I was able to get out on my new to the road XS650SH last night. I ran a couple gallons of gasoline through it.
I got exactly 50 mpg.
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BS34s and white plugs
- Thread starter tommytwohands
- Start date
I got exactly 50 mpg.
My old '84 XS pizzing 'round got about 42 USG/mile. A carbatooted 883 sporty I have got about 54 one a trip to the coast and back over 36, which I thought astonishing. Your "50" seems dead on. Drag over 60 goes up fast...36 is slowandtwisty. Best!
Mine, fitted with a pair of VM34s, returns 60mpg Imperial on average, and that's not cruising like my granny, either. I've never changed anything in the carbs, so it is all down to the PO (one of the eight POs took care of things, the others were wreckers).
Plugs have always been light tan or light gray, depending on the local brew.
I suppose part of my problem is most of my riding is not at hwy speeds for a prolonged period of time. I rarely run straight highway for any distance.
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tommytwohands
XS650 Enthusiast
5twins, I may have been wrong about the needle. I’ve seldom gone this far into a carburetor. It looked non adjustable and I actually used a carb chart you posted to label it as I did above - since I couldn’t actually read the needle
But it may be adjustable - I’ll check after work.
If it is, could I attempt to drop the circlip one notch?
& I believe it’s Canadian as the speedo gauge is kilometers per hour
tommytwohands
XS650 Enthusiast
135 air jet for the main or pilot circuit? Are both removable?
Yes. The pilot air jet is on the intake side of the carburetor to the left when looking down the throat.
Only the pilot air jet is removable, the main air jet is "fixed" (pressed in) .....
This is a valuable fine tuning aid for the idle circuit that many aren't aware of. It can have a big effect on the color ring on the porcelain. A regular small round main jet (N102/221 type) is used here but it flows air, not fuel. If you have a #135 in there now, try a 132.5 and/or a 130. You may be able to close the mix screws up a little as well once you put the smaller air jets in.
This is a valuable fine tuning aid for the idle circuit that many aren't aware of. It can have a big effect on the color ring on the porcelain. A regular small round main jet (N102/221 type) is used here but it flows air, not fuel. If you have a #135 in there now, try a 132.5 and/or a 130. You may be able to close the mix screws up a little as well once you put the smaller air jets in.
tommytwohands
XS650 Enthusiast
https://www.ebay.com/itm/151075831133
Is this a valid main jet for the BS CV carb?
On eBay, it says for a RS HSR carburetor but the description fits the bill.
Wonder if there is any difference or if that’s just the way it’s listed
Is this a valid main jet for the BS CV carb?
On eBay, it says for a RS HSR carburetor but the description fits the bill.
Wonder if there is any difference or if that’s just the way it’s listed
I know virtually nothing about Carburetors
Speaking for myself I am Paranoid get it to lean .Which I know can have disastrous effects.
I have always had more black plugs .I know it can be wrong but it works for me
Vibration Free
I don't care if it is to much fuel as long as it don't get lean.
Higher speeds warm days and longer runs they get more Brownish I don't know why.
The higher heat perhaps.
I would suspect the change of Plugs makes a difference .
I would check the ignition timing so it is not to advanced ..and lean at the same time ---not good.
I would Probably go for richer mixture and don't bother much about the fuel consumption ( don't tell any environmentalists )
Larger Main jets are recommended and that makes sense to me I today ordered 137.5 that I will try .
Speaking for myself I am Paranoid get it to lean .Which I know can have disastrous effects.
I have always had more black plugs .I know it can be wrong but it works for me
Vibration Free
I don't care if it is to much fuel as long as it don't get lean.
Higher speeds warm days and longer runs they get more Brownish I don't know why.
The higher heat perhaps.
I would suspect the change of Plugs makes a difference .
I would check the ignition timing so it is not to advanced ..and lean at the same time ---not good.
I would Probably go for richer mixture and don't bother much about the fuel consumption ( don't tell any environmentalists )
Larger Main jets are recommended and that makes sense to me I today ordered 137.5 that I will try .
This is your main jet:
http://www.nichecycle.com/ncs/categ...ets/n100-604-n100-604-main-jet-by-mikuni.html
This is your pilot air jet:
http://www.nichecycle.com/ncs/categ...ets/n102-221-n102-221-main-jet-by-mikuni.html
This is your pilot jet:
http://www.nichecycle.com/ncs/categ...jets/bs30-96-bs30-96-pilot-jet-by-mikuni.html
tommytwohands
XS650 Enthusiast
You guys are miracle workers
If you need to purchase alternate sizes of any of your jets, make sure you buy real Mikuni jets, not Chinese "close enough" knock offs that everyone seems to sell now days. (e-Bay, Amazon, 4 into 1, etc)
These folks have also have all the genuine jets you need in all sizes, to include the pilot air jets:
https://jetsrus.com/
I've ordered from them many, many times and they always ship right away.
These folks have also have all the genuine jets you need in all sizes, to include the pilot air jets:
https://jetsrus.com/
I've ordered from them many, many times and they always ship right away.
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Very correct regarding getting too lean and melting down.
However, you don't want to go too "pig rich" either as we often call it, because that has a nasty effect of fuel washing the oil from the cylinders and rings and creating premature wear and oil dilution.....definitely hard to achieve the correct balance sometimes though.
My 73 CB350 seems to want to run pig rich no matter what I do with it, very sensitive to even the smallest of adjustments...especially float settings.
The Niche links I posted are genuine. They're price is a bit lower than Jets-R-Us and customer service just as good.If you need to purchase alternate sizes of any of your jets, make sure you buy real Mikuni jets, not Chinese "close enough" knock offs that everyone seems to sell now days.
These folks have all the genuine jets you need in all sizes, to include the pilot air jets:
https://jetsrus.com/
I've ordered from them many, many times and they always ship right away.
I'm sorry, I wasn't trying to imply your links weren't genuine at all, I meant more like eBay, Amazon, 4 into 1, etc... (I edited my post to reflect that). I can see how it came across that way, my apologies.
I was just sharing my one stop shop for all things jetting because I frequently have to buy jets for not only Mikuni but Keihin too...I like their web layout and find them pretty easy to order from as well. They seem like kind of an obscure/unknown site that many dont know about so I was just trying to share an alternative.
No need to be sorry. Your interpretation of my message was faulty, as was my delivery. Two good options for genuine Mikuni brass. I've used both and recommend both without reservation. Niche wins on price is the only difference in my experience.I'm sorry, I wasn't trying to imply your links weren't genuine at all...I can see how it came across that way, my apologies.
Yes, I believe I will definitely be comparing between the two vendors from now on myself. That brass sure adds up in a hurry.
Since I do a lot of fooling around with carbs, I buy my jets in 4 packs. Mikuni sells them this way probably because of all the 4 cylinder/carb bikes out there, and the price per jet is usually better. I'll search eBay from time to time and sometimes a really good deal will pop up, like $10 to $12 for a 4 pack of genuine Mikuni jets.
Just gassed up madness, high compression 750 cammed, she's getting a bit tired, VM34 carbs, fairly high gearing, riding curvy state highways. Couple of hammer down runs to 75MPH or so, (testing purposes onlyI was able to get out on my new to the road XS650SH last night. I ran a couple gallons of gasoline through it.
I got exactly 50 mpg.
)112 miles 2.2 gallons, yup 50MPG.
