Author Topic: Steering right = more RPM.  (Read 7443 times)

Offline Squishy

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Steering right = more RPM.
« on: March 09, 2014, 07:51:59 PM »
Hello.

I need some help with this weird issue because I'm at a loss.
Whenever I steer to the right, even by 5 degrees angle, the RPM on my B400 will rise +- 500rpm. (it will accelerate).
Obviously this sounds to be a perfect case of throttle cable too tight. However turning right in fact loosens the cable instead of tightening it... It's pushing the cable not pulling it.
* Cable is loose
* There is enough slack
* Other cables like choke cable don't move at all when steering.
* Throttle-stop screw isn't touched.
* I tried readjusting but nothing changes.
* It only happens when there's already tension on the cable (= >1% throttle).

 For example if I ride walking-pace, 10% throttle, 1st gear and turn very slight to the right it will accelerate from e.g. 7km/h to 15km/h...
And no I'm not twisting.. It's 100% stationary.

Any ideas..?! I can only some weird tensions going on the inside because it just doens't make sense.
« Last Edit: March 09, 2014, 07:57:14 PM by Squishy »

Offline tomacGTi

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Re: Steering right = more RPM.
« Reply #1 on: March 10, 2014, 11:00:20 AM »
Follow the factory routing and make sure the cable is lubed. Cable drag can make this even worse.

If you've swapped bars, this can exacerbate the situation. You want the absolute smoothest arc possible, any tight bends will cause a dry cable to hang and cause the problems you're experiencing.

Offline Squishy

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Re: Steering right = more RPM.
« Reply #2 on: March 10, 2014, 11:29:18 AM »
Follow the factory routing and make sure the cable is lubed. Cable drag can make this even worse.

If you've swapped bars, this can exacerbate the situation. You want the absolute smoothest arc possible, any tight bends will cause a dry cable to hang and cause the problems you're experiencing.
Thanks.
Cables are routed as per the manual. However for the throttle cable it doesn't mention much.. it just goes right from the carbs straight to the steel clamp on the steeringhead and then to the handlebar grips..
I haven't swapped bars.

It already starts accelerating when I steer only the slightest amount.
I already tried putting it in the wire harness clamp so the cable hardly moves.
Throttle itself is smooth and linear, without hiccups, and it goes back to idle position instantaneously.

I could understand this happening when I steer to the left...but the right?
Even if it were damaged, how can it put more pulling force on the cable when I steer to the right?

Thanks.

Offline erict716

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Re: Steering right = more RPM.
« Reply #3 on: March 10, 2014, 08:17:00 PM »
Check your choke cable. I just got done reinstalling my carbs and as I was pushing my bike i noticed the choke slide was moving as I turn the handle bars right.

Offline greg737

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Re: Steering right = more RPM.
« Reply #4 on: March 10, 2014, 08:26:42 PM »
Check your choke cable. I just got done reinstalling my carbs and as I was pushing my bike i noticed the choke slide was moving as I turn the handle bars right.


I think we have a winner.  It had to be something subtle, hard to notice.
« Last Edit: March 10, 2014, 08:28:13 PM by greg737 »

Offline Squishy

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Re: Steering right = more RPM.
« Reply #5 on: March 11, 2014, 08:08:27 AM »
Check your choke cable. I just got done reinstalling my carbs and as I was pushing my bike i noticed the choke slide was moving as I turn the handle bars right.


I think we have a winner.  It had to be something subtle, hard to notice.
Nope, as said in 1st post I already checked that :)..
I even checked with the fueltank removed.. the choke mechanism doesn't move at all.

I'm quite sure I could see the throttle valve mechanism moving a little bit.. but there was nothing touching it and the throttlecable wasn't being pulled. (as said in fact it was being pushed by steering right).

What would be the easiest way to lube the cable? I thought these shouldn't be lubed because they have already have this layer on the inside of the cable? Also the cable feels pretty smooth.
« Last Edit: March 11, 2014, 10:17:03 AM by Squishy »

Offline erict716

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Re: Steering right = more RPM.
« Reply #6 on: March 12, 2014, 01:04:56 PM »
I saw that after I pressed post. Was hoping you wouldn't call me out on it :grin:

Have you done any work recently?

