CB650 Spark Splug Problem PLZ HELP

If it's broken or just needs tweaked

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Sat Mar 31, 2018 11:20 am

If possible I'd take it for a ride, give the motor a chance to see what it'll run like under load for a distance rather than have it running at a stand still. See if a good run will burn off the fouling so to speak.

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Sun Apr 01, 2018 12:03 am

I took it for a ride in my previous comment I just forgot to say that. It did rev past the 5500rpm and I accidently redlined it which spooked the hell out of me. Past 6k the engine feels like its gonna shake off the bike and gives me a buzzy feeling through the foot pegs passing up my body :D . After I got home I checked the plugs and they were still fouled but my suspicion is the battery. I checked it this morning and it was at 12.34v when it should be higher. Im thinking the battery isnt producing enough power for my sparkies which is why it is fouling. This is the only variable I could think of that changed because I had charged the battery the night before when I finally got my plugs lean with the other air filter a few days back. I currently have the battery charging and will take it out tomorrow on a long run and see if it it still fouls. I did the measurements in the clymer book with the alternator and stator and they check out ok but maybe when it gets hot it craps out because I always have to trickle charge the battery to bring back up to 12.7 weekly if I run it. This is the second battery its gone through. How should I check this?
Anything else I should check out?

edit: I bought the battery in October last year so its still kinda new

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Sun Apr 01, 2018 3:50 am

Electrics is where I start pulling my hair out :roll: but my very basic understanding is that the alternator supplies the power for the spark and the battery stores up any left over charge to start the bike or at times when there is a greater load than the alternator can put out, like having lights on at low revs in traffic.
As for your engine feeling like it was gonna shake out, that brings two thoughts to mind, carbs need syncing or its an old engine design, these SOHC's are never going to be as smooth as a DOHC with all its balance shafts, twin cams and other doohickies that smooth things out. It all depends how bad the shaking is, the faster you go, the more its gonna vibrate.
When you had the carbs to pieces did you have the slides out? were there any small washers under the slide needles? I've heard of this happening on some bikes to richen the mixture.

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Sun Apr 01, 2018 4:51 am

A night owl huh? Me too. I like the high rpm vibration because it kinda makes my bones tingle. I checked the bolts mounting to the frame and they were all good I think that just how they are. I finished charging my battery and Ill take it out when the suns up. As for the slides I split the carbs and removed them for cleaning with wd40, I never really checked them for washers and probably wouldn't have noticed at the time anyways. Ill post the results of the ride in a few hours.

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Sun Apr 01, 2018 6:43 am

Hi WT, "A night owl huh? Me too." No mate, its just after dinner here in the UK :lol:

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Sun Apr 01, 2018 11:05 pm

I guess I didnt notice the flag in your profile pic. :oops: Before taking out the bike the battery was testing 12.72v and it started easily but I had to feed it some throttle a couple of times because it would die down while warming up. Choke seems to no longer have an effect but just bogs it down after a few seconds. Idle was set at 1500rpm when warm and the bike was so damn smooth it was great that advancer thing made huge a difference. Unfortunately plugs were still fouled except for #1 which is still lean and white; the same as the previous tests. The three fouled plugs had a clean white spot near the top of the insulator by the electrode. Battery was measuring 12.67v immediately after getting home from the ride. The measurements from the rotor are 1.2-3ohms when putting both leads on the same ring, seems a bit high. When measuring both rings together with a lead on each it reads 5.5ohms which is good according to the book.

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Mon Apr 02, 2018 4:00 am

TBH, I have no idea what that that flag is supposed to be, there was another guy on here from the UK when I first started using this site and he was using the Union Jack flag so I just grabbed the one I'm using as it has the small Union Jack in it . Well at least the bike is getting a bit better but you still seem to have a bit of a rich problem but as far as I recall, we have tried just about everything that I can think of. I'm not sure if I asked you this or if it was somebody else but asking again won't hurt, is there any fuel smell from your exhaust? You have set your float levels correctly? Have you tried the clear tube method to check your fuel levels? seeing as you have a difference between number 1 and the rest of the plugs I'd just do it on carb 1 and carb 4 to see if there is any obvious difference as getting at the middle two are a bit awkward while they are still on the bike. https://www.youtube.com/watch?v=PHuB1lyagKM Make sure to have the bike on the centre stand and try to get the float bowls as level as possible, the general consensus on the net is that the fuel level should be around 3 to 4 mm below the gasket face on the float bowl.

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Wed Apr 04, 2018 4:29 pm

I think you right about the float problem because I turned my petcock on for a couple minutes and one of them started peeing gas when I came back. I dont have the prime setting on the petcock but if I do this trick wont it be misleading because once the gas empties from the bowl and the float opens the rest of leftover gas in the fuel tube will come down and change the result? Ill give it a try anyhow

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Wed Apr 04, 2018 4:47 pm

#1 was 19.48mm away from the mating surface of the gasket for the bowls and #4 was 26.??mm from the gasket surface. So #1 is actually getting more fuel then #4 but in leaner. How can this be? I opened both drain screw at the same time. Bad stiff air cutoff valves? I dont know what else to do anymore.

