Author Topic: Gas BBQ conversion to natural gas  (Read 6830 times)

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Offline Hoony

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Gas BBQ conversion to natural gas
« on: October 23, 2018, 06:01:18 PM »
Any of you blokes have experience with converting a bbq from lpg to to natural gas.

I bought a generic kit for the regulator hose and bayonet fitting
But jet sizes are different thread. I know you drill them out but how do you know the size. Lpg jet sizes are 0.91mm and 0.96mm
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline 80-85 husky

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Re: Gas BBQ conversion to natural gas
« Reply #1 on: October 23, 2018, 06:36:54 PM »
stuff this up and you will get bang for your bucks... ;D... i hate gas.. any gas... always break out in a sweat when using gas heaters, bbq 's etc Brrr

Offline Momus

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Re: Gas BBQ conversion to natural gas
« Reply #2 on: October 23, 2018, 08:59:00 PM »
Double the orifice area for natural through the LPG reg I think is the start point.

Offline Hoony

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Re: Gas BBQ conversion to natural gas
« Reply #3 on: October 23, 2018, 09:08:49 PM »
ok so if i have an orifice at 0.96mm diameter double is obviously not 1.92mm how do you double a cross sectional area of a circle.
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline pmc57

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Re: Gas BBQ conversion to natural gas
« Reply #4 on: October 23, 2018, 09:52:10 PM »
I did similar a couple of years ago for the son-in-law's BBQ (LPG to natural gas). The BBQ shops will not sell you the jet sizes unless you're a licenced gas fitter but if you do some homework to come up with the conversion tables to calculate the BTU's generated between the two gas sources you can work out the jet size required.
In our case I drilled the existing jets out to 1.85mm with a standard jobber drill and it worked great, from memory the jet size for the LPG could have been similar to yours. If it's a multiple burner BBQ, modify one jet and try it. If it burns a clean blue flame then you know you've got the gas:air ratio correct. 

Offline Momus

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Re: Gas BBQ conversion to natural gas
« Reply #5 on: October 24, 2018, 12:15:26 AM »
I did similar a couple of years ago for the son-in-law's BBQ (LPG to natural gas). The BBQ shops will not sell you the jet sizes unless you're a licenced gas fitter but if you do some homework to come up with the conversion tables to calculate the BTU's generated between the two gas sources you can work out the jet size required.
In our case I drilled the existing jets out to 1.85mm with a standard jobber drill and it worked great, from memory the jet size for the LPG could have been similar to yours. If it's a multiple burner BBQ, modify one jet and try it. If it burns a clean blue flame then you know you've got the gas:air ratio correct.

1.35 mm, #54 or #55 number drill.

Offline John Orchard

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Re: Gas BBQ conversion to natural gas
« Reply #6 on: October 24, 2018, 09:45:49 AM »
What's the difference between LPG and natural gas? Where/how do you buy each?
Johnny O - Tahition_Red factory rider.

Offline Ted

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Re: Gas BBQ conversion to natural gas
« Reply #7 on: October 24, 2018, 11:02:58 AM »
Alan, just go down to BBQ Galore and tell them you want to convert your BBQ from LPG to Natural Gas. They will sell you the right jets for under $5 each. You don’t have to be a licences gas fitter.
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Offline mick25

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Re: Gas BBQ conversion to natural gas
« Reply #8 on: October 24, 2018, 02:05:44 PM »
John Natural gas is low pressure
Bottle gas is high pressure
That’s why you need to re jet
Need bigger jets for natural gas I got mine from bbq joint as ted said

Offline Hoony

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Re: Gas BBQ conversion to natural gas
« Reply #9 on: October 24, 2018, 04:25:55 PM »
both fuel have different air/gas ratios. i have a chart that i am using to Calculate
what i need. the Key is the Burner BTU value, once you know this sizing is easy.

stay tuned.

momus is on the money as he has correctly calculated what i need.
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline xel93

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Re: Gas BBQ conversion to natural gas
« Reply #10 on: October 24, 2018, 04:38:07 PM »
BTU is an interesting point.  We have one barbecue that runs on LPG and another one that is the same brand and type (Weber) but slightly smaller that runs on natural gas.  I think the LPG one is heaps hotter and it is better to use.

It is convenience issue but I would only go for LPG now.

Offline mick25

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Re: Gas BBQ conversion to natural gas
« Reply #11 on: October 24, 2018, 05:36:44 PM »
I noticed the same when I converted mine to natural gas it wasn’t as hot as bottle gas .
I only done the mod years make for the dreaded case of running out of gas half way through a bbq , but now I just use LPG with the safety valve and it has a meter on it to show gas bottle amount .

Offline Hoony

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Re: Gas BBQ conversion to natural gas
« Reply #12 on: October 24, 2018, 06:56:49 PM »
BTU is an interesting point.  We have one barbecue that runs on LPG and another one that is the same brand and type (Weber) but slightly smaller that runs on natural gas.  I think the LPG one is heaps hotter and it is better to use.

It is convenience issue but I would only go for LPG now.

if the Natural gas one has not been sized correctly it wont provide the heating value as LPG. Natural gas runs at 10:1 air/gas ratio and LPG at 25:1

LPG has a much higher (nearly 3 x) energy value (MJ/m3) over natural gas.
« Last Edit: October 24, 2018, 06:59:27 PM by Hoony »
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline Hoony

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Re: Gas BBQ conversion to natural gas
« Reply #13 on: October 24, 2018, 07:02:08 PM »
Alan, just go down to BBQ Galore and tell them you want to convert your BBQ from LPG to Natural Gas. They will sell you the right jets for under $5 each. You don’t have to be a licences gas fitter.

Spot on Ted, but you need to know what jets to buy...they won't or can't tell you even if you provide the burner specs.

my BBQ looks like a non standard jet size (Aldi jobby) so i will drill mine, lots of good info on youtube the charts to size and the math behind it need to be right.
Long time Honda Fan, but all bike nut in general, Big Bore 2 stroke fan.    http://www.youtube.com/watch?v=XJoKP6MawYI
1985 Honda CR500RF "Big Red"
1986 Honda CR250RG
2005 KTM 300EXC "The GruntMeister" ( I love that engine)

Offline Mick D

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Re: Gas BBQ conversion to natural gas
« Reply #14 on: October 24, 2018, 09:03:43 PM »
 Let us know when you are going to fire it up Hoony,,, I will climb up and sit on my roof n watch  ;D ;D



Well what do you know, I have you to thank Hoony for learning how to post pics again,,,
now to remember it ::)
« Last Edit: October 24, 2018, 09:07:41 PM by Mick D »
"light weight, and it works great"  :)