I bought a 1974 cb360 about a year ago and have been working on it off-and on (it's my first bike or attempt at fixing). Unfortunately it has no power whatsoever and wants to die really quickly (within about 5 minutes). It just runs like ****. And my only guess is that the floats are messed up. Can anyone help me? It's making me livid..
carbs cleaned and synched
new clean oil
points and valves adjusted properly
plenty of gas in the tank
compression is fine
spark plugs are in good shape
(I don't have filters on it yet, and I don't think that is the issue).
bike idles well while standing
no smoke
I haven't even attempted to take the engine apart because I wouldn't know what to do with it anyway. My assumption is that it's still the carbs. Maybe it is just the floats? Any other suggestions? I would really really appreciate it. Like I said, I'm really new to all of this and am not quite ready to give up yet...
2007-08-09 13:24:30 · 10 answers · asked by pjilbs 1 in Cars & Transportation ➔ Motorcycles
The carbs, diaphragms, and jets inside are cleaned out very well. I took great care in cleaning them out and putting it all back together.
The gas is fresh as well.
2007-08-09 14:20:12 · update #1
You have pilot jets and main jets. Chances are the pilot jets are clear but when you apply a load to the engine the main jets are restricted. Drop the bowls (it is worth the hassle) and remove float,needle valve and pilot jet. Clean jet with a fine wire and then the bowl,needle and housing with carb cleaner and compressed air, not to much though.Good luck!
Also, since you don't have filters on bike, your air/fuel mixture could be off. Adjust with hotter plug or bigger jets.A little bit makes a big difference.
2007-08-09 13:47:53 · answer #1 · answered by Stephen P 1 · 0⤊ 0⤋
I agree with Don. The throttle diaphragms deteriorate on old bikes that have been sitting for a long time.
They also expand and deform, making it almost impossible to reinstall the tops without pinching them.
If you removed the tops, double check that you didn't squish them.
Check the cylinders compression with a compression gauge.
Just feeling, by pushing the kickstart lever is inadequate.
The only problem the floats would give, is letting the carbs overflow, so don't worry about them.
Is the battery weak? Do you have to keep charging it?
This model has battery ignition.
The battery charges the coils to make spark.
A semi dead battery won't have enough power to run the bike correctly.
Edit
Another common problem with those bikes is the timing advancer.
Sometimes it will get corroded and won't move, or the springs get stretched out allowing the advancer to dangle around.
Remove the points cover.
The points are opened and closed by the cam of the advancer.
You should be able to spin it by hand.
Check the springs, the advancer should stay closed on it's own.
You said you adjusted the points, did you adjust the timing?
When adjusting the timing, adjust it at full advance (engine reving, not at idle).
2007-08-09 13:51:41 · answer #2 · answered by guardrailjim 7 · 2⤊ 0⤋
is the gas "FRESH"?
gas gets "old" after about 3 months,
Also motorcycles are usually built in a high state of tune, meaning high HP to displacement size. So, when you get engines like that, they get persnickety and need to be driven everyday.
When you cleaned the carbs, did you blow out all the passages really really well?
a Lawn mower has a "low" state of tune, and will fire up on Mexican gas after sitting all winter, not persnickety.
Also put the filters on it, that may make enough difference to keEp the gas from not getting sucked thru the Carb ventri.
2007-08-09 14:12:22 · answer #3 · answered by mdcbert 6 · 0⤊ 0⤋
I agree with Steve.
A leak in the manifold system is the first thing I'd check for.
Also, (not sure of the year), about that time they went to those vacuum operated petcocks. Look for a leaky diaphragm or hose there.
Second thing:
Check for tank venting. When it dies, open the gas cap.
If there is a sucking sound you know the vent system is clogged and it's restricting fuel flow.
(Happens a lot on long stored bikes - Wasps, spiders etc. love to stuff snacks in those vent holes/hoses.)
If this is the case, you might have to retune after correcting it.
Best of luck, (My first bike, 72 CB 450)
2007-08-09 14:52:50 · answer #4 · answered by Irv S 7 · 1⤊ 0⤋
Idles well, yet dies in about 5 minutes?
Check what guardrailjim told you.
Then, here's one more little thing that gets overlooked - your petcock. If the screen is partially plugged you will have low fuel flow. The bike will run on what's in the bowls at idle, but not be able to re-fill quickly enough above idle.
2007-08-09 16:05:31 · answer #5 · answered by Firecracker . 7 · 1⤊ 0⤋
Make sure that the rubber diaphrams on top of the carbs. are still free of holes or tears.If the carbs have rubber o-rings on the main jets replace them with metric equivalent.If mileage is over 15,000 miles ,the cam may need to be replaced.
2007-08-09 13:33:52 · answer #6 · answered by (A) 7 · 1⤊ 0⤋
I would bet the rubber boot from the carbs to the manifold is rotted and leaking, if that bike has one. Or the gasket between mainfold and carb. It's a distant memory. If that's what is is the thing is hell to start, but you can start it by really spinning up the motor.
2007-08-09 13:34:46 · answer #7 · answered by steve.c_50 6 · 3⤊ 0⤋
This could be fuel starvation - crud clogging up the fuel tap or hose - remove hose from carb, hold over a glass jar & turn on fuel tap - observe flow rate. if slow, find blockage & clear.
2007-08-09 19:30:00 · answer #8 · answered by no_bloody_ids_available 4 · 0⤊ 0⤋
hi
2016-05-18 03:24:34 · answer #9 · answered by janice 3 · 0⤊ 0⤋
How's the ignition timing?
2007-08-09 13:30:28 · answer #10 · answered by HyperDog 7 · 0⤊ 0⤋