I do most of my own simple servicing ie oil change, brake pads, fluid changes etc but have never tried balancing the carbs. Can anyone advise me a) what I need to do the job. b) How do you do it c) Is it worth me tackling it or should I give the job to the proffesionals to do
Thanks
Carb balancing
To balance the carbs you will need some vacuum gauges and then you need to be able to connect them via hoses to each intake.
I have a bank of 4 vacuum gauges (dial type) that came as a set, fixed to a backing plate. You only need to use 2 of them but having 4 allows me to swap to the other gauges to cross-check, ruling out (or identifying) gauge error.
For the intake connections, there is already a vacuum hose coming from the rear intake. It goes to the fuel tap to ensure that the fuel tap only passes fuel when the engine is turning over, creating vacuum. I cut this hose about halfway along and inserted a 'T' piece, which allows you to attach another piece of hose from this to the gauge. It's easier to do this with the front of the tank raised - just remove the 2 small screws at the front of the tank and prop it up with a piece of wood. You obviously need to go down to your Auto Stores and purchase some vacuum hose and 'T' piece. I also purchased a straight through connector, to rejoin the original hose, after completing the balancing and removing the 'T' piece.
For the front cylinder, unless someone has already done it, you need to remove a blanking screw (silver allen head jobby) and fit a vacuum take-off adapter. I purchased an adapter from my Honda dealer. Getting the blanking screw out is a bit fiddly, as is getting the new adapter in, unless you have very small hands. Don't overtighten the adapter, especially if it is brass. Once the adapter is in place, connect another piece of hose from this to the other gauge and you're ready to go.
For balancing the carbs, the engine should be at running temperature and everything else set up correctly, eg. carb mixture settings, valve clearances etc. You are also supposed to disconnect the PAIR system but I don't think it makes any difference.
I start the engine and watch the gauges while it is warming up. When warmed up, if necessary adjust the screw on the link between the 2 carbs - on the left hand side - to get the readings as close as possible. It doesn't really matter what the reading is, as long as they are equal. Snap the throttle open a few times and re-check and check again on fast idle.
Long winded as this is, it is only a brief guide. I recommend you get a Haynes manual, which has helpful pictures and if possible get some first hand guidance from someone who knows a bit about this sort of thing. Once the carbs are correctly balanced, you don't need to check them again very often. So, if you don't already have gauges etc. it might be worth paying a reputable service centre (if you can find such a thing) to do the job, especially if you are not that mechanically inclined.
I have a bank of 4 vacuum gauges (dial type) that came as a set, fixed to a backing plate. You only need to use 2 of them but having 4 allows me to swap to the other gauges to cross-check, ruling out (or identifying) gauge error.
For the intake connections, there is already a vacuum hose coming from the rear intake. It goes to the fuel tap to ensure that the fuel tap only passes fuel when the engine is turning over, creating vacuum. I cut this hose about halfway along and inserted a 'T' piece, which allows you to attach another piece of hose from this to the gauge. It's easier to do this with the front of the tank raised - just remove the 2 small screws at the front of the tank and prop it up with a piece of wood. You obviously need to go down to your Auto Stores and purchase some vacuum hose and 'T' piece. I also purchased a straight through connector, to rejoin the original hose, after completing the balancing and removing the 'T' piece.
For the front cylinder, unless someone has already done it, you need to remove a blanking screw (silver allen head jobby) and fit a vacuum take-off adapter. I purchased an adapter from my Honda dealer. Getting the blanking screw out is a bit fiddly, as is getting the new adapter in, unless you have very small hands. Don't overtighten the adapter, especially if it is brass. Once the adapter is in place, connect another piece of hose from this to the other gauge and you're ready to go.
For balancing the carbs, the engine should be at running temperature and everything else set up correctly, eg. carb mixture settings, valve clearances etc. You are also supposed to disconnect the PAIR system but I don't think it makes any difference.
I start the engine and watch the gauges while it is warming up. When warmed up, if necessary adjust the screw on the link between the 2 carbs - on the left hand side - to get the readings as close as possible. It doesn't really matter what the reading is, as long as they are equal. Snap the throttle open a few times and re-check and check again on fast idle.
Long winded as this is, it is only a brief guide. I recommend you get a Haynes manual, which has helpful pictures and if possible get some first hand guidance from someone who knows a bit about this sort of thing. Once the carbs are correctly balanced, you don't need to check them again very often. So, if you don't already have gauges etc. it might be worth paying a reputable service centre (if you can find such a thing) to do the job, especially if you are not that mechanically inclined.
Regards, Squirrel.
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blackstorm
- Posts: 133
- Joined: Sun Nov 10, 2002 11:21 am
- Location: Oxfordshire
Here's a good link for do it yourself VTR carb balancing:
http://webpages.charter.net/gnemish/index.html
Click on "Performance" to go to the tech pages.
Michael
http://webpages.charter.net/gnemish/index.html
Click on "Performance" to go to the tech pages.
Michael
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blackstorm
- Posts: 133
- Joined: Sun Nov 10, 2002 11:21 am
- Location: Oxfordshire