Author Topic: carb balancing? (Read 16166 times)

mickvp · « **on:** 18 July 2013, 05:35:05 pm »

sorry for the most basic, stupid (?) question guys. but I see a lot of mention of balancing carbs on this site. This is great, and something I will do at some point. however, what are the symptoms of a carb out-of-balance? i.e. what will I look for to know when its time to actually do it?

As some of you will know, Ive not long passed my test, and only just got my fazer, so technically the carbs could need balanced now but as the bike is new to me, i may assume that the way it works now is normal, if that makes sense? it doesnt run like a bag of bolts in a washing machine or anything, but now and again the idle is oh-so-slightly lumpy? I assume this could be a symptom of the carbs being out of balance?

sorry

darrsi · « **Reply #1 on:** 18 July 2013, 05:55:59 pm »

Before i last had mine balanced the bike was a bit jerky at low speeds, but after 3000rpm it would be okay, which was horrible for me as i ride in traffic a lot.
The balancing sorted that out though.

mickvp · « **Reply #2 on:** 18 July 2013, 06:00:28 pm »

perhaps its worth me just getting hold of a carbtune and doing it for peace of mind then, dont suppose it will hurt any doing it now, and then ill know its right after that. so, herky at low speed then. I assume there is a multitude of things that could be down to carbs being out of balance.

Punkstig · « **Reply #3 on:** 18 July 2013, 06:11:35 pm »

It's such a simple job to do its well worth buying the carb tune (its also nice to have that sense of personal satisfaction doing a job instead of paying a mechanic!)
Biggest give away is the revs at idle, if everything is perfectly synced the needle will stay virtually static at whatever revs the idle is set at, if they're out of balance the needle will wobble and revs will fluctuate of their own accord, the worse the balancing the bigger the fluctuations.

mickvp · « **Reply #4 on:** 18 July 2013, 06:18:11 pm »

Quote from: Punkstig on 18 July 2013, 06:11:35 pm

It's such a simple job to do its well worth buying the carb tune (its also nice to have that sense of personal satisfaction doing a job instead of paying a mechanic!)
Biggest give away is the revs at idle, if everything is perfectly synced the needle will stay virtually static at whatever revs the idle is set at, if they're out of balance the needle will wobble and revs will fluctuate of their own accord, the worse the balancing the bigger the fluctuations.

hmm. you have more or less summed up what happens with mine. a bit wobbly at idle. looks like the credit card will need to brace itself for the hit for a carbtune

And yes, I dont mind doing the job myself, I'm an engineer to trade

elbrownos · « **Reply #5 on:** 18 July 2013, 06:41:39 pm »

I need to do this too, got the Carbtune so I just need to get around it.
People say you need a long screwdriver - how long and flat or philips?

otis · « **Reply #6 on:** 18 July 2013, 07:19:56 pm »

Quote from: elbrownos on 18 July 2013, 06:41:39 pm

I need to do this too, got the Carbtune so I just need to get around it.
People say you need a long screwdriver - how long and flat or philips?

Phillips screwdriver, #2 I believe. I use one that is about 300mm

Punkstig · « **Reply #7 on:** 18 July 2013, 08:49:24 pm »

I used to be quite anal about the fluctuations on my T'cat and was quite frequently attacking the carbtune, but on the T'cat it was ridiculously easy to do, just had to raise the tank (1 bolt) to get to what i needed to.
I've heard on the fazers you need to move the plate under the tank that holds the coils which is easy enough, just a couple more nuts and bolts!

darrsi · « **Reply #8 on:** 18 July 2013, 09:23:31 pm »

http://foc-u.co.uk/index.php/topic,91.0.html

darrsi · « **Reply #9 on:** 18 July 2013, 09:44:18 pm »

You lot chinwagging about carb balancing, made me bid for a CarbTune on Ebay.........and i just won it with my first bid

elbrownos · « **Reply #10 on:** 18 July 2013, 11:05:56 pm »

Is adjusting the TPS important before/after balancing the carbs?
I'd just do it, except I don't have the security Torx bit

darrsi · « **Reply #11 on:** 18 July 2013, 11:18:19 pm »

Quote from: elbrownos on 18 July 2013, 11:05:56 pm

Is adjusting the TPS important before/after balancing the carbs?
I'd just do it, except I don't have the security Torx bit

In the link i posted above i think he was just making sure the TPS wasn't in the wrong position before starting, it should be at 5000rpm anyway, so it doesn't hurt to check it beforehand.
If your TPS is all good then it'll already be on 5000rpm.

Then it says check it again after the carbs are balanced.

