Flat spot

[wismo]

Well finally got out to try the bike after changing the mains.It runs really good other than I noticed it now that I rode around a little longer and really got the bike warmed up I noticed there is a hessitation in the lower rpms.Would this be what is considered a FLAT spot.
Also where should I begin whit this FLAT spot.... Thanks

http://www.katriders.com/vb/showthread.php?t=100743

[Jacobz]

If it gets worse once fully warmed it means that it is running rich at that RPM. Define lower RPMs for us and we should be able to help.

[Court93kat]

Here is the best information on tuning your carbs. Follow this step by step and you can't go wrong.

http://www.factorypro.com/tech/carbtune,CV,high_rpm_engines.html

[wismo]

I mean when I stop let it idle a minute or two say at a stop light then go to take off it kinda stumbles the goes.

After the initial take off it runs sweet. Looking at the link court93 provided

I guess I am running rich. So probaly my next step is going to be turning in the a/f screws ina half turn fron 2.5 to 2.25.
Which brings me to another question can I get at the screws with fairings on. And is anyone using a screwdriver other than the 90 degree angle one to get in there.Reall too lazy to remove carbs in this HEAT.

I do appreciate any more input and thank you for the responses.

[kevin2502000]

Here is the best information on tuning your carbs. Follow this step by step and you can't go wrong.

http://www.factorypro.com/tech/carbt...m_engines.html

That's an awesome read right there, I book marked it

[Court93kat]

Yessir. That is definately a page to save under your favorites. I have it printed out and keep it in the garage as well for even quicker reference.

[wismo]

Just an update on my SLOW progress.

Pulled carbs out this morning and put a/f screws at 2 turns out from 2.5 turns out seemed a little less muddy from a stop to take off but again once I get up to arund 3000 rpms it clears out.

Oh and it did stall while pulling out of a side street mid turn.
Feel free to input.... Thanks..

[kevin2502000]

By reading alone, I think the float levels need to be lowered.

[wismo]

and keep 2 turn or go back to 2.5 on a/f screws

[kevin2502000]

Right now my bike is acting the exact same way. This is what I am going to do, lower my floats down to 14.0, from 14.6, and leave the a/f at 2.5. I have run mine at 2.5 the last year and it ran great. I think that is a good setting.

[wismo]

Really? I was thinking Im running rich thats why I backed off on a/f screws had 2.5 now 2 turns out.Im already at 14 mm.

[Kreylyn]

Really? I was thinking Im running rich thats why I backed off on a/f screws had 2.5 now 2 turns out.Im already at 14 mm.

If you really want to fine tune the A/F so that it's running where it should be, start at 2.5 turns out, and then.... while the bike is at idle... turn in each one till it starts to miss on that one, and then turn it back out 1/4 turn.

Every carb might end up slightly different, but that's what it needs to be to truly be turned right.

Krey

[kevin2502000]

• 3. Low end (full throttle / 2k-3k)
  Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3!
  • • Float height (AKA fuel level & how to..)
  • To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
    • Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
    • If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
    • If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
    • Example: change float height from 15mm to 14mm to richen up that area.

• • • REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.
      • Warning: If the engine is left with the fuel level too high,, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.
        • Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.
      • Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!
    • If there are low-end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs. Click here
• 4. Idle and low rpm cruise
  • • Fuel Screw setting (AKA mixture screws)
      • There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -
    • Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)
    • Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
      • If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.
      • Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.
        • NOTE: A rich problem gets worse as the engine heats up.
          • If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.
        • NOTE: A lean problem gets better as the engine heats up.
          • If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

I reread this, I told you the wrong way, you need to INCREASE the height to lean it out.

If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner