Author Topic: Starting the engine  (Read 31699 times)

Offline K2-K6

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Re: Starting the engine
« Reply #60 on: January 21, 2015, 11:32:55 AM »
It looks to me from the "points picture" that the wire from the condenser is touching the base bracket of the points, this would earth the coils and prevent any firing at all.
The circuit path from the both the coil wire and the condenser have to pass into the small securing bolt and then on to the spring leading down to the points contact area and must be insulated from touching anything else along the way if they earth out on any other part then the current is not there to be switched by the points irrespective of any mechanical setup.

Offline hairygit

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Re: Starting the engine
« Reply #61 on: January 21, 2015, 11:41:34 AM »
Hi,
    The unit should pull off the crankshaft, it sits on the end of the crankshaft on a locating peg, the "bolt" sticking out the middle should screw out, but it is minus its head for some reason!---Ken
No, on the 750's it is a threaded stud, with an m6 nut and the large rectangular headed washer thing that secures the advance/retard mechanism, the smaller fours use a bolt. The stud is screwed into the end of the crank, but there is no reason to remove it at the moment:))
If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline El__burro

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Re: Starting the engine
« Reply #62 on: January 21, 2015, 12:16:18 PM »

It looks to me from the "points picture" that the wire from the condenser is touching the base bracket of the points, this would earth the coils and prevent any firing at all.

Fair point, i guess this may explain the arching on 2.3 to the points supporting metal.
Can you tell me anything about the mark on the advancer mechanism?
(See picture above).


Offline Bitsa (Ralph Wright - RIP)

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Re: Starting the engine
« Reply #63 on: January 21, 2015, 12:52:45 PM »
Yes agree with k2 k6 and Hairygit looks like a fibre washer is missing.The unit should pull off and also the unit has 333 on it the 750 should be 300
Love PO planks.
Cheers
Bitsa
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Offline K2-K6

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Re: Starting the engine
« Reply #64 on: January 21, 2015, 12:58:47 PM »
I just went to look at a known good 750 K6 ignition set and the points cam is unmarked (that notch stamped into your one has probably been put there by a previous owner and may not match anything on another bike).
If you look at the advance and retard mech from the front, then te cam lobe that opens the points should point to 2/3 makings and have the base circle next to 1/4 marks. as far as I can see from your pics yours looks te same as mine.
Going back to the wiring, the lead comimg down to the points from the coils has to have no contact with earth at all until it hits the contact face on the points, points closed keeps it earthed, points start to open the earth is interrupted and the coils then fire HT down the plug leads. Any tracking to earth before it gets to the points face leaves the coils switched off.......nothing..........happens!
I'd reasemble the system and set the points gap then make sure you are getting the points to switch on and off as they should be by disconnecting the leads to the coils and continuity testing while turning the crank to establish if you have got them installed properly befor you can move on.

Offline royhall

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Re: Starting the engine
« Reply #65 on: January 21, 2015, 01:11:04 PM »
Hi all. First thing he needs to do is get the points to open at the correct marks etc. Once that's achieved then move on. No point doing anything whilst the timing cant be set. He's probably getting too much info now and getting frustrated. One thing at a time is the best approach, then move on to the next.
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Offline Bitsa (Ralph Wright - RIP)

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Re: Starting the engine
« Reply #66 on: January 21, 2015, 01:14:20 PM »
Part number 30220-333-004 is a CB400/4 one
                    30220-323-005        CB500/4
                    30220-300-005        CB750 k2
If they are all the same why have different part numbers?I do not know whats the difference but if you fit the right one that's one less thing to worry about. ;)
Cheers
Bitsa
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Offline K2-K6

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Re: Starting the engine
« Reply #67 on: January 21, 2015, 01:28:17 PM »
I was going to ask you bitsa what the 333 comes from but you've already got there. I would take a guess that the 400/4 would need a different advance curve from the 750 so the weights/springs/total advance would have a different spec.
Physically they look compatible and should not stop it running as far as i can see from the pics, you'd have to go with changeing it back to std issue during a rebuild though.
Royhall, I'd argue the oppossite i.e that without a functioning system there's no point in even bothering with getting correct timing as you can't really check it accurately if you have no switching.
My last post seems to have a specifically yorkshire dependent missing H in the te, is there such a thing as a yorkshire typo?  ;)

Offline El__burro

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Re: Starting the engine
« Reply #68 on: January 21, 2015, 01:43:57 PM »
The plate is correct its for a k2, still, after having ensured that the wires only touch the little screw to the points and nothing else i still am struggling to get the points to fully open at the F mark.
I have a spark on 1.4 sometimes but nothing to get exited about.
In this post the guy has my same issue ( thanks Lobo)
http://forums.sohc4.net/index.php?topic=73769.0
Unfortunately he doesn't mention if/how he's sorted it.
Maybe he never did.

Thanks
El__burro

Offline K2-K6

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Re: Starting the engine
« Reply #69 on: January 21, 2015, 02:15:05 PM »
All of those on that thread seem to be running though so it shouldn't stop the engine firing and at least running even if it's rough.

You say you've got sparking, is that the plugs or at the points? the points aren't supposed to spark but you may see some.

Offline mike the bike

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Re: Starting the engine
« Reply #70 on: January 21, 2015, 02:29:19 PM »
.... If the capacitor is faulty
Where's that 10mm socket got to?

Online Bryanj

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Re: Starting the engine
« Reply #71 on: January 21, 2015, 02:38:10 PM »
Thr points should NOT be fully open on the F mark but just opening

Offline El__burro

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Re: Starting the engine
« Reply #72 on: January 21, 2015, 03:14:50 PM »
Thr points should NOT be fully open on the F mark but just opening
So it's normal that they start to open at the F mark and fully open by T????????
 
In the tests I have seen there are sparks at the points too.

The condensers are both fine.

I am lost now?

Offline K2-K6

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Re: Starting the engine
« Reply #73 on: January 21, 2015, 03:47:11 PM »
Ah it seems easy to do this when it's in front of you but just as easy to miss bits when describing it.
As Bryan says the points start to open at the F mark......but you check the points gap with the heel of the points touching the peak of the cam lobe so this would be the maximum the points would open......that seems to be the point at which someone has wacked a mark into the cam i.e. the point at which the cam should contact the points heel when you adjuct the gap.

The coil will start to fire the plug as soon as the points start to seperate right at the beggining of their movement.

Offline El__burro

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Re: Starting the engine
« Reply #74 on: January 21, 2015, 03:53:37 PM »
Okay, that's achievable.
Also as Bitsa pointed out, it looks like the advancer is from a cb400/4. Would it make a difference?
Thanks

 

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