Ducati Monster Forum

Moto Board => Tech => Topic started by: WhiteStripe on July 11, 2011, 01:17:15 PM

Title: Choppy Throttle
Post by: WhiteStripe on July 11, 2011, 01:17:15 PM
I had the pleasure of riding a couple hundred miles the other day split between a Multistrada, Hyper, and a SC1000.

I had never ridden the SC1000 and after about 2 miles adjusting to the position from the Multi I was in love and wouldn't give it back.  I think i need one [evil]

Getting back on my 2006 S2R 1000 it made me realize that my throttle chopiness is not normal based on the other three bikes. 

Basically, there is no way to roll into throttle on my bike without a 'jerk'.  I have always struggled with rolling back on throttle in corners.  I always attributed this to my poor riding, but the SC was smooth as butter, even rolling on and off in a corner with two fingers on the brakes.

So my question is (a) is there something wrong with my throttle, (b) do i need to just lube it and it should help, (c) i am coming up on 6k miles and need adjustment, or (d) S2Rs are just not smooth.

Any opinions or help?
Title: Re: Choppy Throttle
Post by: Howie on July 11, 2011, 01:25:29 PM
First steps would be to lube it and check the free play adjustment.  2-4 mm. is the spec.  Still no good?  Check cable routing for sharp bends.  Also make sure nothing is interfering with the grip, like rubbing against a bar end.
Title: Re: Choppy Throttle
Post by: the_Journeyman on July 11, 2011, 01:35:13 PM
+1 on howie's info.  Slack can cause that jerkiness

JM
Title: Re: Choppy Throttle
Post by: BK_856er on July 11, 2011, 09:21:09 PM
A good state of tune can also make a huge difference in off/on and early power delivery, but first check the easy stuff as already mentioned.

Valve clearances, throttle body sync, cam timing, fuel trim adjustment, etc. all contribute to smooth delivery.

Sometimes an aftermarket throttle tube can also help, but best to get everything else in order first, if required.

BK
Title: Re: Choppy Throttle
Post by: uglyducky on July 11, 2011, 09:27:05 PM
Quote from: BK_856er on July 11, 2011, 09:21:09 PM
A good state of tune can also make a huge difference in off/on and early power delivery, but first check the easy stuff as already mentioned.

Valve clearances, throttle body sync, cam timing, fuel trim adjustment, etc. all contribute to smooth delivery.

Sometimes an aftermarket throttle tube can also help, but best to get everything else in order first, if required.

BK

+1 here.  just had that experience.  once the bike was well dialed in and within spec - throttle rolled on and off super smooth - prior to it i had the same experience.  i was about to sell the bike . . . thought i was gonna kill myself in a corner when the gas came on like a sledgehammer.  but lube and cable kink sounds reasonable too.
Title: Re: Choppy Throttle
Post by: WhiteStripe on July 12, 2011, 10:53:39 AM
Great input guys.

I have no idea how to adjust throttle slack (embarrassed to say) - but I think that the freeplay is definitely more than a couple mm.

Can anyone point me to a resource for adjusting and lubing throttle.

Valves in the fall.

Thanks!
Title: Re: Choppy Throttle
Post by: uclabiker06 on July 12, 2011, 05:24:43 PM
uglyducky what exactly do you mean by "dialed in"?
Title: Re: Choppy Throttle
Post by: Howie on July 12, 2011, 05:52:52 PM
Quote from: WhiteStripe on July 12, 2011, 10:53:39 AM
Great input guys.

I have no idea how to adjust throttle slack (embarrassed to say) - but I think that the freeplay is definitely more than a couple mm.

Can anyone point me to a resource for adjusting and lubing throttle.

Valves in the fall.

Thanks!

Pages 49 & 50 in your owner's manual.  No manual?  Download it here:
http://www.ducati.com/services/maintenance/index.do (http://www.ducati.com/services/maintenance/index.do)
Title: Re: Choppy Throttle
Post by: Buckethead on July 12, 2011, 07:16:05 PM
See also: chain tension.
Title: Re: Choppy Throttle
Post by: WhiteStripe on July 14, 2011, 01:42:45 PM
Chain tension - interesting.  I obsessed about this a few months ago so i think i am good.  Would jerkiness be too tight or too loose, or either?

On stock 15t sprocket.

Thanks all.

Howie, if anyone every deserved a RTFM it was me on this one - thanks for being gentle... :-[
Title: Re: Choppy Throttle
Post by: Buckethead on July 14, 2011, 01:51:46 PM
If your chain tension is loose, your engine has just >| |< that much more time to get up to speed and pull the slack out of the top section of chain as you transition from off-throttle to on.

Too tight wouldn't cause jerkiness until it ate one of your sprocket teeth, but you'd probably notice that.  ;)

All of the other advice here is also good. I just like to start with small, easy fixes first.
Title: Re: Choppy Throttle
Post by: the_Journeyman on July 14, 2011, 04:54:26 PM
RE the tensions issue:

My wife's Hawk has a too loose chain and has this same symptom.  My properly adjusted M750 chain only has a slight pull on and off throttle.  Cables are properly set on both.

JM
Title: Re: Choppy Throttle
Post by: duc_fan on July 14, 2011, 07:22:42 PM
I was gonna chime in with chain tension as well.  When the chain started to go on my SS, the on-throttle transition was getting progressively worse.  Inspected the chain, realised it was shot (o-rings were splitting and some were missing), stopped riding until I got a new one on and properly adjusted.  I adjusted it to the 5mm slack that was clearly labeled on the swingarm... lo and behold, the throttle transitions were smooth again.  [Dolph]

After checking that, as others have stated, start checking other tuning items.  Throttle tension, TPS calibration, TB balancing, etc.  If everything is in spec, it shouldn't be doing the herky-jerk throttle routine anymore.

Good luck.  [thumbsup]
Title: Re: Choppy Throttle
Post by: theprocess on July 15, 2011, 06:13:44 AM
Do you have any mods done? Aftermarket exhaust?

I found (on my 696) with the termis, putting the baffles in smoothes out the throttle at low rpm. Probably something to do with increasing the backpressure as well as reducing sound.
Title: Re: Choppy Throttle
Post by: WhiteStripe on July 15, 2011, 10:07:46 AM
Thanks everyone - may try tightening up the chain a bit as well.

I am running Arrows with baffles - i found the bike to be smoother with baffles, but attributed that to the fact that it seems to run richer with baffles in.  When i richen the FAT DUC too much the bike is very smooth, but power goes down. 

Really appreciate all teh input.