CBR6F engine sounds lumpy?

[itsdave]

Not my words was with a mate last night he had a little look and fiddle with the bike as he has not seen it before. When i started it up he turned and said sounds a bit 'lumpy'. I honestly had not noticed but since then i have noticed it all the time.

Now is this down to it needing a very good service or is it something more serious?

Much thanks in advance

DAVE
____________________
Project cg125 current bike cbr600f sport white+ black watch out for me in central London.

[DrDonnyBrago]

[itsdave]

bike idles around 1k mark when warmed up. The bike does not sound massively smooth at higher revs. I have only had the bike about 6months and most of that was short trips im starting to go through things that need sorting but the lumpy engine noise is something i would like to get sorted first.

exhaust is fine

so ill have to have a look at the spark plugs and see if that brings any joy.

throttle bodies how do you sync or check they need syncing?

thanks for the responce.
____________________
Project cg125 current bike cbr600f sport white+ black watch out for me in central London.

[DrDonnyBrago]

[itsdave]

ok thank you.

the bike has around 28k on it at the moment but think that is mainly motorways as the tyres were rather badly squared when i got it.

and ok so ill have a look at the idle speend and then if that doesnt help ill look at doing the rest i might be back soon with a reply thank you again
____________________
Project cg125 current bike cbr600f sport white+ black watch out for me in central London.

[DrDonnyBrago]

[itsdave]

[0l0dom0l0]

The Fazer suffers from a lumpy idle too. Its perfectly normal on a carbed bike.

Fazer seems to be quite sensitive to after market exhausts. It ran really lumpy with the viper exhaust I had, even after a carb balance. I then changed the viper for the current exhaust and the thing sounds like an FI bike!!

Some bikes just do it regardless. Early R1's are an example.

If you want to 'cure' it the best thing to do is get some fuel system cleaner (redex) and run that through a tank of fuel to clean the carbs. Give it a service if you want to. After you've done that then balance the carbs.

The reason you do it last is because everything will have a slight effect on the balance.

I'm going to do the Fazer again soon as after running the fuel system cleaner through its now a little lumpy. I'll post up a how to. Also a before and after video so you can hear the difference.

It won't be causing any damage so don't worry to much.

Hope that helps.

I'm on my phone so I haven't gone into much detail and haven't read through all the previous posts so sorry if I have repeated anything!
____________________
CBT Passed: 30/08/2009, Theory Passed: 31/08/2010, Mod 1 Passed: 6/9/2010, Mod 2 Passed: 13/09/2010. Restriction ended 13/09/2012.

Bikes: 2007 Derbi GPR 50, 1998 Yamaha Fazer 600 (written off), 2002 Yamaha Fazer 600, 1994 CBR 600F, 2003 Triumph Daytona 600, Kawasaki ZX6R J1.....Current: 2006 Yamaha FZ6, 1998 Suzuki TL1000R and a Honda VFR 400 NC30.

[DrDonnyBrago]

[0l0dom0l0]

[The Tot]

A very good service is what it usually needs if it hasn't done so. 32k mile service WILL include a valve check, new plugs, air filter check and TB sync.

Before I had a chance to put it in for the 32k service, the bike was running like proper dog. I upped the idle to about 1.5k and had to furiously blip the throttle in town because it would refuse to hold at 1.2k. The moment I pull the clutch in, the revs would drop too low and die. The engine would hunt between 1.2 - 1.6k at startup.

I had my throttle bodies synched at 30k when I changed the clutch and it did the job. It takes about an hour for a garage to do, but I'd rather put it in for them to do because it's a dog to get to the adjuster screws on my fireblade without the correct bodged tools which a garage will undoutbedly have.

There wasn't much difference in feel after the 32k mile service either. The garage double checked that the synchronisation of the throttle bodies however just to get it tweaked. It now sits happily at 1.1-1.2k after startup.

Mind you 1st gen honda FI are known for being utter dogs! Even with a stock can, a PCIII sorts out the fuelling slightly to make it less lurchy in town.
____________________
The Tot 2019 Z1000SX - 2007 R1
Never argue with autism