full throttle woes, help with engine cutting in and out.

[N-gin]

1997 Softail, Ultima 113 engine. 74 main, 46 bleeder, 29.5 pilot(slow)
this has got me stumped. Awhile back I installed a Ultima engine. This came with carb and ignition. Since day one after the breakin process it will cut in and out at 3/4 or more throttle at lower rpm, when taking off fast. Its like the engine just gives up for a second and comes to life again. This will happen repeatedly until I let off the throttle.. It does not back fire and carb has been adjusted many times by the book with no joy. I did take off the intake to inspect seals and the seals were torn, so I replaced them. I sprayed the intake with brake cleaner and the idle didn't stumble or rev so they are sealing now. However it still have the same issue. I have tried swapping carbs with another from Ultima and even the ignition. Still the same.
I have a 5/16 petcok 5/16 fuel hose going to a 3/8 carb bowl fill. It is free flowing and no obstruction. The fuel shut off is clean and working properly. I even have wire loom over the hose and over that I have heat protector tube made of fiberglass and silicon.
The bike starts good and runs fine but when you give it the go its cuts on and off. I even took the bowl off and made sure its filling up fast and it is.. Im stumped.
If I keep the throttle open and try to ride it out it will keep the same relative speed and RPM range till I let off the throttle or shift gear.
There is no RPM gauge but if I had to guess it would be around 3k.

[PC_Hater]

Does the Ultima ignition have anything that picks up the inlet vacuum?
A malfunctioning VOES or MAP sensor might cause it. At full throttle there will be no vacuum.

And of course 3000rpm and full throttle might be causing a vibration problem that affects ignition wiring or causes strange behaviour inside the carb bowl. It has been known to happen.

I can't think of anything else except put it on a dyno and then you can do it repeatably and have a chance of finding the cause 'in the act' of doing it.

[1FSTRK]

What ignition and coil are you running?

[rigidthumper]

Can you get to high RPM by gradually adding throttle, or is 3K the rev limit??  Running drag pipes by any chance? 29.5 pilot seems very small for a 113?

[tmwmoose]

I agree, have you just tried a larger intermediate ? ,did you use the same jet size in the second carb? I though the Gs were more finicky with the intermediate than the Es ,(I know there not S&S)

[wfolarry]

When you're riding the bike shut the gas off & see if it gets better as the fuel level drops.
Change your air bleed. You're coming on the main too soon.
How many turns out is your idle screw? This is a good indication of how close the 29.5 jet is.

[wfolarry]

One more thing. If it's an Ultima carb you might be better off throwing it away.

[tmwmoose]

One more thing. If it's an Ultima carb you might be better off throwing it away.

Freakin shame they build a nice motor but won't address their carb ,I guess.
Suprized he made it thru break in. I put a 45 mik on mine real quick like

[N-gin]

Does the Ultima ignition have anything that picks up the inlet vacuum?
A malfunctioning VOES or MAP sensor might cause it. At full throttle there will be no vacuum.

And of course 3000rpm and full throttle might be causing a vibration problem that affects ignition wiring or causes strange behaviour inside the carb bowl. It has been known to happen.

I can't think of anything else except put it on a dyno and then you can do it repeatably and have a chance of finding the cause 'in the act' of doing it.

No Voes hooked up, the vacuum is plugged at the carb and the diaphram is pulled out of shut off valve in the tank.
Engine feels smooth for being sold mount at problem RPM. At higher RPM s when it starts to vibrate but only at very light throttle input. Cruise is good.

What ignition and coil are you running?

I'm running stock with what comes with the engine. I talked with Don at Ultima and he sent another one to replace it.  Installed it and ran it directly to coil with no splices and soldered the terminals to hook up to coil. The coil is an Ultima as well. The wires are spiral core Moroso. Don did offer sending a third ignition with the external settings. He did say they had a bad run of ignitions. I'll call him Monday if I can't find anything else.

Can you get to high RPM by gradually adding throttle, or is 3K the rev limit??  Running drag pipes by any chance? 29.5 pilot seems very small for a 113?

