Twinmax Carb Sync
05-21-2007, 08:23 AM
#2
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Join Date: Dec 2004
Location: Fulton, MO
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Yes, I've used one but it was a long time ago. Here's some directions copied from a website:
It is important on engines with more than two cylinders that you always balance all the cylinders against one which remains the reference or constant. Often there is one cylinder which is intended for this use-your manual will tell you this. It is suggested you use tube "A" for the reference cylinder. For good results, the engine should be near running temperature. On an air-cooled engine or a motorcycle it is advisable to sit a fan in front of the engine/bike to keep the exhaust pipes and motor cooled. On bikes, beware of exhaust pipes getting very hot and blistering nearby plastic fairings, etc. Keep an eye on engine temperature!
1. Ensure there is slack in the cable from the twistgrip or throttle pedal. If there is not a master idle screw, ensure all cable or rod adjusters have some free play-this makes sure that all carbs are sitting at idle, i.e., with their valves shut. Position the TWINMAX conveniently on the bike, such as on the saddle or on top of the frame and switch it on.
2. Connect the tubes to the carbs-one on the reference cylinder and the other on to one of the other carbs.
3. Turn the SENSITIVITY **** fully to MAXI.
4. Adjust the ZERO know until the meter needle is precisely through the middle of zero on the scale; this adjustment is very sensitive and very important.
5. Turn the SENSITIVITY **** back to MINI.
6. Start the engine and allow it to settle to a steady tickover. Don't be afraid of blipping the throttle-this makes certain the throttles are properly seated on their stops.
7. Slowly turn the SENSITIVITY **** until a deviation shows on the scale. The less out of balance the two cylinders being tested are, the more you will have to turn the SENSITIVITY **** to show an imbalance on the scale.
8. If there is present reference cylinder, quickly check each cylinder with one tube and choose the cylinder with the minimum deviation from zero on the scale as the reference cylinder.
9. Adjust the idle/slow running screw on the carb being adjusted (not the reference carb) until the meter shows an equal deviation on each size of zero. The meter is very sensitive, so care must be taken to use small increments of adjustment. Blip the throttle each time you make an adjustment to ensure the throttles are properly seated.
10. Repeat for all cylinders.
Once all the carbs are balanced at idle, they must next be balanced on throttle opening. As before, balance each carb against the reference cylinder.
Note that the balance must be checked as the throttle is opening and the engine is accelerating, NOT as the throttle is being closed and the revs are dropping. With some practice, you will be able to do this efficiently, and you will also be able to check the balance at a constant throttle opening.
You may find that a cylinder will balance fine on the opening up stage, but not on a constant opening; the skill lies in being able to interpret this and achieve a balance between one and the other.
11. Start with the SENSITIVITY **** about the middle of its' range. Run the engine and this time open the throttle gently and run the revs up to 3000 or 4000 rpm and make a note of any deviation on the scale; again, if it is not pronounced, increase the SENSITIVITY.
12. Now adjust the carb throttle actuator-this is either a cable or screw acting onto a plate or rod and may be hidden inside the carburetor top. Be careful to make only small adjustments. Note that if there are locking nuts on the adjusters, doing these up will affect the setting so double check the results and blip the throttle to settle things out.
13. Repeat for all the cylinders.
14. Adjust the slack in the cable from the twistgrip/pedal to manufacturer's specifications.
It is important on engines with more than two cylinders that you always balance all the cylinders against one which remains the reference or constant. Often there is one cylinder which is intended for this use-your manual will tell you this. It is suggested you use tube "A" for the reference cylinder. For good results, the engine should be near running temperature. On an air-cooled engine or a motorcycle it is advisable to sit a fan in front of the engine/bike to keep the exhaust pipes and motor cooled. On bikes, beware of exhaust pipes getting very hot and blistering nearby plastic fairings, etc. Keep an eye on engine temperature!
1. Ensure there is slack in the cable from the twistgrip or throttle pedal. If there is not a master idle screw, ensure all cable or rod adjusters have some free play-this makes sure that all carbs are sitting at idle, i.e., with their valves shut. Position the TWINMAX conveniently on the bike, such as on the saddle or on top of the frame and switch it on.
