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Discussion Starter · #1 ·
Carbs were cleaned last season, still trying to get it to run right. The rear cylinder seems very weak. It'll start, the front pipe will get HOT, the rear will only start to warm after a few minutes. Last night I swapped the coils, same thing. So I swapped the two identical connectors under the seat (to switch ignitor boxes) and the rear got HOT in a hurry, front didn't get hotter.

And of course, when it get's hot, then it stops running right, so testing stops there.

Advice? Does this point to bad ignitor boxes? Should I follow the wire wraps for bad connectors? Anybody?

Thanks.
-Maxx
 

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Sounds like you have a bad CDI box or pulse generator. Get a manual and a VOM and test them.
 

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Discussion Starter · #3 ·
Yeah, I have a manual and a meter... I just haven't gotten them out yet. Seems I only ever have about 20 minutes at a clip to work on it...

Thank you for the input.
 

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Yeah, I have a manual and a meter... I just haven't gotten them out yet. Seems I only ever have about 20 minutes at a clip to work on it...

Thank you for the input.
Such is life...... Me, I'd just skip sleeping one night and get it figured out. Wish I could help more, it just sounds like your at that point where only, the laying on of hands will help.
 

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You're right about the laying of hands, but it's in my nature to over-research on the internet instead. :D
I'm with you there. When I am working on my Shadow or Jeep. The 2 "tools" I have to have are my manual and the Laptop. So I can ask questions and seach on the forums. Course I'll have spent days researching, before I look at the bike.
 

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Discussion Starter · #7 · (Edited)
Okay, a little more info. Last night I:

-Tested the Stator, all yellow wires had something like 0.08 ohms between them (@200 ohms on the meter).

-Tested the reg/rec, between all yellow and green wires I had 495-502 ohms (@2000 ohms on the meter). Between all yellow and red/white wires tested good; 476,496,506 (@2000 ohms on the meter). Note: On both of the readings above, they were the opposite of what the Clymer said they should be (if it said infinite resistance for positive>negative and readable resistance for negative>positive, it was the opposite), which, because of the consistency, I think the guy who wrote the book flipped the pos/neg or I did, and the reg/rec is fine.

Swapped the spark boxes and fired it up. Front still got hot after a minute or two, where the rear still didn't. Didn't run it long because it was 11pm. Opened spark box for rear cylinder, but couldn't slide the circuit board out to examine for cooked components. Peeked inside, nothing looked fried, no evidence of melted or burned plastic, wires etc...

So, I guess I either have a bad wire going from the spark unit connector to the coil, bad plug wire (shouldn't be, replaced them last year), bad plug (shouldn't be, new NGK's last year), or a carb issue. Battery is regularly topped up (new gel mat last year).

Weird: Last owner had autolite iridium plugs in it and it ran better (but would get weak and run crappy after it got warm)... so that makes me think the spark gets weak when it's hot.

Edit - I also adjusted the valves last year, but that went fine...
 

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Discussion Starter · #9 ·
Checked the pulse generators last night, both at exactly 432 ohms. Tested the coils at the lugs, both exactly 2.4 ohms. Tested the coils at the plug caps, both around 32,000 ohms.

Weird thing I noticed: When I have the ignition switch on, then switch the killswitch to run, the lights (headlights, speedo lights, indicator lights), all pulse faintly either 1 time if it just ran or 3 times if it hasn't run in a minute or two. Always. This is barely noticeable when it's not dark out. Don't know if this is indicative of a bad killswitch or ignition switch...

When the bike has sat, it will fire up right away and run for a while (even when I accidentally had one of the front plug caps still off last night. But once it's warmed for a minute or two it is a bear to restart, I have to choke it and massage the throttle to get it to run, then if it does idle, it does at a low rpm like 700-800, then dies.

Feels like it's an electrical issue. Maybe when I turned out the idle air screws last year I didn't go far enough?

Also - last night I checked it while I was goosing the throttle, and both bowls would leak fuel if I opened the taps, so they weren't running out.

AND, another note, and now that I think of it, this may be THE KEY that I had forgotten. I was talking to the guy I bought the bike from yesterday (he unloaded it due to this problem that he couldn't fix), and he said that it ran crappy, then he went around a corner and it ran GREAT, then he hit a bump and it ran crappy again.

^anyone want to tackle THAT puzzle. If you do, I'll buy you a Snickers.
 

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Discussion Starter · #12 ·
Well, finally pulled the carbs again, and focused on cleaning the rear one. Noticed a couple of things - they weren't quite in sync, so I fixed that and set them eyeball (see half of pilot hole). Also, the idle air mix screws were in wrong I believe. The order was: washer, o-ring, spring, needle. Put them back in: o-ring, washer, spring, needle.

Started it up, set the idle, rear pipe warmed up MUCH quicker. Took it for a spin, ran alright, not perfect, but it has last year's gas, so whatever. I'll have to take it for a real spin, put some miles on it and go from there. The main issue though - carbs not in sync.

EDIT - Oh, I also set the idle air screws to 3 turns out.
 

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Have you actually done a sync on the carbs? or just "eye-balled it"? I had a very similair problem to yours when i got my bike. Took me 2 months to figure it out. At idle the rear cylinder would suck air in and not produce exhaust. As soon as i opened the throttle, it would heat up and produce exhaust. My carbs wouldn't even come close to being in sync because the sync screw springs were installed backwards.(yes, it does make a difference). I would do a proper sync on your carbs, it is REALLY easy. there is a thread about syncing carbs with a cheap homeade vacuum gauge.

Good luck.
 

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Discussion Starter · #14 ·
You are Correct, I on the other hand am Lazy. Heh. I just eyeballed it. When I went through the carbs initially, I never messed with the sync, but I did mess with the overall idle. I think they must have been such that they were a little more open in the front, dropping the rear. Anyway. That still doesn't explain the weird issues it had, but I have to really beat on it to see if those problems went away.
 
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