29.5 is what came with it I did tryna 31 and 32, but all that did was make it harder to adjust idle mix and it ran really rich. Black and sooty. Don at Ultima said they come running rich already set at 29.5 , 46, and 78...I did put a 74 main cause the plugs were black..all with the same outcome at problem RPM.
It happens around 25-30 MPH and I can gradually increase to 44MPH, but the engine is screaming at that point..no drag pipes. It is a Drago 2 with 3.55 baffle. It doesn't have a end cap cause they were on back order.. I got a hold of him yesterday and he sent one out.

When you're riding the bike shut the gas off & see if it gets better as the fuel level drops.
Change your air bleed. You're coming on the main too soon.
How many turns out is your idle screw? This is a good indication of how close the 29.5 jet is.

I'll have to try some of this I didn't count the turns out on idle but 2.5 maybe 3 turns on idle.

One more thing. If it's an Ultima carb you might be better off throwing it away.

I cleaned the original and found some garbage in it.. like a cotton substance in the accelerator area..that carb was cleaned and installed..same problem..that carb was sent back and another was sent to me that came straight off a 124 on the Dyno, just rented and sent to me...same issues at problem RPM with new carb.

One more thing. If it's an Ultima carb you might be better off throwing it away.

Freakin shame they build a nice motor but won't address their carb ,I guess.
Suprized he made it thru break in. I put a 45 mik on mine real quick like

I did notice the intake had a big well in it...I had thaughts of the air fuel might be stalling.

[N-gin]

I agree, have you just tried a larger intermediate ? ,did you use the same jet size in the second carb? I though the Gs were more finicky with the intermediate than the Es ,(I know there not S&S)

I have tried 29.5, 31 and 32 pilots
78, 80, 88 74 and 76 mains
46, 40 air bleed I don't think they have smaller..at least I didn't see any

[N-gin]

Idle screw is 1.25 turns out

[Hybredhog]

 The early Ulimas were great with the Mikunis they came with, but I sold a few of the S&S knock off types, and out of the box jetting was damn close. Try unscrewing the gas cap while riding, and do you have an inline filter, they can cause air locks.

[wfolarry]

I agree, have you just tried a larger intermediate ? ,did you use the same jet size in the second carb? I though the Gs were more finicky with the intermediate than the Es ,(I know there not S&S)

I have tried 29.5, 31 and 32 pilots
78, 80, 88 74 and 76 mains
46, 40 air bleed I don't think they have smaller..at least I didn't see any

You want to go bigger on the air bleed. I've got a 72 in my Super G. You want to make the transition from intermediate to main as smooth as possible. Cams, compression, pipes all have an effect on how it tunes. I always find it easier to start at the lean end of the jetting & working my way back.
1.25 turns is good.

[N-gin]

The early Ulimas were great with the Mikunis they came with, but I sold a few of the S&S knock off types, and out of the box jetting was damn close. Try unscrewing the gas cap while riding, and do you have an inline filter, they can cause air locks.

I checked gas cap. It has one small hole drilled in the top..they are after market flush mount style.. the breather on the tank if free and the filter at the end of the hose ( mounted to swingarm) is new.

[N-gin]

I agree, have you just tried a larger intermediate ? ,did you use the same jet size in the second carb? I though the Gs were more finicky with the intermediate than the Es ,(I know there not S&S)

I have tried 29.5, 31 and 32 pilots
78, 80, 88 74 and 76 mains
46, 40 air bleed I don't think they have smaller..at least I didn't see any

You want to go bigger on the air bleed. I've got a 72 in my Super G. You want to make the transition from intermediate to main as smooth as possible. Cams, compression, pipes all have an effect on how it tunes. I always find it easier to start at the lean end of the jetting & working my way back.
1.25 turns is good.

What will the larger air bleed do? Transition faster, or slower.. I did notice at cruise it did run rich....
I think I may have a 68 or 70 laying around...

