SuzukiSavage.com - starting problems

Kwarran

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starting problems
04/17/24 at 04:03:05

Hello everyone! First time posting here with a problem.
I am in the process of assembling my Savage after making some bobber modifications. The modifications I made are: changing the carb, making DragBike Mike's muffler, removing the airbox and moving the battery on the muffler support. Also, I changed the battery with a LiIon one. I tried putting all the cables under the seat.
The problem is when trying to start. The starter tries to spin the engine but the problem that occurs is that the cable from the decompression solenoid gets very hot and starts to melt the housing. I have no idea why it's doing this and how any positive current is getting to it to cause a short circuit there. Did anything like this happened to anyone? Or does anyone have an idea why this is happening?
Bike is '99 with about 47k km on it.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28996 L.A. California Gender:	Re: starting problems Reply #1 - 04/17/24 at 05:54:51 My guess is the decomp starter controller. They can get full of water and corrode.
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ThumperPaul

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Re: starting problems
Reply #2 - 04/17/24 at 10:41:00

That's about the strangest thing I've seen. How the heck can the cable get hot enough to melt the sheathing!

Delete the decomp solenoid and convert it to a manual/mechanical set-up. Verslagen and Lancer can probably walk you through it, but they're out riding in the Texas Hill Country right now. Thread below...

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1589335867/11#google_vignette

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DragBikeMike

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Re: starting problems
Reply #3 - 04/17/24 at 12:20:49

That is crazy strange. Did you actually observe the cable sheath melting, or is there a chance that it was already like that? For that thing to get that hot due to electrical current passing through the cable, it would take a dead short to ground. The solenoid is already bolted to the frame so why would any current be flowing through that cable? A fuse should have blown.

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ThumperPaul Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 2156 Houston, Texas Gender:	Re: starting problems Reply #4 - 04/18/24 at 05:25:06 Agree Mike. I’m looking at the plug wire suspended by a Velcro strap and wondering if it (or an old defective one) fried and dropped down onto the cable sheathing and melted it from the outside (as opposed the the decomp cable getting hot enough from an electrical current that’s not supposed to be there).
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Kwarran

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Re: starting problems
Reply #5 - 04/19/24 at 04:58:07

Thank you all for the replies.

@DragBikeMike Yes, I saw smoke coming out and one time I even saw the metal cable turn red for an instant.

@ThumperPaul I suspended the plug wire with the velcro thinking that maybe some current might leak and get to the solenoid cable and cause it to short and melt. But it turned out it wasn't the case.

I tried last night to disconnect the solenoid wires from the harness and pulled all the harness away from the bike wherever it might come into contact with the frame. Surely enough the solenoid cable didn't get hot anymore and the bike even started! So I would call it a win. For now I'll go with no decompression solenoid and see how it goes. Also, I will have to check the rest of the harness to see where the short might have came from.

Thank you all for the information, will keep you updated how it goes.

Btw DragBikeMike, the bike sounds awesome with the muffler I made according to your plans, thanks alot!

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DragBikeMike

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Re: starting problems
Reply #6 - 04/19/24 at 10:46:38

Kwarran, glad the muffler works good.

I have been pondering your problem. I can't see any way that current could flow through your compression release cable without blowing a fuse. But I don't have a sufficient understanding of the construction and the FSM is silent. Doesn't even provide info on a continuity check.

My clutch cable failed. I expect to receive a new one today or tomorrow. When I pull my fuel tank off to replace the clutch cable, I will wring out my decomp solenoid and provide the results. I've never seen a problem like yours. The solenoid coil should be insulated from ground, so there should be no continuity to the frame, the bracket, the cable, etc. In the event that the insulation fails, the fuse is in the circuit to protect the wiring. A lot of juice has to flow through the cable to get it to melt the sheath and glow red.

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4471 Honolulu	Re: starting problems Reply #7 - 04/20/24 at 20:54:54 So, I go to check out my decomp solenoid and the first thing that strikes me is the gap between the solenoid armature and the coil housing. It's BIG. Easy for a wire to get in between the armature and coil housing. See how close my turn signal relay wires are to the coil housing.
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DragBikeMike

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Re: starting problems
Reply #8 - 04/20/24 at 20:59:40

While the solenoid was still on the frame. I checked continuity between all the metal portions of the coil housing and the engine case. That sucker is grounded good. If an energized conductor touches that housing it should blow the fuse.

With the solenoid off the bike, I checked coil continuity. It's 0.8 ohms, so this sucker should pull about 15 amps. That seems like a lot for the wimpy wires, but by design it is only energized momentarily.

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4471 Honolulu	Re: starting problems Reply #9 - 04/20/24 at 21:00:37 Insulation resistance to ground is 50 megohms. Essentially infinity.
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DragBikeMike

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Re: starting problems
Reply #10 - 04/20/24 at 21:05:35

Close examination of the turn signal wires shows that they are chafing (red arrow). Time to reroute those and get them well away from the armature. All the other wires are tied up well away from this contraption.

I noticed that the armature hits the frame pretty hard (yellow arrow). A wire caught between the frame and armature would eventually fail.

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DragBikeMike

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Re: starting problems
Reply #11 - 04/20/24 at 21:17:04

There is a soft stop between the armature and coil housing. That stop would insulate the armature from the housing. When the solenoid is energized, I bet that the magnetic field centers the armature perfectly in the coil (like a magnetic bearing), so the only path to ground would be through the cable. That would explain how your cable got so hot, but it wouldn't explain why the fuse didn't blow.

Let's assume a wire got pinched by the armature. The juice couldn't flow to ground through the coil housing because the armature is insulated from the coil housing by the rubber stop and the air gap between the armature and coil housing. The only path to ground is through the cable.

Why didn't your fuse blow? Do you have a fuse?

One thing I found very interesting is the wear pattern around the rim of the armature. This thing must rotate a bit every time it's energized. The wear pattern is uniform 360 degrees around.

Very mysterious, very cool problem.

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4471 Honolulu	Re: starting problems Reply #12 - 04/20/24 at 21:23:38 Uniform wear pattern all the way around. This is where the armature contacts the weld on the frame (when the solenoid is deenergized). Only way this can occur is if the armature rotates a bit every time it gets cycled.
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