[eda1bulletc5]

Hi Guys,

With my 2011 C5 w/11500 miles, K&N filter and Silman Short bottle silencer, I can hit around 65 to 70mph before the bike starts sputtering. I know the sputtering basically happens because the bike is running lean because of free flowing intake and exhaust and EFI just cuts off fuel. I was thinking about the following, please feel free to reign in

1. Does adjusting the Air bypass screw adjustment (high/low idling) make any difference to reduce the sputtering?
2. Does putting a new exhaust system like sold by hitchcockmotorcycles part # - 91130 along with DynoJet commander make a difference? Has anyone tried it along with K&N filter as well?
3. With mentioned mods in 2, adding a 19T sprocket help top speed a bit with out adversely effecting low end torque?
4. General question: Does DynoJet on a single cylinder Thumper help as much at all?

Please advice and thanks in advance for your input

Regards,
Sajiv

[ace.cafe]

Theoretically, the EFI is supposed to have enough lee-way in the mapping to allow the use of a free flow kit, and be able to self-adjust for it.
You might have a fuel flow issue or a clogged injector.

Anyway, the exhaust system you mentioned is being used by a few people here, so I should let them mention how they like it. I have read good comments about it.

The taller sprocket is a tight fit in the case, but I think it can make it. Anyway, it should work okay to lower the rpm range a little at cruising speeds, and if you have some minor mods like you are talking about, it should cope fine with it in terms of acceleration too.

I can't say about the Power Commander, one way or the other. I have not tried it. All I can say is that the very few reports which I have read on this forum leave me feeling like it has not been sorted out yet.

A Power Commander or ECU modification on any bike can have an effect on a single cylinder as much as any other bike. The thing about it is that it can only adjust the mixture and the timing, so all it can do is correct them to be best power range instead of best economy range. The real advantage of a modified ECU or PC comes when the engine is modified to make more power internally, and then the ECU or PC can be adjusted to make the most of those modifications.
There typically is some percentage of power increase available with these types of electronic controllers on a stock bike. At this time, I have no data to tell you exactly how much increase to expect on a UCE Bullet.
 

[eda1bulletc5]

Hey Ace,
Thanks for the input.
If this is a clogged  injector, wouldn't the bike have sputtering at any speed rather than just at 65-70 mph where it maxes out?
Can adding a little bit of Techron help maybe to clean up any normal clogging? if there a paint from the tank that is clogging the fuel, this will have to flushed, I guess...

Anyways, I will go ahead and get the EFI pipe and EFI exhaust from Hitchcockmotorcycles

[ace.cafe]

Hey Ace,
Thanks for the input.
If this is a clogged  injector, wouldn't the bike have sputtering at any speed rather than just at 65-70 mph where it maxes out?
Can adding a little bit of Techron help maybe to clean up any normal clogging? if there a paint from the tank that is clogging the fuel, this will have to flushed, I guess...

Anyways, I will go ahead and get the EFI pipe and EFI exhaust from Hitchcockmotorcycles

Yes, it's possible that some additive like that could work.
It's not guaranteed that problems always will show up at all rpms. Speeds near max will often show up some things which can get by at lower loads. I don't know for sure what the problem is, but it seems to me that something is not right. I always try the easiest cures first.
It also seems that most UCE owners report that their bikes max out at around 80 or so. Maybe this thing with your bike maxing out at 70 might be indications of some issue. Perhaps a general check of things like your air filter condition and such.

I think that the exhaust should be good for a couple of ponies, and a reduction of excess weight.
At this time, I believe that it will be able to work with our Ace head work too, if you have any plans in that direction.

[gremlin]

........If this is a clogged  injector, wouldn't the bike have sputtering at any speed rather than just at 65-70 mph where it maxes out?........

modern injectors have four (sometimes more) orifices where fuel is emitted.  if one of those four is clogged, your bike might go lean only under high load.   The same is true for low fuel pressure to the injector. 

[idk]

It may also be worthwhile checking your fuel filter. It could cause those symptoms if it were dirty.

[Jack Leis]

With the EFI pipe from Hitchcock's, you will actually LOSE power unless you use the Power Commander.

[barenekd]

I can't recall anyone having a problem with an ECU engine sputtering regardless of the muffler and pipe on it. Power bands may change, but they still run good. You could possibly be having an electrical problem, too.
I would say you need a good checkout of your fuel system before spending a lot of money on the exhaust system. You could even put the stock one back on and see how that's running.
Bare

[Arizoni]

The first thing I would do if my bike was sputtering at high speeds/loads would be to put a little Techron in the fuel tank and change my spark plug.

[Ducati Scotty]

Water in the fuel?  I think we've seen this symptom from that before.  Anyone else remember that?

Scott

[GSS]

Try Seafoam followed by Techron in the gas and see if it helps.

[eda1bulletc5]

Hey Guys,
Thanks for the inputs.
I have added Techron and took it out for a spin. One other thing that I have noticed is the speedometer is atleast 6 Mph off meaning if I am seeing 70 it is actually 76 Mph (measured using GPS); but it still sputters at 76 Mph.
Another observation is, while climbing a grade (around 3 to 4%) with the throttle fully open the bike was able to achieve only 60mph - no sputtering but just didnt make any difference in speed and stayed at 60mph
I will look into the spark plug and any electrical wiring issues. I did have a quick inspection of the air filter - looked pretty clean. I had cleaned it around 2000 miles back.
Any idea how many miles after adding Techron generally there is an improvement?
Thanks.

[wildbill]

mine had a bad dead spot at 90 kph. after it almost stopped - stopped and wouldn't start it threw a cel. i found out the throttle position plug was not connected properly.
might be worth a check. it's near the neg cable lead from the battery.

[ace.cafe]

Hey Guys,
Thanks for the inputs.
I have added Techron and took it out for a spin. One other thing that I have noticed is the speedometer is atleast 6 Mph off meaning if I am seeing 70 it is actually 76 Mph (measured using GPS); but it still sputters at 76 Mph.
Another observation is, while climbing a grade (around 3 to 4%) with the throttle fully open the bike was able to achieve only 60mph - no sputtering but just didnt make any difference in speed and stayed at 60mph
I will look into the spark plug and any electrical wiring issues. I did have a quick inspection of the air filter - looked pretty clean. I had cleaned it around 2000 miles back.
Any idea how many miles after adding Techron generally there is an improvement?
Thanks.

What kind of air filter do you have in the bike?
A normal pleated paper air filter cannot be cleaned, it must be replaced. The pores in the paper get partially clogged, even if the surface is brushed/blown off.
If you have a K&N gauze filter or something like that, then that's a different story.
Problems with getting enough air are just as bad as not getting enough fuel, and can seem similar.

It seems your bike is not performing up to its full potential, compared to other UCE bikes out there. So, we need to get it figured out.

[eda1bulletc5]

Ace, the bike has K&N filter.
It does backfire once in a while too; when decelerating. In 12 mile ride at least 3 bangs! (hmmm does that read out right?!!  )...I had recently removed the exhaust put in exhaust sealer (high temp) at pipe and exhaust ...made sure the nut at the exhaust header is tight
I had adjusted the air bypass screw for adjusting the idle speed, to lower idle rpm...will this have any effect?