[wfolarry]

It will stay on the low speed jet longer.

[smoserx1]

Does that carburetor use an accelerator pump?

[Hossamania]

I think Gryphon was having problems with Ultima carbs, trying everything to get them to work. I can't remember, but I think he switched to S&S and solved the issues.

[N-gin]

Last time I took the intake off (Wich would be the second time)  I noticed that the flanges were not cut as deep as the HD flanges..Wich would crush the gaskets more. Thinking about this I decided to check again the seals. I warmed it up and sprayed the intake Wich carb cleaner. SOAB! It is leaking again!!! This will be the third time. WTF! Last time I checked for leaks before riding and it was fine.. must have started leaking after riding 
I have tried a thin layer of lube the first time and the second time I tried no lube. I think the flanges are crushing the gaskets too much.. I tightened to spec Wich would put the flange against the head. I did notice the gasket a tad on the squished side. Almost pushed out. maybe I should just snug the bolts and not tighten all the way down..
Can this cause it to stall and come alive like it does at full throttle? It is just a small leak not as gross of a leak like before..but a leak is a leak....
Any thoughts?

[N-gin]

Going on a forth set of gaskets.
I'm thinking the Ultima flanges are too shallow, wich is over crushing the gaskets.

[N-gin]

Better up close..
in the first pic you can see what it is doing to the gaskets

[tmwmoose]

Are you getting a lot of back firing thru the carb burning up the seals maybe? The steps are machined a little different  but are they the same height?

[N-gin]

Are you getting back firing thru the carb burning up the seals maybe? The steps are machined a little different  but are they the same height?

I'm getting no backfiring through the carb at all. Not even a spit or pop. I do have a lot of decell popping in the exhaust tho. 

[N-gin]

I put the new seals in a different way. Instead of torque to spec I have about .047 thou between flange and cylinder head.
I also used the old MM flanges I have.
this is the rear.

[N-gin]

Here is the left rear..
the gaskets are pressed but not crushed.

[rigidthumper]

Is there enough clamp load to keep the fasteners in place? Maybe AN washers under the flange to keep spacing and clamp load?

[feathers]

my thought could you have a valve sticking? I'm not a mechanic but i have a keyboard

[Admiral Akbar]

The problem you are having with the manifold seals is that you are using the wrong size.  Ultima uses a 1.8" port and the OD of the spigot is likely 1.90 to 1.92".. (stock is 1.80 to 1.82) This requires a thinner seal. The fact that you cinched the manifold clamps down might have crushed the ends.  The Ultima flanges I have are the same size as stock HD.

The manifold leak is not causing your high speed miss. If it did anything it would kill throttle response off idle maybe cause a cough and rough idle. Don't know what it is tho. Could be anything. Carb or ignition. I'll let the experts here figure that out.

[N-gin]

Well here is an update..
I checked, double checked and triple checked the intake seals. They are good now. However still with the cutout. The decal pop has gotten better though with the sealing of the intake seals. Progress....

The problem you are having with the manifold seals is that you are using the wrong size.  Ultima uses a 1.8" port and the OD of the spigot is likely 1.90 to 1.92".. (stock is 1.80 to 1.82) This requires a thinner seal. The fact that you cinched the manifold clamps down might have crushed the ends.  The Ultima flanges I have are the same size as stock HD.

The manifold leak is not causing your high speed miss. If it did anything it would kill throttle response off idle maybe cause a cough and rough idle. Don't know what it is tho. Could be anything. Carb or ignition. I'll let the experts here figure that out.

I did match up the seals and they looked the same, however I didn't really look close. Is there a way to tell? thickness, width? They were pretty smashed themselves.

Is there enough clamp load to keep the fasteners in place? Maybe AN washers under the flange to keep spacing and clamp load?

I put a dab of wicking grade Loctite on the bolts and they are pretty snug now.. that green wicking is stronger than I though, hopefully its enough.

