Bandit Alley

MODEL SPECIFIC => SUZUKI BANDIT 250 & 400 => Topic started by: Squishy on March 09, 2014, 07:51:59 PM

Title: Steering right = more RPM.
Post by: Squishy 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.
Title: Re: Steering right = more RPM.
Post by: tomacGTi 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.
Title: Re: Steering right = more RPM.
Post by: Squishy 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.
Title: Re: Steering right = more RPM.
Post by: erict716 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.
Title: Re: Steering right = more RPM.
Post by: greg737 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.
Title: Re: Steering right = more RPM.
Post by: Squishy 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.
Title: Re: Steering right = more RPM.
Post by: erict716 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.
Title: Re: Steering right = more RPM.
Post by: Squishy 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.
Title: Re: Steering right = more RPM.
Post by: erict716 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.
Title: Re: Steering right = more RPM.
Post by: Squishy 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).
Title: Re: Steering right = more RPM.
Post by: erict716 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:
Title: Re: Steering right = more RPM.
Post by: Squishy 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:
Title: Re: Steering right = more RPM.
Post by: Squishy 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:
Title: Re: Steering right = more RPM.
Post by: andrewsw 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
Title: Re: Steering right = more RPM.
Post by: Squishy 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
Title: Re: Steering right = more RPM.
Post by: andrewsw on March 17, 2014, 10:57:03 AM
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.

Okay, then this is almost certainly just a cable routing problem. I've encountered this on my B4 in the past. Basically, through trial and error I've found a routing that works for me. From a position seated onthe bike, it runs immediately to the right and through the flexible wiring harness clip at the engine mount, then forward past the coil, through the clip mounted on the coil, out through the front between the fork leg and headstock, looping back behind the headlight to the grip. I have it pulled fairly tightly under the tank. It's important to have enough slack in the *housing* so that turning the frontend allows it to flex, but not pull. That's most likely what's happening, you've got too much cable under the tank, so that there's not enough slack up front. When I turn my front end, the cable is flexing back at the fork being forced to bend there because of all the crap jammed in behind the headlight. hope this helps.

A
Title: Re: Steering right = more RPM.
Post by: Squishy on March 17, 2014, 01:03:59 PM
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.

Okay, then this is almost certainly just a cable routing problem. I've encountered this on my B4 in the past. Basically, through trial and error I've found a routing that works for me. From a position seated onthe bike, it runs immediately to the right and through the flexible wiring harness clip at the engine mount, then forward past the coil, through the clip mounted on the coil, out through the front between the fork leg and headstock, looping back behind the headlight to the grip. I have it pulled fairly tightly under the tank. It's important to have enough slack in the *housing* so that turning the frontend allows it to flex, but not pull. That's most likely what's happening, you've got too much cable under the tank, so that there's not enough slack up front. When I turn my front end, the cable is flexing back at the fork being forced to bend there because of all the crap jammed in behind the headlight. hope this helps.

A
Well, that's exactly how my cable is routed... as mentioned in the manual.
However it doesn't really matter how I route it. I tried through the middle or to the left, or even through the air with the tank off (nothing touching the cable). No difference.

What happens if you hold it at 2000rpm with the throttle and then move left/right with the handlebars?
Title: Re: Steering right = more RPM.
Post by: andrewsw on March 17, 2014, 01:45:21 PM
I'll try it on my way home tonight. In the past I've noticed this problem, so I suspect it's not a problem for me now, I'm daily commuting and have been for two years straight, so I'm pretty sure mine is good ;)

Is the grip end of the cable properly secured? There should be a small metal plate that is secured by the screw that holds the throttle mechanism together. When the throttle mechanism is secured, it clamps the end of the cable to it as well.

The reason it appears when you're turning right is because it puts more bend into the cable housing and can cause it to cam out of the throttle assembly or otherwise stress it so that it pulls the cable. When turning to the left it generally alleviates some of the bend and reduces the stress on it. :shrug:

Having experienced this problem before, the best advice I have is... just keep messing with it until it stops. heh. not much help, I know.

A
Title: Re: Steering right = more RPM.
Post by: Squishy on March 17, 2014, 03:59:37 PM
You think a new cable will help?
Title: Re: Steering right = more RPM.
Post by: andrewsw on March 19, 2014, 09:38:19 AM
I can't see how a new cable will help if the one you have is truly stock. But, if all else fails, that's the next thing to try, perhaps.

