The Gunson Colortune tool

When I got the stuff to rebuilt my VM29's (no kit's for them)
from Z1 the peice came with a Sudco sticker so I'd think Z1
source's them from Sudco.

zukdave wrote: If the mech. sync is not done BEFORE any tuning you will not get the screw's any were near even
just as OMR said his ain't close to even turn's out.
OK flame on.

Can someone answer this question please? The local bike repair shop owner stated that I needed to resolve the carb issues regarding not getting a cylinder firing and the air fuel mix. Only then would it be worth it to vac sync the carbs. Do I Need to vac sync or perfect the air/fuel first?? Or, do I run air/fuel, then vac sync, then confirm A/F???

Previously my 3rd cylinder was not firing, so I replaced the A/F needles on Keihin CV34 carbs. The 3rd cylinder required around 3-4 turns out to get the exhaust warm.

I just got the Gunson Colortune in the mail, and I am excited to use it.

BTW, here is the most recent manual: gunson.co.uk/items/pdf/Products/G4074-English.pdf
Questions: (pages will not
1) page 12 - Do I have the Variable Choke Carb or Slide Type Carb? Both sound applicable.

2) page 15 - Multible throttle body injection - help...

FaultedGeologist wrote:

zukdave wrote: If the mech. sync is not done BEFORE any tuning you will not get the screw's any were near even
just as OMR said his ain't close to even turn's out.
OK flame on.

Can someone answer this question please? The local bike repair shop owner stated that I needed to resolve the carb issues regarding not getting a cylinder firing and the air fuel mix. Only then would it be worth it to vac sync the carbs. Do I Need to vac sync or perfect the air/fuel first?? Or, do I run air/fuel, then vac sync, then confirm A/F???

Previously my 3rd cylinder was not firing, so I replaced the A/F needles on Keihin CV34 carbs. The 3rd cylinder required around 3-4 turns out to get the exhaust warm.

I just got the Gunson Colortune in the mail, and I am excited to use it.

BTW, here is the most recent manual: gunson.co.uk/items/pdf/Products/G4074-English.pdf
Questions: (pages will not
1) page 12 - Do I have the Variable Choke Carb or Slide Type Carb? Both sound applicable.

2) page 15 - Multible throttle body injection - help...

I think you have to use an iterative approach. Hook up you carb sync manometer, balance the carbs and then tune each cylinder with the Gunson, then check the balance and adjust if necessary and then recheck with the Gunson.. Each adjustment (fuel vs balance) will affect the other.

To help with carb Sync I found a paper clip the size I needed to set the slide gap. I know some folks use wire and that works as well just figured I would pass along another item.

Old Rider wrote: To help with carb Sync I found a paper clip the size I needed to set the slide gap. I know some folks use wire and that works as well just figured I would pass along another item.

What is the slide gap?

FaultedGeologist wrote:

zukdave wrote: If the mech. sync is not done BEFORE any tuning you will not get the screw's any were near even
just as OMR said his ain't close to even turn's out.
OK flame on.

Can someone answer this question please? The local bike repair shop owner stated that I needed to resolve the carb issues regarding not getting a cylinder firing and the air fuel mix. Only then would it be worth it to vac sync the carbs. Do I Need to vac sync or perfect the air/fuel first?? Or, do I run air/fuel, then vac sync, then confirm A/F???

Previously my 3rd cylinder was not firing, so I replaced the A/F needles on Keihin CV34 carbs. The 3rd cylinder required around 3-4 turns out to get the exhaust warm.

I just got the Gunson Colortune in the mail, and I am excited to use it.

BTW, here is the most recent manual: gunson.co.uk/items/pdf/Products/G4074-English.pdf
Questions: (pages will not
1) page 12 - Do I have the Variable Choke Carb or Slide Type Carb? Both sound applicable.

2) page 15 - Multible throttle body injection - help...

I think you have Keihin CV 34 carbs in which case:
1 you don't have slide type carbs so can disregard the slide gap. Your choke lever operates a choke flap also called a butterfly which blocks air from the air box
2 you don't have fuel injection so no throttle bodies

JR wrote: I think you have Keihin CV 34 carbs (YES) in which case:
1 you don't have slide type carbs so can disregard the slide gap. Your choke lever operates a choke flap also called a butterfly which blocks air from the air box

This makes sense now... slide=up and down, flap=rotation on center line.

So am I able to do one tune, then the other; or back and forth in search of unity? Any further confirmation of order or strategy would be great. Digging back in to the carbs and red wine...

Like Stazi said in his post #646334 above. Good advice

The carburetor slides Mine doesnt have the lil clips they have to be set and then set screws. Think if I remember correctly mine were .028 and I have the lil square You set these from the engine side so the carbs have to be removed from the engine. I did find one slide was off at least .010. I been researching the Gunson the Motion pro sync and just a quad set of vacuum gauges. Im really thinking of just going old school with a set of vacuum gauges.
I have seen folks make the homemade tuner out of 4 bottles, which i did as well after spending a small fortune in vacuum hose and making a mount for it all I can truely say for what it is it works but you cant fine tune with the 2cycle out I used, LOL! It sure does get a lot of looks hanging on the garage wall though. John.

Old Rider wrote: I been researching the Gunson the Motion pro sync and just a quad set of vacuum gauges. Im really thinking of just going old school with a set of vacuum gauges.

I did opinion research across the interwebs on them all, here is sum:

4x Vac gauges are old trusty, but require sync every use on a single vac source before use. Bulky, so storage and transport sucks.
$60 on Z1, or $200 for real nice set.

Motion Pro liquid sync set can get sucked into engine, and frequently gets air bubbles in it so one or more carbs cannot be set.
$90 at Z1, cheaper on Amazon.

Morgan Carbtune comes from UK or ebay for a premium. It uses stainless rods to show vac pressure, and is durable, portable, and needs no calibration.
$100 to $116 shipped depending...

I want the Morgan Carbtune and a set ov old gauges to test for myself the differences. Local shop uses classic gauges.

I have a mercury manometer set. You'd have to TRY hard to suck the mercury into your engine, at which point you have no business messing with carbs or engines for that matter. The Mercury manometers are the most accurate if you ask me as you don't have to worry about a needle gauge being calibrated properly.