M900 popping when accelerating

mxgrant185 · April 30, 2013, 08:41:50 AM

I have a 96 m900 with 32xxx miles on it. When the clutch is pulled in or it's in neutral I can rev the bike as high as I want to with no problems, but while riding, if I get on the gas quickly to beat traffic or to pass my bike starts popping REALLY bad. It only does it for a few seconds though and once it stops the rest of the acceleration is smooth. Could the timing be out of tune, could the clutch be catching, or could the jetting be off? I have no idea what the issue could be and don't know the last time the bike was serviced. All I know is jap bikes are flying past me and I can't stand the front wheel up anymore.

Anyone have any ideas??

Howie · April 30, 2013, 09:42:40 PM

If the needle jets (emulsion tubes) are original that is a possibility since they would be pretty worn and should be changed anyway, but more likely are bad carb diaphragms or sticking slides. Also look at the spark plugs.

mxgrant185 · May 01, 2013, 10:19:59 AM

But if it is the carbs, wouldn't it do it in neutral as well?

Howie · May 02, 2013, 03:25:11 AM

No load (neutral) the slides don't move much.

mxgrant185 · May 02, 2013, 07:52:46 AM

Well that would kinda make sense then, because if I slowly build up speed it won't pop at all. So it seems more like the slides/diaphragms. Anyone know where to buy a rebuild kit? Or would it just be easier to buy a nice set is used carbs?

koko64 · May 02, 2013, 08:23:34 AM

Follow Howie's advice.
The spark plugs have a story to tell.
Check your carbs out before buying another set (memper has some for sale). Check for worn oval needle jets, torn diaphragms, air leaks, pinched hoses, fuel tap and pump plumbing, etc.
Any recent mods?

Cloner · May 02, 2013, 11:04:14 AM

No rebuild kit from Ducati, though they do list individual o-rings, gaskets, and other parts needed for service. Yamaha TDM 850 (a non-US model) used the same Mikuni carburetors, so you can often get less expensive repair parts from Yamaha. The diaphragms are rediculously expensive through Ducati, so any source you can find is certainly better.

mxgrant185 · May 02, 2013, 12:45:06 PM

I know when I took my carbs off the float springs seemed weak and there was a tear in a diaphragm that I repaired but the jets seemed fine.

Unfortunately I now have way bigger problems to worry about. I woke up this morning to find my bike missing. Someone had stollen it, left it in lowes parking lot and had smashed the ignition with a screw driver. My bike is now at the impound lot being searched for prints and being held as evidence for the next several days

Cloner · May 02, 2013, 01:05:35 PM

Quote from: mxgrant185 on May 02, 2013, 12:45:06 PM
I know when I took my carbs off the float springs seemed weak and there was a tear in a diaphragm that I repaired but the jets seemed fine.

Unfortunately I now have way bigger problems to worry about. I woke up this morning to find my bike missing. Someone had stollen it, left it in lowes parking lot and had smashed the ignition with a screw driver. My bike is now at the impound lot being searched for prints and being held as evidence for the next several days

What a douchebag. I hate a frikkin' thief.

If you want a "new" diaphragm and don't mind used parts give me a holler. I'm pretty sure I have a couple around in at least functional condition. Most repairs to diaphragms don't last long.

mxgrant185 · May 02, 2013, 01:26:25 PM

I'm extremely interested and don't mind gently used parts at all. Pm how much you want and we can work something out

garryc · May 02, 2013, 02:49:19 PM

Was looking at ebay italy the other night and I think there was a pair of new 38's with a buy now price of 110 euro's if I remember correctly
Item number 380618285486
This is the ebay item no for the new l hand switch I bought, should be able to find this then go to the seller other items.
Great seller, I have previously bought a new pair of ajustable showas from him.
Need to play around a bit with translations unless you read italian
If you can't find it pm me and I will try to get the link over the weekend

mxgrant185 · May 02, 2013, 06:18:36 PM

Well I managed to get my bike from the impound lot. I need a new ignition, a new top triple, new bars, a new seat lock and maybe a new regulator. Not to mention powder coating the Frame and new paint on the fender and tank. As pissed as I am atleast I got the old girl back. The duc gods were obviously on my side for this one.

Howie · May 02, 2013, 11:08:47 PM

WOW! Sorry to hear this. Anyway, a source for carb parts http://www.sudco.com/

koko64 · May 03, 2013, 01:46:01 AM

Glad you got her back.

mxgrant185 · May 03, 2013, 12:21:51 PM

So am I, hopefully my insurance covers it. What brand of carbs do ducatis use? And they are 38mm correct

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M900 popping when accelerating