Author Topic: Slowly - CB650 Custom 1980 (Read 20440 times)

SOHC4 Cafe Racer Fan · « **Reply #50 on:** July 19, 2016, 10:45:00 AM »

You can go even smaller, but then it becomes less easy to read, especially at speed. http://www.lossaengineering.com/collections/motrocycle-parts/products/motogadget-mini

Azzarius · « **Reply #51 on:** July 20, 2016, 09:50:11 AM »

Hi Everyone,

Electric squid
Following the idea to relocate some of the component under the seat, I had to make some modification to the electric squid to bring all the cable to the under seat location. That had been somehow uneventful. Some heat shrink sleeves and some electric welding.

Cheers

Azzarius · « **Reply #52 on:** July 22, 2016, 10:07:55 AM »

Hi Everyone,

Questions

I have few questions. I have tried to start the back and haven't been too successful at it. I've put fuel and oil and tried to start the engine. It did run 2-3 times for about 5 sec. and died each time I touch the gaz. Then fuel started flowing from 2 of the carb overflow cup(stuck floats, floats that need adjustment, cracked overflow pipe, else; don't know yet as I already clean up the carb and I thought I put them back correctly). There might be half a million reason for it but here are my main suspect:

- connectic not ok:
In re-checking my connectic for the spark plug, I realised that two of them weren't in the right place. That after the engine had started and ran 5 sec.(may be it ran on 2 cylinder only). I've been reading around and I need clarification. My understanding is that each of the 2 coils will both provide 2 sparks(a good one and a spare one). Both lead on a coil will produce the same spark at the same time thus one coil will feed Cyl1 and Cyl4 and the other one will feed Cyl2 and Cyl3. If that is the case, it means that I can swap 1-4 together and 2-3 together and it would still work ? Also, since they both have 2 sparks, I could interchange 1-4 and 2-3 as well as the spare spark would become the good spark and vice versa ? And at that point, since they all have 2 sparks, what ever order they are connected in, shouldn't there always be a spark at any cylinder at the proper time ?

The way I see it

	cyl up	cyl down
C1	real spark	spare spark
C2	spare spark	real spark
C3	spare spark	real spark
C4	real spark	spare spark

- Carb not ok: will elaborate later with more questions

- no fuel: will elaborate later with more questions

Cheers

calj737 · « **Reply #53 on:** July 22, 2016, 11:34:50 AM »

Coil "A" serves cylinder 1&4. Coil "B" serves 2&3. Both cylinders get a spark from the same coil at the same time.

Depending upon the position of the valves, that cylinder is in compression or not. It is important that the ignition wires from your CDI be connected to the proper coil. The Blue or Yellow wire serves a given coil so the firing sequence and timing is correct. Your wiring diagram will identify which ignition wire connects to which coil, which serves which cylinders.

Overflowing fuel certainly sounds like a float problem; either a stuck float or float level too high, or a cracked overflow tube.

Azzarius · « **Reply #54 on:** July 23, 2016, 05:05:01 AM »

Hi calj737,

But there are 2 led coming out of each coil. Can they be inverted? Meaning, Can I take the one in Cyl1 and swap it with the one with Cyl4 and vice versa ? Same for Cyl2 and Cyl3 ? Each pair of cylinder is at the same stage at the same time, so 1 & 4 and 2 & 3 should be swapable ?

As for the color, from the pic I took when dismantling the bike, I had been able to see that the blue wire goes on the upper prong of the left coil. Now there is a + and - on the coil. Should the color wire blue/yellow be connected to the + and the black on - ? Does it matter ?

thnx

rb550four · « **Reply #55 on:** July 23, 2016, 06:12:15 AM »

Shifter side manages cyl 1 and 4 , that coil will spark at the same time on both of these cylinders only.
The longer lead goes to#4
Brake side manages spark on cyl 2 and 3 , also sparks at the same time for these two cylinders only.
The electronic ignition that works off the crank, will allow spark on the forward side for cylinder 1 and 4 , but the spark will not be able to happen for 2 and 3 until the crank rotates to the opposit side pick up of the electronic ignition that 1 and 4 fired on,so they can't be switched . 1and 4 fire at different times than 2and 3.
The two coils spark at different times according to the firing position of cylinder #1 on the shifter side Take the spark plug caps off the spark plugs so it doesn't start while you are doing this) You should use a test light to be sure that #1 will fire on the F mark for 1-4 at top dead center combustion stroke (when is this you ask, when intake and exhaust valves are in the closed position, both tappets on #1 will have play and the piston will be in the top of the cylinder ). if it's way off switch the blue and yellow wires and see if it improves.If it's close , rotate the plate until it fires on the F mark.
Who's to say the PO had them right or timed properly in the first place.

