View Full Version : Carb balancers and air boxes
Got my hands on a set of carb balancers as i'm doing a rejet this weekend, so in anticipation i deceided to do a dry run this evening.
All the tubes were connected already i have a scottoiler attached so i used the T junction for the back carb and the 1st dial, and the front carbs nipple already had a closed off pipe which i joined to the 2nd dial.
I warmed up the bike and connected the gagues up started her and the needles fluttered away, and continued to do so, and still continued to do so, infact they were both pretty much in sync but the issue was i coudlnt get an exact reading at all, they were moving so much and so fast it was terribly hard to tell where they were resting / stopping.
I adjusted the carb dials so the needled didnt move as much however the needles were still jumping back and foth on both side way to much to dertermine if it was close to a good sync.
At the moment i know the bike is running well, and i assume if any thing they are only a little out of sync.
My question is how steady should those needles get ?
My second issue was getting the airbox back on, possibly the most fustrating thing ever, i could apply pressure on each end and they would sink, but the catches would simply not take hold, should i use some wd40 around the lip to help this ? or perhaps shoudl i remove the bottom attachments and simply attempt to bolt those on to the carbs with the air box attached ?
any idea's ?
insert a 'restrictor' in the lines.. basically a narrower hose inside the main hose, connect the restricted end to as near the carbs as you can.. 5cm then insert restrictor then attach rest of main hose..
or just 'pinch/bend' the hoses when you are doing readings. (fish tank air hose clamps work well)
either of those methods should reduce the 'fluttering' of the needles.
Oh god damn,, i just realised, the gagues came with T connectors and little screw's on the top, clearly these are the damn restrictors.
*feels like a fool*
the screws on the gauges are for calibrating the gauges (you have calibrated them?)... the little connectors with a valve on top are indeed the restrictors...
The needles are both starting at the same position on the gauge's
The needles are both starting at the same position on the gauge's
Just run each needle against the same carb one at a time and adjust so they all read the same under a vaccuum.
Thats a handy tip alright, saves worrying about unbalanced gauges.
Now any tip's on the air box
Now any tip's on the air box
Not entirely sure what you mean with the airbox but sounds like it might just be the rubber boots that wont stay connected, that right?
Getting them on can be a problem if they are older and have gone hard, best solution is to replace them with fresh ones. But if its not sitting properly maybe they arent fully positioned. Is this a curvy SV?
They do need some wiggling, I normally take the air filter out and check that all the lips are on right. Else go round and give them a little assistance.
Sir Trev
10-07-09, 11:36 AM
I never bother removing the airbox when I check mine. My (possibly fallible) logic says test the balanaces with the bike set up for normal use, and when I ride it the airbox is always attached.
Can anyone shed light on why you would do it with the airbox removed??
They do need some wiggling, I normally take the air filter out and check that all the lips are on right. Else go round and give them a little assistance.
Good idea grinch, weird thing is i just lashed on the gagues there a few mins ago, she was a little out, all fixed now, and the air box popped back on relatively easy.
odd how things go i guess
The last time I did it, I balanced the carbs with the airbox off so I could easily get to the adjuster screw and then tested it again with the airbox back on.
Good idea grinch, weird thing is i just lashed on the gagues there a few mins ago, she was a little out, all fixed now, and the air box popped back on relatively easy.
odd how things go i guess
Sometimes you get lucky, most times its a bit of trouble.
johnnyrod
10-07-09, 01:26 PM
The fluttering has two possible causes - you have crap gauges (if they have restrictor clamps in line with the hoses then this is probably the case, like these):
http://www.busters-accessories.co.uk/productInfo.aspx?catRef=EVG2&kw=vacuum
or it's runnning lean. If it' is running lean, you need to upjet of course but if you take the appendix thing off the left side of the airbox and plug all the holes, you can get to the balance adjuster while the airbox is attached.
The fluttering has two possible causes - you have crap gauges (if they have restrictor clamps in line with the hoses then this is probably the case, like these):
http://www.busters-accessories.co.uk/productInfo.aspx?catRef=EVG2&kw=vacuum
or it's runnning lean. If it' is running lean, you need to upjet of course but if you take the appendix thing off the left side of the airbox and plug all the holes, you can get to the balance adjuster while the airbox is attached.
Ya those are the balancers i have, they worked pretty ok when i adujusted the T connector, she's running a little rich on top end, but she's getting rejetted on sunday, hense the dry run with the balancers today
MattCollins
10-07-09, 03:41 PM
Don't know why you lot persist in fa*t ar*ing around with gauges...
