2000 M750 shuts down but fires rite back up

[stevebussard]

Here we go again.
   2000 M750, I can ride anywhere from 2 - 30 miles, and it will pop and sputter a bit, then die.  It doesn't always shut down completely, but won't do any more than idle.  At first I lifted the tank to find the breather tube had slipped off the bottom of the tank.  Put it back on, and ran fine for 30 miles.  Got off the highway, and it started to run on one cylinder, then died completely.  Lifted the tank, nothing was wrong, tried to start it, and it fired rite up...  Rode a couple miles home with no other issues.  Rode to work today (about 12 miles) and it ran fine until I pulled in the parking lot.  Popped, sputtered and died.  Lift the tank, put it back down, and it fired rite back up.  When it dies, if I just try to restart it, it will idle for a couple seconds, but will not rev up, then it dies.  I'm leaning toward a fuel filter, but I just replaced it less than 100 miles ago.
   I picked the bike up about 4 weeks ago now, and have had all kinds of fuel delivery problems.  The bike was serviced last year, and wasn't ridden more than 100 miles after everything was complete.  Service records show the tank had a lot of rust, they flushed it and supposedly sealed it.  I can't tell that it was sealed, unless the sealant is what is breaking free, and clogging my filters.  Is there any sort of crank sensor on my bike that may be killing it, and I'm just thinking it's a fuel issue?  I know electrically my bike is fairly simple compaired to the newer fuel injected bikes.  I've had to track down and replace two relays and a signal flasher already.
   When this tank of fuel is run out of the bike I am going to pull the tank off and flush the whole thing.  Is there anything specific anyone would recomend using to do this?  I was going to use a high pressure hose, and then flush the water out with some berymans B12 or seafoam.

[koko64]

Here we go again.
  2000 M750, I can ride anywhere from 2 - 30 miles, and it will pop and sputter a bit, then die.  It doesn't always shut down completely, but won't do any more than idle.  At first I lifted the tank to find the breather tube had slipped off the bottom of the tank.  Put it back on, and ran fine for 30 miles.  Got off the highway, and it started to run on one cylinder, then died completely.  Lifted the tank, nothing was wrong, tried to start it, and it fired rite up...  Rode a couple miles home with no other issues.  Rode to work today (about 12 miles) and it ran fine until I pulled in the parking lot.  Popped, sputtered and died.  Lift the tank, put it back down, and it fired rite back up.  When it dies, if I just try to restart it, it will idle for a couple seconds, but will not rev up, then it dies.  I'm leaning toward a fuel filter, but I just replaced it less than 100 miles ago.
  I picked the bike up about 4 weeks ago now, and have had all kinds of fuel delivery problems.  The bike was serviced last year, and wasn't ridden more than 100 miles after everything was complete.  Service records show the tank had a lot of rust, they flushed it and supposedly sealed it.  I can't tell that it was sealed, unless the sealant is what is breaking free, and clogging my filters.  Is there any sort of crank sensor on my bike that may be killing it, and I'm just thinking it's a fuel issue?  I know electrically my bike is fairly simple compaired to the newer fuel injected bikes.  I've had to track down and replace two relays and a signal flasher already.
  When this tank of fuel is run out of the bike I am going to pull the tank off and flush the whole thing.  Is there anything specific anyone would recomend using to do this?  I was going to use a high pressure hose, and then flush the water out with some berymans B12 or seafoam.

Good plan.

Went through the same thing and fixed it with what your planning. I also used a local brand tank cleaner. You have some different brands there Stateside. Some crud in the tank still flaked off over a three month period when I went through three or four filters. Tank is clean now and no problems.

I have read on this site that not all sealants work and may flake off making the problem return. I think DP had a sealant to recommend. I would change the filter and do a post mortem to see what's clagging it. I found a combination of congealed fuel, rust and old sealant. The bike was an import that had been sitting around for years.

