Loud idle after open road use - normal?

**jasonzc** · 22nd December 2009, 21:39

Hey guys,

So i finally got a bike couple of weeks ago, Suzuki VL250.
Great bike! decent power, easy to throw around corners.

One thing that i noticed though, the bike idles really loud and a little 'fast', after prolonged periods of motorway use. (i commute 40kms each way) Was just wondering if this was normal?

Other than that i dont think i have too much to worry about, though this is first bike so not sure what is 'normal' and what isnt..

**wbks** · 22nd December 2009, 22:16

Doesn't sound like anything to worry about. Probably just your bike warming up a bit more, assuming you don't use the choke on startup? I wouldn't really bother going out of your way to "fix" it unless it's revving excessively high or it really bugs you. If it's your first bike maybe you just aren't used to the idle speed of a bike? Congrats on getting a bike anyway.

**LBD** · 23rd December 2009, 01:24

Originally Posted by jasonzc

Hey guys,

So i finally got a bike couple of weeks ago, Suzuki VL250.
Great bike! decent power, easy to throw around corners.

One thing that i noticed though, the bike idles really loud and a little 'fast', after prolonged periods of motorway use. (i commute 40kms each way) Was just wondering if this was normal?

Other than that i dont think i have too much to worry about, though this is first bike so not sure what is 'normal' and what isnt..

Idle speed I don't know about, but noisy after an open road run could be a symptom of old or low grade oil....What happens is after a good run the oil is hot and viscosity will have dropped, older or low quality oil will drop viscosity more than new or better quality oil and as such will be much more noticable....

**stanleychung** · 23rd December 2009, 09:03

Hi jasonzc, recently having just sold my VL250 to a lovely family and upgraded. I also agree they are an excellent bit of kit. Well cared for your VL will be a rewarding experience. Cherish it when you have it.

As for the loud-er exhaust and fast-er idle i can say when i had mine it did that too. Mine had the carb re-jetted by the factory for better winter running and it behaved the same too. After a long-ish run it would sound a lot louder and idle a bit faster.

Didnt have any dramas, it wasnt excessive on mine. The bike just kept plugging along.

Although worth checking is the hoses around the airfilter to carb. I remember mine had one hose going from carb to the left (when sitting on bike) airfilter to a valve on the side of it. Make sure that is still securely connected because sometimes service people "forget" to reconnect it after reassembly. Might cause the bike to suck in more air than it expects. But on mine forgetting to connect that hose just meant my cold starts were harder.

Enjoy your ride.

**avgas** · 23rd December 2009, 09:25

might be worth dialling out the idle screw a fraction. I find it best to set idle with a warm running bike, if you set it when it is first started - when it warms up the mix sometimes gets a bit rich.

**AllanB** · 23rd December 2009, 09:29

What's louder - the exhaust note or the engine noise?

Exhaust will probably be nothing more than the slightly higher idle (more revs more noise) - the higher idle is probably due to the engine running hotter.

If it is engine noise - I agree re old oil.

**Slyer** · 23rd December 2009, 09:52

It sounds like the idle was adjusted to being perfect at cold rather than when warmed up.
As the engine gets warmer it runs at higher RPM than when cold, ideally the idle will be low when cold and then perfect when warm. You use the choke to increase the richness when cold so that it idles faster. Literally like choking a person, the choke limits the amount of air thus making the air/petrol mix richer. Running richer meaning it uses comparatively more petrol. Cars do this automatically but bikes with carbs are less hi-tech.

To fix this issue you are having, wait till the the engine is fully warmed up with the choke fully off and there should be an idle adjustment knob somewhere near the carbs. Turn this till it idles how you think it should be sounding and leave it like that. You will then find that once cold the engine will run a bit lower RPM than you would like, use the choke to compensate.

Hope this helps.

If you want to learn more, read up on this. Very well written:
http://www.carbibles.com/fuel_engine_bible.html

**jasonzc** · 23rd December 2009, 21:17

thanks guys for the excellent answers.

I think its a combanation of old oil and just engine heating up. My neighbour took a look 'listen' and recons its dandy and new oil will help too. So hopefully that will get taken care of for the 5000k service (nearly there).

Anyways ill be off this week to do some more riding.

Thanks for all the answers! glad it was no biggie~

Happy holiday season all!

**jasonzc** · 23rd December 2009, 21:26

Originally Posted by Slyer

To fix this issue you are having, wait till the the engine is fully warmed up with the choke fully off and there should be an idle adjustment knob somewhere near the carbs. Turn this till it idles how you think it should be sounding and leave it like that. You will then find that once cold the engine will run a bit lower RPM than you would like, use the choke to compensate.

Hope this helps.

If you want to learn more, read up on this. Very well written:
http://www.carbibles.com/fuel_engine_bible.html

Prob wont end up having to do this, but if someone had the same or a worse prob, this would certainly be good advice.

Great link by the way, finally get to 'see' how a rotary works.