It's a tamper proof T25 torx driver that fits the TPS, the one with the hole in the middle of it.

mickvp · « **Reply #12 on:** 19 July 2013, 01:19:54 pm »

carbtune now ordered, so ill get this sorted in the next week or so hopefully. anyone got a link to where i can get a suitable T25 for the TPS, just in case i need it (might as well order one for the few quid it will be)?

darrsi · « **Reply #13 on:** 19 July 2013, 01:43:53 pm »

Quote from: mickvp on 19 July 2013, 01:19:54 pm

carbtune now ordered, so ill get this sorted in the next week or so hopefully. anyone got a link to where i can get a suitable T25 for the TPS, just in case i need it (might as well order one for the few quid it will be)?

http://www.ebay.co.uk/itm/Silverline-Turbo-Twist-Tamperproof-Security-Screwdriver-Torx-T25-x-100mm-250523-/380468262420?pt=UK_Hand_Tools_Equipment&hash=item5895acf614#ht_1715wt_1170

mickvp · « **Reply #14 on:** 19 July 2013, 02:03:27 pm »

oh, a hole like that in the end? thats ok then, my wera torx set has holes like that already - always wondered why they were there

Cheers buddy

Hedgetrimmer · « **Reply #15 on:** 19 July 2013, 02:15:05 pm »

I'm guessing that'll be the same size torx for the 1000's TPS?

darrsi · « **Reply #16 on:** 19 July 2013, 03:01:00 pm »

Quote from: nick crisp on 19 July 2013, 02:15:05 pm

I'm guessing that'll be the same size torx for the 1000's TPS?

Apparently not........ http://foc-u.co.uk/index.php?topic=3024.0

Hedgetrimmer · « **Reply #17 on:** 19 July 2013, 03:12:25 pm »

Ah, thanks for that

mickvp · « **Reply #18 on:** 20 July 2013, 03:02:54 pm »

carbtune has arrived - im going in!

mickvp · « **Reply #19 on:** 20 July 2013, 04:04:28 pm »

erm... should it be this bouncy? how are you supposed to balance this?!? :


www.youtube.com/watch?v=ee5pnOYkW3E

...Or have I a problem somewhere?

elbrownos · « **Reply #20 on:** 20 July 2013, 04:08:38 pm »

Did you put the restrictors in?
It's the piece of clear tube with a tiny bore. You need to cut it into 4 and put a piece in each of the 4 Carbtune hoses.

mickvp · « **Reply #21 on:** 20 July 2013, 04:11:40 pm »

Quote from: elbrownos on 20 July 2013, 04:08:38 pm

Did you put the restrictors in?
It's the piece of clear tube with a tiny bore. You need to cut it into 4 and put a piece in each of the 4 Carbtune hoses.

ah... that will be why then. perhaps reading the instructions WOULD have been a benefit

Cheers buddy

mickvp · « **Reply #22 on:** 20 July 2013, 07:09:57 pm »

yes. fitted those clear resistors, and there was still very slight bouncing, but it was much removed from that video.

Its worthy of note to those considering this that the Philips screwdriver is indeed a #2, and needs to be at least about 200mm, it also needs to have a fairly low profile shank, as I tried with a magnetic snap on one with variable heads, and that wouldnt fit down the gap!

I also tried it with a halfords pro screwdriver, which went down ok, but was so tight in the gaps that i couldnt get the angle required to get onto the screw correctly (which risks rounding it). in the end it was an el cheapo screwriver ive had for about 5-6 years which has a very narrow shank which turned out to be the perfect tool for the job, typical!

On the up-side, the bike seems much better now, it is revving much more responsively and smoothly all the way through the revs, the clutch action seems slightly smoother (that may be in the mind though?).

The idle is still very slightly lumpy, so I think I will change the plugs/oil filter/air filter/oil, and then balance the cars again, this should solve my issues I would have thought, I need to do it anyway as im not sure when it was last done.

Thanks everyone for their help, a good purchase is the carbtune, its a nice bit of kit

darrsi · « **Reply #23 on:** 20 July 2013, 07:24:17 pm »

Cheers for the heads up, i'm waiting for mine to arrive, and i also ordered a 300mm long #2 screwdriver so that should do nicely.

darrsi · « **Reply #24 on:** 26 July 2013, 04:17:41 pm »

Finally did my first carb balance today

In fairness i could have just left them alone when i turned the engine on, but #4 carb just needed a tweak so couldn't resist.

I should've read this post again first as my shiny new 300mm long #2 screwdriver that i ordered actually had a hexagon shank which didn't fit into the gap for 3 & 4 carb screw, so put it all back together and got a round version from Halfords and as mickvp says you can't quite get a good enough angle on the screw, so i ended up using a cheap old short flat bladed screwdriver that was laying about instead

I checked my TPS beforehand and for some reason it was at 0rpm which was a bit odd as i only set it last week, but i reset it again to 5000rpm, and checked again afterwards and it was still where it should be.

Quick question though, i understand that the levels on the Carbtune should be as close as possible, but are there limits that are classed as acceptable (or non acceptable), and if so what are the limits that would make the bike misbehave, just out of curiosity?