Fuel line setup for Murrays carbs

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Fuel line setup for Murrays carbs

26 May 2025 15:24
#912887
Hello I recently purchased a 1977 KZ 650 B1 and man this thing is frustrating the hell out of me but I am muddling through with my limited skills. I finally got sick of trying to get the carbs tuned right since somewhere in the past the air box was ditched. I purchased some Murrays carbs and im not sure what the best fuel line setup is and was hoping for some advice on the layout. Did you use the provided fuel hose? Pictures would be great. I bought a overpriced petcock off ebay from some place in the UK called madmopeds for a pretty hefty sum and the POS leaks like a seive with it in the off position. I'm currently refurbishing the original Petcock. Found a NOS bowl screen on fleabay. I dont really see a good way to run inline filters with such a shirt distance between petcock and T fitting splitter provided by Murray. Anyway thanks for listening

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Re: Fuel line setup for Murrays carbs

27 May 2025 04:24 - 27 May 2025 04:28
#912901
I'd guess the lack of replies tells you all you need to know about Murray carbs. You wasted your money buying them. If they worked Kawasaki would have fitted a 2 carb setup originally and saved the cost of fitting four carbs.
Murray carbs link two cylinders that are on opposite strokes and at best you can only set them up as an average of two unrelated opposing cycle cylinders. 
You stated when you bought the bike it ran fine with the original four carb bank. 
If they got shit in them from the rusty tank then all you needed to do was clean the tank, fuel line, and the carbs without Messing with any of the settings. 
Put clean stock carbs back on, set them up as per the factory service manual, fine tune them once fitted. Job done.
You've edited your original post. 

Z1000J2 somewhat modified!

Last edit: 27 May 2025 04:28 by Warren3200gt.

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Re: Fuel line setup for Murrays carbs

27 May 2025 04:30 - 27 May 2025 04:37
#912902
+1 - what ever caused the issue with the original carbs (rust etc) will have the same effect on the replacements. If this set up makes more HP and torque as Murray claim, why has every engine tuner since the 1950's favoured "one intake venturi per cylinder" ?
Last edit: 27 May 2025 04:37 by Wookie58.
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Re: Fuel line setup for Murrays carbs

27 May 2025 05:33
#912903
If the tank has been properly cleaned, there should be no need for an inline filter. If you want to use one for insurance, a Golan super mini is pretty short, and might fit. I would put it in the single line, before the splitter.
As far as routing goes, I cannot imagine there are many choices. The fuel line should take the most direct path that does not cause kinks or sharp bends. Is there any reason to not use the supplied fuel line?
Pictures would be helpful.
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1981 KZ1000 LTD awaiting resurrection
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www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24

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Re: Fuel line setup for Murrays carbs

27 May 2025 05:52 - 27 May 2025 06:09
#912904
+1 - what ever caused the issue with the original carbs (rust etc) will have the same effect on the replacements. If this set up makes more HP and torque as Murray claim, why has every engine tuner since the 1950's favoured "one intake venturi per cylinder" ?
Ok, I'll play devil's advocate.....
Why did nearly every auto manufacturer favor multiple cylinders per venturi? Seems like they all worked rather well. For example, Ford flathead v8 originally had a one-venturi carb. Triumph TR6 got by with two single venturi carbs feeding six cylinders (at least in the U.S. ☹️). Nearly every modern US v8 came with a single 2v or 4v carb.
Murray has always made some, um, bold claims about their products, but that does not mean that a two-cab setup cannot work.
That being said, to the best of my recollection, the folks around here who have tried either a single carb on a twin or twin carbs on a four, have been folks who could not get the stock carbs to work, and assumed that reducing the carbs by half might equalize their level of problems to their level of skill. Yes, that is a basic mathematical fail. It takes only a little more skill and knowledge to get four singing together in perfect harmony than it does for two.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
Last edit: 27 May 2025 06:09 by TexasKZ.
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Re: Fuel line setup for Murrays carbs

27 May 2025 06:07
#912905
Meanwhile.......

If the tank was really rusty, some sort of acid treatment is the only hope to get it really clean. If it is mostly dirty with maybe a very little surface rust, the following method is surprisingly effective at dislodging dirt, debris, and dried fuel residue.

www.kwick.biz/how-to-flush-your-fuel-tank/
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24

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Re: Fuel line setup for Murrays carbs

