running rough / but not mis-firing???

[Guest]

Like night and day. I was running smooth on Saturday, then Sunday... all of a sudden, she's riding rough with a deeper tone. It seems to be running rougher across the board, from idle to 5th. HOWEVER there is no loss in power at all. I'm pulling the same all the way through the power band as I was when I was running smooth and I'm pulling well. All pipe are hot.

what's going on?

[Steve]

Sounds like one or more of your inlet valves might be stuck, changing your float levels.

Has it been doing this long enough to notice a change in gas mileage?

.

[maro]

no, only noticed it yesterday...thru today. I'm due for a fill up in about 15 miles, so I'll take notice. I just glanced at the clymers. Mentioned checking all the plug gaps, etc. but plugs were check recently and everything was fine.. I'll check again for good measure

so How do I go about diagnosing which valve? How would I get it unstuck if that is the culprit. Are there other things I can do first before diving into valves that could solve this?

[SPARKSS]

Running rough through all the range would often point to a misfire of some sort (doesn't always mean that ignition stopped!). Hold it at a steady rpm (2000 to 2500 should do) and listen....is there any irregularity to the engines running? If so then you do have a misfire happening of some sort. Similarly running (or at idle if noticed there), one-by-one remove each spark plug wire and note how the engine reacts (usual don't-get-shocked precautions). You should see a uniform rpm drop and especially.....not a rise! No change indicates no cylinder contribution.......a huge change indicates that the engine is relying on that cylinder a lot. A rise can indicate the likes of switched wires (engine fighting itself......and not UNCOMMON....the switch will usually be 3 for 4 or 1 for 2).
Is there any exhaust leak (or is this the perceived problem). Is the air filter / filters intact and the airbox (if still used)?

This may help you start to diagnose where or what the problem appears to be.

[Ed Vrolijk]

In your first post you mentioned a deeper tone. Can there be something wrong with your exhaust?
Ed

[chuckycheese]

Battery?

I agree with all of the above. What kind of shape is your battery in???

[maro]

I'm going to check what sparkks mentioned about the plug caps. though they are new NGK's

In your first post you mentioned a deeper tone. Can there be something wrong with your exhaust?
Ed

That's what I was thinking initially. How do I trouble shoot this?

I agree with all of the above. What kind of shape is your battery in???

battery is brand new and getting good voltage

[catbed]

i would take a look at the plugs, possibly get new ones.

[maro]

So all the plugs seem to be in good order. I pulled each cap off while running, and they all bogged the idle down when removed. some more than others (1 & 2). #3 plug was a little rich (blackened), so I replaced it and leaned the mixture screw a quarter turn. I also refueled, so I will check MPG on the next tank and compare. The bike is really running as strong as ever, it just feels like she is purring a bit louder and harder than before.. Honesty, if I were on the bike for the first time, I wouldn't think anything of it. She sounds like a REAL motorcycle now, not as thunderous as a Harley, but she was a bit softer sounding a few days ago. Maybe becuase it was so hot out a few days ago and for the last few weeks. These bikes seem so tempramental. When I put different brand gas in they seem to run different.

and steve mentioned a stuck valve. What are the symptoms of this? What else should I check. Maybe it is just the exhast, but the muffler looks okay?

[SPARKSS]

Well by gosh, ENJOY that real-motorcycle ya have there! With respect to troubleshooting the exhaust, look for any holes in the system before the mufflers. If none found, and it's running good (as you mentioned), then it's likely that baffelling has rusted away and may have exited the muffler already - this will surely cause an increase in noise and, as long as it's actually gone (and not fallen inside blocking the exhaust) then no harm done - ride 'er!
If you're uncertain as to whether this sort of thing has taken place, you might try shining a bright light into the muffler outlet and look inside to see if both are the same or similar (or at least not obviously blocked).

Sounds like you got the hang of doing the running cylinder contribution test ok - keep that for future reference.