87 vt700c front cylinder not firing

[bobberboi]

hello all!

first off - i try to find every possible thread for help before i start asking questions. however, i've declared myself officially stuck and need to ask for help.

I started rebuilding bikes a year ago and have taught myself most of everything i know(alot of thanks to online forums). anyways i had a friend give me 2 classic honda shadows. ive been working on the 87 vt700c trying to figure out why the front cylinder doesn't fire.

it didn't have this issue before. when i got it, it just had really bad throttle repsonse but both cylinders fires. I rebuilt the carbs but one of the diaphrams was ripped and i had a set of 85 carbs laying around and use the diaphram from that. ever since i've had this firing issue. it slides well and does what its supposed to when i blow compressed air into the carbs.

the carbs are getting sufficient gas. It has incredibly bad throttle response right now(need to go back into the carbs cause its been sitting the past 2 months). however, I can ride it the way it is but once i get up to 2.7k rpm then the front cylinder will fire and it will stay firing unless i go back down to idling speeds.

I switched the front coil plugs to the rear(also switching the wires the coil pack connects to). when i have the front coil pack running on the rear cylinder(connected to the corresponding rear coil pack wires(blue/black)), the bike will start like it normally does and idles with full choke. when i tested the front coil plugs on the rear cylinder(with the front coil pack wires(yellow/black)), the bike wouldn't start.

with that information, it seems the coil packs and plugs are all working. what should i be doing next to figure this out?

sorry if it was a bit long but thanks in advanced

Connor

[tubes_rock]

Quick question, what are you calling the "Coil pack?"

Your bike only has one ignition module for both cylinders, so there is no "front" ICM and "rear" ICM. You can swap the function of them by swapping the pulse generator wires and coil leads and get the "front" circuits of the ICM running the rear cylinder and vice-versa, but I want to be sure we're on the same page.

--Justin

[John Hopkins]

There is a carb overhaul post floating about..maybe that will help...

John.

[93gc40]

If you have spark at all the plugs, I would look at the fuel system as the issue.

[bobberboi]

Originally Posted by tubes_rock

Quick question, what are you calling the "Coil pack?"

Your bike only has one ignition module for both cylinders, so there is no "front" ICM and "rear" ICM. You can swap the function of them by swapping the pulse generator wires and coil leads and get the "front" circuits of the ICM running the rear cylinder and vice-versa, but I want to be sure we're on the same page.

--Justin

i'm not talking about the ignition module. the black cylinder shaped packs that have 2 coil plugs on both sides of the frame is what im referring to. sorry if im mixing up the lingo.

I'll keep testing things and following my manual. ill post once i spend another couple hours on it. thanks for the responses

Connor