed to be running fairly lean

- Significantly decreased torque (can't even really roll off before bike stalls)
___
The previous owner took it to a shop before I got the bike from him, and from the report (which I've attached)
224919

Fuel pressure 48-52psi at all times, lines are routed properly, no kinks
Battery voltage low (I've connected it to a conditioner)
Swapped out whatever was in tank for 91 octane
Backfires into the intake
Low idle, does not take throttle well
Plugs were fouled (they didn't list how), swapped
118v 124a
Tightened belts to spec
LEAKDOWN TEST - GOOD (more on this later)
Low compression (makes 125-118, spec is 131-160)
"Vehicle needs engine work - tear down before quoting"
___

Several users here had almost identical symptoms, but they never posted resolutions to the problem. I've found suggestions, but as I'm working with a limited repair budget I'd like to make sure everything is done properly/with consideration the first time. I live in the rockies, nearest dealership is on the west coast so it's not feasible to have it diagnosed by professionals unfortunately.

The advice given by the shop before the owner picked it up (days before I purchased the bike from him) was to check the pistons, rings, essentially suggesting a topend rebuild. I'm not opposed to doing so, and I believe I have the skills necessary if I go about it in a logical way, but that rebuild would wipe my budget (~$1500) so I want to be certain that I've troubleshot every conceivable cause of these problems before I start dropping wads on expensive parts.

IN ADDITION that successful leakdown test would suggest it isn't the piston / rings, but I'm not certain and would appreciate the correction if I'm wrong
___
Based on my limited research and knowledge, those listed symptoms could be.....
ECU incorrectly mapped for the pipes on the bike (not sure if this particular exhaust would require one, pictured below)
224916

TPS sensor issue
O2 sensor issue
Ignition system (coils specifically)
Issues with fueling and exhaust? Possibly clogged injectors resulting in a stream instead of a spray -
Black soot on headers, unsure if it's normal for Ducatis
224914

Additional weirdness, it looks like someone put mighty putty on the oil pressure switch - it wasn't even hand tight, and when I tried to crank the bike in my garage it spewed oil out
224921

- oil is also well past maximum fill level it seems (after losing oil due to switch not tightened)
224920


___
I've got the Haynes manual, and I've done modest work on a few of my other bikes before (oil changes, KLR doohicky, yamaha cam chain tensioner, etc).
I'm hesitant to take it into a local shop, as nobody in my area is particularly excited about the idea of working on an early 2000s Duck


This is as far as I've gotten. If anyone has advice or suggestions, I'm all ears and would appreciate any direction you can give me -
 

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Looks good cosmetically. If there's no tank dents, it's a score! Not sure about the cans off a Honda Civic or whatever. But that can wait. I don't know what your budget for the project is, but dang. $250 to tell me it's screwed. Can't imagine what they'd charge to fix it. If it were mine, first thing I'd do is perform my own compression test. Hopefully the battery is up to the task. Testers are cheap these days. Might not be Snap-On, but it's good enough to help decide to issue a death certificate or not. Best way? Pull the throttle bodies off completely. Doesn't sound like you're gonna make it to bike night on it anytime soon anyway. Pull both plugs and give at least three good spins on each cylinder and record each peak every time and see where you're at. Wouldn't hurt to get the exhaust out of the way either. Heads are coming off in the next episode anyway. No matter how the compression test goes.
 

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Do a LOAD TEST on the battery, just checking voltage doesn’t tell you enough. Clean the ground points. Drain the oil and replace. Check that oil pressure switch, it sounds like someone might have stripped the threads. Can you fix it yourself if it’s stripped ?
Run a can of SeaFoam through the injectors and see how it runs after that.
I would do a valve adjustment and see if that changes the results of compression test and
improves how well it runs. This is an expensive thing if you don’t or can’t do it yourself.
Replace the belts after the valve adjustment if you are unsure of their age.
 

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Discussion Starter #4
Doesn't sound like you're gonna make it to bike night on it anytime soon anyway. Pull both plugs and give at least three good spins on each cylinder and record each peak every time and see where you're at. Wouldn't hurt to get the exhaust out of the way either. Heads are coming off in the next episode anyway. No matter how the compression test goes.
Newbie question but it's fine to do a compression test without both plugs removed and the entire exhaust assembly removed?
 

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Hi,
i have had a VERY similar experience with a M900Sie over the last three months, which is now fixed.


Basically you have to assume everything is wrong and just work through it. I highly recommend getting the LONLEC ADB cables to hook up the ECU to your laptop. This will give you a chance to see if sensors are behaving as they should, Download GUZZIdiag which is free software to Interface with the ECU. Your fuel pressure tested good (mine didnt) so if the bikes been standing you might need to run some injector cleaner through it or removes the injectors and clean them.

