Dies @ 120mph..?

[Skyshadow]

I cant seem to figure out why my '01 750 Dark keeps dying when i hit 120mph. It spudders a little then when I pull in the clutch the engine completely cuts off. I have to pull off the road then crank it over with the choke on for 2-3 min. I have been thinking I'm getting a lean condition or something because I have Remus slip ons and K&N filter with stock jets. any suggestions?

[ducpainter]

Sounds like the fuel pump isn't keeping up.

You might be a little lean with that set up, but the bike was lean stock and that wouldn't cause cutting out and dying.

Check all your lines for kinks and if you don't find anything it might be time for an electric pump.

edit....

when was the last time you replaced your filter?

[Skyshadow]

Fuel filter? very recently, I'd say a month ago.

The '01 model has a fuel pump? I thought it was gravity fed with a regulator..? please, school me up on this.

[ducpainter]

Fuel filter? very recently, I'd say a month ago.

The '01 model has a fuel pump? I thought it was gravity fed with a regulator..? please, school me up on this.

They come from the factory with a vacuum operated fuel pump and fuel shutoff.

The pump is mounted to the frame on the r/h side. It is hexagonal. The fuel shutoff is mounted under the tank hinge.

It could be as simple as a bad vacuum line.

The monster will gravity feed to a point, but as the tank level drops it will stop feeding.

[Skyshadow]

OOh, the doofis mech at the Duc shop in OKC said that was a fuel regulator. Is there a way i can check it before I go and replace it all together?

[ducpainter]

OOh, the doofis mech at the Duc shop in OKC said that was a fuel regulator. Is there a way i can check it before I go and replace it all together?

If you disconnect the line from the pump to the carbs and crank the engine fuel should spurt from the line. It won't be very much pressure or volume. It doesn't take much to supply a carbed engine.

[speedknot]

I think your bike is telling you something.

My bike did the same when I had the airbox lid off.  I had the K&N with DP Conti pipes and stock jets and it would cut out around 110-115mph.  I put the lid back on and it solved that problem.  I'll be honest though, when I get the bike up to that speed, it feels like its going to lift off the road or rev out too high.  I may be wrong but I'm not sure this bike is suited for sustained speeds like that.  Aerodynamics definitely plays a part because my CBR600 could comfortably do 140mph without the wind drag or drifting.

[Timmy Tucker]

Shit, my M750 struggles to with anything over 100. It may be diet time again. What kinda speed is the 750 capable of?

[speedknot]

Shit, my M750 struggles to with anything over 100. It may be diet time again. What kinda speed is the 750 capable of?

You're not the only one.  I can push it to a little over 100mph while fully leaned forward with a tail wind.  Even then it feels like the bike is going to break apart.  I've heard others with M750's say the same thing. 

[zooom]

MAN...I got nothing to add except to say that when I read the thread title, I thought someone else was trying to push their Capirex to 140 and was trying to figure out why they failed.

[Skyshadow]

I think your bike is telling you something.

My bike did the same when I had the airbox lid off.  I had the K&N with DP Conti pipes and stock jets and it would cut out around 110-115mph.  I put the lid back on and it solved that problem.  I'll be honest though, when I get the bike up to that speed, it feels like its going to lift off the road or rev out too high.  I may be wrong but I'm not sure this bike is suited for sustained speeds like that.  Aerodynamics definitely plays a part because my CBR600 could comfortably do 140mph without the wind drag or drifting.

Weird, mine sits around 7000rpm at that speed and seems pretty stable. I mean not like my old R6 and I doubt it could go much faster but without the cut off I think it would do just fine at those speeds.

[Skyshadow]

Shit, my M750 struggles to with anything over 100. It may be diet time again. What kinda speed is the 750 capable of?

Weird again, I can keep my above 100 with ease. But I only weigh 160lbs... (not saying your fat though man lol)

[speedknot]

I forgot to mention...  I believe its universally accepted that the speedo is somwhere around 5-10mph off, on the high side.  I did the GPS and Honda Civic digital dash ride along to confirm that my speedo shows 10mph faster.

Hey sky, did you check that your intake isn't taking in too much air?  I mentioned how my Duc reacted in an earlier post and I distinctly remember that when I put the pods on my CB400F, the engine would skip and sputter when at high speeds or I got hit with a cross wind.  That went away when I put the stock airbox assy. back on.

[gregrnel]

My 620 dies at 180! What can I do?

[speedknot]

My 620 dies at 180! What can I do?