01 Fuel Injection question

[mtbrights]

My o1 has a slip on Two Bros muffler, otherwise stock. I bought it used this spring (19K) and ran it this summer. It runs rougher at 3-4k than I would think it should and the bikes midrange is (very) flat until 6500-7K when it runs nice and clean. Throttle response is also difficult to manipulate in parking lot situations. on/off etc...

I suspect it's running lean until the 6500 RPM level, because it's like flipping a light switch, but don't know what the algorithm looks like for the stock fuel injection. I've searched for threads in this regard but haven't come across this particular problem on this board.

I may have to resort to Dynojet but I would prefer to rule out any potential FI problems beforehand. Any thoughts.

Edit: No codes flash on the FI light.

[maddog]

Are valves within spec?

Are plugs good?

is air filter clean?

Have the starter valves been synched?

Clogged injectors, from sitting idle, could be a problem.

I'd lean toward the starter valves needing to be set.

[mtbrights]

I checked and replaced all the above myself when I got it except for the starter valves. SO I will try to check them tomorrow and let you know. Thanks for the tip.

[mtbrights]

Maddog had it right as the starter valves were off on three and four. Much smoother throttle response and runs much nicer. I didn't realize I didn't even have to take the air cleaner off. I just tapped into the hoses on either side of the air cleaner with the homemade carb syncronizer I built as outlined on this site also.

Pretty fruitful day for me thanks to this site.

[kingsley]

Another happy customer! I read somewhere the starter valves are only in use for the first 4% of throttle, then have no effect.

But they seem to have a lot to do with the overall smoothness through the RPM range. Easy tweek with the home made manometer.

I synced mine with PAIR enabled (contrary to manual, from a detailed thread I read elsewhere) as that is the way it will be running normally.

[mikeym]

Maddog had it right as the starter valves were off on three and four. Much smoother throttle response and runs much nicer. I didn't realize I didn't even have to take the air cleaner off. I just tapped into the hoses on either side of the air cleaner with the homemade carb syncronizer I built as outlined on this site also.

Pretty fruitful day for me thanks to this site.

Could you give me a run down on how to check the starter valves? I'm not even sure what they do....

Thanks...

[kingsley]

Could you give me a run down on how to check the starter valves?

You can find it in the free download-able service manual (got mine off VFRD)


Google "homemade manometer" for ideas if you're going to build your own.