In my case the valve service had been ignored for so long that the valves werent sealing anymore and the heads had to come off to lap the valves and then re-shim everything. Not as bad a job as it sounds TBH.

What i dont really understand is how the leakdown test comes up good but not the compression test. If the compression is low it has to be "leaking" out somewhere. Normally indicated by the leakdown test.

Chris
 

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Newbie question but it's fine to do a compression test without both plugs removed and the entire exhaust assembly removed?
Technically and sensibly you can perform a simple compression test without doing all those things. With a questionable battery having the plug out of the cylinder not being tested allows the starter and battery to devote the greatest possible cranking power to the cylinder being tested. They both have to come out at some point anyway to check both cylinders. Any compression test has to be done with the throttle propped wide open. So don't forget to disconnect the injectors as well. If you take them off all together, well it doesn't get anymore wide open than that. As far as the exhaust goes, there's something going on there. Chances are it is beyond just a matter of tightening up the nuts. Just replacing the gasket requires removing the exhaust. And who knows, you may have an obstruction in the exhaust. Uncommon, but not impossible. Unfortunately the way the first chapter of this story really ends, is with the heads coming off. Which entails removing all of those things. I would definitely check your valve clearances first with the heads still on the bike. Maybe by chance they'll be good. Maybe they won't. Probably could use valve seals while you're at it. I know that I would definitely want a peek at those combustion chambers with all that going on. It may sound daunting, but it's really not. And you can save much frustration by getting that stuff out of the way right off the bat. Instead of spending a lot of time trying to work around it, only to take it off later anyway. Trust me, messing with shims and stem seals, or anything else valve related is so much easier on the bench than on the bike. When something you've been riding for years starts acting up that's one thing. But when you have no idea what has been done or not done. No clue how it's been treated. Might as well start from the feet up.
 

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Hi,
i have had a VERY similar experience with a M900Sie over the last three months, which is now fixed.


Basically you have to assume everything is wrong and just work through it. I highly recommend getting the LONLEC ADB cables to hook up the ECU to your laptop. This will give you a chance to see if sensors are behaving as they should, Download GUZZIdiag which is free software to Interface with the ECU. Your fuel pressure tested good (mine didnt) so if the bikes been standing you might need to run some injector cleaner through it or removes the injectors and clean them.

In my case the valve service had been ignored for so long that the valves werent sealing anymore and the heads had to come off to lap the valves and then re-shim everything. Not as bad a job as it sounds TBH.

What i dont really understand is how the leakdown test comes up good but not the compression test. If the compression is low it has to be "leaking" out somewhere. Normally indicated by the leakdown test.

Chris
Yeah, that doesn't really make any sense. You can pass a compression test with flying colors and fail miserable on a leakdown.
 

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I had 150psi compression, which the experts said was borderline and a possible indicator of Valve issues. The Leakdown confirmed this, with nearly 20% leakage from primarily the inlet valves.
With the heads on the bench, upside down and the combustion chambers full of Alchohol (medical) it would run straight out. After the Valves being lapped it sat there for two days not leaking a drop. The leakdown test then came up to less than 5%. I haven't checked the compression since.

I think cleaning the injectors also helped ALOT in my case and possibly here too. was quite simple to do with some fuel hoses in different sizes and a can of WD40
 

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Newbie question but it's fine to do a compression test without both plugs removed and the entire exhaust assembly removed?
Yes fine just ground the coils with spark plugs to heads so you don’t fry ignition.
 

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was quite simple to do with some fuel hoses in different sizes and a can of WD40
please be more specific, Normal WD40 is a lubricant, almost useless to clean injectors.
However, they do make a carb and throttle body cleaner, WD40 carb and throttle cleaner. and it's one of the best ones. Obviously the one your referring to
It contains chemicals that can dissolve built up residue.
just my 2 cents.
 

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View attachment 224917

When I was a kid, I saw Monster 900 on the cover of some motorcycle enthusiast magazine and it was love at first sight. The big monster has been my dreambike since I realized I wanted a motorcycle, and about a week ago I took the first step towards making that dream a reality

I just got my hands on a project bike, but I may have bitten off more than I can chew. It has a fair share of problems (been scouring the web to try and diagnose the issue, but so far I haven't had much luck pinpointing the issue) -

First, the good -
Bike is almost immaculate cosmetically
Lowish mileage (13k)
Electrical seems fine at first glance, cable routing looks good, no DIY jank as far as I can tell
New tires (nice)

From the mouth of the previous owner (discussing the previous previous owner) the fuel line blew, unsure of whether it was a clog or what - the guy pulled the fuel filter and completely bypassed it which sets off all sorts of red flags in my book.

