Author Topic: New Guy Here (Read 5292 times)

summitwrx · « **on:** August 26, 2014, 06:05:54 PM »

Hey guys, new to the forums, and new to bikes with motors. My name is Chaz and I have decent background in automotive and diesel engines, but am new to bikes. Sadly my first post is sort of a cry for help.
I bought an 81 CB650 custom, it had a mess for wiring. I bought a good condition used main harness, and am having some trouble. Brand new battery, replaced every fuse, put on new harness. Im getting power to the starter solenoid, rectifier, starter motor, but no power at the ignition switch or starter button. My multi meter crapped out so I've been using a test light to trace power.

There is no gauge set, so a few wiring connectors are left undone near the headlight housing from the main harness. No taillight, or signals either.

I had to pull the wiring harness as it made my OCD tendencies flare up; I am a bit of a perfectionist.

Anyways I'm looking foreword to the forum, any help on my current issues or tips to make the bike look/perform better are greatly appreciated!

calj737 · « **Reply #1 on:** August 26, 2014, 06:35:01 PM »

Welcome and welcome to 35 year old bikes

Here's a quick link to some info on your bikes switches:
http://manuals.sohc4.net/CB650/79650SMC19.pdf

And attached is a color coded wiring diagram for you.

It's not uncommon for the ignition switches on these bikes to be wonky after all this time. A good inspection and cleaning of the contacts, wires and connectors throughout your bike will serve you well.

summitwrx · « **Reply #2 on:** August 26, 2014, 07:42:23 PM »

Thanks calj737. I have a manual and have been cleaning up all the contacts along the way. If the switch was bad, should I still see power going into the ignition switch, just not out of it?

calj737 · « **Reply #3 on:** August 27, 2014, 04:07:48 AM »

Yes you should see it head there, but get lost there too I'd think.

Did you check both sides of the fuse for 12v? And the block connector right afterwards? The RED wire carries the power to the ignition switch, so it should not be difficult to find where it drops it. If you do have 12v on RED all the way to the ignition switch, then the BLACK becomes switched 12v.

summitwrx · « **Reply #4 on:** August 27, 2014, 09:08:59 AM »

Going to buy a new DVOM today to check actual voltage, I've been using a test light. I have power at nearly everything near the battery, solenoid, rectifier unit, I'm showing power on the stator brushes. Im not seeing power on the main red wire at the red connection near the fork, or at the ignition switch or fuse box. I bench tested the starter motor and it looks great. Going to a yard today to try and pull an ignition switch but mostly to look at all the grounds and connections of the main harness since I have a few unplugged.

summitwrx · « **Reply #5 on:** August 27, 2014, 06:39:50 PM »

Well the colored diagram was a huge help. Got a few wires sorted out and she turns over! Probably hasn't been started in a while, so I'm going to charge the battery a bit more and get some starting fluid. I appreciate the help I have already received from this forum. Ill post some more pictures as I get things together.

calj737 · « **Reply #6 on:** August 27, 2014, 07:14:37 PM »

Starting fluid is not needed. Confirm the carbs are getting fuel by opening the drains at bottom of bowls. Then, if she does fire, check each exhaust pipe for equal heating. This is the most effective determination for initial diagnosis. No fuel, no start. Fuel, no heat, no fuel to cylinder. Unless you have a spark problem. But first diagnose fuel.

summitwrx · « **Reply #7 on:** August 27, 2014, 09:15:35 PM »

Thanks, I'll check the drains.

summitwrx · « **Reply #8 on:** August 28, 2014, 10:49:05 AM »

So I am getting fresh fuel out of each carb, Im getting spark, I put in fresh oil. It will turn over all day long but won't fire off. Guess I need to check timing now?

Also the brand new battery on a full charge only last about 5 minutes of on/off cranking before it dies and I need to recharge it.

I am not finding a neutral safety switch by the oil pressure sensor, would this keep it from starting even though its in neutral and the clutch is pulled in?

calj737 · « **Reply #9 on:** August 28, 2014, 11:43:21 AM »

Not likely. But there are a few other places that could be interrupting your ignition. The KILL switch should be checked with a volt meter. But an easy troubleshooting method is to lay a spark plug (each in turn) on the engine case and then hit the starter button. Check for spark and the intensity of it. If you're getting spark at each, then it's on to points, condensers and timing of course.

summitwrx · « **Reply #10 on:** August 28, 2014, 03:17:46 PM »

All the plugs are getting spark via the test suggested. The plugs all look dry; however with a plug out and the engine turning over its apparent that fuel is getting to the cylinders. By points do you mean the CDI/ATU?

