Ninja EX500 carbs on an XS650?

I believe I read that one of the carb brackets needs to be notched. Can anyone tell me where to do this, the motor is not in the bike yet so it is hard to figure it out. A pic would be perfect. thanks tim
 

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When I first notched the bracket, I made it wider than it needed to be, which doesn't hurt anything, but also made it too shallow, stopping at the point of the angle. After installing the CVK's, I knew it was tight - there was tiny clearance to the frame post with the bike not running but not enough to accommodate vibration when it was, and the enricher on the righthand carb eventually unscrewed itself. Took it all out and filed more relief as shown in the second pic, plenty clearance now.
 
Ooooooh look what I got for Easter ...
GPZ500 carbs.JPG

I couldn't see you guys getting all the fun so I grabbed these two sets for a song off ebay last week.

I've got as far as post #20 so I've still got a lot of reading to do to catch up but I'm really looking forward to this project. They appear complete and one set was clearly cleaned and in use recently which will make things a lot easier.

I've just cleaned my BS38s again for this season and after 3 years of trying to buy a spare set of BS38s I've thrown in the towel and gone over to the dark side.;)
 
Ooooooh look what I got for Easter ...View attachment 98224
I couldn't see you guys getting all the fun so I grabbed these two sets for a song off ebay last week.

I've got as far as post #20 so I've still got a lot of reading to do to catch up but I'm really looking forward to this project. They appear complete and one set was clearly cleaned and in use recently which will make things a lot easier.

I've just cleaned my BS38s again for this season and after 3 years of trying to buy a spare set of BS38s I've thrown in the towel and gone over to the dark side.;)
You'll really like them when you get them dialed in. I couldn't find a way to fit an inline fuel filter like the ones in your pic - the fuel inlet T is too far off center toward the lefthand carb. You can use a rail filter instead. The top bracket needs to be relieved past the point of the angle in order to get enough clearance in front of the frame downtube - ask me how I know!
 
You'll really like them when you get them dialed in. I couldn't find a way to fit an inline fuel filter like the ones in your pic - the fuel inlet T is too far off center toward the lefthand carb. You can use a rail filter instead. The top bracket needs to be relieved past the point of the angle in order to get enough clearance in front of the frame downtube - ask me how I know!

thanks for the heads up . The 2x inline filters are for my BS38s that will be going back on today .
The GPZ500 are going to need a lot of work yet before I can fit them. I'm hoping to use my existing throttle cable and I have a bar mounted choke that I shall link up too.

I can't believe how small and light these are compared to the BS38s .the fuel bowls are half the size and only a single fuel line ...amazing.
 
thanks for the heads up . The 2x inline filters are for my BS38s that will be going back on today .
The GPZ500 are going to need a lot of work yet before I can fit them. I'm hoping to use my existing throttle cable and I have a bar mounted choke that I shall link up too.

I can't believe how small and light these are compared to the BS38s .the fuel bowls are half the size and only a single fuel line ...amazing.
I used my OEM throttle cable, shortened about 3/4", after fitting the long-shank cable adjuster shown in the pic to the carb set. I got this adjuster on eBay. I don't know if the shank on our clutch cable adjusters is long enough for them to attach to the carbs and still have a decent range of adjustment. The rail filter is Kawasaki P/N 49019-1085, available from Ron Ayers, current price $4.36 each. I bought two and put one in the open leg of the vent line just to keep anything from getting into the carbs through that opening.
 

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cheers Aldo thats a very neat and ingenious solution.
It might be a while before I get to the point of fitting a pair of these GPZ500 carbs theres a lot of work to do yet cleaning and getting a selection of jets and needles etc.

i'll do a vlog as I go . Someone really needs to go through this thread and pick out the important stuff and put it into a seperate tech thread . Its just too much to read through now at 40+ posts
 
Afternoon, chaps! I've been running these on my '77 and they are ruddy great... however, almost all of my riding is through central London, where i actually never get anywhere near WOT.. Today i took a jolly sunny trip to brighton where i found that after 3 or 4 mins at WOT 60mph+ she starts stumbling and missing and eventually stops dead.. not ideal on the M23! i coasted to the hard shoulder, pulled plugs and they were quite grey/white, and once bike had sat for couple minutes she started again, idling like a clock.. so am thinking that my rarely used mains are to small! however, i am already running 140's and quick skim of this thread i couldn't see many(any?) folks running larger mains than that... i have uni-foam filters, pretty much straight through pipes and Boyer electric ign.. hell, am gonna order them anyway, but what size ye reckon?
 