He also swapped out stock for K&N air filter and sloppily cut the lid of the airbox down.
View attachment 224915
Bike has some sort of aftermarket carbon exhaust, not sure what the brand is as they all look fairly similar. The bike itself has some unfortunate (maybe minor, maybe major) issues that prevent it from getting on the road

___
SYMPTOMS

- Low idle, doesn't take throttle well

- Low compression (makes 125-118, spec is 131-160)

- Inconsistent idle (it jumps from 1k - 1.5k - 1k)

- Backfiring out of front end, shop said it seemed to be running fairly lean

- Significantly decreased torque (can't even really roll off before bike stalls)
___
The previous owner took it to a shop before I got the bike from him, and from the report (which I've attached)
View attachment 224919
Fuel pressure 48-52psi at all times, lines are routed properly, no kinks
Battery voltage low (I've connected it to a conditioner)
Swapped out whatever was in tank for 91 octane
Backfires into the intake
Low idle, does not take throttle well
Plugs were fouled (they didn't list how), swapped
118v 124a
Tightened belts to spec
LEAKDOWN TEST - GOOD (more on this later)
Low compression (makes 125-118, spec is 131-160)
"Vehicle needs engine work - tear down before quoting"
___

Several users here had almost identical symptoms, but they never posted resolutions to the problem. I've found suggestions, but as I'm working with a limited repair budget I'd like to make sure everything is done properly/with consideration the first time. I live in the rockies, nearest dealership is on the west coast so it's not feasible to have it diagnosed by professionals unfortunately.

The advice given by the shop before the owner picked it up (days before I purchased the bike from him) was to check the pistons, rings, essentially suggesting a topend rebuild. I'm not opposed to doing so, and I believe I have the skills necessary if I go about it in a logical way, but that rebuild would wipe my budget (~$1500) so I want to be certain that I've troubleshot every conceivable cause of these problems before I start dropping wads on expensive parts.

IN ADDITION that successful leakdown test would suggest it isn't the piston / rings, but I'm not certain and would appreciate the correction if I'm wrong
___
Based on my limited research and knowledge, those listed symptoms could be.....
ECU incorrectly mapped for the pipes on the bike (not sure if this particular exhaust would require one, pictured below)
View attachment 224916
TPS sensor issue
O2 sensor issue
Ignition system (coils specifically)
Issues with fueling and exhaust? Possibly clogged injectors resulting in a stream instead of a spray -
Black soot on headers, unsure if it's normal for Ducatis
View attachment 224914
Additional weirdness, it looks like someone put mighty putty on the oil pressure switch - it wasn't even hand tight, and when I tried to crank the bike in my garage it spewed oil out
View attachment 224921
- oil is also well past maximum fill level it seems (after losing oil due to switch not tightened)
View attachment 224920

___
I've got the Haynes manual, and I've done modest work on a few of my other bikes before (oil changes, KLR doohicky, yamaha cam chain tensioner, etc).
I'm hesitant to take it into a local shop, as nobody in my area is particularly excited about the idea of working on an early 2000s Duck


This is as far as I've gotten. If anyone has advice or suggestions, I'm all ears and would appreciate any direction you can give me -
View attachment 224917

When I was a kid, I saw Monster 900 on the cover of some motorcycle enthusiast magazine and it was love at first sight. The big monster has been my dreambike since I realized I wanted a motorcycle, and about a week ago I took the first step towards making that dream a reality

I just got my hands on a project bike, but I may have bitten off more than I can chew. It has a fair share of problems (been scouring the web to try and diagnose the issue, but so far I haven't had much luck pinpointing the issue) -

First, the good -
Bike is almost immaculate cosmetically
Lowish mileage (13k)
Electrical seems fine at first glance, cable routing looks good, no DIY jank as far as I can tell
New tires (nice)

From the mouth of the previous owner (discussing the previous previous owner) the fuel line blew, unsure of whether it was a clog or what - the guy pulled the fuel filter and completely bypassed it which sets off all sorts of red flags in my book.

