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I was driving on the highway today in fifth gear and the bike (stock 73 Honda CB350G) had difficulty maintaining 60 mph in fifth gear. I recently installed a sidecar so I thought perhaps it was too much weight and just dropped to fourth and I was fine. After a stop to pick up my passenger, an hour or so later, the same thing happened but all of a sudden fouth wasn't enough and I needed to pull over.
I restarted the bike and there was a good quanity of blueish smoke coming out of the right tailpipe. I was stopped in a pretty dangerous spot on the shoulder where the 401 meets the 403 south so since the bike was running I limped along the shoulder, down the 403 and got off at the first exit (Eglinton).
The bike was super slugish below 3000 and wouldn't go much above 5000. I could only manage about 30 mph. If I put my hand close to the exhaust the left side is hot and powerful and the right side you can still feel but is barely doing anything. The bike will still rev MUCH higher in neutral, but under load it's like it hits a wall.
Before this happened I found that the bike would only run without stalling if the choke was on. I've only had it a short while.
I'll be taking it in on Monday, but I wanted to hear everyone's thoughts on what the issue could be. The bike's downstairs if you want me to check something, but I'll warn you I'm a mechanical dufus.
First step is to remove the right plug and check for fouling. If it's black and sooty then either it's getting too much fuel or the spark is too weak or non-existent.
First step is to remove the right plug and check for fouling. If it's black and sooty then either it's getting too much fuel or the spark is too weak or non-existent.
OK here's a shot of both plugs. The one on the right in the shot is from the offending cylinder. It may not be readily visible in the photo, but there is quite a bit of soot on it as compared to the plug on the left. In fact there's LESS soot on the right one than there was between pulling the plugs and taking the photo:
In addition the plugs I pulled from the bike were NGK B6ES and not NKG B8ES (ie: six not eight) that the owners manual indicates are the proper plugs for the bike. On top of THAT the spark plug wires were really gunked up where the elbow connector meets the wire to the engine. I tried to clean the gunk out and in the process broke off the little screw like thing on the inside of the connection wire (on the right side wire). So clearly there are lots of problems with electrical delivery to the right side. The left wires were gunky too but the plug was not nearly as bad.
At a minimum now I need to new spark plug wires. Does anyone know where I can get them on short notice in Toronto? Ideally I'd like to pick them up Monday morning. Anyone know the part number?
I have NOT yet verified if either side is getting spark. I bought a little "Powerbuilt Spark Plug Wire Tester" thingy at Canadian Tire to check the spark from the outside of the wire but it was not showing spark even on the left cylinder that I KNOW is firing.
So Dr.J is on the right track, the right side is either gettting too much fuel or the sparkis too weak or non existant. If the situation does not improve with new plugs and wires what should I do next?
Also, the fact that the bike needs the choke on all the time to run can't be good, what do I do about this?
Christopher
P.S. Canadian Tire carries the NKG B8ES plugs for the CB350 at two for $6.99 the CT product number is 18-3907. The gap for a CB350 is 0.028 in to 0.032 in, I gapped my new plugs right in the middle of that at 0.030 in.
next I think???? should be the coils check to see the output. I am not sure on hondas but the manual should say what the output should be all you need is a little ohm meter. funny thing about coils is a lot of them are similar with output I run the coil from 1986 nija 250 on my 1973 yamaha tx 650. just what I found in the salvage yard that worked.
believe me I still knnopw nothing next to most bike guys but I try to keep learnign and doing new things
the only dumb questions is the one you don't ask
The good news is I'm getting spark. The bad news is I have NO compression on the right side. The mechanic at Rosy Toes thinks I have a hole in my piston. I'm looking at a top end rebuild or hunting down a good used engine :-(
The good news is I'm getting spark. The bad news is I have NO compression on the right side. The mechanic at Rosy Toes thinks I have a hole in my piston. I'm looking at a top end rebuild or hunting down a good used engine :-(
That sucks. I know Ted at Rosey Toes has a cb350 that was on fire and parked out back. It's mostly stripped (I removed the stator from it to put on by cb350g) but the engine is all there. Ted charged me pennies for the stator and I'm sure he wouldn't rip you off if you need the engine.
Hole in your piston? I've never heard of that happening to a stock 350. It would take a lot of force to punch through the dome. Maybe the rings are broken? Good luck with your motor.
Hole in your piston? I've never heard of that happening to a stock 350. It would take a lot of force to punch through the dome. Maybe the rings are broken? Good luck with your motor.
I agree that the "hole" may have been a bit of a guess, I was actually thinking that it could be the rings. I was watching when he connected the leak tester and the air was basically passing straight through the spark plug opening (where the hose was connected) and out through the oil tank opening (?) below.
Now I am a newbie at mechanics, but I do consider myself handy. In my VW van I have changed the alternator myself, I know it's not much but it's a start. Is a piston ring something I could change myself if that were the problem? What shop manual should I buy for this bike?
If you have a manual, a pulse and can read you can rebuild that engine.
Make lots of notes or take pictures. It's amazing how many pieces come off looking like they can only be replaced one way....only to find on re-assembly that each side is different and it can fit both ways....
If you have a manual, a pulse and can read you can rebuild that engine.
Make lots of notes or take pictures. It's amazing how many pieces come off looking like they can only be replaced one way....only to find on re-assembly that each side is different and it can fit both ways....
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