[tmwmoose]

Next time your at your indy shop get a set of S&S seals there thinner. But for the life of me I can't remember what I used on my Ultima S&S or oem

[BKACHE]

Just a couple of things to check.
I had a broken copper end of my + connector to the battery. The break was inside the shrink wrap so I could not see it. The wire held it together until vibration at speed would break the connection. Once I finally started pulling on wires the break opened up and I found and fixed.
This can also be a breaker. A shop owner in NE Mpls showed me a resettable breaker that would cut in and out. Replaced and all good.
Good luck 

[N-gin]

Just a couple of things to check.
I had a broken copper end of my + connector to the battery. The break was inside the shrink wrap so I could not see it. The wire held it together until vibration at speed would break the connection. Once I finally started pulling on wires the break opened up and I found and fixed.
This can also be a breaker. A shop owner in NE Mpls showed me a resettable breaker that would cut in and out. Replaced and all good.
Good luck

This bike was all apart. Even the harness. Most of everything was replaced. So it can be anything, right. All the relays and circuit breakers were replaced. Battery has cleaned and connections checked( doesn't mean they are good). I'll check them again. 

The things that gets me is it is a full on and full off effect with the throttle at WOT.  It does spit, sputter, pop, hesitate, miss, or anything like that.

The affect of the WOT problem is as if I was to open and close the throttle constantly and keep the same speed..

[Nutoy]

I know this is stupid question did you check rev limit settings? sure sounds like rev limiter to me.

[N-gin]

There is no external setting. Just a closed unit.

[1FSTRK]

If you have eliminated carburation, one thing I have seen a few times with aftermarket electronic ignitions is you will get one that will not allow enough coil saturation time and with the right compression and load on the engine it will act like it is going rich in the manor you describe. I had one that did not show up until I started running it hard at about 500 miles.  If all else is ruled out I would try a known good ignition and coil combo just to rule this out.

[N-gin]

If you have eliminated carburation, one thing I have seen a few times with aftermarket electronic ignitions is you will get one that will not allow enough coil saturation time and with the right compression and load on the engine it will act like it is going rich in the manor you describe. I had one that did not show up until I started running it hard at about 500 miles.  If all else is ruled out I would try a known good ignition and coil combo just to rule this out.

Ultima is going to send a ignition. This time with external settings.. I do have extra dual fire coils I can choose from. This is single fire but its easily changed. And as far as ignition i can always go back to the stocker. Everything is still on the bike, just plug it in. I'll try it if my next step doesn't work.

I rode it around today and put 100 miles on it..I'm thinking it's running low on fuel. If I short shift to the next gear it will do the same thing at WOT. And the thing that gets me is if it was ignition cutting out why does it not backfire.
I'm going to put a pingle 3/8 single out shut off in the tank and run a 3/8 hose to the carb..somthing in the back of my mind says it's running the bowl low and the 5/16 isn't enough weight to feed the carb.

I did try and pull the chock and it seemed to not do anything differently.

[Admiral Akbar]

If you have eliminated carburation, one thing I have seen a few times with aftermarket electronic ignitions is you will get one that will not allow enough coil saturation time and with the right compression and load on the engine it will act like it is going rich in the manor you describe. I had one that did not show up until I started running it hard at about 500 miles.  If all else is ruled out I would try a known good ignition and coil combo just to rule this out.

So how did you verify that it was dwell time? With an asmelloscope? Or were you just guessing?

[tmwmoose]

With an asmelloscope?  only your nose knows

[Schex3x]

Rig a timing light on the bike so you can see the strobe to watch if the ignition is drops out.

Get the right intake seals, not tightening the flanges until the step bottoms out is just a rig, S&S or Cometic has the thin ones you need.

[N-gin]

Rig a timing light on the bike so you can see the strobe to watch if the ignition is drops out.

Get the right intake seals, not tightening the flanges until the step bottoms out is just a rig, S&S or Cometic has the thin ones you need.

timing light keeps flashing.
got to be fuel

[N-gin]

Problem fixed
I got a Pingle for the fuel tank, with a 3/8 outlet.