Don't know about jet sizes but to me it sounds like it is starving for fuel. Does the petcock flow enough? A friend had a Sportster with similar issue. It died after WOT acceleration but run just fine when riding "easy". Turned out that the tuned engine wanted more fuel than the small aftermarket petcock would flow.
 
I doubt that it's a problem with jet size. From what you wrote, it may be that the vent in your gas cap, which is a very small passage, has been slowly plugging up over time and now doesn't allow enough airflow into the tank at sustained high speed to replace the volume of gas being consumed, creating a vacuum in the tank that eventually stops the flow of gasoline. Try cleaning out that vent.
 
aah! actually this did happen previously, and i did drill out the teeny tiny hole but perhaps it has clogged again.. i will clean it out and see... just took a pic of plugs and actually they don't look too bad... the soot is from the lower end stuff, where things are a touch on the rich side but i would rather be rich than lean!
 

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and in fact the first time this happened, i though it was fuel starvation, stopped, flicked to reserve and carried on, but by then was in built up area so was doing the same kind of speed..
 
the next time you get a chance to run it and it starts to splutter and die ...try applying a little choke if you can do it without falling off :)

The choke will give you an extra shot of fuel .....enriching the mixture. If the engine immediately recovers you'll know it is a fuel starvation issue at that throttle position .
I have fixed a choke lever to my bars which makes it much easier cold starting. You can apply exactly the amount of choke you need and gradually reduce it as the engine warms up. Its also useful for testing purposes.

Will you be riding The Distinquished Gentlemens ride in September ?
Johnny
 
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I've been running these for a couple of years and really like them. Mine are 140 mains and I have no problems when giving it a bit of wellie, however truth be told 70 is about the most comfortable speed on Dual Carriagway/Motorway as a combination of thin seat and hard suspension does tend to make a very dull ride there. Most of my riding is around the curvier roads of Wiltshire - much more fun!

One weird thing with mine is I seem to get a vacuum when it goes onto reserve so have to 'jiggle - tech term' the fuel hose where it joins the tank to get air in and the fuel running through again.
 
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Peanut! i have yet to fit any sort of remote choke operation... i just poke it in with my finger until it warms enough to run without (never more than 10-20seconds) however, it did occur to me that one easy way to test tank vacuum question, is just to burn it up with petrol cap slightly open.. might give that a go, as an easy thing to rule out at least..
i did the DGR the year before last, and may do this year! was good fun, London awash with custom and classic bikes ridden by berks (like me!) in tweed, and getting lost!

thanks guys, it does seem unlikely that running 140s is too lean, but have ordered next size up just in case.. will report back... !
 
Peanut! i have yet to fit any sort of remote choke operation... i just poke it in with my finger until it warms enough to run without (never more than 10-20seconds) however, it did occur to me that one easy way to test tank vacuum question, is just to burn it up with petrol cap slightly open.. might give that a go, as an easy thing to rule out at least..
i did the DGR the year before last, and may do this year! was good fun, London awash with custom and classic bikes ridden by berks (like me!) in tweed, and getting lost!

thanks guys, it does seem unlikely that running 140s is too lean, but have ordered next size up just in case.. will report back... !
Your frame of reference for choke operation is not clear to me. The "choke" (actually an fuel-adding, not an air-starving mechanism) is "on" when the bar that operates them is pulled to the left ("left" when in riding position on the bike) and the shafts of the enrichers are showing. In that context, "poking it in" would turn the enrichers off. The attached pic, taken from the engine-in ("front") of the carbs shows the simple cable-type choke operator that I use - I believe that it's shown and identified somewhere in the long EX500 carbs thread on this website..
 