27 May 2025 06:15
#912906
+1 - what ever caused the issue with the original carbs (rust etc) will have the same effect on the replacements. If this set up makes more HP and torque as Murray claim, why has every engine tuner since the 1950's favoured "one intake venturi per cylinder" ?
Ok, I'll play devil's advocate.....
Why did nearly every auto manufacturer favor multiple cylinders per venturi? Ease of tuning with annual service intervals - economy/performance compromise  Seems like they all worked rather well A 1000cc car from the same period as our KZ's made around 50hp . For example, Ford flathead v8 originally had a one-venturi carb. Triumph TR6 got by with two single venturi carbs feeding six cylinders Virtually all "tuned" TR6's had triple DCOE Webber carbs fitted (UK spec TR's had Bosh mechanical fuel injection and 150hp Vs the export carb models 125hp). Nearly every modern US v8 came with a single 2v or 4v carb. Is that why a 6 litre V8 engine made less than 200hp ?
Murray has always made some, um, bold claims about their products, but that does not mean that a two-cab setup cannot work.
That being said, to the best of my recollection, the folks around here who have tried either a single carb on a twin or twin carbs on a four, have been folks who could not get the stock carbs to work, and assumed that reducing the carbs by half might equalize their level of problems to their level of skill. Yes, that is a basic mathematical fail. It takes only a little more skill and knowledge to get four singing together in perfect harmony than it does for two. Hence why production cars had a more simple set up (most people just want them to work from one service to the next without any hassle)
Do like a good debate :) just makes me smile with some of the claims these people make for their products - 
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Re: Fuel line setup for Murrays carbs

27 May 2025 07:54
#912912
+1 - what ever caused the issue with the original carbs (rust etc) will have the same effect on the replacements. If this set up makes more HP and torque as Murray claim, why has every engine tuner since the 1950's favoured "one intake venturi per cylinder" ?
Ok, I'll play devil's advocate.....
Why did nearly every auto manufacturer favor multiple cylinders per venturi? Ease of tuning with annual service intervals - economy/performance compromise  Seems like they all worked rather well A 1000cc car from the same period as our KZ's made around 50hp . For example, Ford flathead v8 originally had a one-venturi carb. Triumph TR6 got by with two single venturi carbs feeding six cylinders Virtually all "tuned" TR6's had triple DCOE Webber carbs fitted (UK spec TR's had Bosh mechanical fuel injection and 150hp Vs the export carb models 125hp). Nearly every modern US v8 came with a single 2v or 4v carb. Is that why a 6 litre V8 engine made less than 200hp ?
Murray has always made some, um, bold claims about their products, but that does not mean that a two-cab setup cannot work.
That being said, to the best of my recollection, the folks around here who have tried either a single carb on a twin or twin carbs on a four, have been folks who could not get the stock carbs to work, and assumed that reducing the carbs by half might equalize their level of problems to their level of skill. Yes, that is a basic mathematical fail. It takes only a little more skill and knowledge to get four singing together in perfect harmony than it does for two. Hence why production cars had a more simple set up (most people just want them to work from one service to the next without any hassle)
Do like a good debate :) just makes me smile with some of the claims these people make for their products - 
A debate among friends without shouting or name-calling? What a concept!

I see no reason that a properly designed two-carb setup would not work on the op's KZ. Yes, there would be a performance penalty, but I wonder how much? My guess is somewhere between 5 and 10 percent. Keep in mind how much you paid for that guess. Also, I have no idea if the Murray system is well designed, or just well marketed. 
Based on my limited knowledge, one of the challenges of a system with fewer venturi than cylinders is providing sufficient volume at wot, while maintaining sufficient velocity at lower revs. U.S. auto manufacturers used intake manifolds with significantly large plenums that were heated so that fuel droplets that formed due to low velocity would be vaporized on contact with the manifold. On an air cooled inline four with a cross-flow head, I do not see an elegant way to do that.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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Re: Fuel line setup for Murrays carbs

27 May 2025 08:33
#912918
Completely agree there is no reason why it wouldn't work (as you point out automotive history proves that) I just don't see the point in "de-tuning" a motor to make less power !!!

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Re: Fuel line setup for Murrays carbs

27 May 2025 08:44
#912921
Completely agree there is no reason why it wouldn't work (as you point out automotive history proves that) I just don't see the point in "de-tuning" a motor to make less power !!!
The older I get, the more pointless stuff I see. In this case, if this gets another KZ back on he road and the owner is happy,  I can live with that.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
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www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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Re: Fuel line setup for Murrays carbs

27 May 2025 09:48 - 27 May 2025 09:59
#912928
I finally got sick of trying to get the carbs tuned right since somewhere in the past the air box was ditched. . 

You should have asked here first for advice on running without the airbox.
All you need is air corrector jets, a slight main jet increase and you get to retain the original carbs with a performance boost thrown in.

As for the Murrys carbs. They are a backward step in terms of performance in this application and are known to run very rich and boggy on the bottom end whilst returning lower MPG.
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/23-for-sale/611992-air-c...lide-mikunis?start=0





Last edit: 27 May 2025 09:59 by zed1015.
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Re: Fuel line setup for Murrays carbs

27 May 2025 10:25
#912930
Aaaand this is why I usually avoid forums. I didn't need a bunch of crap about "wasting my money" or why the clapped out POS carbs that had been sitting in a barn for a few decades are so much better. I got all the rust out of the tank but for a little surface rust that isn't an issue. You dont like Murrays carbs? Fine I didn't ask for opinions on that. I was just seeking some possible ideas from someone that may have them on their bike. To those few who were actually encouraging. Thank you. I guess I will just keep working on this thing myself without the helpful advice of the experts. This thing sat in a barn in New Mexico for decades and im pretty proud of my work thus far considering my limited knowledge.

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