1972 CB350 No Power.

[dustyxbla]

I'm helping my buddy fix up a barn find. It's a cb350 and it doesn't have any power. Motor sounds healthy when I kick it though! I tested the battery and its not bad. The bike doesn't get any lights, turns nothing. So I figured it was the ignition switch, as it seemed the only thing that controlled ALL the power. It testes bad and I replaced it. got a new one yesterday and it didn't fix my problem. What tests can I do to help locate problems. Again, no lights, horn, turns, nothing. Much thanks guys!

[Gixxus Christ!]

What happens when you jump the poles on the solenoid (if electric start)

[Gixxus Christ!]

Also check ground and main fuse between ignition switch and battery. Should be a red wire, not the fat one that goes to the solenoid tho, a thin one.

[dustyxbla]

What happens when you jump the poles on the solenoid (if electric start)

It has an electric start, but I'm not sure it works now or even for the last owner. I'll post some pictures to bring you up to speed. What do you mean by jumping the poles?

[Gixxus Christ!]

There will be a wire from the battery going to the solenoid and a wire from the solenoid going to the starter. They will each be connected to a post with a nut. Put anything metal across both posts to jump or bypass the solenoid and deliver power straight to the starter. That will tell you that you have ground and power. From there you need to chase down the hot side of the wiring from the battery and find either a blown fuse or broken wire.

[dustyxbla]

Nothing when bridging the solenoid. But a multimeter on the solenoid positive and ground reads 12.6 volts. Cleaned and checked ground. It didn't change anything. Inline fuse in tact.

[dustyxbla]

There will be a wire from the battery going to the solenoid and a wire from the solenoid going to the starter. They will each be connected to a post with a nut. Put anything metal across both posts to jump or bypass the solenoid and deliver power straight to the starter. That will tell you that you have ground and power. From there you need to chase down the hot side of the wiring from the battery and find either a blown fuse or broken wire.

[dustyxbla]

Fixed it. Exposed (but hidden) wire! Now to figure out points ignition timing.

[Gixxus Christ!]

Points are easy. Clip a test wire from the wire leading from the point to ground and turn the crank slowly until it lights, then check and see if the mark is lined up with the F. The plate the points are on will have screws you loosen to turn the plate until the points close and the light lights right when the timing mark hits F. Points need dressed periodically, get some krokus cloth and use it to sort of flatten down the contacts and remove any corrosion, then spray out with contact cleaner. Points also need gapped. Get some feeler gauges and find out the spec for gapping And the process for adjustment. this is all considered routine maintenance meant to be done with each oil change. 70's technology sucks, there's a reason they use optical timing or trigger wheels now.

[ReconRat]

Double check timing after tightening down the screws and plate. It can move a bit. Also, there's two marks off to the side that should be 32-34 degrees full advance range. Use a timing light for that. You can time it there if reving up some minimum rpm. You have to time both sets of points, one for each plug. Your best performance is typically with new points and timed at max advance. Timing at full advance doesn't work well if the points are worn, they just won't time in the same and it runs a bit rough. Mostly good when points are new. Worn points probably time in best at the F mark (idle). Make sure it's not idling too high, that would goof it.

 

You should check the advance mechanism by revving up and seeing it hit in between those two marks anyway. To confirm the advance is working well.

 

Carbs on the 350 can be checked in a fun way. Straddle the bike and reach down with both hands and flick the throttle cable lever at the carb, left and right. Compare the sound and response of each cylinder revving. It should be reasonably the same for both cylinders.

 

350 carbs needed cleaning or work almost every Spring to get back to working well. You can remove cables and loosen the carb clamps and just turn it out a bit to get at the bottom cover. Usually just opening the bottom and cleaning out crap helps a lot. Sometimes just draining the float bowl is good enough. There's a plug to drain it with.

[dustyxbla]

Thanks a ton, guys! I was covered in grease and feeling successful yesterday. I never could figure out the points to adjust them. I guess I understand rotating the ignition plate to advance or retard the timing, but I don't know how to set the points gap, and I'm not sure what all the letters on the rotor mean. I looked a bunch online yesterday, but I'm afraid this is one of these thing I need to see.

I'm really happy with yesterday. I turned a $300 Honda into a functioning bike. It spits and sputters and definitely needs the carbs cleaned. But other than some backfiring she flies down the road. The guy I'm fixing it for is a buddy and has never even ridden a motorcycle. Wish I could have captured his smile when I took off down the road on a bike everybody told him would never run (duh, its a Honda).

Surprisingly, he wants to restore the bike (not cafe it). So I'll be ordering parts and replacing them. Points are on the list as well as new "stock" air filters. There was a family of mice living in it raising hell.

[dustyxbla]

https://vimeo.com/126598303

Above is the very first time it started, it got much better.

And here's the bike when I started.

[Gixxus Christ!]

Points are easy. Download a pdf file of the factory service manual if you need to. Or I can screen shot you the instructions from my 750, dollars to donuts they're the exact same points, honda was good like that. The marks are as follows: T 1 is the cam timing mark for #1 cyl. f1 is the firing mark for 1. Same for 2.

[Gixxus Christ!]

[Gixxus Christ!]

This should get you close. Gap should be .012

[bowdog]

Crazy, you are a good man!

[ReconRat]

The 550 and 750 had points on little plates on the big plate. Both gap and timing adjust. (Is this found on newer 350s? I don't know.) Much better, but doesn't last any longer. I replaced with Dyna pointless ignition and hot coils. Good increase in performance.