He also swapped out stock for K&N air filter and sloppily cut the lid of the airbox down.
View attachment 224915
Bike has some sort of aftermarket carbon exhaust, not sure what the brand is as they all look fairly similar. The bike itself has some unfortunate (maybe minor, maybe major) issues that prevent it from getting on the road

___
SYMPTOMS

- Low idle, doesn't take throttle well

- Low compression (makes 125-118, spec is 131-160)

- Inconsistent idle (it jumps from 1k - 1.5k - 1k)

- Backfiring out of front end, shop said it seemed to be running fairly lean

- Significantly decreased torque (can't even really roll off before bike stalls)
___
The previous owner took it to a shop before I got the bike from him, and from the report (which I've attached)
View attachment 224919
Fuel pressure 48-52psi at all times, lines are routed properly, no kinks
Battery voltage low (I've connected it to a conditioner)
Swapped out whatever was in tank for 91 octane
Backfires into the intake
Low idle, does not take throttle well
Plugs were fouled (they didn't list how), swapped
118v 124a
Tightened belts to spec
LEAKDOWN TEST - GOOD (more on this later)
Low compression (makes 125-118, spec is 131-160)
"Vehicle needs engine work - tear down before quoting"
___

Several users here had almost identical symptoms, but they never posted resolutions to the problem. I've found suggestions, but as I'm working with a limited repair budget I'd like to make sure everything is done properly/with consideration the first time. I live in the rockies, nearest dealership is on the west coast so it's not feasible to have it diagnosed by professionals unfortunately.

The advice given by the shop before the owner picked it up (days before I purchased the bike from him) was to check the pistons, rings, essentially suggesting a topend rebuild. I'm not opposed to doing so, and I believe I have the skills necessary if I go about it in a logical way, but that rebuild would wipe my budget (~$1500) so I want to be certain that I've troubleshot every conceivable cause of these problems before I start dropping wads on expensive parts.

IN ADDITION that successful leakdown test would suggest it isn't the piston / rings, but I'm not certain and would appreciate the correction if I'm wrong
___
Based on my limited research and knowledge, those listed symptoms could be.....
ECU incorrectly mapped for the pipes on the bike (not sure if this particular exhaust would require one, pictured below)
View attachment 224916
TPS sensor issue
O2 sensor issue
Ignition system (coils specifically)
Issues with fueling and exhaust? Possibly clogged injectors resulting in a stream instead of a spray -
Black soot on headers, unsure if it's normal for Ducatis
View attachment 224914
Additional weirdness, it looks like someone put mighty putty on the oil pressure switch - it wasn't even hand tight, and when I tried to crank the bike in my garage it spewed oil out
View attachment 224921
- oil is also well past maximum fill level it seems (after losing oil due to switch not tightened)
View attachment 224920

___
I've got the Haynes manual, and I've done modest work on a few of my other bikes before (oil changes, KLR doohicky, yamaha cam chain tensioner, etc).
I'm hesitant to take it into a local shop, as nobody in my area is particularly excited about the idea of working on an early 2000s Duck


This is as far as I've gotten. If anyone has advice or suggestions, I'm all ears and would appreciate any direction you can give me -
It sounds like you are on the right track to fix the basic compression 1st & then move on. Your photo of the case forward of the clutch says that you have an oil leak too. I’m not sure what the hose is near your R/S foot-peg is but the previous owner of mine thought disconnecting the evap cannister would make the bike better & ended up misrouted fuel lines so badly that he had to bring it back to the dealer! If your PPO removed the fuel filter, there may be some odd routing going on too.
Your photos also show aftermarket parts that include the saddle, clutch cover, Termignoni pipes (DP), & some anodized pieces (all appear to be good stuff). IMHO neither of the two 1.5M ECM are mapped for the cans. The DP ECM on mine was the root case of a REALLY bad lean misfire @5% throttle/ 3,500 rpm (@sea level & @altitude). The solution was a PC III with an advanced map that allows adjustment the vertical cylinder’s map separately from the horizontal one. But be aware there are 2 versions of the PC III (race & CARB legal) as well as 2 versions of the Ducati 1.5M ECM (stock & DP). Also be aware that logging AFR for your bike or dyno-tuning is likely to be required to get that maps right. Unless the PO/PPO added bungs to the exhaust & attached O2 sensor(s), our M900s don’t have them. FYI, a WB O2 sensor allows you to log the AFR & so you can create on-the-road fuel maps. Considering that the injectors are Weber-Marelli with 13K on them, custom fuel maps would be a good thing (I’ll avoid further tangents such as matched injectors…).
 

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While the exhaust is off... Getting a couple 14mm bungs fitted up is definitely a good idea. I know finding a good location is a pain for the vertical in back, but, yeah... It's probably hard to envision at this point I'm sure. But down the road once the mechanicals are sorted out. If you get to the point where you really want to get it running right, and keep it that way. You'll be glad to did it.
 
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