Acceleration Problems

[Steve1rc]

I bought my Fazer in November, its my first bike, so I'm learning as I go!

I've found though, that as I go to accelerate from about 5000/6000 revs that it initially accelerates fast, but then seems to lose power. It makes a grumbling sort of noise, and vibrates, and eventually (sometimes) it accelerates again. I'm not snapping round the throttle, I'm turning it slowly, but it has proved to be awkward on several overtakes now!


It doesn't always happen either, it always seems to be when it's more inconvenient.


People have suggested it's the carbs flooding, or the tuning of them. I was wondering if anyone has any ideas what it could be? I'm recovering from a knee injury so can't ride, so now is the perfect time to try and sort all the problems out and keep me sane!


Thanks for any help


Steve

[Dead Eye]

Based on those symptoms it is more than likely carb / fuel supply issue. Several other people have similar issues to varying degrees of severity. The worst case so far being red98's 35 page thread that is still hanging around on this forum :P

I'm sure someone with a little more experience and knowledge with the carbs will be along shortly

[Steve1rc]

Thanks for the reply, hopefully mine isn't that troublesome! It doesn't happen too often, it's just very noticeable when it does; It still accelerates, it just seems to lose most of it's power. Usually however it still accelerates fast enough to have to hold on tight!

I've found a really detailed carb tuning guide in the articles section of this forum (http://foc-u.co.uk/index.php/topic,91.msg340.html#msg340) So if I can get hold of a carbtuner I may try this, if it could help.

[Ruby Racing]

I've found a really detailed carb tuning guide in the articles section of this forum (http://foc-u.co.uk/index.php/topic,91.msg340.html#msg340) So if I can get hold of a carbtuner I may try this, if it could help.

Balancing your carbs certainly wont do any harm and hopefully will cure the problem. Let us know how you get on.

[packie]

Before you go deep into the carbs, you might want to take it a stage before that and check that your fuel pump is pumping juice properly into the carbs to begin with. See the Fuel Pump thread thats active at the moment on how to do this.


Also check that your fuel filter isn't blocked. Just to eliminate another thing, check that your back brake isn't siezing a bit. I had a problem on acceleration and it was a slightly sticking back brake.

[darrsi]

Balance carbs.....

[Exupnut]

Sell the 600 and buy a blue thou. then u will have NO acceleration problems.

[red98]

hi steve 1rc...........do you have any history with the bike ?....if not start with the easy things,service items first,plugs,air filter etc
....saying that it does sound like carbs to me so a balance and clean would be good....i see your in fleet parhaps another foccer close by could lend you some gauges......do you do all you own maintence ?

[Steve1rc]

hi steve 1rc...........do you have any history with the bike ?....if not start with the easy things,service items first,plugs,air filter etc
....saying that it does sound like carbs to me so a balance and clean would be good....i see your in fleet parhaps another foccer close by could lend you some gauges......do you do all you own maintence ?

It had a service recently (When I bought it in November) But I could always just look over the main parts again, I have nothing better to do!

I'm intending on doing all the maintenance; I've only recently started riding, but I like maintaining my cars myself, and would like to do the bike too.

[reillypadraig]

sounds like you have a few issues allright. i wont give you heaps of advice because im still stuck on my carbs, i had some acceleration problems that i didnt have before, the slides were sticking, might worth a look if ur carbs are off, u can get to them even without you carbs off, just take off ur ignition coil and fuel pump assembly and you can just unscrew the top bolts and remove the diaphragm and a bit of silicone spray on the slides and back in with them, some dirt can get stuck in them and cause a little hesitation in opening


  no harm having a look, if that doesnt cure it then you may have to take of the carbs, just one simple thing you could do before removing them

[Fazerider]

It's unlikely to be the carbs out of balance, if they were they'd be making that felt a lot further down the rev range... rough tickover and jerky throttle response as you pull away from a standstill are the signs of that. Once the butterflies are open beyond 20º a half degree difference between them doesn't amount to much. I'd check the TPS is correctly adjusted though and, if you've a multimeter, have a look to see the voltage changes smoothly as you open and close the throttle.
As Red says, it's well worth checking a few other things before pulling the carbs out for a clean.
Take the plugs out, hopefully they were new at the last service, but have a look at the colour to see if they give a clue as to whether one or more cylinders is getting too much or too little fuel.
The original plug caps tend to break down electrically once they reach a certain age and give various running problems, lots of owners replace them with straight NGK ones.
Again the air filter might well have been changed at the last service, but check it's clean and seated OK. Also check the air intake itself is clear and nothing loose can flap about to interfere with the air flow.
If all that reveals nothing untoward then, as Padraig says, debris in the carbs or sticking slides is likely to be the problem.

[packie]

It's unlikely to be the carbs out of balance, if they were they'd be making that felt a lot further down the rev range... rough tickover and jerky throttle response as you pull away from a standstill are the signs of that. Once the butterflies are open beyond 20º a half degree difference between them doesn't amount to much. I'd check the TPS is correctly adjusted though and, if you've a multimeter, have a look to see the voltage changes smoothly as you open and close the throttle.

Ditto that. My carbs were well drunk on my bike and she accelerated no problem and smoothly from 2,000 rpm to the redline every time. I did them to sort the rough idle and to quiten the motor on tick over. Sounds to me either not enuff spark (plugs), air (filter) or fuel (pump/filter/carb blockages). So i'd try in that order too leaving the carbs till last.

[Steve1rc]

It's unlikely to be the carbs out of balance, if they were they'd be making that felt a lot further down the rev range... rough tickover and jerky throttle response as you pull away from a standstill are the signs of that. Once the butterflies are open beyond 20º a half degree difference between them doesn't amount to much. I'd check the TPS is correctly adjusted though and, if you've a multimeter, have a look to see the voltage changes smoothly as you open and close the throttle.
As Red says, it's well worth checking a few other things before pulling the carbs out for a clean.
Take the plugs out, hopefully they were new at the last service, but have a look at the colour to see if they give a clue as to whether one or more cylinders is getting too much or too little fuel.
The original plug caps tend to break down electrically once they reach a certain age and give various running problems, lots of owners replace them with straight NGK ones.
Again the air filter might well have been changed at the last service, but check it's clean and seated OK. Also check the air intake itself is clear and nothing loose can flap about to interfere with the air flow.
If all that reveals nothing untoward then, as Padraig says, debris in the carbs or sticking slides is likely to be the problem.

Brilliant, cheers for that, and thanks everyone!

The sun's out, so I'll have a bit of a play with the bike today, going through everything that's been said, tools permitting! Hopefully I'll be able to find out whatever this is!

[darrsi]

It's unlikely to be the carbs out of balance, if they were they'd be making that felt a lot further down the rev range... rough tickover and jerky throttle response as you pull away from a standstill are the signs of that. Once the butterflies are open beyond 20º a half degree difference between them doesn't amount to much. I'd check the TPS is correctly adjusted though and, if you've a multimeter, have a look to see the voltage changes smoothly as you open and close the throttle.

Ditto that. My carbs were well drunk on my bike and she accelerated no problem and smoothly from 2,000 rpm to the redline every time. I did them to sort the rough idle and to quiten the motor on tick over. Sounds to me either not enuff spark (plugs), air (filter) or fuel (pump/filter/carb blockages). So i'd try in that order too leaving the carbs till last.

You must have an alcoholic bike then, 'cos when the carbs are out of balance the bike will run like crap, as if it's got a sore throat!!!