Azzarius · « **Reply #56 on:** July 23, 2016, 03:09:45 PM »

Hi Everyone,
Here is what it sounds like. I have been able to get it to run for a little longer. It sounds better when the choke is engage, It dies as soon as I give it some gaz. Hope it gives you more info. Here is you tube of the engine.

Cheers

CBJoe · « **Reply #57 on:** July 23, 2016, 05:33:53 PM »

Probably a Jetting issue....Did you re-jet already or are you running the stock jets for those carbs?

maybe post your main and pilot jet #'s and see if one of the other folks who have put CB750 Carbs on their 650 have recommendations.

Cheers, Joe

Azzarius · « **Reply #58 on:** July 23, 2016, 05:57:26 PM »

Hi CBJoe,

The jets are the "original one"( well the one that were on the bike when I bought it; I bought it looking stock, with air box etc... now I have put pods filter so eventually I will have to jet it bigger). But even with the original one, shouldn't it rev up ? Especially when the choke is engage, since it reduces the air intake as airbox would do ?

thnx
cheers

CBJoe · « **Reply #59 on:** July 24, 2016, 08:30:44 PM »

Quote from: Azzarius on July 23, 2016, 05:57:26 PM

Hi CBJoe,

The jets are the "original one"( well the one that were on the bike when I bought it; I bought it looking stock, with air box etc... now I have put pods filter so eventually I will have to jet it bigger). But even with the original one, shouldn't it rev up ? Especially when the choke is engage, since it reduces the air intake as airbox would do ?

thnx
cheers

No...not necessarily. If you have the original carbs set up as stock with those emgo pod filters added it likely will idle poorly and not be able to rev as you have much more air coming from the removed airbox. There are quite a few posts on the topic out there, but as I remember, the 650 PD carbs never did like running with pods. I had a setup similar to what you are running and had to up the main jets and never did get it running right before I sold the bike.

Here' s an old post that lists some numbers for you to shoot for...but take it as a staring point.

http://forums.sohc4.net/index.php?topic=91301.0

I believe that many folks have had luck using the front part of the stock airbox to equalize the intake into the carbs, but ditch the back half in place of one large oval filter.

Regards, Joe

Azzarius · « **Reply #60 on:** July 27, 2016, 09:29:26 AM »

Hi guys,

Thnx for the input. In ready through these thread, one thing that keep coming back is the ignition timing. That hasn't been done on the bike since the rebuild. So before going into vacuum tuning, I will try to get my hand on a timing light and ensure that my timing is correct. Then next step will be the vacuum adjustment. Then I will likely have to rejet and re-vacuum. I have a bit less time during the week to go through these more lenghty so hopefully during the w/e I will have time to kill one or two of them.

cheers

Azzarius · « **Reply #61 on:** July 27, 2016, 09:34:23 AM »

Hi Everyone,
Horn
Here is small update. I've painted the casing of the horn as it was ugly when I put it back. Small 10 min item but still it had to be done and looks much better.

cheers

Bankerdanny · « **Reply #62 on:** July 27, 2016, 03:43:58 PM »

Nice. It's little details like that that separate the craftsmen from the hacks.

Azzarius · « **Reply #63 on:** July 29, 2016, 09:21:56 AM »

Hi Everyone,
Spark Unit
Here is another small update. In searching for my carb synch. I saw someone who fixed his Spark Unit, by filling it up with epoxy. Since mine looked like that what ever black goo used to fill it melted away on the rest of the bike, I've filled it with epoxy(Only had white one; still it's not a visible part and the white side are facing each other). Once it's dry(cured), I will remove the excess and put it back in place. This should prevent what was left of the black goo to stay in place if ever the condition that melted it in the first place occur again. In looking on some forum, I saw that many people did have that issue but that the melting of the black goo, didn't prevent it from working.

cheers

kslrr · « **Reply #64 on:** July 29, 2016, 09:33:47 AM »

One thing that can cause the Spark Units to over heat is trying to start the engine on a weak battery. This causes the spark Units to over amp.

crusierlover · « **Reply #65 on:** July 31, 2016, 02:57:30 PM »

I so very much want to see how this turns out.I am working on the same bike.

