Throttle balance done

[Tigertriple]

I know that a lot of people are a bit unsure about removing the fuel tank on the Tiger. I have now done tis several times and can almost do it with my eyes closed. My reason for mentioning this is because it's a easy job once you have done it for the first time and wil save you a lot of cash on jobs you can do yourself rather than pay dealer prices. Anyways,

I have recently bought a Morgan Carbtune after reading several posts on the subject of throttle balancing. I had a go at doing this job last week and found it to be very simple to do. I replaced the vacuum hoses at the same time as the originals had been butchered by the last owner who had fitted a Scotoiler and made a complete arse of removing it.

It's difficult to take a photo of the carbtune as the rods are moving, however the balance has worked a treat and the tickover and throttle response is much better. I also fitted a new fuel filter while I had the tank off.


Bixxer Bob suggested in a previous post that I should use T pieces to allow the balance to be done with the stepper motor left in place. I ordered up the bits before I removed the tank, but noticed that it is not possible to acces the no 2 balance screw with the stepper motor in place. Thank anyway Bob as your suggestion made sense at the time.

I made up a cruise control out of a latex glove which I used to jam the throttle open at 1200rpm while setting the balance.



The original vacuum hoses were in a state so I replaced them with 6mm vacuum from a  auto suppliers.





While the tank was off I gave the K&N a good clean and re oiled it. I also gave the airbox a wash out as it was a bit grotty. Oveall a good learning experience and the bike is running a lot smoother.  :D

Yes, I did remember to remove the paper towel from the throttle inlets  

[Danny955i]

Looks great! I just put new vacuum lines on mine as well... how did you manage to run the bike with the tank off? Or did you simply route the lines under the tank, and re-install everything on-top with the tank propped up somehow?

I need to get one of those balance tools.

[Tigertriple]

Looks great! I just put new vacuum lines on mine as well... how did you manage to run the bike with the tank off? Or did you simply route the lines under the tank, and re-install everything on-top with the tank propped up somehow?

I need to get one of those balance tools.

I should have taken a pic of the tank which was set up on a old table beside the bike. It was just at the right height to connect the fuel line and pump connection.

If you buy a carbtune I would recommend buying it with a case as it will keep it from getting damaged. Here is the link for the company I bought mine from. Also they deliver quickly.

http://www.carbtune.co.uk/carbdtls.html (http://www.carbtune.co.uk/carbdtls.html)

[Bixxer Bob]

....Bixxer Bob suggested in a previous post that I should use T pieces to allow the balance to be done with the stepper motor left in place. I ordered up the bits before I removed the tank, but noticed that it is not possible to acces the no 2 balance screw with the stepper motor in place. Thank anyway Bob as your suggestion made sense at the time...

 :oops: Forgot to mention the need for a right angle screwdriver... :D

[Bixxer Bob]

....Bixxer Bob suggested in a previous post that I should use T pieces to allow the balance to be done with the stepper motor left in place. I ordered up the bits before I removed the tank, but noticed that it is not possible to acces the no 2 balance screw with the stepper motor in place. Thank anyway Bob as your suggestion made sense at the time...

 :oops: Forgot to mention the need for a right angle screwdriver... :D

[Tigertriple]

....Bixxer Bob suggested in a previous post that I should use T pieces to allow the balance to be done with the stepper motor left in place. I ordered up the bits before I removed the tank, but noticed that it is not possible to acces the no 2 balance screw with the stepper motor in place. Thank anyway Bob as your suggestion made sense at the time...

 :oops: Forgot to mention the need for a right angle screwdriver... :D

No problem, I will be buying an angled driver to have another go at it with the stepper motor on. I went for a 100 mile ride yesterday and the bike is running fantastic. I can't believe what a massive difference this has made.  :D

[Tigertriple]

Just a quick add on to my original post. I have now modified the air box after reading Chris Canning's post on the subject. While the air box was off I did the throttle balance again this time with the stepper motor connected as recommended by Bixer Bob

As I don't have an angled driver to adjust the balance I removed the stepper motor and used a couple of small bolts to hold it together.




The balance is now even better and the air box mod has made a massive improvement to the smoothness of the engine and the pulling power in all gears. I'm back to running with a 19 tooth front sprocket and can't believe the difference this mod has made.

As I was not sure how this would work out I bought a used air box of ebay for 20 quid so that I would have a spare if I arsed it up. The best bit is it came with a brand new K&N filter :lol:

[chairhead]

Thanks for the link,
been thinking about buying one to use on both the Tiger and the Bandit for a while now and have just treated myself :D ,the airbox mod does make a hell of a difference,with a bit of luck i should be able to balance mine over the weekend :D

[Timbox2]

So how did you connect the carbtune up with the stepper still on?  T pieces of some sort Im guessing??

[Tigertriple]

So how did you connect the carbtune up with the stepper still on?  T pieces of some sort Im guessing??

I should have taken some pics of the connection. Yes I used T Pieces which worked fine.

[Tigertriple]

Thanks for the link,
been thinking about buying one to use on both the Tiger and the Bandit for a while now and have just treated myself :D ,the airbox mod does make a hell of a difference,with a bit of luck i should be able to balance mine over the weekend :D

No Problem, happy to help. I good investment for your workshop kit :D

[iansoady]

I'm a bit confused as to how you can balance the butterflies with the stepper motor (IACV) connected up.

What we're trying to do is to ensure that all the butterflies act in perfect unison - ie open by the same amount when opened by the twistgrip. If the stepper motor is in circuit then idle speed is maintained by it bleeding air behind the butterflies, and the butterflies completely closed.

Even if the butterflies are slightly out of adjustment I would expect the springs to close them completely (as there will be play in the linkage) therefore giving an erroneous result.

The way I do it is to disconnect the IACV and connect the carbtune to the spigots on the throttle bodies then to hold the throttle slightly open (with the big O ring) so the butterflies are resting on the adjusters to give around 1500 rpm. That makes sure that under operating conditions the butterflies are all acting together.

Or have I missed something?

[Tigertriple]

I'm a bit confused as to how you can balance the butterflies with the stepper motor (IACV) connected up.

What we're trying to do is to ensure that all the butterflies act in perfect unison - ie open by the same amount when opened by the twistgrip. If the stepper motor is in circuit then idle speed is maintained by it bleeding air behind the butterflies, and the butterflies completely closed.

Even if the butterflies are slightly out of adjustment I would expect the springs to close them completely (as there will be play in the linkage) therefore giving an erroneous result.

The way I do it is to disconnect the IACV and connect the carbtune to the spigots on the throttle bodies then to hold the throttle slightly open (with the big O ring) so the butterflies are resting on the adjusters to give around 1500 rpm. That makes sure that under operating conditions the butterflies are all acting together.

Or have I missed something?

Hi Ian,
This is all new to me. My first balance was done in the way you do yours. When I posted the details of doing the balance, Bixer Bob mentioned that he had seen it being done by  a Triumph Dealer with the stepper motor left in place so that the bike would tick over without the need for a stopper on the throttle.

As I had the tank off again I gave it another go as mentioned and it appears on the carbtune to be a more even balance. I can't say that the bike runs better than the first adjustment apart from the fact that the air box mod was not there  the first time. With the air box being a separate issue it's hard to compare. However the bike runs far better now that the air box has been modified.

I take your point about the objective of the balance, but either way I'm pleased with the results. :D