calj737 · « **Reply #11 on:** August 28, 2014, 04:24:23 PM »

Yep, pardon me, lost track that this was a 650.

summitwrx · « **Reply #12 on:** August 28, 2014, 06:30:46 PM »

Im at a loss here. Reset all plug gaps, have spark on every plug. Clean fuel comes out of the drain screw on each carb. The plugs are very dry after turning it over for about 5 minutes. Whats the best way to assure that fuel is getting into the cylinders? got a timing light so I'm going to check that, but for some reason I don't think fuel is getting into the cylinders.

calj737 · « **Reply #13 on:** August 28, 2014, 06:51:28 PM »

Can you drop the bowls, pull the jets and clear them? Also, check the float levels. I'm not a 650 guy, so I'm suggesting things that are typical with the pre-78 SOHCs. I know the carbs on your bike differ, but unfamiliar with their controls.

spfldpianist · « **Reply #14 on:** August 28, 2014, 08:35:05 PM »

I'm looking for drain tubes for my 76 cb550. Also the clamps. The three honda dealers I have talked to have no clue about these. I have the 4 small tubes coming out of the cylinders

Sent from my iPhone using Tapatalk

summitwrx · « **Reply #15 on:** August 30, 2014, 03:39:46 PM »

I will be cleaning the carbs sometime this week. In the meantime I found a fender laying on the ground in the junkyard, got it for 10$ so I might chop it up a bit and see how it looks on the bike.

I also drove up to the top of Rocky Mountain National Park and saw a few elk.

Everyone have a good holiday weekend!

78 k550 · « **Reply #16 on:** August 31, 2014, 11:23:07 PM »

Welcome,
First Thursday of every month many meet at G&B fish and chips across from Slone's lake.

Paul

summitwrx · « **Reply #17 on:** September 01, 2014, 05:08:40 PM »

Thanks Paul, I'm sure it will be a while before Ill make one of those.

Can anyone give me advice on the exhaust; it appears to be just cut off right under the foot pegs. Will this affect performance, I got some black exhaust wrap and was just going to wrap them and be done with it. Im also going to run pod filters and probably put bigger carb jets in...Any advice is appreciated though!

summitwrx · « **Reply #18 on:** September 03, 2014, 06:13:34 PM »

Can anyone recommend a reputable website to order a full engine gasket set from? It appears the PO used rtv silicon on every mating surface...Needless to say Im leaking a lot of oil.

calj737 · « **Reply #19 on:** September 03, 2014, 06:52:45 PM »

http://www.cyclexchange.net/Engine%20Parts%20(Non-Cafe-Gaskets).htm

summitwrx · « **Reply #20 on:** September 03, 2014, 09:04:57 PM »

Maybe I'm tired and missing it but that link leads to a cb750 set, can't find any cb650c sets on their page.

calj737 · « **Reply #21 on:** September 04, 2014, 04:07:24 AM »

Still can't seem to keep up with this bike being a 650...

You asked about your exhaust. It will likely perform very poorly as all the back pressure is removed by the shorter pipes without baffling. I would anticipate significant tuning problems as a result of them being cut off. Just what you wanted to hear, right?

summitwrx · « **Reply #22 on:** September 04, 2014, 09:16:22 AM »

Are the Athena gaskets good quality?

I figured the exhaust would be an issue. Though I wonder how it ran before, I am curious if the PO had pod filters and bigger jets, no air filter/s came with the bike at all. The carbs surprisingly look as if they had been cleaned, but I still can't get her started and I think it's not getting fuel.

summitwrx · « **Reply #23 on:** September 08, 2014, 02:58:47 PM »

Got some of the top end torn down and found some homemade gasketry going on...no good. It also appears to me the camshaft is in backwards considering the drive for the tachometer is on the left side of the bike, while it should be on the right...also explains why when turning over the tach never moved at all.

I don't know much about the profiles on the cams if exhaust and intake are different lobes? but I imagine this is also why it would not start.

Given I don't know the mileage and don't have the head off is it a good idea to get new piston rings or wait till I tear it down; what should I be looking for ring wear?

calj737 · « **Reply #24 on:** September 08, 2014, 03:21:18 PM »

Jeezus effin' hell! Tear the WHOLE motor down. Once you've had a machinist measure everything, determine and decide what pistons you may need.

Yeah, cam backwards=no go! ROTFLMAO while shaking my head....

I know you didn't do it, so my later is not pointed at you. But really? Was the PO on meth!!??.

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Author Topic: New Guy Here (Read 5292 times)