Cafe Racer Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
148 Posts
Discussion Starter #1
ok, after a really horrible work week i return to find my 75 cl360 will not idle properly. sems to be hitting on only one cylinder. only had a few minutes to try and start it (had too much to do!), but first thing after work tomorrow i plan on tearing into it. so, after riding it only a week ago (ran fine, did backfire once though) what process should i take to narrow down my problem? since i am not an expert on this bike i can only ask what a more knowledgeable person would do. (has plenty of fuel in tank, battery is well charged, and switches are on)
-how does one check the points for proper function?
-if i have fuel flow through both carbs (bleeder screw) does that mean i am getting fuel?
it will kick start, but after a moment it dies off. i believe all the switches and fuses are fine, but some faulty part of the spark or fuel system is my belief.


03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
5,782 Posts
First thing I would do is check/replace the plugs. Looking at the plugs can tell a lot. Pull the plugs and report back as far as color, i.e. white, tan, black. and condition, i.e. wet, dry, oily.

Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

·
Registered
Joined
·
3,431 Posts
My 360 seems to eat left side spark plugs. They to only last 100 miles or so, then just crap out. I thought the problem was the coil or some thing, but just put in a new plug and off I go. I bought a bunch of plugs at the same time so maybe it was a bad batch.

Any thoughts on this Ken?

Thanks,
Jack
 

·
Registered
Joined
·
5,782 Posts
I don't really have a good idea, but I have had cases where a bike just didn't like a certain brand of plug. My cb400f race bike would eat the electrodes off of ND plugs. NGK and Champion were fine. I had a CB350 race bike that would eat Champions like candy. ND and NGK were fine. So I don't know the cause but I just kept the right kind of plug in them to cure the symptoms.
This sounds like it might be a Xander450 question. I might suspect a coil problem or maybe a condenser issue. I really haven't seen this occur with an electronic ignition. Can timing do this?

Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

·
Registered
Joined
·
1,112 Posts
For checking/adjusting the points at idle, you can "static" time it. All you need is a test light, an oil pan (it'll only drip a little), a 14mm wrench, a screwdriver to take the points and stator cover off....and a manual.

Seriously though, its a simple procedure that I suppose on a 360 is very similar to a 350 (which I am familiar with). There are some marks on the rotor that, when lined up with the timing mark on the stator case, indicate when the points should be firing. The manual will do a much better job explaining it all than I could.

On another note, has the bike recently run out of gas or have you removed the fuel lines from the petcock? In such cases, an air bubble can form in the fuel line that restricts flow. Your problem sounds like it may be caused by fuel starvation.

Like Ken said, check the plugs after trying to start it. If they are wet, chances are you've got enough fuel. If they are dry, you've gotta re-prime the lines.

Does a 360 have that stupid "fuel crossover" line that 350's have? I capped mine cause I was sick of spilling fuel everywhere every time i had to remove the tank. Now, if I get careless I get the ironic pleasure of running out of gas with my tank half full. I've gotten some strange looks standing on the side of the road as I lean the bike wayyy over to the right so fuel trapped on the left side can spill over.

Old bikes rule...





Honda go sideways!
 

·
Registered
Joined
·
278 Posts
My bet is you have at least two problems to solve. A lot of things happen when you leave a bike sitting, even for a week - the battery drains somewhat (maybe 5%), the gas in the carb bowls evaporates, leaving additive sludge in your jets and other very narrow passages through the carb. Points sag, but not in a week. So these things happen, but they won't, by themselves, prevent your bike from running normally. That is to say, if all else is good, your battery can be a little low, your carb can have a bit of shite in it, and it'll be okay. Bikes get unreliable when combinations of problems develop.

Odds are your carbs are the main culprit here. If you want to test that theory, put a new spark plug in the non-running side, spray carb cleaner down the throat of that side's carb for about three seconds and then immediately try to run the bike. If that side runs for a few seconds, your carb was the issue - clean them both and replace that side's spark plug and you'll get your cylinder back. But you shouldn't stop there, because an unreliable bike is in many ways worse than just walking.

If you don't know how to set your timing (sounds from above like you don't), it's a fair bet your timing's off because that does need to be done relatively often (for my old Hondas, twice yearly, or as often as I decide to have my engines apart for some reason or other). The manual's got instructions so I won't repeat them, but I'll offer this - you can time statically without a timing light if you haven't got one. Just do it in a quiet place. Pull your plugs and ground them against the engine. Then, when you slowly turn over the flywheel, listen carefully - your plugs will click when they fire. Dynamic timing is more accurate, so definitely use a timing gun if you've got one available.

Oh, and you probably also need to take the slack out of your cam chain.

...and to answer your question about testing points: Pull the spark plug for that side. Re-attach the plug to the plug wire and ground against the engine so that the tip is touching grounded metal and your hand is nowhere near it. With the points cover plate removed and the bike on (but not running), push the point that corresponds to the plug open (they correspond visually - left point operates left plug) with a screwdriver. The plug should fire every time you push the point open. That tests to see if the ignition system works - you'll have to follow the timing procedure to make sure it's tuned.