 

The old 350 type points plates don't have both gap and timing adjust for each set of points. Set the left gap, set the left fire with the base plate position, and then alter the right gap till it's firing correctly at the other fire mark. Obviously worn points will make that right gap get worse and worse, till new ones are bought. You might even find yourself cheating on the left gap trying to keep old points working.

 

Even if you don't have a light or timing light handy, you can time it in just by carefully listening for the click of the spark when the gap opens. Don't try any adjust turning backwards. Turn the rotor correct direction when checking and adjusting. It's ok to back up a little and try again. Don't try turning clear around backwards. Don't try turning with the little bolt at the center of the ignition plate. Big mistake if it breaks off, it's the end of the cam shaft.

 

You have marks for top dead center, Fire, and the two for max advance range. And another set of the same on the other side of the rotor for the other points/cylinder. There's a variety of markings on rotors. It's either LT and LF (left) on one side and just marks on the other (right), or just T and F (left) on one side and marks on the other for the right points/cylinder. Or even something different.

 

It's a Zen thing, you have to be One with the bike sometimes.

[Gixxus Christ!]

Looks like recon is the brain trust when it comes ton the 350. I forgot the points run directly off the cam on those bikes... anyway there should be enough info here for you to muddle your way through it. Would be a good idea to ditch the points for a dyna ignition tho, then you never have to fuck with it again.

[gsxkat1100]

Looks like recon is the brain trust when it comes ton the 350. I forgot the points run directly off the cam on those bikes... anyway there should be enough info here for you to muddle your way through it. Would be a good idea to ditch the points for a dyna ignition tho, then you never have to fuck with it again.

 

+1! I'm looking into Dynas on my old bikes too.

[Gixxus Christ!]

I've heard from people on cb750 pages that the new dyna units aren't as reliable as the older ones. There has been one on my 849 project since before I bought it and it makes fire every time but I'm not sure how old it is.

[Gixxus Christ!]

Seems that dyna never made a cb350 specific ignition. Pamco did, along with boretech and Charlies place.

This forum may help:

http://www.hondatwins.net/forums/50-electrical-discussion/23961-electronic-ignition-pamco-vs-dynatek.html

[ReconRat]

I had to stretch my brain to remember some of this stuff...

 

I went with Blue Goose hot fire coils. Instead of coils from Dyna. Sadly, those are long gone. But still, getting rid of points with a Dyna can be worth it. Depends on how many sets of points you are buying. They aren't cheap, and sometimes the only thing you'll find is the entire base plate assembly. Costs even more. I replaced mine (CB550) with Dyna after finding a short on a brand new base plate assembly. That kinda pissed me off.

 

I always kept all the old points and base plate parts. You never know when you'll need a piece or two. Although it would be impossible to find them now, I bet I still have them for 160, 350, and 550.

[dustyxbla]

Gah! Good looking out guys!

I'll have to look into the pointless ignition.

The points are on a separate plate from the ignition advance plate (I think the part names are right?).

I'll leave it up to my buddy. He's in for a world of hurt with this bike. I'm not for chopping up bikes, but even new air filters are $100, where the beautiful, but dreaded pods are $20.

I'll review all these awesome comments next time I get my hands into it. I got mad and put the cover back on and put two quarts in it and called it a day. I'm sure another cycle of engine oil won't be a bad thing judging by the amount of gunk on/in the motor.

The oil smelled like gas, obviously this isn't great, but what causes this? Sitting and seeping?

The bike "needs" all new switches and levers. New cables as they're frayed. Brakes need looked at, they're frightening. New tires front and back. ALL new hoses. PO replaced them, but did a terrible, terrible job. Woke up to a gallon of gas on the garage floor. Petcock also needs replaced or fixed. Seat is torn and foam is really bad. Carbs need cleaned, hopefully everything in them is able to be reused. Has mix matched ignition coils which I'd like to update as well as at LEAST a new points plate.

He's excited as all get out, and so am I. Showed him the power of the eternal Honda motors!

I'd absolutely love to strip this girl down and make her into a slim and sleek sex machine, and I'm sure the price tag will deter him from a full restore. He just doesn't understand the amount of work, or money will be invested.

Timing is intimidating. I didn't know how to start a bike in February, and now I'm riding and fixing them (with all your help). I'll dive into timing eventually, but as you can see I've got a lot to do for him (including teaching him to ride) so that might become a secondary priority. You guys are the best. Might start a restore thread if anybody's curious to see what we do to this purple pig.

[ReconRat]

Yes, some fuel probably leaked into the crankcase. Usually it's the fuel tank petcock leaks. Or somebody didn't turn it off. It should be gone after an oil change or two. Plus when the engine heats up, the fuel will evaporate pretty quick. But a lot of fuel in the oil is rough on the engine. Thins the oil out too much. I've actually seen a fuel leak completely fill the crankcase. CB450s were bad about that. Saw one trash the rings and even one that trashed the valve seats (I know, how the heck did it do that.). Owner never shut the fuel off manually.

[ReconRat]

Most carb air pods are too small to flow a necessary maximum amount of air at full throttle. Yet people use them all the time. The end result is not enough air at full throttle, so the vacuum pulls more fuel than it should. Which washes the cylinder walls and weakens the oil barrier between piston rings and cylinder walls. Sooner than later, the rings fail. Same thing happens with a dirty air filter. Oddly, no filter at all isn't as bad as a very dirty air filter.

 

I remember a Kaw 900 that would pull the oil out of the engine through the breather tube, at sustained full throttle, if the air filter was even a little bit dirty. Which of course trashed the air filter. Pain in the butt.