Problems over 4k RPM

[Pain]

I took my H out yesterday, it was damp and cold, but by no means the first time it has been out in the damp and cold, though I think it had been a while since it was run (A few weeks).

Over 60mph when I opened the throttle the bike would often hesitate and sputter before taking off. Over 80, sometimes, it would continue run rough, but when I stopped all the cylinders seemed to be working. Plugs were new last year, carbs were cleaned over last winter, and I went through 2 tanks of gas, so I doubt I got a bad tank. Unless I got 2 bad tanks.

Thanks

[TopCatGr58]

Hey Pain,

You might first try a can of Techroline or Seafoam, not the full can of course, but several ounces and run it thru?

Also, check your vacuum advance plate, make sure it's not binding or getting stuck, vacuum hoses intact, no cracks, etc.
T.C.

[underdog57]

Try pushing in the enrichener when you get that flat spot .
If it stays bad , yer running rich .
Mine has cleared up a lot , been using sea foam . Adjusted float level ...Plus a lot of cleaning ...

What do your plugs look like??

Bob

[Pain]

It happened on the Interstate, after the bike was warmed up and the enricher all the way in.

The plugs are new last summer, maybe 11 or 12k on them. I will pull them out and check them - tomorrow I hope.

Seafoam is great stuff, I will probably pick up some of that too.

Another thing, my mpg was much, much worse, mid upper 20s, instead of mid 30s.

[Pain]

Problems over 4k RPM

So my delightful fiancee adn I are out crusing the black hills, and whenever I cross 4k on the tach the bike starts to shudder, sputter, and generally not gain any power. Quite a change from the smooth power curve I am used too.

I had this problem before coming out here, and have been addeding seafoam to every other tank. The vacuum lines were replaced, since one was kinked, with heavier ones. All the plugs are black with white spots, before the lines were replaced, they were just black.

We are here until Sunday, the bike is already being trailered back to Milwaukee (Oh, the horror). It is less of a problem than you would think, since Her bike really isn't that fast, and we can keep pace with each other, but if I can fix it without a major teardown, I would like too.

Major teardowns will have to wait until I get home. I am on vacation, after all, and want to see some sights rather than take my bike apart in a parking lot.

[Snow]

Sounds like a carb jet transition point to little old me - does the power pick up again once your get past, oh say, 4500 or 5000 rpm? Do you know the jet sizes in the carbs? Have you ever set the float level?

[Pain]

I don't know if power returns, I can't get the revs any higher.

The carbs were rebuilt during the winter, 05-06 by my mechanic, who I trust to do a good job, the jets were factory spec. No problems since. No idea where the floats are.

I might try replacing all 4 plugs, if I can find some, and see what happens to the new ones. I don't know how long I had the vacuum line issue.

[jeffe]

Pick up coils?

[TopCatGr58]

Hey Pain,

I merged your previous recent thread with this one, but then realized that you may be talking about a different machine?? You didn't say which one of your bikes is misbehaving??

Could be electrical vs. fuel. Sorry to hear it broke down during your vacation.
T.C.

[Ken Talbot]

Originally posted by Pain
The carbs were rebuilt during the winter, 05-06 by my mechanic, who I trust to do a good job, the jets were factory spec. .

If factory spec means the same number as the old jets, but the new jets were K&L brand, you will now be running way too rich. That will keep it from revving...

[Pain]

Originally posted by TopCatGr58
Hey Pain,

I merged your previous recent thread with this one, but then realized that you may be talking about a different machine?? You didn't say which one of your bikes is misbehaving??

Could be electrical vs. fuel. Sorry to hear it broke down during your vacation.
T.C.

The merge is fine. internet acess is on my phone, so finding the old thread was not easily done. Same bike, tho. i should've taken the other one, but my SWMBO packed alot.

Had the bike out tonight, and in lower gears it went above 4.5k with only a slight shudder and the same. Going to get up early, and go on the interstate for some experimenting.

[BLUEJEEPLAB]

Pain,

I'd say carbs unless you have fiddled with your fuel lines recently. I learned the hard way that a fuel line can look fine when putting the tank in place, but after it warms up the line develops a kink if you don't get it back in exactly right. Incidentally, 4.5 K was right where the kink in my line starved the left side.

[underdog57]

I had shuddering just about dissapear turning in the idle mix screws .
I need to put new plugs in and try to resync and idle adjustment.

the jet needle could be the culprit if its been changed and is a bad set as mentioned ....on your bike...

bob