CB750F DOHC...not sure where I'm headed.

Ok lesson learned - never assume anything. My relay is definitely bad, and so are the 4 10 amp fuses that looked good. New battery is in and my new relay will be here tomorrow. I also found a complete headlight assembly on CB1100f.net for a pretty fair price. I'm taking this next Thursday and Friday off and hope to have all the electrical sorted out before the weekend. There's a motorcycle salvage yard nearby so if I need coils or anything else I'll be able to get them there pretty quick.
 
I found some unexpected free time so I got out my meter and checked the coils and both look good. I also fooled around with brakes some. Looks like the entire system will need a rebuild.
 
Well the wife is pretty sick tonight so all I was able to do was plug in the new relay. All the lights work correctly as well as the horn. Also, one sign before that the relay was bad was there were sparks when connecting the battery cable to the unenergized relay. None tonight, but it's also not starting. I think either the ignition switch or start button may be the problem. No time to troubleshoot it tonight though.

I need to get some new plug wires. I'm planning to go to NAPA and just make my own. What kind of wire should I get? Regular copper core?


Edit.
I managed a little more time on this tonight. I'm getting 12v thru the starter switch so I guess all that leaves is a bad connection or break between there and the relay. I guess the good news is wire is cheap, although I really didn't want to unwrap the harness.
 
You can test the continuity of the signal wire with your meter on the ohm scale without unwrapping the harness. Also check your grounds. especially the main ground cable to the engine case.... and starter mounting bolts... clean, clean , clean.

As fas as ignition cables (plug wires) you can use either, I did read somewhere about noise from solid copper wires bleeding through to the electroninc ignition so I went with resistor wires. Found a long single Accel replacement at the auto parts store that was enough to make all 4 on the CB. Cheaper than buying an entire set.
 
Thanks, that's some good info. I installed a new battery ground cable as the original was in bad shape. The starter turns great when you jump across the relay.

My main problem is you need 3 or 4 hands to hold the test leads on the tiny connectors while pushing the start button and looking at the meter.
 
UPDATE
I now have the bike turning over. Spark looks very weak though. I have new plugs and will pick up new wires on Thursday and will most likely run the relay to coil mod for a stronger spark. I put in some fresh gas and tried to get it to fire up but no luck so far.
 
I was afraid you'd ask that.

Lesson learned - No matter how certain you are that something is good, go ahead and check it anyway. Especially if it's something easy to check. Turns out it was the clutch switch. For some reason I thought it didn't matter as long as the bike was in neutral and the neutral switch worked.
 
It lives! Sort of. I got it to start today but it's running pretty rough. A lot of smoke at first but not anymore, probably just the oil I put in the cylinders so it could soak when I first got it. It actually fires up pretty quickly but doesn't want to idle very long. All 4 pipes get warm. Now on to the valves, carbs, brakes, exhaust and tires.
 
Ok I need some carb advice because I know nothing about them. Symptoms are, bike starts very easily with choke on, running around 2500 rpm. When the choke is pushed back in after letting it warm up, it bogs down and dies. Before that though, it sounds good and there is little to no hesitation when twisting the grip. I'm guessing a rebuild is in my future.
 
HUZZAH! on getting it started.
Might want to check the idle speed stop screw adjustment. May have gotten backed off at some point. It's a long shot but always pays to check the easy stuff first.
Honestly with the shoke on the idle speed will climb higher than 2500 as she warms up. May have some gummed up passages / pluged jets in those carbs. I would be willing to bet she will get better and better each time you run it. Might try some seafoam and see if she gets better with time.
 
Thanks. I mixed up some Lucas Safeguard ethanol treatment with 5 gallons if gas just because I had some on hand. It's definitely getter better just not much so far.
 
A day of ups and downs. It's idling pretty smooth now with no choke. I checked valve clearances and replaced 3 shims. I believe I can get it on the road without rebuilding the carbs. HOWEVER, something is wrong with the clutch. With it on the center stand and running, I put it in gear to check the transmission. The tranny seems fine but the clutch has no effect. I went thru all the adjustments with no luck.
 
Please elaborate "has no effect".
On the center stand shifted into gear and clutch lever released the rear wheel doesn't move?
But when not running you can spin the wheel freely?
 
Sorry, just the opposite. When on center stand running and shift to first, wheel starts spinning even with clutch pulled in. It's not disengaging.
 
Not being there it is hard to tell, but the wheel may rotate a little with the clutch in...the cable may need adjusted... or the clutch plates may be stuck together from setting.
Try this test. On the center stand, engine off and in gear, pull in the clutch and see if you can spin the rear tire by hand
 
I just finished going through all three calipers and both master cylinders. I have new pads in, all I need is the new brake lines then I can fill and bleed it. The seat cover is now redone in a tasteful camo duct tape. I may be offering this service in the near future.
 
Not much done this week because I was out of town on business. Today I got my new brake lines installed and the rear brake is filled and bled. I'm going to have to replace the front master as its leaking pretty bad and not building any pressure. I'll probably go with a CBR600 F3 m/c. A local salvage shop has a good used one for $50. Headlight is wired up but not mounted. Anyone need a 79 CBX1000 headlight mount? The guy I bought my light from sent the wrong part. It's not worth shipping back so I plan to pick up some universal fork mounted ears. I'm planning on rebuilding the clutch on the 20th since I'm off that day. After that, all I have left is tires and figuring out a solution for my rotted out exhaust. I cut the mufflers off today, it's pretty loud. I may have to pick up some shorty slipons for it.
 
Brakes are now done. I left the front brake lever strapped down to make sure there was no more air in the line but otherwise one more job completed. I went with a 98 cbr600 master cylinder. These brake lines are a pain to bleed. I ended up using a syringe to push fluid up from the calipers.

A week from tomorrow I will rebuild the clutch, then probably start cleaning up the exhaust welds and start figuring out which slipons I need to order. I cut the mufflers off just past where they were welded in order to maximize how much pipe was left behind. I'll also need to either remove the center stand or fab up a bracket to limit how far up it travels.
 
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