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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

High idle speed on honda xr125

I recently bought a xr and after having a tiny bit of trouble getting the bike to tick over as it was freezing outside and the bike hasn't been in regular use for a while but eventually after getting around that problem the bike started ticking over very fast almost sounding as if it the throttle was open and also when given more throttle it sounded slightly strained, would this be sorted out by just lowering the idle speed or would it be a problem with the throttle not closing properly?


Thanks for the help.

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  • Posted 3 years ago (28 October 2012 12:58)

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jaffa90

Joined:

Mar 09

Posts: 9034

jaffa90 says:

idle

If the bike has not been used for a bit the pilot jet could be partly blocked and your screwing in the idle screw too much.

It`s  possible that you have unwanted air going in inbetween the carb and engine.

It`s possible that the throttle cable has no play when off.

It`s possible the choke/starter jet is not shutting off.  

It`s possible that you have been turning the air mixture screw.:shock:

[This Reply has been modified by the Author]

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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

Screws

I haven't touched any screws yet but because i'm being very cautious dealing with things that I have no experience with however i'm 90% sure when i have a little play with the idle screw i'll be moving the right one i've been looking in the hand book and i'm pretty sure i've found it (fingers crossed lol) howeverthe thing with the throttle could definitely be a problem because as I said it sounds like the throttle is almost permanently on and the bike is revving really hard, what would you suggest is most likely?

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jaffa90

Joined:

Mar 09

Posts: 9034

jaffa90 says:

throttle

The carb has a slide/piston what goes up and down inside a cylinder/bore,that`s the round section at the top.This slide goes up the bore when you turn the throttle/twistgrip and goes down under spring pressure to the idle screw when you release the throttle.

You may have a binding throttle cable or slide or a weak return spring preventing the slide hitting the idle screw.

Also as my first post.

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ricklincs45

Joined:

Aug 05

Posts: 9

ricklincs45 says:

Adjustments

A couple of simple things to check.  As other poster has mentioned, you may not have any free play in the throttle cable, this will cause the throttle to be partially open instead of fully closed.  Take hold of the twistgrip with your index finger and thumb; you should be able to rotate the throttle slightly without feeling any resistance whatsoever - this is cable free play.  If you CAN feel resistance, you need to put free play into the cable.


Regarding the tickover screw, this is the screw that is exactly in the middle of the carb' body.  You can adjust this and you won't mess anything up.  If the bike speed up or slows down too much, simply turn the screw back to where it was.

Try those two things and then post back if it doesn't sort the problem.

Rick

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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

Solutions

Thanks for the helpful suggestions I will try them in a couple of hours and let you know how I get on, if I find there is no free play in the throttle is that an easy fix even for somebody with no experience? 

[This Reply has been modified by the Author]

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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

Idle

Well I gave the idle screw a full rotation anti clockwise and it sounds perfect now, ticks over exactly how I would expect however it already struggled to start ticking over from cold as it was so i'm guessing the lower idle speed will make that problem even worse which is a bit of a worry but i'll see what it's like when I have a look at it tomorrow. Also made sure the throttle had some play and the handbook said 2-6mm so it's definitely somewhere around that now, thanks for the help!

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ricklincs45

Joined:

Aug 05

Posts: 9

ricklincs45 says:

Tuesday

Glad to hear you're nearly sorted with her :smile


Btw; don't expect the bike to tick over properly on a cold engine, it won't happen.  You'll need to get her moving and generate some warmth into her before she'll tick over nicely.

All the best, Rick

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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

Cold

Oh is that just simply not going to happen regardless of idle speed/choke?


What would your best advice be for me looking to get the bike in the best shape asap? Would it just be choke fully on, start the engine with 1/4 throttle, immediately switch to half choke and keep gently revving the engine for a while then turn the choke completely off after about 10 seconds or something?

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Dabbsy

Joined:

Aug 02

Posts: 500

Dabbsy says:

Choke

Each bike is individual as is each day in terms of temperature and humidity. You want to get the bike running well enough that it will pull away without bogging down. Get yourself rolling and get a feel for how it is pulling and you will find you can get the choke off fairly quickly once the motor starts to do some work.

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Fizzeetoast

Joined:

Jul 12

Posts: 51

Fizzeetoast says:

Start from cold

I actually had a little try today and it was perfect absolutely no problems what so ever so i'm really happy about that as I was a tiny bit worried. One really dumb question though if anyone has got the time to answer (rather than me make a new post for something so silly) I wanted to move the shifter down a little bit as it feels a little bit high for my foot at the moment, is that as simple as it looks or is there more to it? There appears to be a bolt which I can undo and then just change the position of it?

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