Hi all.

tried the search option but brought up anything and everything.

So, I've got my first CBR600. My first 4 cylinder bike actually.

19,000. Plugs are good, oil is good and I've cleaned the air filter. starts fine on the choke, get's to temp no problem, and I've had 140 out of it so far. It's a creaming beast!

But the idle is all over the place.

I know enough about bikes to get me in trouble.

rough riding round town, but at 5-6000rpm it's a monster.

lights works, and like I say starts no prob off the button so assuming battery OK? Maybe it's the spark leads?

what should be my starting point?

Oh, and I've done over 400 miles in the last 2 weeks and only used Super unleaded.

ART Pro Race Exhaust on it too.

 

Hi, CBAR , I would say first thing is to get a workshop manual, have a peruse of it , get to grips with your bike, and anything else you need to know just shout up, have a look on this site for workshop manual ,if you cant find one I'll PM you with one

 

Possible that carbs need attention.
Pilot jets, poorly seated carbs,perished rubbers or mixture screw is my guess. Pilots are a carbs out job, however, you might be lucky with your mixture screw. It requires delicate tweaks.
What condition was the air filter in ( you did put it back together nice ?) If the filter was in poor condition debris can get through to carbs and block a jet(s).
Those lovely screws on the carb bowls need a decent correct size driver to even attempt to undo. Round them and you'll be pinching your fingers with grips. Not fun.
Not sure of the history of the poor running so if the exhaust upgrade wasn't combined with carb setting then jet sizes might have required changing or needle adjustments made.

 

Thanks guys.

I actually have it up for sale, but the last thing I need is to have it in bits.

I'm hoping for a more systematic, typical, most likely easily fixed solution.

For instance, I've seen on a few forums where replies have been 'Plug Leads' or rectifier.

CaBaret thanks for the offer of the manual. I'm no stranger to taking a bike apart but with this being my 1st 4 cylinder i'll admit it has me intimidated.

wes 17, that's the last thing I wanted to hear haha. Basically anything and everything.

With the fact that it runs amazingly well at higher revs, i'm hoping this points to something else easily diagnosed.

However, something just occurred to me. Exhaust popping when I let off the throttle. Fuel being dumped into exhaust??? So one of the carbs is out? Maybe vacuum gauges would be a 1st thing to use?

 

OR one of the plugs is bad OR battery not great OR coil??? I'm now unsure of the timing etc. and cycle of sparks etc.

 

Seems the popping is normal. It's not backfiring at all. checked the plugs again and they're perfect looking. However, only evidence of a service was at 13,000 back in 2009. Now has just over 19,000

I did clean the main Air intake filter using Brake cleaner, and removed all the flies etc.

Are all the smaller air filter for Float chambers etc Life Time filters?

 

Popping isn't normal. That with the fact that you have a rough idle makes it sound like you are running lean.

 

Jeeeeez. took the Direct Air intake box off to check the filter again and it's covered in Dust/Sand!!!!

So no doubt all that crap has ended up in the carbs

However, the idle was a problem before i took this out the first time, that's why i checked it. I should have oiled the filter too, so I've made it worse likely.