Topic: CB 750 Project 1 - Rides Well but a few tweaks needed

[timbo750]

Managed to get in to the shed after a long unwanted absence. Didn't really do anything except work out were I left things, the question I have for the brains trust out there is about the coil wiring.

I have fitted 5ohm dyna coils and didn't get much of an explanation of which terminal is for which plug. You will see from the photo that there are two screw terminals but i don't know which one is for which plug wire.

[Terry in Australia]

That's an easy one Tim, the reason they're not marked is because it doesn't matter. Cheers, Terry.

[calj737]

Terry is correct, but you do need to use the same screw terminal on each coil for the same power/ignition source. That's what matters.

[timbo750]

So each cylinder gets a spark on the compression and the exhaust stroke.

[mystic_1]

Correct.  "Wasted Spark Ignition".

mystic_1

[timbo750]

I suppose it makes for simpler ignition and wiring but I have to admit that it had me thinking that dyna had let me down, not so it now seems. I will say though that the head scratching on this one has increased my bald spot.

[timbo750]

Managed to get a bit more done. Started fixing the main cable loom to the frame, I test fitted an old tank to make sure nothing was rubbing and nothing catches. But now I need to find a 'Starter Motor Safety Unit' that connects to the red connector.

[Terry in Australia]

G'Day Tim, you, me and Cliff (Maduncle) all have the same wiring loom! Test to see if you have power to the coils before you go looking for the clutch lockout thingie, but if you don't, Scottly sent me a PM yonks ago about how to bypass it. Hey I finally scored a K0, so if you've still got that front hub, let me know what you want for it? Cheers, Terry.

[timbo750]

Thanks terry. Still a few wires to hook up so will test then.  Yes I do have the K0 hub and I think I found some other K0 part in a box but can't remember now what it was. Not sure what a K0 hub is worth Terry.

[Terry in Australia]

No worries mate, my standard offer for anything is 50 bucks, so you can decide if that's enough, or not. Cheers, Terry.

[timbo750]

Terry, my first thoughts were 100 bucks so how about 75 and I will drop it off some time.

[timbo750]

Terry, I am thinking I may have to bypass this safety unit thingy as the wiring harness is new and most likely correct. If you have that bypass info and could forward that would be great, I have tried to find a schematic for how they work internally but with no luck, if I had that I could wiring up a diode or relay to do the same.

[timbo750]

Well I think I have sorted a solution to the safety unit. After studying the wiring diagram I have determined that I can do similar with a relay using the neutral switch to activate.

Turns out these things were never fitted to the Australian delivery bikes. I called into TT motorcycles in mornington on Thursday and he had never heard of it before.

[maduncle]

Well I think I have sorted a solution to the safety unit. After studying the wiring diagram I have determined that I can do similar with a relay using the neutral switch to activate.

Turns out these things were never fitted to the Australian delivery bikes. I called into TT motorcycles in mornington on Thursday and he had never heard of it before.

Okay - so I am interested in what you are doing to deal with that unnecessary red terminal block - as I will need to do something too.

EDIT: oh look, this is on the forum in another thread.

"If you unplug the SSU and remove it you can by-pass it's function by jumping the solid Green wire to the Dark Green/Red wire( there is also a light green/red ). That's it, your done........the starter will now spin whether your in gear or N or clutch is pulled or not...  N light will still work when in N 'tho..........."

I love this forum.

[timbo750]

Yeah, I thought about that and I  trust myself to clutch every time I start the bike but I would also like a safe guard. I have worked out a bypass and will post once I have a decent drawing done.

[timbo750]

What I meant to say is that I have worked out a alternative. Here it is.

[mystic_1]

Wow that's fairly brilliant.  Nicely done!

mystic_1

[Terry in Australia]

Well done Timbo, that looks very professional. I didn't bypass the wires to the plug, but everything works as it should, except the kill switch. If the bike was mine I wouldn't care as I never use the kill switches on my bikes, but as it isn't mine, I might have to rethink it before I hand it over to Mike.

