Throttle hesitation

[piper51]

My 2000 Valk has a big  hesitation in the throttle when cracking it open from idle. Would that be a vacuum leak or something else? Acts like its starving for fuel. If there is another thread about this let me know where it is and I'll check it out. Thanks in advance.

[Michvalk]

Might be a vacum leak, or it might be the petcock is starving the bike for fuel. Could be needing some seafoam or a similar cleaner run through. There are a few other things that "could be", but, I would bet on the carb cleaner. Go with the easy things first and go from there

[Ricky-D]

If the carburetors have been "messed" with (jets etc.) you should note that in the thread, likewise any modifications to the exhaust, air box, or ignition.

A full picture is necessary for a good analysis.

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[Patrick]

The problem could be either.. How does it run at higher engine speeds ?? If it runs OK right to WOT then the problem probably is not with fuel delivery/petcock.. When were the vacuum lines/caps last checked?? If you don't know or can't remember back that far, then it wouldn't hurt to replace them.. Has any work been recently performed leading to this problem??

[piper51]

I haven't done anything to the bike except put seafoam in it.  It seems to run good at higher rpm and speed. Its just when you first start out or crack the throttle from Idle to higher rpm it hesitates or sometimes will choke out altogether. Do they have a throttle advance in there somewhere? There have been no modifications that I am aware of to the bike. I have had it about a year now.

[9Ball]

plugged secondary jets....common symptom.

[Chiefy]

If you slowly advance the throttle out to about 1800 RPMs, does it miss and run bad?   While you're riding around on it at low rpm in higher gears. does it badly?  If so, does choking it make it run a whole lot better?

If so, it sounds like your slow speed jets could be clogged,  Seafoam/techron/sentry applied with heavy doses frequently helps.  Put a heavy dose in, and take at least a 10 mile ride in higher gears, going slow so that the rpms stay around 2000 or lower.  Then park it overnight and see where you stand.  Many guys put chemicals in, then rev the p*ss out of the bike.  But doing that doesn't get any chemical where it needs to go....the slow jets.

Never a bad idea to check for vacuum leaks.  Check the hose style clamps on the top of each carb.  They come loose.

Let us know how it goes.

[Patrick]

Yep, it sounds like you have a case of the infamous varnished low jets.. You didn't say how much Sea-foam you used.. Use a full can and run a couple tanks thru it like Chiefy said.. But, check the vacuum lines and caps and replace if needed.. If the engine doesn't perk up, its time to get your hands dirty and clean some carburetors..

[piper51]

I have run a couple cans of seafoam through the bike, but haven't done the low rpm ride. I will try that and see what happens. Do I use a can per full tank or half a tank? I really don't want to take the carbs apart if I don't have to. So, if I have to do the carbs should I do a desmog also? Thanks again for you posts and help. Piper

[Chiefy]

I have run a couple cans of seafoam through the bike, but haven't done the low rpm ride. I will try that and see what happens. Do I use a can per full tank or half a tank? I really don't want to take the carbs apart if I don't have to. So, if I have to do the carbs should I do a desmog also? Thanks again for you posts and help. Piper

You'll get some yays and nays about desmoging.  But if you have a mind to, then if you pull the carbs, it would be a good time to do it.

I wouldn't hesitate to use a full can in a full tank.  I'll let someone who has tried a full can in a half tank comment, cause I've never tried it.

[Ricky-D]

piper51 states: 

"My 2000 Valk has a big  hesitation in the throttle when cracking it open from idle."

I just want to point out that the carburetors on the Valkyrie are constant velocity (CV) carburetors.

There absolutely will be some hesitation in throttle response if compared to a non CV type carburetor found on many other motorcycles.

So the question about what is a "big hesitation" may have play in this thread.

Not to dismiss gasoline additives being a good thing to try anytime there seems to be a carburetor/fuel related problem.

Just wanted to point out some hesitation will be normal.

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[9Ball]

I have run a couple cans of seafoam through the bike, but haven't done the low rpm ride. I will try that and see what happens. Do I use a can per full tank or half a tank? I really don't want to take the carbs apart if I don't have to. So, if I have to do the carbs should I do a desmog also? Thanks again for you posts and help. Piper

Sometimes too many additives can cause problems with starting and smooth running...if you have old gas and add a full can it may cause the problems you describe.  I would consider siphoning out the old gas and starting with fresh..