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Ninja EX500 carbs on an XS650?
- Thread starter Highside
- Start date
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- Tags
- cafe carburetors custom engine
troopthrowback
XS650 Addict
The bike does rev past the 3k threshold but continues to pop out the exhaust, with an increased fervor as the revs climb. I will recheck my float height again and test run later this week. Since I've changed back to stock headers (and will add shorty glass packs) I will retry with the current setup before I change anything else. One thing at a time, right? Needles clips are at #5 (bottom) with one shim.
troopthrowback
XS650 Addict
Switched pipes since I made a skid plate (well, Wonderboy made it) back to the stock headers and added some old shorty glass pack mufflers from a triumph twin.
I reset float heights per spec and routed the float bowl breather to a remote tube out of the way of possible debris.
Didn't rejet since I changed the pipes as went for a test ride today for about 25 miles. Wow. I didn't realize how restrictive that MAC 2 into 1 pipe with muffler was. It was stifling this beast! It's a real ripper now and makes music with those little mufflers. Loud (but nothing like the open headers alone, that's roar was ridiculous!) but not too loud. Good bark on acceleration. Most of all it really gets when you crack the throttle. Nice smooth power surge all the way up to about 6500 (as far as I got it with no real straights in the roads I ran) with only a slight hiccup if I slammed it all the way open from a 1500 rpm trot.
I'm very pleased. I'm dismissing my foibles with these carbs as my own issues and not due the parts themselves. They are not complex. I'll defend my error by the fact that I referenced only these pages for setup and no other sources. The float bowl vent thing hadn't yet been discussed. But beyond that these carbs seem a great modification to the motor. I've always liked the cvk on the modern bonnevilles and my Harley friends love them on their sportsters. If you like to tinker you should give these a try.
Now to clean up my old bs38 and send to eBay!
I reset float heights per spec and routed the float bowl breather to a remote tube out of the way of possible debris.
Didn't rejet since I changed the pipes as went for a test ride today for about 25 miles. Wow. I didn't realize how restrictive that MAC 2 into 1 pipe with muffler was. It was stifling this beast! It's a real ripper now and makes music with those little mufflers. Loud (but nothing like the open headers alone, that's roar was ridiculous!) but not too loud. Good bark on acceleration. Most of all it really gets when you crack the throttle. Nice smooth power surge all the way up to about 6500 (as far as I got it with no real straights in the roads I ran) with only a slight hiccup if I slammed it all the way open from a 1500 rpm trot.
I'm very pleased. I'm dismissing my foibles with these carbs as my own issues and not due the parts themselves. They are not complex. I'll defend my error by the fact that I referenced only these pages for setup and no other sources. The float bowl vent thing hadn't yet been discussed. But beyond that these carbs seem a great modification to the motor. I've always liked the cvk on the modern bonnevilles and my Harley friends love them on their sportsters. If you like to tinker you should give these a try.
Now to clean up my old bs38 and send to eBay!
scabber
XS650 Guru
Troop that is good news you got the problem solved. I never liked the 2into1 exhaust and advised against it many times. The CVK is the carb of the future for the 650 my opinion and others who have tried them. Newer and better. Old carbs don't get it done replace. Well worth the effort. 
troopthrowback
XS650 Addict
Brilliant! You know it'll hold up to fuel then.
christopher9
XS650 Enthusiast
Good idea! you can make it the thickness you want. I didn't want to rob parts from functioning carbs.
troopthrowback
XS650 Addict
So this weekend is the real test for these carbs in my mind. I've entered in this 300 mile enduro and will be riding my Yambler in it, carb swap and all. I'll give a report on the carbs over the haul and any issues. For a full ride report I'll post it up on the off road XS thread and link it here.
I'm running 5" long Uni foam filters and have a spare set ready at the halfway mark to swap in as per recommended by old timers on this route: dust is an issue.
Other than that 138/38 and 1.5 turns out with GJH needles set on the bottom clip with a shim. Shorty glass packs (perhaps with some wire inserts for spark arresters if I can get it together last minute) in stock headers. Stock bore 650 with old points and stock alternator. Big fat AGM battery, too.
I routed the float bowl breather up under the seat with some spare fuel line to keep it clear of debris and high for water crossings. I figure I'll avoid getting my butt wet so that's a good spot.
I feel confident these carbs will be fine. I appreciate their simplicity, apparent quality of manufacture, light weight, and success in so many other applications. The ready ability to find parts is a big plus, as is the change in power characteristics.
Wish me luck! (With my level of off road skill I'm going to need it...)
I'm running 5" long Uni foam filters and have a spare set ready at the halfway mark to swap in as per recommended by old timers on this route: dust is an issue.
Other than that 138/38 and 1.5 turns out with GJH needles set on the bottom clip with a shim. Shorty glass packs (perhaps with some wire inserts for spark arresters if I can get it together last minute) in stock headers. Stock bore 650 with old points and stock alternator. Big fat AGM battery, too.
I routed the float bowl breather up under the seat with some spare fuel line to keep it clear of debris and high for water crossings. I figure I'll avoid getting my butt wet so that's a good spot.
I feel confident these carbs will be fine. I appreciate their simplicity, apparent quality of manufacture, light weight, and success in so many other applications. The ready ability to find parts is a big plus, as is the change in power characteristics.
