New engine, low rpm issue

[ZeDevil]

Hi guys,
I have recently purchased a complete S&S V111 assembled engine, 585 cam, with IST ignition and Super E carb and installed it, replacing my worn out V107. I strictly followed the break-in procedure described in the manual. Now the engine has around 2500 miles on it and I have an issue I have not yet figured out.

The engine starts easily, pulls hard, no power loss, however if I try to ride at steady speed in gears 1,2 or 3 at around 2000rpm it is rough, stumbles or surges and I can hear that it pops in the exhaust. No backfire in the carb. At first I thought it might be jetted a little lean so I changed the intermediate jet from .295 to .31 and eventually .32 - at which point the engine definitely ran rich and sluggish so I went back to .31 intermediate jet. But no matter what jet I would try the constant low rpm issue would not go away. I checked for intake leaks and everything seems air-tight. I run a 2 into 1 Supertrapp exhaust so I can't really determine which cylinder is causing problems, but the only thing odd that I noticed is the color of the spark plugs - the front is perfect: brown or caramel, while the rear is white. No matter how rich I jet the carb the rear spark plug remains white, while the front darkens to the point it would foul.

Again, the engine runs fine in higher rpms and the issue completely disappears in higher gears but it's kind of annoying not being able to run smooth in lower gears and low rpm.

Is there anything I could do? Should I worry about this or just let it be?
There are no authorized S&S Dealers within reasonable distance so I can't have the bike checked by an expert. The engine is still in warranty, of course.

(left is front spark plug, right is rear)

 

[BWG56]

Have you tried changing the main jet? and what air filter are you running, the aux bowl vent needs to come out depending on air filter.

 

[ZeDevil]

Everything installed is stock, as it came already assembled in the box. The filter is stock, the cover is S&S slasher cover.
I did change the main jet to bigger sizes, although I know it's only used at higher rpm.
Didn't try the bowl vent, though.

 

[heybaylor]

I would be concerned at the different plug readings.
contact SS and pose your question.
if no leaks in intake (check again) then the cam and or ignition would be suspect.
jets and bowl vents effect both cylinders

old mechanic say "fix the obvious and sometimes the difficult goes away"
hope this helps

 

[bruce]

call S&S they have always been very helpful in the past.

 

[Lorenzo]

I think you should be running the Super G carb. The E is too small a bore.

 

[ZeDevil]

The Super G was not an option, the E came standard on this engine. S&S says it gives better results than the G on this particular engine setup.

I'm still waiting for a reply from S&S on the issue described.

 

[Th3InfamousI]

Purely based on the plugs I'm gonna guess intake or exhaust leak on the lean cylinder. You said you checked intake..what about exhaust?

Check for Possibly crack in that exhaust pipe too



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[ZeDevil]

Purely based on the plugs I'm gonna guess intake or exhaust leak on the lean cylinder. You said you checked intake..what about exhaust?

Check for Possibly crack in that exhaust pipe too

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I actually had a different exhaust before and the engine did the same thing, only worse because the pipes were really short (V&H short shots) . Now I have this 2into1 Supertrapp and it runs much better, but the issue is still present, even if less noticeable.

I just went again and sprayed half a can of WD40 around the intake gaskets, MAP sensor, etc. No leaks.
Can't dig inside the motor either, as that would void the warranty I guess.

 

[Th3InfamousI]

I actually had a different exhaust before and the engine did the same thing, only worse because the pipes were really short (V&H short shots) . Now I have this 2into1 Supertrapp and it runs much better, but the issue is still present, even if less noticeable.

I just went again and sprayed half a can of WD40 around the intake gaskets, MAP sensor, etc. No leaks.
Can't dig inside the motor either, as that would void the warranty I guess.

You spray around the exhaust gasket?

My rear cylinder runs leaner and like you mentioned I always thought it was due to the short rear pipe I run

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[ZeDevil]

Ok, here's what a S&S Tech had to say about it after exchanging a couple of emails:

Hi Brent,
Yes, a new S&S single fire ignition coil was purchased and installed. Part #55-1571.
I carefully checked again for intake leaks (spraying WD40 at the seals, flanges, MAP sensor port) while the bike was idling and couldn't notice any change in rpm.
I have attached a picture of the plugs (white one is from the rear cylinder).

IS the rear plug the darker plug? And what pipes are you running?

The front plug is the darker one. The rear is lighter in color.
I'm currently using a 2 into 1 Supertrapp exhaust which makes the issue less noticeable than another set of pipes I've had, just to see if it makes a difference.

I took a look at the pics and talked to the other guys and they do not think it is an issue because the plug is not stark white and the other plug is not black.

Ok, that's a relief.
But what about my initial issue with running rough at low rpm in lower gears?
I had a V107 with a 600 cam in it that acted the same, it was almost impossible to ride around town at 30-40mph. Just like this new one.
Anything I could do about that, or it's more of a trademark for these engines?

