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Discussion Starter #1 (Edited)
Cleaned CVK carb on 360. Idles nice, but rough on the way up. I did not replace the little o-ring in the idle adj screw. Would that make a big difference? I have adjusted the idle rich and lean and now it is in the middle.
No exhaust leaks and has a clean filter. Low hours. At high rpm it appears to have a miss. ( Did not change the plugs or clean them due to the low hrs.) Any advice on what and where to look will be appreciated.


Surely there must be an expert out there who knows how to tune a CVK and would like to share some insight in to this problem. Give it a try, I dare ya.
 

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carb tuning

I'm def not an expert with kawi yet, but id start with a plug and fresh fuel. preferably 93 octane if you have access to it. And from what i have read on this site, a valve adjustment is a frequent occurrence on these bikes.
 

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Discussion Starter #3
Great minds think alike. Got some 93 octane, with a little sea foam, installing plugs today. If that fails then I'll do a valve adjustment. I also ordered new idle adjustment screws, that you can reach. Thanks for the tip.
 

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Great minds think alike. Got some 93 octane, with a little sea foam, installing plugs today. If that fails then I'll do a valve adjustment. I also ordered new idle adjustment screws, that you can reach. Thanks for the tip.
Idle adjustment screw; or the pilot screw? thats the one i can't get to.
 

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Cleaned CVK carb on 360. Idles nice, but rough on the way up. I did not replace the little o-ring in the idle adj screw. Would that make a big difference? I have adjusted the idle rich and lean and now it is in the middle.
No exhaust leaks and has a clean filter. Low hours. At high rpm it appears to have a miss. ( Did not change the plugs or clean them due to the low hrs.) Any advice on what and where to look will be appreciated.


Surely there must be an expert out there who knows how to tune a CVK and would like to share some insight in to this problem. Give it a try, I dare ya.
Why did you clean the carb in the first place?
If the machine is stock, put all the carb settings back to stock; there should be no tuning involved.
Then find the problem.
 

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Discussion Starter #6
Bike sat up for a year in a hot barn with regular fuel running to the carb. Was a mess of sticky goo. Also cleaned the tank and fuel lines and replaced filter. Since the first post I have been able to tune it close but still have a skip in transition speed range. Ordered new idle adjustment screws, accessible from outside of the CVK. And you are correct the settings were best at the original position. The CVK appears to be very sensitive to minor adjustments. Thanks for your reply.
 

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93 octane will go bad just as quickly as 87, plus it burns cooler and slower, so could be adding to your problems if the 360 calls for 87 octane.
The CVK carbs are not overly sensitive to tuning changes, but they are very sensitive to being gummed up and not clean.
Clean it again.
 

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93 octane will go bad just as quickly as 87, plus it burns cooler and slower, so could be adding to your problems if the 360 calls for 87 octane.
The CVK carbs are not overly sensitive to tuning changes, but they are very sensitive to being gummed up and not clean.
Clean it again.

I would agree that the 93 will go bad just as quick, but it burns hotter when its ignited. the octane rating makes it more resistant to detonation but actually burns hotter than 87. Its more explosive hence the more power you get out of the same amount of fuel. I have never seen any engine run worse on 93 if it only calls for 87 from the factory.
However like Novakaw650 said; if the passages are gummed none of that will make a difference.
 

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Unless its necessary with a higher compression piston, etc, you're wasting your money with the higher octane.
Exactly.
slim86: check basic gasoline theory; the higher the octane, the slower and cooler it burns.
 

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Unless its necessary with a higher compression piston, etc, you're wasting your money with the higher octane.
Exactly.
slim86: check basic gasoline theory; the higher the octane, the slower and cooler it burns.
See thats the thing im sorry i dont have 3,000 posts on here, and dont know kawie's like the back of my hand but im pretty sure that 15 years of working on motors and ASE certs i know enough about gas...

Google it, 93 burns slower, and requires more heat to ignite; equally it creates more heat upon explosion. hence in older engines they specify not to use high octane as it will burn the valves and piston up. Newer engines wont burn up like that (well with pump gas at least). Higher octane does burn slower so if you dont have the compression ratio (hence enough air in the cylinder) to match the extra fuel it may (in very low compression situations) have a slight effect. that would have to be less than 8:1 probably closer to 6:1 compression ratio. However that would be very uncommon.

so yes in my other posts, it may have a VERY small part in my problems, but i've never seen an issue from it. even in a cheap walmart lawnmower that i bought 10 years ago, never changed the plug, or had to clean the carb, and the tank has never seen anything but 93 octane! im pretty sure im doing something right, im sure luck would have run out after the third or fourth winter of it sitting outside.
 

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Slim, I'm not gonna attack you but am interested in picking your brain a little.

I've had ASE mechanics tell me to run premium and I'll get that money back in higher mpg's. I tried it, no luck. I track every tank, write down so i could tell you EXACTLY what I get, even going back 15 years. 4 months later there was no difference. So I went back

Had an '02 2500HD with a reprogrammed computer. Ran great all day long on 86 octane at my elevation of 4,000'. However, when I dropped below 2,000' I could hear it starting predetonation. On a trip near College Station with 87 in it, I thought I was going to blow my engine ascending a hill when it downshifted. I immediately found a station and added premium and it went away immediately.

I haven't had any trouble with any other vehicle except that one that had been altered.

