wee bit o' tech assistance needed...
 

so in the past week or so, i fiddled with the knurled knob on the right side to sync the bike at 4k rpm. the bike has had a stumble/hiccup at low rpm (2k-3k rpm). that was around 24k and while i rode "around" the issue for 7k miles, i decided to fiddle with the bike to make it better. oh, such noble thoughts.

now having done just that, it sure is smooth at 4k rpm. but holy cow, is the stumble/hiccup more like hiccups with a side of heart burn/acid reflux. it is harsh and nearly stalls the engine. and idle now, yes, readjusted, and reading balanced, is irratic between 1100-1400 and turning the brass screws are not yielding as great an effect. pulling on the fast idle lever sinks it right in the meat of the problem and the bike tries harder to stall that to keep running.

so what i am thinking is:
a) read up on the whole 0=0 dealeo and see about that...perhaps the TB's, or at least one, is closing too much.
b) its time for new cables
c) shoot her and put me out of her misery :P

any words of wisdom is, as always, much appreciated.

repoe3

repoe, one time i adjusted my throttle bodies and had very similar problems. turned out that one of the plastic housings around the cable was getting caught up on the knurled roller. i shifted it back into it's "centered" position so it wouldn't get caught up and all was well with the world. could be something that simple.

If you don't have something like a TwinMax, you need to get one. Do a very precise valve adjustment, then ride your bike for about 30 miles and balance your throttle bodies. If you haven't changed spark plugs in a while, replace them. My personal choice is the Autolite 3923's. I change them every spring.
First slacken your choke and accelerator cables, not much just so there's no pull on them. Then make sure the brass screws on the throttle bodies are clean, then using the TwinMax, zero them. Engine speed should be around 1100 rpm.
Now, snug the choke cable, but just so it doesn't alter the running of the engine. Now using the TwinMax snug the accelerator cables and adjust until you have a nice smooth running engine. Run the engine speed up to about 4000 rpm and adjust cables until you again get a zero on the TwinMax.
If this doesn't fix it, you have at least eliminated the major source of problems on oilheads.

repoe, just to clarify what i wrote. the cable was getting hung up only when i released the throttle, causing a terrible stumble. at speed, the cable was stretched so it cleared the interference and was smooth as silk (well, boxer silk anyway). when i released the throttle, it would get hung up again and shake and studder.

thanks, gots me a twinmax...just checked the valves a week ago, they were spot on...again, without any adjustment. you got me on three points...i need to check the throttle and fast idle cable adjustment and might be time for new plugs just for good measure. this is a twinspark, and i have found...let me rephrase that, i have NOT found replacement plugs anywhere BUT the dealer :|

done the rest of the adjustments as outlined in your post. thanks.

repoe3

hmm, trying to picture what you are describing. you almost exactly described the conditions, it is more on throttle release.

repoe3

Check and make sure one of the cable's haven't come out of position. Or a rock isn't caught in one of the throttle pulley's.

roger that. you know, there is no noticable resistance or grit or what not, so the action is smooth. thinking i have either an adjustment out of whack or there is a hang up like scott is describing. kinda feels like one side if closing more than the other, maybe too much so.

repoe3

i'm not describing it well enough. basically, you have a wire cable within a plastic sheath. when the throttle is twisted, the wire and sheath pull out of the knurled roller down at the part you adjust. when you release the throttle, if the sheath is not centered in the knurled roller, it will not slide back in. instead, it will get hung up on the edge, causing problems.

make sense? probably when the sheath is seated properly it doesn't move. but if it's not, it will.

Thanks Scott, that's exactly what I was trying to say in my post. I've seen this happen before and if Repoe is sure about the valves and throttle body sync, this could be it.

repoe, look at page 18 here.

First time I did my TB sync I did this and it drove me nuts. Was trying to figure out what I did for more than an hour. Symptoms exacly as repoe3 desribes and here I was trying to figure out why my adjustments screwed up the bike so much. Damn sheath! :mad:

I had a similar issue with my S.
I did the valves, TBs, 0/0, and ran fuel injector cleaner, all to no avail; I finally fixed it by accident.

In frustration one day, I slightly rotated one of the fuel injectors, and my erratic idle/stalling issue went away immediately.

Not sure if there was some crud that got knocked loose when it rotated, or a gasket or hose was not seated properly, possibly causing a vacuum leak...whatever the issue was; it was fixed.

thanks folks...just went a looked at the bike and i have about a 1/16" of space between the top of the knurled adjuster and the sheathing. i tried to push it down a bit and did...but still have some gap. funny how i have overlooked that all this time.

repoe3

did that solve the problem?

i gots no idea...i cant just run out and take a ride, i am at work.

can you :P

but at least i have something to fiddle with and see if it had any affect.

repoe3

repoe; any honda shop has a wonderfully-pedrfforming plug in the NGK BKR7EA-11, about $2.50 each and a honda motorcycle part number.
I HATE that stupid 'choke' cab le...it's a ctually a fast idle cable and totally unnecessary on an FI bike unless you're terminally lazy.
I relocated the 'choke' cable to it's most useful place...onto the workbench.
when you start 'er up from cold and it's tuned correctly, all you should have to do is hold the throttle at 2KRPM for about 15-30 seconds and then let it shut and you'll have a wonderful stab le idle as she warms up...when it's dialled in. correctly.

jony, this is a twinspark and it uses two different sizes...finding the outside plug is not the challenge...the smaller underside one, is. dont assume that any ol's auto shop in an urban area carries a lot of things. they have some stuff, but i have come up sort more times than not...as such i gave up looking anymore.

as for your opin on FI bikes...i bow down to your vast experience with bikes, but i respectfully disagree with you all the same. your summary of how the bike should could would act at start up is still how the S responds. but i see the point in having it.

while the rotax engine is a COLD natured beast. add to that fact that eyetalian electronics may not always feed all the juices back through the charging system, she can be tempermental until she reaches normal operating temps. the fast idle, IMO, is a must. it allows me to ween the bike off a faster idle as it gets warmer from 100 degrees to the norm temp of 172 degrees. the S is less tempermental, no doubt.

the newer RSV's have a stepper motor and no fast idle and new owners are b!tching and complaining about how hard it is to start...specifically when they are told NOT TO TOUCH THE THROTTLE.

besides, there are times i start the bike and walk to put on my helmet or gloves, having the fast idle is nice.

repoe3

no problem, opinions are what makes the world go 'round and no offen se taken, jus' tryin' to hep out a fellow bro.
I'm really wierd when it comes to this stuff anyway. no matter what it is, how good it is, where or when it was made, I always have to hack, cut, weld, reprogram, upgrade, screw up and butcher anything I get my grubby little mitts on:)...sometimes it even gets better...

Actually, I can . . . but that comes with as many problems as benefits . . .

Either way, let us know if your problem is solved.