Azzarius · « **Reply #66 on:** August 01, 2016, 08:29:12 AM »

Hi Crusierlover,
Well at this point in time, it looks very good

but it doesn't start

. I've ordered new jet (from 90 to 120) I should receive them this Wednesday, but still. I have been able to get the bike to run idle but no more. So it seems that there is something.

cheers

crusierlover · « **Reply #67 on:** August 01, 2016, 10:42:51 AM »

Quote from: Azzarius on August 01, 2016, 08:29:12 AM

Hi Crusierlover,
Well at this point in time, it looks very good but it doesn't start . I've ordered new jet (from 90 to 120) I should receive them this Wednesday, but still. I have been able to get the bike to run idle but no more. So it seems that there is something.

cheers

Unfortunately the pods make it a lot of trial and error,mostly error until the right size jets are found for the bike.And taking the carbs off and on is no easy task.The stock air box makes it much easier to tune, but with it in place it is also near impossible to get the carbs in and out.I have 2 80 and 1 79.One has 750 carbs,no airbox,no pods, just screen wire over the carbs.It has sat for 2 years at least.I am not going to mess with it anytime soon.I did however own a 1980gs1000 with pods one time.And a 1981 kz1000 with pods one time.They ran great.But the prior owners had done all the carb work before I owned them.But with bigger jets,correct cleaning,vacuum gauge multicylinder carb tuning devices it is doable.Admittedly carbs and electrics are over my head.

purplechickenweasel · « **Reply #68 on:** August 01, 2016, 11:55:06 AM »

I may have missed it in the thread, but did you thoroughly clean the 750 carbs before running them?
When I tried 750 carbs, they went well with the stock air box, and touchy with the pods.
Have you checked the exhaust header pipe temps?

Pcw

Azzarius · « **Reply #69 on:** August 01, 2016, 06:34:30 PM »

Hi PurpleChickenweasel,
it's a 650 but I don't think it changes much from the 750. I did clean them carb pretty good, checked that all the needle holes where clean, spayed a deal of carb cleaner and compressed air. I've check the float height to be as per spec. I also did one more check once I put back the carb on. I did open the flush valve and did a height/level test with the overflow line ( I have put transparent one for the time being). Two of them are lower than I expected but I should receive my new jet this Wednesday and I will check why these 2 carbs were lower. In reading in the forum, I found out that with pods and mac 4in1(not on yet) I should go to 120 from 90. Anyway It's 1.99 each jet so it's not too big of a loss if they don't fit.

As for the checking the exhaust header pipe temp, I haven't. What should I be looking for? What would it tells me? (guess here: if 2 or 3 out of 4 are hot it means that I'm missing explosion in one cylinder? else ?)

thnx
cheers

purplechickenweasel · « **Reply #70 on:** August 02, 2016, 06:09:00 AM »

Not sure on exact temp, but a over our under temp cylinder indicates too rich or lean in comparison with the other cylinders.
I will put my temp gun on mine today and see what I get.
But my bike is a bored out 650 (652cc) using '84 ninja carbs with a 4 to 1 exhaust.
What elevation are you at?
I would recommend jet size, but it can vary depending on elevation.
120 doesn't sound too big unless you are above 6 or 7000 ft elevation.

Pcw

Azzarius · « **Reply #71 on:** August 02, 2016, 08:40:35 AM »

HI Pcw,

I live pretty much at sea level. The 120 came from someone who did the same thing. Went from air box to pods and changed the 4in4 to a mac 4in1. Currently the jets are 90(original). I still have the 4in4 exhaust, because I want to make sure I can restart the whole thing before investing into an exhaust that will cost me almost as much as the bike itself

cheers

Azzarius · « **Reply #72 on:** August 03, 2016, 09:17:39 AM »

Hi Everyone,
Good news I got my jet today. I'm going to go from 90 to 120. I should try to fire it up tonight.

cheers

Azzarius · « **Reply #73 on:** August 03, 2016, 06:02:48 PM »

Hi Everyone,

Semi good news. The engine starts, it even revs up. I've been able to do about 100 meters with the bike. That said, it seems that following PCW advice and checking for temperature that only exhaust 1 and 4 are hot. 2 and 3 I was able to put my hand on it. It was warm but not burning as you would expect the exhaust to be at the exit of the engine. That tells me that I'm running on 2 cyl. or 3, exhaust 3 was warmer than 2 but still not burning.

I've swapped the coils. Still the exhaust 1 and 4 are the hot one. So the coil are not dead. May be the wiring to the right coil(feeds cyl 2 and 3) are not good. May be a bad spark unit, given how they looked before I put putty in them, it;s possible that they one is dead. I guess I could swap them and see if the opposite cylinders become hot. That would point to it if it changes.

Also, some oil dropping from to oil pan. That s%$ks since I will have to drain the oil to try to seal the oil pan better, possibly change the seal and buy another 4 pints of oil

.

Still have to install, rear flasher (and receive my flasher unit from china), the rear brake light, license plate ....

More to come I guess ...

Cheers

purplechickenweasel · « **Reply #74 on:** August 03, 2016, 08:06:39 PM »

Glad you got it to rev and move under its own power.
Looks good so far.

And I used my temp gun today, and got between 225 and 245 at idle(5min or less of idle), and around 340 to 375 after a 22 mile ride to work.

Pcw

News:

Author Topic: Slowly - CB650 Custom 1980 (Read 20440 times)