Really your only things that would cause it is your carbs and fuel lines.

Offline Squishy

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Re: Steering right = more RPM.
« Reply #7 on: March 12, 2014, 01:32:14 PM »
I can see the throttle valve thingy (where the cable is attached) move a very small amount when i push the handlebars to the right.. but nothing is pulling it.. unless the pushing force on the cable somehow makes the cable be pulled :S.

Offline erict716

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Re: Steering right = more RPM.
« Reply #8 on: March 12, 2014, 08:08:37 PM »
Is the nut/bolt of the throttle cable fully tightened to the carbs? That may cause some pull if the outer cable moved.

Offline Squishy

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Re: Steering right = more RPM.
« Reply #9 on: March 13, 2014, 08:43:51 AM »
Is the nut/bolt of the throttle cable fully tightened to the carbs? That may cause some pull if the outer cable moved.
Good idea..
Still i would think it should be happening when I steer left not right.
But you never know.
I hope I can tighten it without removing the airbox again  :yikes: (done that way too many times this year).
« Last Edit: March 13, 2014, 08:53:18 AM by Squishy »

Offline erict716

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Re: Steering right = more RPM.
« Reply #10 on: March 13, 2014, 09:44:35 AM »
Well based on my limited experience digging into this bike, I have found you basically have to take the air box off to do....anything :grin:

Offline Squishy

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Re: Steering right = more RPM.
« Reply #11 on: March 13, 2014, 12:18:52 PM »
Well based on my limited experience digging into this bike, I have found you basically have to take the air box off to do....anything :grin:

Haha touché  :bigok:

Offline Squishy

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Re: Steering right = more RPM.
« Reply #12 on: March 15, 2014, 12:18:45 PM »
Okai, I spent all afternoon trying to fix the problem.
Tank off, airbox off...
Checked the nut on the carb as you mentioned, but it was tightened. Loosened it anyway to check but it didn't make a difference.

I was actually able to get it on video what happens when I steer left/right:
(MP4, 43MB):t
https://dl.dropboxusercontent.com/u/22072961/mf/gaskabel.mp4?dl=1
(I put it on the stand and sat on the seat so the front wheel was in the air so I could steer very quickly)

Anyway, I loosened the cable from the handlebar and checked whether it was really a throttle cable problem or something else.. but it's definitely the throttlecable because the throttle valve now stopped moving when steering.
However, when I tighten the cable with my fingers and then move the outer cable around i can actually feel it tightening and I see the throttle valve moving.
So I tried fixating the entire cable as much as possible so the outer cable hardly moves at all, but to no avail.

It really baffles me.. 
I now put the cable through another path more to the left and the throttle valve moves a lot less now.. but it's not entirely gone.
 :rant2:
« Last Edit: March 15, 2014, 05:02:01 PM by Squishy »

Offline andrewsw

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Re: Steering right = more RPM.
« Reply #13 on: March 16, 2014, 11:34:47 AM »
Maybe the cable is actually a little too short for the housing? Or adjusted too tightly? When the throttle control is closed all the way, there should be just a hair of slack in the cable, otherwise any motion at all will adjust butterflies and away it goes.

A

Offline Squishy

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Re: Steering right = more RPM.
« Reply #14 on: March 17, 2014, 10:13:45 AM »
Maybe the cable is actually a little too short for the housing? Or adjusted too tightly? When the throttle control is closed all the way, there should be just a hair of slack in the cable, otherwise any motion at all will adjust butterflies and away it goes.

A
Yes I'm thinking this is the problem. But I don't see how this is possible when I have (supposedly) the stock cable and fitted it as mentioned in the manual.
I cannot adjust it any looser - the adjuster is turned all the way and the bolt on the carb is also tightened for max slack on the inner cable.
This way, there's enough slack (but only just) - I can move the handlebars left/right without problems. Only when I'm already applying throttle it will rise.
 :S