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sorry if that wasnt clear... when i say "poke" i mean i poke it from the the right when sitting on the bike and slide the spring loaded bar to the left, activating the enricheners, as you rightly say.. i have yet to rig up any form of remote "choke" control, simply because i dont need it.. even in very cold temps, the bike starts on the button with 20-30 seconds "poke" to get to stable idle temp.
 
sorry if that wasnt clear... when i say "poke" i mean i poke it from the the right when sitting on the bike and slide the spring loaded bar to the left, activating the enricheners, as you rightly say.. i have yet to rig up any form of remote "choke" control, simply because i dont need it.. even in very cold temps, the bike starts on the button with 20-30 seconds "poke" to get to stable idle temp.
OK, sounds good.
I too have been experiencing "engine quits" after 8-10 miles that suggest slow fuel starvation, even with good fuel supply thru my petcocks, clean bowls and jets, and good float settings. Just today while working on something else, I noticed that the cylindrical vent hole on the side of the left carburetor just above the bowl at the rear of the carb was "mudded" in totally. It wasn't just plain mud - it was a small wasp nest in there with tiny greenish-yellow worms. The corresponding vent on other carb was clear, so I tested air flow using a small rubber hose fit tightly over the outer end of the vent. It took some huffing and puffing, but some air would move thru it, both in and out - I don't know what it vents. I cleaned the "mudded" one until I could get the same in-and-out air flow, using Q-tips and spray carburetor cleaner. I haven't started the bike and test-rode it yet, still need to set timing, but thought I'd mention this as a possible that you could check out whether these vents on your carbs are clear. I'm still dealing with some pissed-off wasps. Today's learning is that plugging doesn't just happen in the internals of these carbs where I was looking but could not find it.
 
ok, so... i drilled out the vent hole in the cap, still had issues, and in fact just flipped the cap open and restarted just to be sur but had same problem, so we can rule that out. i got to thinking it might be a issue with timing as the only things different with this bike since it last was able to cruise60+ with no issues, are the ex500 carbs and the Boyer ignition... so i reset the ignition with timing lamp, so that the advance stop advancing where it should. prev i had set it as per the instructions which says to set from idle... however idle is adjustable but the point at which it should be fully advanced is set in stone (or rotor!). after that the running was smoother and power bands more gradual all the way through.. but still the same initial problem... i checked my needles (JJJ) which were set in the middle, so moved them to the bottom slot, which was terrible, so moved them again to second to bottom slot, which seem a lot better...but not perfect. i finally upped main jet to 142's and bingo! cruised a few miles at 60 and no issues...in fact best its run so far! yet to do long journey, to know 100% but will be driving from brighton to london shortly, so will find out soon enough... also, fitted new clutch cable, new ss braided brake hose, fork brace and fork dust caps.
 
Where is it rich, Idle, top end or midrange? Depending on where it rich is where you make changes.
The carb guide ha a "Tuning For Mods" section. Yes the carb guide is for the stock carbs but the same basic principles apply.
Start with the WOT testing to get the mains right, then do the midrange testing to get the needle right, then do the idle testing to get the pilots right.
Leo
Now cut that out WER! No grease on diaphragms! If anything a touch of pure silicone like dielectric silicone, yeah it's expensive, but cheaper than a new diaphragm. There's a trick with "shrunk" diaphragms and working the cap just so to get it back down with the diaphragm in the groove. You'll get there.
I'm not a carb guru but I do have a little common sense. Here is the problem I am now having and it has me stumped. The bike starts 1st kick every time and runs like a top, but after the bike is warm the Rpms are dropping them the bike will stall out. I have had these Damn carbs off at least 10 times and I have checked (float height, needle postion, air leaks) them and cleaned them before I put them back on. These carbs are very promising but I can't figure this issue out. I have looked at the float needles and they seem to be in good working order also, but I'm losing gas if it sits to long ( I have clear fuel lines). :banghead:
Someone please tell me how to determine if the float needle aren't seated properly. All signs lead to this being the problem.

Could it be that I put the needle floats on the tang backwards
 
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