My four wheelers all run 86 because there is no pinging telling me I need to raise the octane to stop predetonation.

I did have a highly modded 400EX that would get 91 but it had a higher compression piston.

I've tried octane boost, aviation gas, 1/2 aviation gas 1/2 91 and in a blind test I couldn't have picked one over the other.

All that being said, that '02 so far has been the only engine that ever told me it needed a higher octane but that was only when I dropped below 2,000' elevation, necessary below 1,000'
 

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drkill, Did you ever run 93 or 87 exclusively in one vehicle and pull the heads for any reason and look at the valves and combustion chambers?

My main reasons for 93 are the cleaner burn of it, and you can load a motor much more with the higher octane. your truck would be giving you a problem when going towards sea level because of the denser air. It would take some time for your ecu to calibrate timing and the fuel maps to compensate for it. some tunes with aftermarket programers will just not give you what your looking for no matter what. not to say it was junk by any means, but it i have seen some programmers not look at the factory knock sensor and ignore that sensor. which will give you your symptoms. but a programmer that only uses 87 isn't doing very much for you in the first place. what kind of tune was it on? the whole point to a tuner is to add timing and utilize the octane. Most vehicles should show you some difference in mpg. I find that weird that you saw nothing.

I too track all my mpg's, and have always seen some kind of increase though im at sea level. but never instantly a difference with my wifes murano i have to run three tanks before the ecu will change and see a difference in mpgs. typical increase ive always seen is .5 mpg untuned.

I dont just use 93 for detonation control its cleaner burning, and i personally see mileage increases. last comment; i had an 01 VW GTI with the 1.8T motor that i ran nothing but 93 in all 225,000 miles when i sold it. with the factory software it got 30mpg with 87, 31.5 mpg with 93 on that same tune. with the 93 tune it would get 33mpg. if i ran 92 on the 93 tune it would set a light and pull timing and boost out with in 10 miles. (it was an accident, pump said premium but their premium wasn't 93 come to find out it was 92).
 

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I'm not saying you have to run 93, just that i've had good results with it. and have NEVER see where it was hurting how any engine ran.
 

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BS,; if you burn a higher octane than needed, it increases carbon buildup due to slower, cooler burning. This is not a hopeful guess, this is fact.
I also run a Mercury Optimax; it calls for 87. As per Mercury; "if you use gasoline higher than the recommended 87 Octane, you must do a decarbonizing treatment every tankful of fuel.
 

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Discussion Starter #16
Good advice but not on subject

You guys have the knock theory down pretty good. However, It appears that my carb is ok but the timing may not be advancing on run up. Is that possible? Need some expert advice on timing advance in a 360 Prairie. Then it could be the cam. Pops and sputters on run up, idles perfectly, give it some choke and it will run up a bit then spit and sputter. This Kawi is a sick puppy.
 

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Bike sat up for a year in a hot barn with regular fuel running to the carb. Was a mess of sticky goo.
The CVK carbs are not overly sensitive to tuning changes, but they are very sensitive to being gummed up and not clean.
Clean it again.
It appears that my carb is ok but the timing may not be advancing on run up. Is that possible? Then it could be the cam.
So it ran well, sat for a year and gummed up the carb, but the problem is now the timing or the cam? What makes you feel that sitting for a year adversely affected either of these parameters?
 

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Discussion Starter #18
carb or cam

The reason is that I overhauled this carb carefully and tested each port, replaced the idle screw, it is clean clean clean. I set the adjustments per service manual + years of amateur experience. New plug. Posts on forum say cams go out on the 360's. It will idle all day, no smoke, sounds smooth. When I bring the speed up it hesitates, backfires, stalls, just acts like the spark timing is not advancing. If this were a '53 Plymouth flat-head six I would say the distributor timing was off, but it's not and I'm baffled. Also, before I overhauled the carb this is how it ran. It's like cleaning the carb had no affect. I just don't know where else to look for a problem. Give me a clue and I'll check it out, Thanks.
 

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The reason is that I overhauled this carb carefully and tested each port, replaced the idle screw, it is clean clean clean. I set the adjustments per service manual + years of amateur experience. New plug. Posts on forum say cams go out on the 360's. It will idle all day, no smoke, sounds smooth. When I bring the speed up it hesitates, backfires, stalls, just acts like the spark timing is not advancing. If this were a '53 Plymouth flat-head six I would say the distributor timing was off, but it's not and I'm baffled. Also, before I overhauled the carb this is how it ran. It's like cleaning the carb had no affect. I just don't know where else to look for a problem. Give me a clue and I'll check it out, Thanks.
Okay, so now we know it didn't run right before; that's not to say that it's not still a dirty carb.
The cams don't wear, but the valves will go tight. That usually causes a hard starting symptom rather than a miss.
Spark plug, coil wire, coil connections all good?
It also sounds like the carb slide isn't opening; are you able to see if the slide is opening when you open the butterfly (with the engine running)? Also, the CV carb needs the complete air box and filter in installed to react correctly.
 

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Discussion Starter #20
check draft tube

You may be on to something in you last comment about the air box and vacuum draft tube. Mine is connected to the carb but may not be connected to the air box.

Cranks up without throttle or choke and idles perfect. Rules out some of the other possible causes. Could be that the slide is not performing to spec. Will check today and reply. Thanks for all of your tips. Eventually WE will get this bike running right.
 
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