Not firing on cylinders one and four

I wish I could give you the exact reasoning behind this, but it centers around the Hitachi HA1825P IC, which is a proprietary device so no data sheet was ever released on it. All I know for sure is the test set I built for it I was confounded when I first applied a signal to the Orange input channel and noted that the output signal was actually on the opposite channel - the grey wire.

I did do some other testing but never really completed it, but one test I did try was to disconnect one of the pick-ups to simulate an open and see if the bike would start and run on two cylinders - it would not start and all I got was a couple of backfires, which kind of quickly led to be discontinuing that test.

One other test I did was to center the reluctor between the two coils and then swipe a feeler gauge across the coils. If the feeler gauge was swiped across the 2, 3 pick-up the 1, 4 plugs would spark. If swiped across the 1, 4 pick-up the 2,3 plugs would spark. And, just to confuse matters a bit more if the reluctor was centered on the 1,4 pick-up and the key turned on then when the TCI shut down to safe mode the 1, 4 plugs would spark. If the reluctor was centered on the 2, 3 pick-up and the key turned on the 2, 3 plugs would spark when the TCI switched to safe mode.

So, to say the least it all got a bit confusing, and I never really took it any further as my focus on other projects got in the way, but I might revisit it one day. It is interesting to note that in the initial post on this thread the bike seemed to be running on two cylinders (with a bad pick-up), which does seem logical.

 

i think someone just put the wrong color wires in the connectors

 

That is where l get difficulties with the electronic issues l am fine with the spanners but

So the Hitachi HA1825P IC which l assume is part of the TCI is causing the 1 & 4 and 2 & 3 issue and vice versa. Thanks for your reply Rooster.

 

Maybe you could remove one pick-up wire from the TCI connector and see if your bike will start :-}

 

ok, i tried that, gray wire out of the smaller connector (tci out). started right up (surprised me how easily) #1&4 pipes got hot.
then took the gray wire out of the bigger connector (tci in) and no start
so what did we do here, other than get my connectors greased up and the rr shined up with a wire brush

 

At initial appearance it proves that the TCI has to have both pickup resistances on the inputs in order to operate.

 

So I am not color blind and didn't mistakenly mis-wire the connector.

In future reference to troubleshooting tips we are more educated on what to recommend when a bike is running on only two cylinders, but because it is so easy to ohm out the pick-ups that will likely still be suggested.

You have a shiny regulator and clean TCI contacts : -)

I think it is more than that, I have resistors simulating the pickup resistance so I think it is more about the signal being present and the timing relationship. I will have to revisit that one just to be sure though, as the resistors are switchable.

 

i think the pickup coils are inductors but tested with an ohms reading

 

All coils are inductors. The resistance test is to be sure that a winding hasn't shorted, since component failure is the only thing that will matter to a mechanic. The induction value (and other associated values) only matter(s) when the circuit is designed and the coil manufactured.

 

OK, so I got my new part and was about to commence surgery and I noticed something different than expected. This whole time I'd been doing my resistance measurements on the six position plug as follows.

Orange to black (this checked out in the correct range)

Grey to black (this showed as an open circuit)

I was examining my ebay part and I noticed that at the crank I had the following colors on the pickups. One pickup was orange and black. The other pickup was grey and brown.

Wait what? I thought the black was a common ground. Looking back to the six position plug I observed the following colors. Orange, black, grey, brown.

I redid my resistance measurements on the pickup coils, this time measuring orange to black, and then separately, brown to grey. This time both my resistance measurements were in spec. Now it's looking like I don't have a bad pickup coil after all. At least my ebay parts were cheap (and they also ohmed out in the correct range, so now I have a spare).

This is all well and good, but now I'm back to ground zero on my problem solving.

I'm tempted to put it all back together and see if it behaves. If so I can blame that metal dust in the crank on the pickup rotor. Not sure if that would cause this if it lead to a ground out somewhere.

It's that or the TCI, unless anyone has any other guesses I can look at.

 

Oh no good sir. You are one step forward. You are now sure of one thing that is not causing the problem.

 

My apologies for not getting this right. The Haynes manual does show a 4 wire setup for the 1981 650 Maxim, but shows two separate black wires. For the 1982 Maxim the Haynes manual shows a brown wire, but they tie that to the black to make the black common.

From the testing that you did in your initial post the TCI could be suspect, unfortunately the best way to test it is to swap it out or try in another bike unless you have the necessary equipment to evaluate. You could also repeat your test which I think you did already, but if you swap the coil primary side connectors and 1 and 4 spark and 2 and 3 don't then that is fairly conclusive that the TCI has an issue since we now know the pick-up coils are OK.

I was also confused by this comment, where it seems to imply that spark is seen on all four plugs?

PM sent

 

I did see a weak spark at each plug, but compared to the sparks on say... My Vulcan, it was piddling. A spark is a spark though. Could just be a low battery charge. Maybe an intermittent issue where I was seeing say... half as many sparks as I really should be? At some rate, half as many is still more than I can differentiate.

 

That's a difference in the type of ignition system . TCI ignitions have a "weaker" looking spark that is of a longer duration than a CDI ignition produces.

 

if you look back at your photos you will see brown wires on both pickup coils. the wires should be spliced together and have a common connection . 3 connections in the tci connector not 4 . you can see brown wire in wiring diagram and it splices into black wire

 

Sounds more like a fuel issue than ignition.

 

unspliced tci wire with 1 wire in put in wrong location needs to combine with black wire as shown in wiring diagram

 

Ryengoths Photo from another thread

 

Are those wiring diagrams and pictures particular to the 1981 model? From what I've been gathering, there was a different set up between 80-81 and 82. From what I can see this stock setup with a brown and black each running all the way from the crank to the TCI module looks unmodified. I've had the bike about five years and 14,000 miles and I haven't monkeyed with it. I don't have a black and white wire at all, and looking at my side stand, it doesn't look like there was ever a switch on it.

 

if you look at photos you posted you see 2 brown wires running from the pickup coils,
I see you have a Black label tci it is for 81 650 the midnight model
I have a black label tci on my shelf I will check it out saturday for connection between 2 tabs and if it runs an 82 650 wiring setup
from what has been established in the forums the only differance in tci's is weather there is a black/white wire which goes along with a sidestand switch circuit
the black white wire grounds out the tci when sidestand is deployed killing engine.
wiring diagram is for 80,81 650 maxim from FSM
if your bike has been running 5 years like that it may be possible that the internal connection between tabs has failed.


no brown wire on this wiring diagram from FSM



5V2-82305-10-00

haynes