1999 Monster M900 Issue: Cutting out like it is hitting a rev limiter

[zolor]

I am reaching out to you Monster guru's as I have reached the end of my wits on what is going on with my M900 and I feel that I have tried every piece of advice I have received from the resources I have and from what I have read.

So here's the issue:

When the bike is revved up to around what I am guessing 5-6k (I don't have a tach), it starts cutting out as if it has a rev limiter and it seems to do this slightly worse when it gets hot, but it will do it cold or hot. It will cut out at standstill or on the road and it does it throughout all gears. At first I thought it was the ignitors, so I bought a working pair, installed them with no luck. I did the same for the coils but this made no difference. I then got some P8 pick-up coils from electrex world in the UK, installed them, set the air gap, timing, but still had the same thing. I have essentially replaced all of the electrical components in hopes of tracking down the cause of this problem. In all, here is what I have replaced:

Electrical:
• Ignitor Units
• Coils
• Plugs
• Wires (ca cycleworks)
• Pick-up coils (electrex world)
• Battery

Then, when none of this worked, I thought that it might be a fuel related issue, or at least figured it couldn't hurt, so I replaced the following:
• Fuel Pump (electric)
• All hoses
• Fuel Filter
• Re-built Mikuni Carb (Dynojet Stage 1)
• New Carb Boots
• Air Filters (uni pods) - NOTE: issue was going on before when I had k&n filter replacement
• New tank breather hoses (clear and functional)


I am hoping that someone might be able to help me figure out what's going on as I have been trying to track down this problem over the past couple years and I simply have no clue what to try next.

Here are the specs on my bike and modifications if they help:

1999 Monster M900
17,000 miles
Mikuni Carbs
Marvin Carbon Exhaust
Uni Filter Pods
Recent Valve Adjustment
New Belts
Recently Timed
Carbs Synced
No Vacuum leaks that I can find

Here is a video of the sad state my monster is in:

[ducpainter]

what do the plugs look like?

[greenmonster]

Air Filters (uni pods)

Have you replaced the main fuel jets in carbs w bigger sizes ones?
Open breathing like pods require 2-3 size bigger ones.

[ducpainter]

Have you replaced the main fuel jets in carbs w bigger sizes ones?
Open breathing like pods require 2-3 size bigger ones.

OP says stage one jetting

[greenmonster]

And Stage 1 kit is for open mufflers, not mufflers and pods/open airbox.

[ducpainter]

And Stage 1 kit is for open mufflers, not mufflers and pods/open airbox.

correct

but I don't think it would act like it hit the limiter because of that.

I could be wrong.

To the OP...when did the bike start acting like this?

[zolor]

The cutting out has been present for as long as I've owned the bike, only recently has it started to get worse. I am starting to lean toward some sort of wiring issue as I have replaced pretty much everything else I can think of.

I rode an old Yamaha TX750 that had weak positive going to the coils and it would cut out.  Nothing at all like it was hitting a rev limiter...more like one cylinder would cut out.  I ended up running a relay directly to the battery/ignition and it worked wonders.

I looked at the electric diagram and it seems Ducati's are a little different and the POS goes through the Kokusan ignitors.

Could this be something similar like the coils aren't getting enough juice under load?

btw:  Plugs are slightly sooty, but I think that's because I recently synced the carbs and was playing around with the enrichment screw.  Problem was the same before I touched them and with my old carb.

[Howie]

Though I agree with Nate that jetting shouldn't make the bike feel like it hit a limiter I would correct the jetting and treat your bike to a new set of plugs before going further.  Stage 1 is way lean with pod filters.  On the US bikes it is a fix for lean emissions tuning.

[zolor]

Thanks for the leads....I just ordered a DynoJet Stage 2 (make that Factory Pro)  kit and I'll post an update after I get it installed later in the week.  I'll also be installing new plugs.

[YellowDuck]

Did you put the electric fuel pump on the bike? I would take a really good look at that setup since it's not factory.

[zolor]

Nice call on the Fuel Pump.  I had a failing Mikuni pump when I got the bike and swapped it out for a generic electric I had laying around the shop.  If I remember right, the box said it was 2-3 psi and for carb'd motorcycles.  Just to rule this one out, I have a Mikuni replacement on order from ca-cycleworks.  Do you know if a stock Mikuni pump is sufficient for upgraded jets (think my kit will have 150 mains and 42.5 pilots).

[koko64]

No worries. I'm running 165s with the Mikuni pump.

[ducpainter]

I think your generic electric is a better choice.

[The Mad King Pepe']

For what it's worth you DO NOT need a fuel pump with carburettors. As long as you're not leaned over in a turn with less than a gallon of gas in your tank, that is I'm not telling you to get rid of it, but you can take the pump off and run the engine without. If the engine doesn't cut anymore, you've found the issue.

Very nice bike, btw!