I can't remember, but I think you checked fuel tap, fuel pump, breather and lines last time?

[J5]

next time it happens open the tank cap

if the breather is blocked and causing a vacuum then fuel wont get through

if it works then look at the breather its prob blocked

[Howie]

You could also do a necropsy on you fuel filter looking for debris.  Yep, it sounds like either a fuel delivery or venting problem.  Also make sure your fuel hose is not kinking when the tank is down.  Check the vacuum fuel shut off/petcock, whichever you have.

[stevebussard]

I had used compressed air to blow out the vent cap earlier, but there was no issue there.  Opening the cap made fuel splash out under braking, but didn't change the outcome  .  On my way home, I replaced the standard fuel filter with a glass filter with replacable cartridges, and re-routed the lines.  Once home, I removed the tank and disconnected the main line fitting, and fuel level sensor from the bottom.  I shook the tank vigorously and drained the fuel into a gas can using a filtered funnel.  I repeated this for roughly 4 hours, and couldn't believe what came out.  I'm amaized it ran at all.  Put the bike back together, and it was running great...  Now i'm back to the float sticking in one of the carbs.    The pain and suffering never ends does it?  It's kind of like owning a really fast car that breaks everytime you hit the gas, but you love it, because it's so much fun.  In any case, I know at some point this weekend, I will be pulling the carbs off AGAIN to clean out the float bowls.  I hope with all the garbage I flushed out of the tank, I will be able to ride it for more than 1 day without problems once I clean the carbs out again.
   Does anyone know of companies that produce a plastic tank?  This may be my next move, if the problem isn't solved.

[koko64]

So Cal Cycleworks makes a plastic tank that is shaped more like a SBK tank but will fit your Monster.

Once the crap clears you should be ok, but you may have to clean out that filter each week for a month untill the tank is clear (and drain the float bowls). Consider a tank cleaning and sealing kit that works as some have used on the forum.
I changed to a race type washable filter with a bronze gauze element and ran it in line after the fuel tap so it was an easy maintenance task.

Glad you found the problem.

[Howie]

Proper treatment with POR 15 should fix the rust problem since the tank is not perforated.

http://www.por15.com/CYCLE-TANK-REPAIR-KIT/productinfo/CTRK/

You can do it yourself or send the tank to ducpainter for hinge reinforcement and a really cool paint job  Following directions is important.

[stevebussard]

   I cleaned the float bowls today, and flushed the petcock.  The flapper (or whatever is inside it) was stuck open, causing the fuel to keep flowing into the carbs.  I lost about a gallon over night through the overflow tube on the left carb.  Cleaning them did the trick for the fuel dumping on the ground.  I went out for a ride tonight, and could only manage to make it about 6 miles.  I had the delivery port plug up on me 3 times.  My filter is roughly half full of crud already, even after all the flushing last night.  Looks like I'll have a long road ahead of me.
   Thanks for the info on the tanks koko, I had run across them last night, and I'm not sure if that's what I am looking for.  The ergonomics of the tank on my 998 were the only thing I wasn't crazy about, and this does look very similar to it, but it may have to do if I get to that point.
   Thanks for the info on the sealer howie.  My dad and I were just talking about that last night, and he used that on his BSA Goldstar tank about 15 years ago, and it's still looking good.  I know it's pretty expensive, but it's a lot cheaper than a new tank.  I could certainly use a new paint job, but I think I'd just want to go with a flat black, lol.

[ducpainter]

If you go the POR route seriously consider brazing the hinge at the same time.

You don't have to paint the tank to do it.

[stevebussard]

If you go the POR route seriously consider brazing the hinge at the same time.

You don't have to paint the tank to do it.

