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Buying Carb Sync gauges... is this the best deal around?

I built a set of gauges similar to those above in 1975 to synch the VM style carbs on my Honda 550 Four Supersport. At first the needles did bounce all over the place. After explaining the problem to the supplier, they provided "snubbers" to fit in the gauge inlets to damp the needles. Thereafter the gauges worked fine.

I cannot remember the spec of the Honda carbs, but the allowable range was about 5 divisions on the gauge. Calibration was not a problem, as the difference between the 4 gauges was only about 1 division, when connected to the same carb.



I used to take time to synch the carbs to exactly the same reading on all the gauges. When I traded the Honda in on a new GS850G, the salesman said that he had never heard that model Honda idle so smoothly!

Until today these gauges are still used to synch the CV carbs on my GS850G!
 
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That ebay vacuum gauge will work but consensus with pros is they are cheap crap. A good vacuum gauge sync tool will cost a pretty penny, cheap dial gauges don't hold up against the wild fluttering/vacuum swings a bike can dish out.
 
I ordered my Carbtune today. It came to 67 pounds, which included a pouch and shipping.
 
Vmass said:
I ordered my Carbtune today. It came to 67 pounds, which included a pouch and shipping.
Click to expand...

I received the Carbtune in 7 days from order date. Looks like a cool tool.....My plan was to order the sync tool from Z1 so I would have it when the Carbtune arrived.....oh, well....plenty of other things to do this weekend.
 
Ordered a Morgan Carbtune yesterday after reading reviews. Did think about the dial type but didn't want to be calibrating each time also they look a bit bulky to store. Paid ?67 all in with the case too as they are doing a special deal at the moment. Hopefully here tomorrow to try it at the weekend. Just need to find out what im actually adjusting on the carbs? Pilot air screws or the linkages? Keep reading conflicting info :confused:
 
You need to adjust the linkage screws when you synch the carbs. Be sure to follow the correct order as described in the manual.

As a bonus, when you tweak the idle mixture using the highest idle method, you will also be able to observe the optimum point as the highest reading on the gauges.
 
2BRacing said:
You need to adjust the linkage screws when you synch the carbs. Be sure to follow the correct order as described in the manual.

As a bonus, when you tweak the idle mixture using the highest idle method, you will also be able to observe the optimum point as the highest reading on the gauges.
Click to expand...

Havent worked out the linkage set up yet. Ive tuned carbs years ago but mostly cars. I have a Haynes manual but it doesn't show my carbs I think mine are VM28ss? they have the long rectangular tops. :confused:
 
Devon bloke said:
Havent worked out the linkage set up yet. Ive tuned carbs years ago but mostly cars. I have a Haynes manual but it doesn't show my carbs I think mine are VM28ss? they have the long rectangular tops. :confused:
Click to expand...

You should have the 28s. Same as the VM26SS carbs - just a bit bigger:)

Take off the carb tops and you'll see the screws with the locking nuts that you adjust (probably still got a dab of yellow paint on them from the factory). You don't need to adjust them much - fine tweaks only.
 
I've got a carbtune now and are tempted to start having a go at a carb balance. Ive read more since then and thing its best to do things properly. First job I think is to get the tank cleaned out properly, either myself or at a tank refurb specialist. At ?150 though gotta give it some thought. Then a new fuel tap, although mine is serviceable I think it only works on vacuum on reserve. Prime works ok but worried about starvation and running lean. New fuel lines then, although its a daunting prospect, ill have the carbs apart for new bits and a clean. I have no bath so will just clean all parts by hand. At the same time ill check all the valve clearances (yet another tool to buy). Will then check the clutch hub nut and plates then the dreaded starter clutch and see what left of it :rolleyes: The engine itself looks brand new and has new gaskets. Then I can ride it :) Oh got fork seals to do, check why speedo don't work (got new cable, hope its this and not the head) Check the calipers and pads, although these have been rebuilt with all new bits, Ill check anyway. Think that's it for now :D
 
Nessism said:
You can do that, but the needles will bounce all over the place. Those metal tube Carbtune gauges are vastly superior.
Click to expand...

Then, you turn the dampers down and the needles cease to bounce.
The dampers in the lines are nothing more than aquarium air-hose flow-adjust fittings, dead cheap. I have a set I bought thirty years ago and was amused to see what had been used. Still, they worked perfectly fine. The rubber tubing supplied is now pretty cracked though, so it would be as well for anyone who picks up a set of used ones to throw the old tubes away and replace with some decent modern silicone rubbber.

Steve said:
Because you will STILL have the problem of matching them to each other whenever you use them.
Click to expand...
Decent gauges have a zero-ing screw to match them and stay matched. Check it occasionally, but mine never drifted out once zeroed in.
 
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