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Discussion Starter #1
I've put the rebuilt engine in my bike. No start. The carbs and ignition were working when they were on the engine I just took out. I did the stator test for 1/5 through 7/5 and they're all ok. I run Ignitech so the blue and white readings aren't needed. There is spark, but it doesn't seem strong. Have I missed something? Timing? Anyone with similar experience?
 

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81 Gl500i 83 CX650E
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What model of bike are we talking about?
 

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Discussion Starter #3
It's a 78 CX500. The bottom one in my signature line.
 

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So many things that can stop it from running. Kill switch in off position, fuel petcock in off or not enough gas in tank to run in normal position. Left and right ignition coils mixed up. Cam chain timimg wrong. With ignitec ignition is your battery charged , and last that comes to mind are the ground wires attached. Oh have you checked the engines compression ?
 
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First of all:

When installing the Ignitech CDI, it is essential to ensure that there is clean contact with the vehicle's electrical system.

Increased transfer resistances at the plug connections can lead to malfunctions.



In rare cases it can happen that one of the pickups is defective and the Ignitech receives incorrect pulses.

In order to be able to confirm or exclude this error, the resistances must be measured according to the graphic below between terminals 1, 2, 4 and 6 and ground (5) on the 8-way connector on the motor side and must be within the specified tolerance.

If one of the values deviates significantly from the target values, the engine must be opened and the relevant pick-up has to be replaced.


Lima_Sollwerte Pickups.jpg
 

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Discussion Starter #7
I ran all the externals on the '78 engine right up to the day I took it off the bike. Carbs were good and synched, the ignition system was fine as well. I'm going after a compression tester first to see how the compression is as it's new rings, bearings and valve seals. If the compression is good, then it could be I put a dodgy component in the engine when I built it like the rotor. It' a fairly new stator and tested perfect when I entered the readings into the motofaction test page.

Like I said, all things being equal, the carbs and ignition worked perfectly on the '78 right up to the day I took it out. This thing should have popped and spluttered when I put it in and attached the carbs and such to it. I usually just fill the engines with oil and hook up the bare minimums then have a quick poke at the start button to see if there;s life. This is the first time putting engines in the bike that it's a no go.
 

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Discussion Starter #9
I don't know the source. It's a bitsa engine. I've checked the spark on both sides and it seems strong enough. Would that rule out the rotor? I took the plugs out to check the spark so I put my face down near the rocker cover and cranked the engine and could feel puffs of air on my face. I REALLY don't want to undo the entire engine if it's something stupid I can sort without taking it all apart again. I'll buy a compression tester to see where the compression is. It's has new rings and bearings but I've never done all this on a bike engine. Possible I screwed up the rings? I also cleaned up the valves and lapped them and put Viton valve seals on. Something is amiss. I hate starter fluid so I won't be doing that. It should, for all intents and purposes, at least pop when I crank it over, even with no exhaust or coolant. Nothing.
 

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It must be a CDI stator or you wouldn't have spark.

And you have new coils right? They have clean to bare metal mounting points? The ignitech has a clean power supply and grounds?

Take out the balance port screws and squirt in a little petrol and see if it coughs.
 

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'84 CX650E that is evolving into a GL500
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Did the bike sit very long between engines? If it was more than a week or so and you didn't drain the float bowls it could be a simple as stale fuel in the carbs. Also, make sure nothing has taken up residence in the air filter (easy to check and you never know).

If it was a TI bike I'd be suggesting that the timing advance might have been installed 180 degrees out (= lots of spark at the wrong time) but I don't think there is anything like that with CDI.
 

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...the carbs and ignition worked perfectly on the '78 right up to the day I took it out. This thing should have popped and spluttered when I put it in and attached the carbs and such to it. I usually just fill the engines with oil and hook up the bare minimums then have a quick poke at the start button to see if there;s life. This is the first time putting engines in the bike that it's a no go.#
If a coil is defective on one of the two pickups (there are 2 coils in each pickup), you won't notice it with the CDI, but with the Ignitech.

Therefore you should carry out the measurement described in # 5 and check if all 4 coils are working.
 

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Discussion Starter #13
I've gone out and put a little raw fuel in the balance port. It cranked like it has been doing,then sounded like it got harder to crank over, then produced a fireball out the exhaust. I'm guessing when the raw fuel got to the right ratio, it lit.
 

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Discussion Starter #14
Hi Bob, No it didn't sit that long and I drained the bowls after installing them on the rebuild, just to be sure.I don't like starter fluid. It should have fired right up.
 

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Do you have the ignitech outputs to the correct cylinders? If I recall correctly, it should be white to the left, orange to the right.
 

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Discussion Starter #16
Do you have the ignitech outputs to the correct cylinders? If I recall correctly, it should be white to the left, orange to the right.
Yep. They're correct.
 
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Discussion Starter #17
I've checked the timing by bringing the rotor around to TL and the rockers wiggle as they should. I fear something mechanical is amiss. I don't think there's adequate compression for whatever reason. Can I re-use the head gaskets if I need to remove the pistons again? It's never ran and only been torqued the once with Copper Gasket sealer spray.
 

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Why do you want to remove the pistons again?

You write at the beginning that your sparks are too weak.

After you have measured the resistances of the pickups and the assignment of the ignition coils, the spark plug caps and the spark plugs themselves remain the cause of weak sparks.

The NGK DR8ES-L are very sensitive once they get wet. I would always use new spark plugs to isolate the error and find the cause.

If you have spark plug connectors with 5 kOhm interference suppression, I recommend spark plugs D8EA from NGK.

Have you ever measured the resistance of the spark plug connectors, if it's still 5 kOhm ore more?

Have the ignition coils a good mass without transition resistance?


Have you set the valve clearance at the correct TDC (end of the compression stroke)?

If you had the engine open, it could also be that you have incorrectly positioned the timing chain and the timing is incorrect. If you have shifted it by only one tooth, you can hardly tell from the outside.

But for all this you don't have to remove the cylinder heads or the pistons again.
 

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Discussion Starter #19
Why do you want to remove the pistons again?

You write at the beginning that your sparks are too weak.

After you have measured the resistances of the pickups and the assignment of the ignition coils, the spark plug caps and the spark plugs themselves remain the cause of weak sparks.

The NGK DR8ES-L are very sensitive once they get wet. I would always use new spark plugs to isolate the error and find the cause.

If you have spark plug connectors with 5 kOhm interference suppression, I recommend spark plugs D8EA from NGK.

Have you ever measured the resistance of the spark plug connectors, if it's still 5 kOhm ore more?

Have the ignition coils a good mass without transition resistance?


Have you set the valve clearance at the correct TDC (end of the compression stroke)?

If you had the engine open, it could also be that you have incorrectly positioned the timing chain and the timing is incorrect. If you have shifted it by only one tooth, you can hardly tell from the outside.

But for all this you don't have to remove the cylinder heads or the pistons again.
I think you misunderstand. taking the heads off and those pistons back out is the last thing I want to do. That's why I'm sorting out a compression tester and possibly a leakdown tester. Taking the back of the engine off to have a look is about as far as I'd like to go, but it may end up I have to pull the heads and pistons. Thank you for the input though. Any and all advice is good.
 

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I have to agree that the next step should be checking that the valve clearances were done at TDC compression and not TDC exhaust and then making sure that the coils, caps, plugs &c are good.
 
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