Hi all, im planning on getting some vacuum gauges, the most common being 0 to -1 bar, is this enough resolution to see whats balanced? The cylinders can vary by a max of 5kpa, which is see-able on a 0 - 100kpa gauge, but how strong is the vacuum to begin with?

I bought this one last month.

MexicanGringo wrote:Hi all, im planning on getting some vacuum gauges, the most common being 0 to -1 bar, is this enough resolution to see whats balanced? The cylinders can vary by a max of 5kpa, which is see-able on a 0 - 100kpa gauge, but how strong is the vacuum to begin with?

Based on the Morgan carb tuner...

When balancing the carbs I find at just above idle my cylinders vaccum is between 20-30 cm hg which is 346.64 millibar (MB) which is 0.346 bar

To sync carbs properly you have to get the cylinders within 1 line on the morgan carb tuner scale (2cm Hg) of each other (26.66millibar) 0.02666 bar

I think your gauges are not senstive enough to acuratly balance the carbs. unless you can distinguise 0.02.

Can you not get the morgan carb tuner? it comes with everything and they ship everywhere, will save you time and hassle, plus you can use it on low vaccumn bikes like bmw's by hanging it upside down (can't do that with dials)

plus you can subside it by charging friends a small amount to balance their bikes

Cheers,it prob would have been a better idea to buy that, but already bought the gauges. Theyr pretty cheap tho, four 63mm 0 to -1bar gauges were 350ZAR which is about 25pounds..

The haynes recons 40mmhg difference, so the morgans more accurate at 20mmhg, unless its a different scale of hg.. 2.6kPa(26MB) on these gauges is about 4mm of needle travel so should be ok, but i still got to get all the fittings to rig it up... How much is that morgan out of interest, id like to know if this is worth the effort

*edit* oh ok, 55pounds is about 730ZAR so its a bit cheaper this way

MexicanGringo wrote:Cheers,it prob would have been a better idea to buy that, but already bought the gauges. Theyr pretty cheap tho, four 63mm 0 to -1bar gauges were 350ZAR which is about 25pounds..

The haynes recons 40mmhg difference, so the morgans more accurate at 20mmhg, unless its a different scale of hg.. 2.6kPa(26MB) on these gauges is about 4mm of needle travel so should be ok, but i still got to get all the fittings to rig it up... How much is that morgan out of interest, id like to know if this is worth the effort

*edit* oh ok, 55pounds is about 730ZAR so its a bit cheaper this way

I guess it depends on how accurate your gauges are.

And yes.. max 26millibar difference is what its easy to sync to with the morgan. You can regularly pick them up on ebay for about £30.00

With the morgan you get 4 x heat resistant good quality heatproof hoses (these are about £10 to buy on their own) with some plastic resistors to stop the gauge bouncing like mad.

You also get 8 x adapters for fitting to the engine as theres a large and a small size (honda use the small one) as well as a nice carry case to put it all in.

I priced it up once building one to simliar spec and I couldn't do it for the price.

Good luck with your build tho, i'd like to see some pictures when it's done :)

I'm guessing your building something liek this...

http://cgi.ebay.co.uk/CARB-CARBURETTOR- ... 3ef2a59dc7" onclick="window.open(this.href);return false;

I put one together and works pretty good. You have to damp the gauges otherwise the needles are all over the place.You can do this with small thumb screws on the hoses where you connect to the gauges .

Just a little tip that Mr Oliver gave me. Set the carbs up either off the bike or remove tank and airbox then set the butterflies up so you can just see the small holes on all four carbs. And bish bosh jobs a godd'n. I put the gauges on after and this was near as damn it. No hand burning overheating etc. Hope this helps even if you want to do this to get it close and final adjust.

scotjell wrote:Just a little tip that Mr Oliver gave me. Set the carbs up either off the bike or remove tank and airbox then set the butterflies up so you can just see the small holes on all four carbs. And bish bosh jobs a godd'n. I put the gauges on after and this was near as damn it. No hand burning overheating etc. Hope this helps even if you want to do this to get it close and final adjust.

That is a good way to start if there fairly close.. it also relies on the carbs all having the same airflow (which doesn't always happen!)





^^ You can always get one of them

scotjell wrote:Just a little tip that Mr Oliver gave me. Set the carbs up either off the bike or remove tank and airbox then set the butterflies up so you can just see the small holes on all four carbs. And bish bosh jobs a godd'n. I put the gauges on after and this was near as damn it. No hand burning overheating etc. Hope this helps even if you want to do this to get it close and final adjust.

+1!

Now thats a driver!!!!!