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Poor high speed performance

9 posts from 4 voices
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  1. priebe22

    Hello all. I am having an issue with when moving from half to full throttle performance at most any speed. As when entering a highway. I recently pulled my carbs and did a bunch of work on my 06 1100 Customer. Removed and plugged the fuel solenoids using the MaxAir kit. Removed the stock, grooved main jet holder with a pre-06 non-grooved holder. Increased the mains to a 145. Replaced the mixture screws with the new max mix screws. The bike starts, idles, takes off from stop just fine. In fact, perhaps a little better performance in that range than prior to all the above mods. However, when I go from half or 3/4 throttle to wide open the bike stumbles badly and gives the impression it had just died, then a second latter it blips and jumps forward, then back to the stumble/stall state, then i blips forward, then back, then blips and so on. It is almost like it is not getting a steady fuel flow in the main jet circuit. It does slowly increase speed as the vacuum builds back up and the other circuits kick in supplying fuel missing from the main circuit. Any thoughts? I am going to check fuel flow from the pump and float level. Other than those two things I am stumped.

  2. Fulldild1

    Did you install Max-Air POD Filters? Did you reset slide needles? What are your current carb settings and exhaust type? What color are your Spark Plugs? When it's stumbling does the use of your choke make it somewhat better? Any chance you could be hitting the rev limiter?

  3. priebe22

    No PODS installed. Bike came with an Yamaha speed-line ram-air type system. I upgraded the filter to a K&N. Jet sizes are in original post. Mix screws out three turns. Plugs look perfectly normal. Will let you know about the use of the choke. No chance of hitting the rev limiter as the bike continues to gain speed. The stumble happens at a wide range of RPM. It all depends on the throttle position. I can pull it to WOT at 2k and by the time I reaches 3k it starts to stumble because it seems to have run out of fuel or can no longer pull fuel through the main circuit.

  4. priebe22

    Also have a Road Burner two into one full system installed.

  5. 78ordon

    No PODS installed. Bike came with an Yamaha speed-line ram-air...

    If you still have the stock airbox under the tank, I think you might be rich.
    According to the KB you should be running maybe 117.5's with stock intake and performance pipes.

  6. Fulldild1

    I can't find anything on Speed-Line, with the exception of a "Harley" part, but these are the settings for the Kuryakyn Hypercharger the only Ram-Air I know of for the 1100. There is a DIY Ram air that cuts 1-3 holes in the black mount portion of the stock air filter housing. Anyway, from this info, it sounds like you are running rich not lean. Did you try the choke/enrichener trick to see if the stumble starts any earlier Rpm wise? The 145 jets you have installed is the jetting recommended for the Max-air POD kit. Can you get me a pic of the air system that is on your bike or a P/N?


    Hypercharger - From Kuryakyn:

    With "Full" performance exhaust
    • 1.2 Pilot Air Bleeds in both carbs (1.2mm or .047" 3/64 drillbit)
    • One .020 shim added to raise each needle for a total of 2
    • 125 Main Jet in the front cylinder’s carb
    • 122.5 Main Jet in the rear cylinder’s carb
    • Pilot Mixture Screw (PMS) 2 turns out from lightly bottomed

    The staggering of the Jets has to do with airflow thru the stock airbox under the tank.

  7. 78ordon

    I can't find anything on Speed-Line, with the exception of...

    He might have the Speedstar like I have, except mine is just on for looks.

  8. Fulldild1

    Probably is, that's why I wanted a pic.

  9. quicgmicg

    Sounds like you guys are right on track. It's just way too large of main jet. If I remember correctly, the mains really start kicking in about 1/2 throttle on up. With a 145 and stock air box, it's going to really dump the fuel. I think 78ordon is right on suggesting in the 119 range from what we know about the set up.

    This picture stolen from the KB....Thank you Dave Sloan!

    If there are many miles ridden with this set up, pulling a plug may confirm the rich condition.


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