With the cam you have and gearing these engines like to run at 3000rpm or better. Low RPM and high gears will make them buck.

In other words: abandon all hope of ever respecting a speed limit sign again and either GO WOT or GO HOME!

 

[05 old dog]

i agree with what tech has to say...600 cam does not like to idle around town, but loves wide open highways....my hardest part was learning to do a low speed turn in town...

 

[BWG56]

i agree with what tech has to say...600 cam does not like to idle around town, but loves wide open highways....my hardest part was learning to do a low speed turn in town...

That's been said many times Its a higher RPM cam

 

[Hirter6Pack]

My 107 has the super G bucks at low speeds 25 mph is impossible. It's between gears.

 

[FrankBDPS]

In his first post he states he is running the 585 cam. But I agree these engines don't like low rpm. Choose a lower gear and keep the rpm above 3000. Good luck!

 

[ZeDevil]

Thank you all for your input, I really appreciate it
I understand the logic behind "keep the rpm above 3000", but it's kind of weird doing that in 1st, 2nd or 3rd gear when I'm just trying to maintain a constant speed, don't you think? (and I don't think you can lug the motor when in 1st or 2nd gear at 2000 rpm.)

I have no problem in 4h gear and above because I don't ride below 2500rpm in high gears. EVER. plus the wind resistance starts putting some load on the motor so the issue disappears and the motor runs smooth.

Like I said, I'm somewhat used to this condition, this dog has been my only bike since 2011 and I have well over 90k miles with it. This is just a new engine I put in it and thought I might be able to tame it a bit, make it more user-friendly. Maybe with a different cam.
But until then.. WOT

 

[FrankBDPS]

David,you answered you're own question in you're second paragraph. Use you're gearing at lower speeds to keep you're rpm up and you're speed down. You should be able to cruise comfortably at 35 mph in second gear. Ride safe!

 

[pauly]

I don't care what any one says, the plugs should not look so different.
Something is not right,

Paul.

 

[francoblay1]

Thank you all for your input, I really appreciate it
I understand the logic behind "keep the rpm above 3000", but it's kind of weird doing that in 1st, 2nd or 3rd gear when I'm just trying to maintain a constant speed, don't you think? (and I don't think you can lug the motor when in 1st or 2nd gear at 2000 rpm.)

I have no problem in 4h gear and above because I don't ride below 2500rpm in high gears. EVER. plus the wind resistance starts putting some load on the motor so the issue disappears and the motor runs smooth.

Like I said, I'm somewhat used to this condition, this dog has been my only bike since 2011 and I have well over 90k miles with it. This is just a new engine I put in it and thought I might be able to tame it a bit, make it more user-friendly. Maybe with a different cam.
But until then.. WOT

Remove the Bowl Vent Plug and go up on the Air Bleed Jet to a .060

 

[Alexey]

Hi guys,
I have recently purchased a complete S&S V111 assembled engine, 585 cam, with IST ignition and Super E carb and installed it, replacing my worn out V107. I strictly followed the break-in procedure described in the manual. Now the engine has around 2500 miles on it and I have an issue I have not yet figured out.

The engine starts easily, pulls hard, no power loss, however if I try to ride at steady speed in gears 1,2 or 3 at around 2000rpm it is rough, stumbles or surges and I can hear that it pops in the exhaust. No backfire in the carb. At first I thought it might be jetted a little lean so I changed the intermediate jet from .295 to .31 and eventually .32 - at which point the engine definitely ran rich and sluggish so I went back to .31 intermediate jet. But no matter what jet I would try the constant low rpm issue would not go away. I checked for intake leaks and everything seems air-tight. I run a 2 into 1 Supertrapp exhaust so I can't really determine which cylinder is causing problems, but the only thing odd that I noticed is the color of the spark plugs - the front is perfect: brown or caramel, while the rear is white. No matter how rich I jet the carb the rear spark plug remains white, while the front darkens to the point it would foul.

Again, the engine runs fine in higher rpms and the issue completely disappears in higher gears but it's kind of annoying not being able to run smooth in lower gears and low rpm.

Is there anything I could do? Should I worry about this or just let it be?
There are no authorized S&S Dealers within reasonable distance so I can't have the bike checked by an expert. The engine is still in warranty, of course.

View attachment 45041 (left is front spark plug, right is rear)

OK. Let's try. Only in the event that there are no leaks !!! And in the cylinders the same compression !!!!
1. Different length of pipes. The pipe is shorter - the spark plug is lighter.
2. Coil single fire. The front cylinder is always first. The rear cylinder is always slave. If we remove the spark plug wire from the front cylinder engine dies. If we shoot from the second, the engine works very badly.
I also have different spark plugs. I agree. This is not entirely correct. But this is the cause of the different pipes. And other factors.