2. Connect the tubes to the carbs-one on the reference cylinder and the other on to one of the other carbs.
3. Turn the SENSITIVITY **** fully to MAXI.
4. Adjust the ZERO know until the meter needle is precisely through the middle of zero on the scale; this adjustment is very sensitive and very important.
5. Turn the SENSITIVITY **** back to MINI.
6. Start the engine and allow it to settle to a steady tickover. Don't be afraid of blipping the throttle-this makes certain the throttles are properly seated on their stops.
7. Slowly turn the SENSITIVITY **** until a deviation shows on the scale. The less out of balance the two cylinders being tested are, the more you will have to turn the SENSITIVITY **** to show an imbalance on the scale.
8. If there is present reference cylinder, quickly check each cylinder with one tube and choose the cylinder with the minimum deviation from zero on the scale as the reference cylinder.
9. Adjust the idle/slow running screw on the carb being adjusted (not the reference carb) until the meter shows an equal deviation on each size of zero. The meter is very sensitive, so care must be taken to use small increments of adjustment. Blip the throttle each time you make an adjustment to ensure the throttles are properly seated.
10. Repeat for all cylinders.
Once all the carbs are balanced at idle, they must next be balanced on throttle opening. As before, balance each carb against the reference cylinder.
Note that the balance must be checked as the throttle is opening and the engine is accelerating, NOT as the throttle is being closed and the revs are dropping. With some practice, you will be able to do this efficiently, and you will also be able to check the balance at a constant throttle opening.
You may find that a cylinder will balance fine on the opening up stage, but not on a constant opening; the skill lies in being able to interpret this and achieve a balance between one and the other.
11. Start with the SENSITIVITY **** about the middle of its' range. Run the engine and this time open the throttle gently and run the revs up to 3000 or 4000 rpm and make a note of any deviation on the scale; again, if it is not pronounced, increase the SENSITIVITY.
12. Now adjust the carb throttle actuator-this is either a cable or screw acting onto a plate or rod and may be hidden inside the carburetor top. Be careful to make only small adjustments. Note that if there are locking nuts on the adjusters, doing these up will affect the setting so double check the results and blip the throttle to settle things out.
13. Repeat for all the cylinders.
14. Adjust the slack in the cable from the twistgrip/pedal to manufacturer's specifications.
05-21-2007, 10:08 AM
#3
Senior Member
SuperBike
Join Date: Jan 2007
Posts: 2,116
Yeh, I've got one...
Trying to set you fuel screws (pilot) with it or any such device on the VTR is almost impossible, you need to be on a dyno with a EGS/A-FR meter. Plumb the vacuum lines and plug them so you can sync without having to completely pull the tank; just tip the front up to get to the sync screw on the left side adjacent the rear carb.
05-21-2007, 07:49 PM
#5
Senior Member
SuperBike
Join Date: Jan 2007
Posts: 2,116
Wait until your year tire is shagged before doing a dyno, then replace the tires. I like the new Conti Sport attack front & Road Attack rear skins.
05-21-2007, 08:38 PM
#7
Senior Member
SuperBike
Join Date: Jan 2007
Posts: 2,116
Tire manufacturer's do not warrant their product after a dyno run though I don't know how they'd prove you did one. Now if the dyno operator is careful and does not abuse your engine and drivetrain you might be OK; i.e., if they do not overheat the engine and tires. However, expect to loose about 1,000 miles worth of tread life from a meaningful dyno run, which will accelerate "squaring off" of the tread profile.
05-21-2007, 11:02 PM
#8
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Join Date: Dec 2004
Location: Fulton, MO
Posts: 105,287
3 pulls on a dyno will not flatten the tire that much. If the bike had so much power that it was slipping on the coarse surface of the drum then maybe, but with only about 100hp I don't see it happening.
05-21-2007, 11:34 PM
#9
Senior Member
SuperBike
Join Date: Jan 2007
Posts: 2,116
Have a good and safe trip to NC, wish I could join U.
05-22-2007, 06:22 PM
#10
Senior Member
Superstock
Thread Starter
Join Date: Oct 2006
Posts: 277
Yes, i got it done today 103hb and 65 fb and need to lower the clip 1down, 1/2 turn fuel screw seem like the plan to tear it up again. The rear tire ok, i do ask about manf warranty he said no, never and i bought them there.
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