A
Title: Re: Steering right = more RPM.
Post by: erict716 on March 19, 2014, 11:30:30 AM
Isn't there a little play at the top of the cable, that goes into the throttle on the handlebars? I thought there was an adjustment screw. You may be able to get some slack out of that.Also are your carbs fully seated in the boots? If they are not in the right location (or angle) it may cause the cable length be longer. Just trouble shooting off the cuff there.
Title: Re: Steering right = more RPM.
Post by: Squishy on March 19, 2014, 11:34:44 AM
Isn't there a little play at the top of the cable, that goes into the throttle on the handlebars? I thought there was an adjustment screw. You may be able to get some slack out of that.Also are your carbs fully seated in the boots? If they are not in the right location (or angle) it may cause the cable length be longer. Just trouble shooting off the cuff there.
Adjustmentscrew is turned all the way for maximum slack.
Carbs are seated properly :(
Title: Re: Steering right = more RPM.
Post by: Squishy on April 25, 2014, 06:03:37 PM
Can anyone verify/tell me whether this nut is positioned as on the picture or whether the nut goes under the mount on the carburetor?
(https://dl.dropboxusercontent.com/u/22072961/MF/1396599976_gaza-suzuki-58300-10d30.jpg)

Thanks
Title: Re: Steering right = more RPM.
Post by: andrewsw on April 25, 2014, 06:44:11 PM
the nut goes below the mount on the carbs. In fact, you'll see that there is a hexagonal recess to receive it. It's a royal pain in the ass to get it all together and if the nut isn't there, or is above the mount, that will almost certainly be the cause of your problem.

A
Title: Re: Steering right = more RPM.
Post by: Squishy on April 25, 2014, 07:00:33 PM
the nut goes below the mount on the carbs. In fact, you'll see that there is a hexagonal recess to receive it. It's a royal pain in the ass to get it all together and if the nut isn't there, or is above the mount, that will almost certainly be the cause of your problem.

A
Here's a picture I made a while back..
https://dl.dropboxusercontent.com/u/22072961/mf/2014-03-16%2017.35.14.jpg
Either it's beneath the mount or not there (don't remember)..however I don't see how the latter would cause my problem..

Sigh, I had hoped it had to be on above the mount so I had something new to try.. Today I went to the local dealer and the mechanic didn't understand it either..
He said there should be more slack when it's fully loosened and could only guess it wasn't the original cable...
I checked the cable and it says 10D30 which matches part of the OEM cable's code.
Title: Re: Steering right = more RPM.
Post by: andrewsw on April 25, 2014, 07:13:58 PM
Can't tell from the picture, because the nut gets recessed into the mounting lug and it not visible from above. If it's missing, then any flex of the cable housing has the possibility of mis-aligning or pulling the end of the housing out of the lug. If that happens, it could easily tweak the throttle, and it only takes a little smidge to make a difference.

A
Title: Re: Steering right = more RPM.
Post by: Squishy on April 25, 2014, 07:23:07 PM
Can't tell from the picture, because the nut gets recessed into the mounting lug and it not visible from above. If it's missing, then any flex of the cable housing has the possibility of mis-aligning or pulling the end of the housing out of the lug. If that happens, it could easily tweak the throttle, and it only takes a little smidge to make a difference.

A
You're saying the nut is fixed into the mount from beneath and then you screw the cable in from above?
If I understand correctly you won't be able to feel the nut under the mount and I'd have to remove the carbs to check?

Thanks.
Title: Re: Steering right = more RPM.
Post by: andrewsw on April 25, 2014, 09:15:48 PM
You're saying the nut is fixed into the mount from beneath and then you screw the cable in from above?

pretty much that is correct

If I understand correctly you won't be able to feel the nut under the mount and I'd have to remove the carbs to check?

If the nut is missing, you can pull the cable housing out of the lug without unscrewing it.

A
Title: Re: Steering right = more RPM.
Post by: Squishy on April 26, 2014, 05:32:42 AM
You're saying the nut is fixed into the mount from beneath and then you screw the cable in from above?

pretty much that is correct

If I understand correctly you won't be able to feel the nut under the mount and I'd have to remove the carbs to check?
If the nut is missing, you can pull the cable housing out of the lug without unscrewing it.

A
Ah..well in that case the nut must be there, because I can loosen and tighten the cable bolt.
I thought the mount itself had a screw thread...It's been a while since I actually removed the cable from the carb..usually I just let it on when removing the carbs.
Title: Re: Steering right = more RPM.
Post by: Volumetrik on November 10, 2016, 02:59:59 PM
I know this is a super old thread, but I am interested to know if you have solved the problem ?
Have you tried buying a new throttle cable ? They're like 17 bucks.

I have a smaller similar issue where the bike will rev to 4-5k when I turn the handle bars fully when parking the bike or doing u-turns. I am going to check the cable routing.

Title: Re: Steering right = more RPM.
Post by: Squishy on November 10, 2016, 03:21:10 PM
I know this is a super old thread, but I am interested to know if you have solved the problem ?
Have you tried buying a new throttle cable ? They're like 17 bucks.

I have a smaller similar issue where the bike will rev to 4-5k when I turn the handle bars fully when parking the bike or doing u-turns. I am going to check the cable routing.
Weirdly, I did not.
I even bought a brand spanking new, original bandit 400 throttle cable from my suzuki dealer. The problem is the same, no matter how I route the cable.
Even when I put the cable in mid-air (no tank), the problem is there. If i tighten the cable down all the way it's better, but still there.
Btw it only happens for me when I'm already applying throttle. If you get revs with closed throttle the clearance is not right
Title: Re: Steering right = more RPM.
Post by: Volumetrik on November 10, 2016, 03:28:10 PM
Thanks for the response ! It is definitely a weird issue...

Yeah I get the rise with closed throttle. I will buy a new cable anyways because my plastic adjuster is broken and I can't get the right clearance dialed-in.