Here #1 carb
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#4 Carbie
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#4 spark plug
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Prepare yourself because I just figured out how to upload pics :D

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Thu Apr 05, 2018 3:42 am

When you use the clear tube it is best to hold the tube against the float bowl and do one carb at a time, the vid was just to give you the basic idea. Have a sharpie marker at the ready, hold clear tube against float bowl with one hand, undo drain screw with the other, wait for fuel level to settle without moving the tube up or down. When the fuel level has settled you can move the clear tube down against the float bowl and you will see the fuel rise to up to the level again, do not move the tube up against the float bowl or you will get a false reading. When you are happy that you have the correct level in the tube mark it with the sharpie on the side of the bowl then do the same on your #4 carb and compare the differences.
When you have fuel peeing out of your overflow give the offending float bowl a couple of taps with a plastic screwdriver handle to reseat your float valve.

" I dont have the prime setting on the petcock but if I do this trick wont it be misleading because once the gas empties from the bowl and the float opens the rest of leftover gas in the fuel tube will come down and change the result? Ill give it a try anyhow"
I thought you had the slide carbs on your bike? if you have then just switch your fuel to ON because you won't have a vacuum tap.

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Folsoml
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Re: CB650 Spark Splug Problem PLZ HELP

Postby Folsoml » Thu Apr 05, 2018 5:39 am

GeorgeSweety wrote: I thought you had the slide carbs on your bike?


Those are PD 50's--which are the slide carbs.

WiseTurtle wrote: if I do this trick wont it be misleading because once the gas empties from the bowl and the float opens the rest of leftover gas in the fuel tube will come down and change the result?


I'm guessing by now you've seen that the level of fuel in the tube will not rise past the level in the bowl?

WiseTurtle wrote: So #1 is actually getting more fuel then #4 but in leaner. How can this be?


The amount of fuel in the float bowl has no effect on how lean or rich that cylinder runs. The engine can only take in as much fuel as is allowed by the jets and settings on that carb. It's like how the amount of fuel in the fuel tank has no effect on how the engine runs (except of course when the amount is "none" :lol: Once the level gets to "some," however much more you add changes nothing.)
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Thu Apr 05, 2018 8:43 am

Folsoml wrote:The amount of fuel in the float bowl has no effect on how lean or rich that cylinder runs. The engine can only take in as much fuel as is allowed by the jets and settings on that carb. It's like how the amount of fuel in the fuel tank has no effect on how the engine runs (except of course when the amount is "none" :lol: Once the level gets to "some," however much more you add changes nothing.)


"Symptoms of Incorrect Float Heights
In an extreme case, if the floats are set too high, fuel will overflow via drillings inside the carb body. In addition, fuel may flow into the engine unrestricted, which, if the engine is not running, can cause hydraulic lock – that is, as the piston rises on the compression stroke it cannot compress the fuel.

If fuel is leaking from the carb, it can potentially cause a serious problem – fire. If the fuel height is too high but the bike is running, the engine will have a tendency to display a rich running condition, which will make the throttle response slow and the engine note muffled. This condition is generally accompanied by a strong smell of unburnt fuel from the muffler. If the fuel height is too low, the engine will display a lean running condition, where the engine typically hesitates before accelerating or surges as the throttle is opened. The bike may also misfire when the throttle is closed."

Above taken from here, https://www.fix.com/blog/motorcycle-car ... djustment/

It boils down to the amount of pressure inside the float bowl caused by too much or too little fuel in the float bowl, otherwise why even bother having a spec for a float height as it wouldn't be needed.

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Thu Apr 05, 2018 10:51 am

Yeah I did the float test wrong so Ill do it again when I get back home later today. College is such a drag here :( Whats your opinion on the spark plug pick that I posted. Why the white spot?

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WiseTurtle
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Re: CB650 Spark Splug Problem PLZ HELP

Postby WiseTurtle » Fri Apr 06, 2018 2:58 pm

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GeorgeSweety
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Re: CB650 Spark Splug Problem PLZ HELP

Postby GeorgeSweety » Sat Apr 07, 2018 2:02 am

Hi WT, that metal hoop in pic 1 is just a vent pipe guide, the vent pipes between 1&2 and 3&4 carbs should point up and pass through the hoops towards the back of the engine. I have no idea what that plastic T piece has been used for but it has been added by a PO.
Pic2, I don't know what you are showing that one for?
Pic 3 The red thing looks like a fuel filter but where the hell is it connected to? Have you disconnected the fuel pipe and it is just resting on top of the carbs? If it is connected there then I have absolutely no idea what is going on.


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