First hit with google:
http://www.obairlann.net/reaper/motorcycle/manometer.html
Don't know why you lot persist in fa*t ar*ing around with gauges...
First hit with google:
http://www.obairlann.net/reaper/motorcycle/manometer.html
great for having in the workshop. but who wants to cart an 8 foot board around with them.. suppose you could cut it into sections and hinge it. but its not very bling :smt112
carbtune every time for me...
Might splash the cash and buy a carbtune in a while, new tyre soon tho, as new front end is going on nxt week
Old Git
10-07-09, 08:01 PM
Don't know why you lot persist in fa*t ar*ing around with gauges...
First hit with google:
http://www.obairlann.net/reaper/motorcycle/manometer.html
Im wiv u, made one similar only 1m tall, filled with oil, not used yet but should work fine.
Im wiv u, made one similar only 1m tall, filled with oil, not used yet but should work fine.
dont think oil is good.. it tends to stick to the tube and you cant get a reading correctly, its also to slow..
water with dye in it..
you'll be grinding iron bars next to make your own screwdrivers next :rolleyes:
you'll be grinding iron bars next to make your own screwdrivers next :rolleyes:
There's an idea !!!
Clutch out of her to night, so far so good, installing the K5 shift star in the morning, once i find a set of circlips :( there's ways something to stop ye.
Oil drained, coolant drained ..
There's an idea !!!
Clutch out of her to night, so far so good, installing the K5 shift star in the morning, once i find a set of circlips :( there's ways something to stop ye.
Oil drained, coolant drained ..
is this the Factory Pro detent star you're fitting? Would be interested to know how much improvement this brings. Has to be worth a few milliseconds per gear change :-)
No No !!! I have a curvey so it's a K5 star im fitting, sorry should have clarified that
MattCollins
11-07-09, 03:10 AM
great for having in the workshop. but who wants to cart an 8 foot board around with them.. suppose you could cut it into sections and hinge it. but its not very bling :smt112
carbtune every time for me...
Who carts carb balancing junk around with them?
A namometer is nothing more than two columns of water which are always perfectly calibrated. We don't need absolute values, just an eyeball on the difference in height of those columns. No backing board is required. Just hang it in a tree, verandah post, wherever.
Cheers :)
yes it is very cheep and verrrry good way of balancing carbs, but i like tools its just me...
and i do carry them about with me when mates need it done.
MattCollins
11-07-09, 03:42 AM
:) As I said, it doesn't need the backing board. Roll it up and stick it in a tank/tail bag.
I like quality tools too, but vacuum gauges have always fallen into the junk category for me... Bling designed to make the wallet lighter.
If you want quality bling that works properly, mercury balancing set is the way to go.
Cheers :)
the carbtune ones are pretty good to be honest.. yes they flutter but not that bad (unless you get the tubes the wrong way round) and for the price of them its a good investment, they are as accurate as you need. balance 2 sets of carbs and thats them paid for.
have you ever tried doing 4 carbs by adding T and elbow pieces?
MattCollins
11-07-09, 06:32 PM
I have done 4 carbs with a namometer if that is what you mean. Bit of fiddling with one, much easier with three.
Svsmokey
12-07-09, 05:15 PM
Yeah , airbox boots are a pain . I use a piece of stout string wrapped around the circumference of each of the boot grooves . Carefully feed the 4 string ends thru the holes . Set the air box in place, hold it down and pull on the string ends. The string will roll the boot lips in place. Advise lubing the boot lips AND the string. Hope this helps
They do need some wiggling, I normally take the air filter out and check that all the lips are on right. Else go round and give them a little assistance.
Tested this theory today, struck in 155 mains and shimmed the needles, new bmc rs filter, and the airbox/carbs went on easy as pie :D
johnnyrod
13-07-09, 12:07 PM
Some people swear by their home-made manometers but I bought my gauges about 15 years ago (Davida) and they still work perfectly, and are very easy to use. I've got a pair which as Matt knows is siilar to manometer in that you can only connect 2 vacuums, but it doesn't matter as you can balance any number of cylinders with a bit of swapping around. My only criticism is that they sell crap ones that make people think they're all as bad as that.
Tested this theory today, struck in 155 mains and shimmed the needles, new bmc rs filter, and the airbox/carbs went on easy as pie :D
Ah, after 70,000 miles and numerous removals they can be a bit touchy now.
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