Carb Syncing/Throttle Lock

[jwurbel]

Will be checking on carb sync after next valve adjustment. What do you folks use to hold specific RPMs? Is the cruise control a viable alternative? Thanks in advance.

[dirtrider]

Hi jwurbel

 

Cruise control won’t work sitting still, even if wheels spinning it will be very abrupt.

Just use your hand on the throttle, you don’t need to hold it at any RPM for more than a couple of seconds. In fact you want to see how the balance is on slight throttle up as well as slow throttle down.

You will see how easy it works with just your hand on the twist grip.

 

[ShovelStrokeEd]

Throttle up is probably the most important. Using a throttle lock will put the bike in basically a throttle down condition. As others have stated, use your hand.

[Huzband]

As already stated, I use my wrist. With a Twin-max or manometer, I slowly increase the revs from idle to 3-4k, watching the meter all the way. No need to hold it as I'm looking for discrepancies along the way. No discrepancies, no adjustment.

[KDeline]

As already stated, I use my wrist. With a Twin-max or manometer, I slowly increase the revs from idle to 3-4k, watching the meter all the way. No need to hold it as I'm looking for discrepancies along the way. No discrepancies, no adjustment.

 

 

I have never got them to stay even through rising RPM's. Also I read that they were to be set at just above idle. I get that spot on but then at 4000 RPM they are uneven. So what is the best?

[Huzband]

As already stated, I use my wrist. With a Twin-max or manometer, I slowly increase the revs from idle to 3-4k, watching the meter all the way. No need to hold it as I'm looking for discrepancies along the way. No discrepancies, no adjustment.

 

 

I have never got them to stay even through rising RPM's. Also I read that they were to be set at just above idle. I get that spot on but then at 4000 RPM they are uneven. So what is the best?

 

In my best technical experience....beats me.

[dirtrider]

 

I have never got them to stay even through rising RPM's. Also I read that they were to be set at just above idle. I get that spot on but then at 4000 RPM they are uneven. So what is the best?

 

Hi KDeline

 

I don’t know what’s best but the service manual says to balance the above idle at 1400-1800 RPMs. It should also be the same or real close on slowly opening throttle.

 

Personally I just get it as close as possible statically then ride the bike for a base line. Then play with the right hand side slightly to get the best throttle response and engine smoothness.

 

Even engine vacuum side to side is just an indicator that the engine has the same pressure drop across the throttle plates side to side, it in no way means equal engine power side to side. Sometimes a little tweak on the cross side balance will equate to a smoother running engine at road load under power as that can equalize the engine power side to side. You are “really” after equal engine power side to side as that is what you feel while riding, using engine vacuum to get there is just a quick and dirty way to get it close but not perfect.

 

If you have the ability to lock the steppers with a GS-911 then you can also use the service manual procedure of retaining the idle offset through the off idle setting. In this case if the held stepper warn idle has a 3” higher H2o column on the right you should retain that offset at the 1400-1800 RPM setting range.

 

 

[Don_Eilenberger]

I have never got them to stay even through rising RPM's. Also I read that they were to be set at just above idle. I get that spot on but then at 4000 RPM they are uneven. So what is the best?

Go back and check your valve adjustment. Do it REALLY carefully. Doing a TB sync without first doing a really obsessive-compulsive valve adjustment is a total waste of time.

 

So far - 42k miles - when my valves are correct - the TB is correct, I've never had to adjust it. The cables really do not change length.