I'll take you up on the hub too mate, thanks for that, and I want any other K0 parts you might come across. Cheers, Terry.

[timbo750]

Keep in mind guys I haven't tested it yet, however it is a very logic process so I can't see why it wouldn't work.

Terry I think the head is K0 but too keen on pulling that off the engine now.

[Terry in Australia]

No worries mate, if it ever does come off I've got a minty K2 head here that Cliff had hydro-blasted, and there are new bronze valve guides in a bag that I don't need as well. Cheers, Terry.

[mystic_1]

Keep in mind guys I haven't tested it yet, however it is a very logic process so I can't see why it wouldn't work.

No, I think you're really onto something here.  Here's a thread from a while back where a few of us were kicking around the design of the SMSU:

http://forums.sohc4.net/index.php/topic,145726.msg1657876.html#msg1657876











Also in that thread are a couple of different bypass methods:

I tested these this morning.  They work.  I.e. the starter solenoid responds to the starter button only if the clutch lever is pulled in or the transmission is in neutral.

I'd quote you the page number if I had one of my books handy, but... 

Find the Dark-Green/Red wire that went into the red connector that plugged into the safety module, pull it out of that connector and change the end to a male bullet, and plug it into the extra Green wire that is hanging near the rear of the battery box. Presto, it becomes a K0-K2! Just don't forget to pull in the clutch or find neutral before starting, or you'll make the DOT mad... 

Do let us know your results, lots of people run into problems with this interlock circuit eventually.

mystic_1

[Terry in Australia]

So if you don't have the SMSU thingy your starter motor won't engage? Well there you go, I've cured cancer, there's nothing hanging off the red plug on my bike, I haven't bypassed anything, but lo and behold, I press the button, and it fires right up. I am a freaking genius!

Timbo, Cliff, if you're using the older style switchblocks like I am, without the additional wiring for the SMSU, you don't need to do anything, it'll work fine. Cheers, Terry.

[maduncle]

So if you don't have the SMSU thingy your starter motor won't engage? Well there you go, I've cured cancer, there's nothing hanging off the red plug on my bike, I haven't bypassed anything, but lo and behold, I press the button, and it fires right up. I am a freaking genius!

Timbo, Cliff, if you're using the older style switchblocks like I am, without the additional wiring for the SMSU, you don't need to do anything, it'll work fine. Cheers, Terry.

Excellent ...

[timbo750]

Well its been far too long. But it's been a cold and wet winter in Melbourne, work and the kids sport have also been taking up too much time.

I had to actually take a few steps back with the wiring. I was worried that I was attaching the main loom in the wrong spot on the frame so I pulled it out so I could get the carbies and throttle cables in,  which I managed to do today.

One of the hardest parts of all to find was the little split pins on the choke linkages, no where local had anything small enough. Got some mail order from Brisbane , after paying for postage it cost me about 30 bucks for the little suckers but I now have a few spares.

I am now hoping I can keep things moving along so I can be riding before too long. No timeline though, that always backfires.

Sent from my SM-G920I using Tapatalk

[maduncle]

Well its been far too long. But it's been a cold and wet winter in Melbourne, work and the kids sport have also been taking up too much time.

I had to actually take a few steps back with the wiring. I was worried that I was attaching the main loom in the wrong spot on the frame so I pulled it out so I could get the carbies and throttle cables in,  which I managed to do today.

One of the hardest parts of all to find was the little split pins on the choke linkages, no where local had anything small enough. Got some mail order from Brisbane , after paying for postage it cost me about 30 bucks for the little suckers but I now have a few spares.

I am now hoping I can keep things moving along so I can be riding before too long. No timeline though, that always backfires.

Sent from my SM-G920I using Tapatalk

Hey Tim - glad you are back into it.

You can use race wire and race wire twist pliers instead of those little split pins on the carries - works a treat.

Let me know if you want to see how that wiring harness fits to a complete bike - mine is in and all tucked out of the way.