LOL, I know I wouldn't have to paint it.  What is the issue with brazing the hinge?  I hadn't heard of an issue with it, and havn't seen an issue with mine.  I think I am going to go with the POR15, and I could have my uncle braze it at the same time, do you just braze along the bottom edge?  Anyone have pictures they could post?  Thanks
   Also, just a thought on getting as much rust out of the tank as possible before sealing it...  I wonder if rigging a vaccum pump to fit the fuel feed line, and then sucking the rust through the hole would help.  I'm concerned that if I just seal over the rust I will have the same issue in the near future.  Thoughts?

[stevebussard]

Another thought on my way into work this morning; is it possible it's my starter relay?  It went out last week (two days before this started happening).  I went to Auto Zone and matched it up with a GP Sorensen relay.  Everything matched, except one terminal is labeled 87 instead of 87a.  I figured for $5 I'd try it, and it worked great.  The problem I was having was when I kicked the kickstand up, and hit the starter button, it wouldn't turn over.  It turns over no problem now, but I'm wondering if this might?? be part of the problem.  The day after I replaced that relay I ran out of gas (because the float in the sending unit got plugged with rust).  That was when all my problems started.  Makes me kind of wonder.  I think I'll try putting the stock relay back in and see what happens.

[64duc]

Another thought on my way into work this morning; is it possible it's my starter relay?  It went out last week (two days before this started happening).  I went to Auto Zone and matched it up with a GP Sorensen relay.  Everything matched, except one terminal is labeled 87 instead of 87a.  I figured for $5 I'd try it, and it worked great.  The problem I was having was when I kicked the kickstand up, and hit the starter button, it wouldn't turn over.  It turns over no problem now, but I'm wondering if this might?? be part of the problem.  The day after I replaced that relay I ran out of gas (because the float in the sending unit got plugged with rust).  That was when all my problems started.  Makes me kind of wonder.  I think I'll try putting the stock relay back in and see what
happens.

Highly unlikely, but free.  Free is good.

[stevebussard]

64duc was rite.  I put the old one back in, got it to fire, and instantly it started coughing and sputtering.  Put the new one back in and went on a 60 mile round trip ride.  The first 30 miles I had to stop about every 5 miles, but on my way home, I made it all the way with just a couple hiccups.
   The POR15 will be here Thursday.  I'm going to try and get the tank resealed this weekend.  I got the heavy duty kit to strip out any old whatever is in the tank.  I hope everything works, I really don't want to cancel my Indy trip because of rust in my gas tank.  Wish me luck!

[CarbonMonster750]

Reading your post definitely brought me back to the days when I was struggling with my 2000 750m, here's how i resolved it.
1. Ducati steel tanks have a fine habit of cracking the weld at the bottom of the tank due to stress put on that joint when you lift the tank up especially if the tank is rusty or full of gas. I had this problem as well and ended up having to take the tank off and had it soaked in a vat of acid for like a week and then the welds reinforced/redone I also had the inside of the tank relined to prevent rust from flaking off and clogging my fuel filter or gumming up my carbs. I then had my tank painted by a local custom shop pearl blue with a white stripe and carbon accents, overall the gas tank cost me about 530 dollars all together to restored and get exactly how i'd like it, not a bad deal considering a new tank would run you 1800+ dollars
2. fuel delivery, after my tank was restored I had trouble getting consistent fuel delivery which often led to my bike pretending like its out of gas and me on the side of the road taking off my seat to wiggle some fuel into the line I ended up resolving this issue by getting a 3 1/2lb rotary electric fuel pump and mounting it to the frame I also replaced the little fuel cock that bolts onto the bottom of the tank about 140 dollar fix plus labor.
heres a before and after of my tank actually discovered the dent after the acid bath apparently the previous owner had concealed hope this helps 

[greenmonster]

What is the issue with brazing the hinge?

If stressed to much/often, it starts to leak.


Can`t say what the tank dirt does to the fuel pump.
But, I got a strange problem w my vacuum one.
I worked f around 45 mins, the I could only have very little throttle and limp home.
It did not shut down completely.
The behavoiur was like in your first post.