Wish me luck! (With my level of off road skill I'm going to need it...)
scabber
XS650 Guru
That's another good luck from me. The carbs should not be a problem. Sounds like a good test for them.
mrbatavus
XS650 Member
recently threw a set of stock 05 ninja carbs on a non running bike.
it idled, but the throttle plates are super stiff in either direction? do i need new bushings?
it idled, but the throttle plates are super stiff in either direction? do i need new bushings?
scabber
XS650 Guru
I would spray some WD-40 or some light oil and lube the shaft. It might free it up.
troopthrowback
XS650 Addict
This last weekend was the Sheetiron 300, a two day, 300 mile dual sport rally hosted by the Oakland Motorcycle Club. I rode my 1978 xs650, the Yambler, to which I'd swapped carbs from a 1999 ex500.
Here is my ride report:
http://www.advrider.com/forums/showpost.php?p=24199680
As far as the carbs go, they performed flawlessly. Absolutely magical on the 300 miles of trails and fire roads. My 5" uni filters continued to work fine on day 2 even thigh they appeared to be caked with dirt and dust. I had brought along a second pair to swap but never needed to.
The motor started first or second kick with little effort, when dead cold I would hold the choke open with one hand (no cable fitted) and kick from seated as it would fire right up. Let the choke snap shut and give a little throttle for 15-20 seconds until warm. That's it.
I'm trying to think of what else to say. The carbs worked! I ditched out rather than crossing a rather deep creek on day 2, which most agreed was too deep for the Yambler. I honestly had not a single problem with the carbs. On every type of terrain the response was instantaneous and easily controlled. The last 40 miles of day 1 was spent on a single cylinder due to a faulty points condenser. The carb (the one operating) did a fantastic job feeding that 325 cc single and got me to the finish.
I'm very happy with this swap and I'm never looking back. Time to clean up my bs38s and get rid of them, I'm sold!
Here is my ride report:
http://www.advrider.com/forums/showpost.php?p=24199680
As far as the carbs go, they performed flawlessly. Absolutely magical on the 300 miles of trails and fire roads. My 5" uni filters continued to work fine on day 2 even thigh they appeared to be caked with dirt and dust. I had brought along a second pair to swap but never needed to.
The motor started first or second kick with little effort, when dead cold I would hold the choke open with one hand (no cable fitted) and kick from seated as it would fire right up. Let the choke snap shut and give a little throttle for 15-20 seconds until warm. That's it.
I'm trying to think of what else to say. The carbs worked! I ditched out rather than crossing a rather deep creek on day 2, which most agreed was too deep for the Yambler. I honestly had not a single problem with the carbs. On every type of terrain the response was instantaneous and easily controlled. The last 40 miles of day 1 was spent on a single cylinder due to a faulty points condenser. The carb (the one operating) did a fantastic job feeding that 325 cc single and got me to the finish.
I'm very happy with this swap and I'm never looking back. Time to clean up my bs38s and get rid of them, I'm sold!
scabber
XS650 Guru
Good to hear your weekend went well and the carbs performed flawlessly. Thanks for the feedback and ride report. Have a fun summer on a great bike for having fun with.
Mine were completely stuck when I got the carbs. I used carb cleaner and patience, eventually they came back to normal. Must be some varnish in there, I don't think they can be replaced.
Some jetting feedback after I attempted to go with no-name mufflers on stock headers:
First ride out, they idled very well but wouldn't take any WOT. They also didn't sound too nice for my taste. Thought they were running lean so I went one size up on mains (140 now). Better but still cannot take WOT.
I don't like the sound of the exhaust at all, so I went back to the stock '78 special exhaust, which is actually in great shape, lo and behold going up one size on the mains actually improved 1/2 to WOT pull quite significantly over 138 and stock exhaust.
Just when I thought they couldn't run better, got a wow moment and am convinced to just keep the stock exhaust as it's got the best performance and sounds great as it is.
My set up for now is: 40 pilot, 140 mains and JJJ needles at halfway point, on UNI pods and stock exhaust.
First ride out, they idled very well but wouldn't take any WOT. They also didn't sound too nice for my taste. Thought they were running lean so I went one size up on mains (140 now). Better but still cannot take WOT.
I don't like the sound of the exhaust at all, so I went back to the stock '78 special exhaust, which is actually in great shape, lo and behold going up one size on the mains actually improved 1/2 to WOT pull quite significantly over 138 and stock exhaust.
Just when I thought they couldn't run better, got a wow moment and am convinced to just keep the stock exhaust as it's got the best performance and sounds great as it is.
My set up for now is: 40 pilot, 140 mains and JJJ needles at halfway point, on UNI pods and stock exhaust.
scabber
XS650 Guru
Welcome to the site. Getting another set of bs 38 carbs is not the best solution. The CVK is. Try them and find out for your self. So far no one who has is putting there old carbs back on.
With a bit of shopping around you might find a set of the EX500 carbs cheaper than a so-so set of BS carbs.
The needles and jetting has pretty much been figured out. As scabber says, try them. You just might like them.
Leo
The needles and jetting has pretty much been figured out. As scabber says, try them. You just might like them.
Leo
christopher9
XS650 Enthusiast
The most I have paid for a set of these cvks was $100 off a low mile 2002 ex500, and I got another set for $50 with the Kawasaki push/pull throttle. I have some 38's but they are original to my 78 even when I swap them they are staying with the bike.
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