How do these always get so long??

A
 

·
Registered
Joined
·
148 Posts
Discussion Starter #7
will do. once i get everything done here, i'm gonna start playing with the cl. i've been wondering how to adjust the timing if needed, adjust the cam tensioner, and the manual i downloaded gives a great deal of info. breaking that info down in to manageable parts is difficult since i have to unlearn alot. seems the points system was outdated since my very first bike, so i never have worked on one, i comprehend the theory, pretty well. carbs are something i never EVER wanted to have to fiddle w/....(fuel injected/ throttle body on the aprilia!!!), but i hear tearing a set of carbs down is required to call oneself a "cafe rider", hehehe.
i'll get an update ASAP, thanx again

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
3,453 Posts
Don't be afraid of your carbies. I've had to tear apart my carbs almost a dozen times. It gets easier every time. Most parts only fit in the place where they belong. Just don't skimp on time spent cleaning them. Do one at a time, so you have something to reference when it's time to reassemble.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #9
ok pulled both plugs after turning the bike over a few times. it did start and ran for a few seconds, but still sounded as if it was hitting on only one cylinder. plugs were within normal color (a little brown and black but still clean) and both had some fluid on them which gave them both a wet look. both smelled strongly of fuel. opened the points and turned the kick start over a turn or two and both points opened. not sure if they are in time as needed, but they aren't stuck closed either. i have two of the see-thru fuel filters and both have very little fuel in them.... msybe what little fuel is getting to them is limited. i will attempt to draw fuel through the system and prime the carbs... i expected some fuel/ flooding smell if i had flooded the bike, but hasn't happened.

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
278 Posts
quote:
ok pulled both plugs after turning the bike over a few times. it did start and ran for a few seconds, but still sounded as if it was hitting on only one cylinder.
You did what?

quote:
plugs were within normal color (a little brown and black but still clean) and both had some fluid on them which gave them both a wet look. both smelled strongly of fuel.
Nothing about that sounds normal to me. Beige sounds normal. Brown and black sounds fouled.

quote:
opened the points and turned the kick start over a turn or two and both points opened. not sure if they are in time as needed, but they aren't stuck closed either.
That doesn't really demonstrate anything - points rarely sag enough to stay closed throughought the travel of the cam lobe. Kick the bike over until your points stay closed, flip the switch to on, and then push them open with your screwdriver. Watch the plug spark. No spark, tell us and we'll instruct.

quote:
i have two of the see-thru fuel filters and both have very little fuel in them.... msybe what little fuel is getting to them is limited. i will attempt to draw fuel through the system and prime the carbs... i expected some fuel/ flooding smell if i had flooded the bike, but hasn't happened.
The filters rarely LOOK as though there's fuel flowing through them. Just turn off your petcock and drop your float bowls - they should be approximately 1/2 full (there is an exact setting, and we'll get to that).

Follow me here - you can visually determine if you're getting spark, and you can simply test if your carbs are the problem by spraying something combustible (i.e. carb cleaner, starter fluid) directly into the throat of the carb with throttle held open and the spray can straw stuck under the carb slide.

A
 

·
Registered
Joined
·
148 Posts
Discussion Starter #11
ok, heading to buy a few plugs.... ngk BR8ES are in it now, gonna buy a few more to clarify the good plug/ bad plug question....baby steps right???

did get flow thru the see-thru filters finally just disconnected the line from the petcock and the air trapped in the filters was evacuated! bike still runs but sounds like it's hitting on one cylinder. and it makes sense to be the left side/ while sitting on, since it has a warm pipe, right...? just offering more info

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
278 Posts
Excellent, the more info the better. As for which side is running - yep, pipe temp is a good indicator. Another way to tell is to manually manipulate the throttle arm on the carb. If you lift the running side, engine speed will increase; if you lift the non-running side, the engine sound will change but the speed won't increase significantly.

A
 

·
Registered
Joined
·
148 Posts
Discussion Starter #13
ok new plugs in it, got the b8es which manual calls for, not the br8es which has higher resistance and was in it....
well put them in, and after 2 cycles of inactivity the right side fired up!! yeah, but bad news... the bike idles fine even comes off the "stumble" just right!(after throttle most old bikes i have ridden struggle for a second to get back in sync) and damned if the bike won't respond to throttle. i tried a few times to gradually apply throttle and see if it catches up, but the bike won't respond to throttle like it did.
so i pulled the new plugs just to inspect and they are identical to the old ones with some light black/ grey on them. i even charged up the batt. while i drove to the parts store so i remedied two at once.

so what next???

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
5,782 Posts
Did you replace the plugs or just check them. As Xander suggested, several marginal components can cause a system failure. So change your plugs and see what happens.

Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

·
Registered
Joined
·
148 Posts
Discussion Starter #15
i changed them with new ones to what the manual calls for the non-resisted type by ngk the b8es, the previous owner put in br8es and it ran great up until a few days ago (it sat for a week)

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
3,453 Posts
Correct me if I'm wrong, but aren't the first steps here to adjust the valves, then make sure the timing is set properly? Then new plugs. At this point I think you'll be ready to rebuild your carbs (which I'll bet is the culprit) & solve this problem once & for all. This sounds suspiciously like a carb problem to me.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #17
ugggh, that sounds kinda like a long and blahhh process. but if i do it everyone will be hearing about how i broke something that i don't even know the name to. well, i'm still waiting on some more info from xander on the culprits, but if it ran well before it sat a few years, had carbs cleaned, and ran well again, sat a week, and doesn't run.... well i see a pattern here... a carb cleaning!

03 rsv Tuono (STARF8R)
81 cb750f (stolen)
75 cl360 ("Chupa"thingy)
 

·
Registered
Joined
·
5,782 Posts
I am not sure we are done with the ignition yet. Sitting a few weeks should not cause a major carb problem and refusing to rev out can be an ignition problem. I am a little suspicious of the points. I would clean the points, set the points gap and static time the engine.Dirty points or almost closed points with partially fouled plugs will cause these symptoms. Then I would DO WHAT XANDER SUGGESTED AND CHECK FOR SPARK WITH NEW PLUGS BY MANUALLY OPENING AND CLOSING THE POINTS!!! Diagnosis over the internet only works if you follow the steps and report back.
Ken


AHRMA 412
Vintage racing - old guys on old bikes
 

·
Registered
Joined
·
3,431 Posts
Did you happen to check your air filters? When I first got my bike it ran awful. It had the original air cleaners and they were filthy. Took them off and it ran much better. Just a thought.
 

·
Registered
Joined
·
278 Posts
Good progress. Don't be disappointed that you didn't entirely fix the problem - it is extremely rare that fouled plugs, once replaced, actually solve a problem. Fouled plugs are a symptom, not a cause.

So here's what we know:

Your plugs foul. There are five main reasons why that happens, in no particular order:

1. Your rings, valve guides or valve stem seals are worn. Not likely in this case - your plugs would be black and oily, unlike gas-fouled plugs, which are gray/black and fluffy.

2. Your timing is retarded - that is to say, your plugs fire later in the stroke than they ought to. There is an optimal point in the range at which they need to fire (not TDC, but just before it); this gives the gas enough time to combust and produce the resulting shock wave that will force the piston back down. If it fires too late, not all the fuel burns. What doesn't burn gets deposited on your plugs, piston and cylinder domes and the walls of your exhaust path. This is likely.

3. Your ignition is weak or intermittent. Points often get contaminated, resulting in failure to consistently connect electrically. Then, though the bike will run, it won't burn all the fuel - same effect as above. If you run the test from my previous post, you'll be able to tell us if your plugs spark consistently and what the spark looks like (i.e. fat blue spark, tiny orange spark, etc).

4. Your carbs are fouled. More specifically, deposits in the air channel of your mixture path have caused a shortage of available air through the idle circuit. You'll likely find you're also lean at full throttle for essentially the same reason - the same crap that's clogging your air paths through the idle circuit is also clogging the fuel through the main jet at throttle.

5. Your carbs are damaged or not set up properly. Damage isn't all that common unless someone's been mucking about with them (the exception being 350's with the rubber diaphragms that are notorious for failing). Bad setup, on the other hand, is extremely common.

Let's assume you have a combination of problems 2-5.

2. You can probably get back on the road without addressing your timing, but if your fear of points outweighs your interest in having a reliable bike, you bought the wrong machine. Sell it to someone cheap on caferacer and buy a bike with electronic ignition and fuel injection. While you're at it, go ahead and paint it pink and buy yourself some tassles. Let's come back to 2 in a minute.

3. See previous post.

4. Clean your carbs. I mean, REALLY clean them. The bit you need to pay the most attention to is the channel behind the mixture screw. Your manual will tell you which one that is. Stick the carb cleaner straw down the hole and spray the hell out of it. Carb cleaner will spray out of a hole in the float bowl. Plug it with your finger and keep spraying until carb cleaner pops out of another hole on the venturi wall. Worried about cancer? See above, re: pink bike w/ tassles. Remove and clean every jet and passage. Use an entire can of carb cleaner on the pair. Oh, and resist the temptation to stick a pin through brass jets.

5. Setup: write down the jet sizes while your carb's apart - we'll tell you if you've got the right ones in there. What's your elevation? Maybe your carbs are fine but your air's too thin and you need to jet down. When you put them back together, set the mixture screw 1.5 turns out, then follow the book directions to adjust it to get it perfectly dialed in - or check back here.

SO. Do 3 first, it takes five minutes and there's a lot that that rules out. Then 4-5, as that will probably get your bike running on both sides. Then do 2 so I won't make fun of you.

A
 
1 - 20 of 27 Posts
Top