The neighborhood 450 (everyone's tried to work on this thing)

[Guest]

This is going to be a centralized thread to keep track of my 81 gs450l so I dont keep making new threads for every little thing I have a question or issue with.
I'll start with whats been done so far.
Got the bike from a craigslist add and rode her 3 hours home (no truck atm)
Strapped her down to my bench to get a better look at everything.
I was expecting to just remove/ drill and tap some holes, but someone had already tried. Oversized exhaust bolt. Broken tap under one of the intake boots with a 1/4'' sheet-metal screw holding to boot on. Snapped a cam cap bolt. She was in a bad way.



Bought a used head assembly for $60ish on eBay and all the oem gaskets/ seals I would need from partsoutlaw.com
I found out the the bolt holes on the stock 81 valve cover are different form the ones on the 87. Had to reorder that gasket. Otherwise there the same.



Cleaned up and shined the top of the stock pistons. Replaced all the rings and re-honed the cylinder walls wile I had it apart.



I found studs for the exhaust side and am going to run anti-seize with lacing wire on the nuts.



Changed the stock 115 main jets to 137.5
I used a spare air filter and some PVC with rubber hose for a replacement for the hacked/ drilled stock air box. No saving that poor thing.



Here's what the stock mufflers look like without the baffles if you have ever wanted to see that.



Last was getting the placement of the aftermarket regulator to work, but still fit under the stock side cover. (It's snug, but works)



I'll update as I make progress. Thanks!

[Oldman99]

Started the coil mod today.
Heres how things looked when I first un-wrapped the harness.



Heres how it looked with the relay. 12.32v to the coils with the key on. Is that voltage right? Theres nothing to them with the key off, but I think I'll put a switch in the battery to relay supply wire. I dont know if I like a live hot wire sitting under my fuel tank all the time.

[Oldman99]

Today's endeavor is to install a switch and proper inline fuse for the coil to battery supply wire. I also go my petcock rebuild kit in the mail, but that will wait until the tank is done with the inside cleaning. Dose anyone know what size fuse I should use for the coil relay?

14448850_543282332535709_7779356876181837644_n.jpg

[Oldman99]

Wanted to do a little cleaning.



Turned into motorcycle archaeology.

[Steve]

Started the coil mod today.

Heres how it looked with the relay. 12.32v to the coils with the key on. Is that voltage right? Theres nothing to them with the key off, but I think I'll put a switch in the battery to relay supply wire. I dont know if I like a live hot wire sitting under my fuel tank all the time.

With 12.32 volts (I am assuming that is with the engine not running?), why are you bothering with the relay? Even if you have a fully-charged AGM battery, that is only half a volt drop. If you have a wet-cell battery, that is only about a quarter-volt drop. You won't improve on that very much.

Just out of curiosity, did you check any other voltages before starting your coil relay mod?
Open up the headlight bucket. Turn the key ON, check the voltage at the headlight terminals, then check the battery voltage without turning the key OFF. You want it measured under the same circumstances. If the voltage drop is less than a volt, you can recover part of that by cleaning all the connectors. If the drop is more than a volt, you might need a relay there, too. In fact, measure the voltage at the fusebox that feeds all the individual circuits. You might be better off to do just ONE relay that powers the fusebox, instead of each individual circuit. Easier and cheaper, too.

.

[Oldman99]

One of the other owners had removed all fuses except for one inline fuse that feeds power from the hot side of the starter relay to the key and from there to everything else.
I'm doing to coil relay to try and lessen the demand on the stock harness. I should have tested the power before doing the relay and also with the engine running for proper back to back testing. So what size fuse should I use?

[Steve]

Each of your 3-ohm coils will draw about 4.5 amps, so the coils will draw a potential 9 amps. The draw is somewhat intermittant, reducing the average draw just a bit, so a 10-amp fuse should be fine. That is what Suzuki installed at the factory.

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[SVSooke]

One of the other owners had removed all fuses except for one inline fuse that feeds power from the hot side of the starter relay to the key and from there to everything else.
I'm doing to coil relay to try and lessen the demand on the stock harness. I should have tested the power before doing the relay and also with the engine running for proper back to back testing. So what size fuse should I use?

No they didn't replace the fuse box,on the 400/450's one's all there is

[Oldman99]

Each of your 3-ohm coils will draw about 4.5 amps, so the coils will draw a potential 9 amps. The draw is somewhat intermittant, reducing the average draw just a bit, so a 10-amp fuse should be fine. That is what Suzuki installed at the factory.

Awesome! Thank you.

No they didn't replace the fuse box,on the 400/450's one's all there is

Wow, thats nutty. Thank you for letting me know. The only bikes I've had with one or less fuses have been dirtbikes and none of them had lights or batterys, so I was worried about frying something.

(yay for my first ever multi-quote. lol)

[Steve]

OK, since there is only one fuse, you had better add another 5 amps to the capacity so the headlight doesn't blow it.

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[John Park]

OK, since there is only one fuse, you had better add another 5 amps to the capacity so the headlight doesn't blow it.

.

I can't find the specs for the original fuse, but the bikes I've had had a 20 in there. The battery should be capable of blowing that it a short situation, and having the fuse fail at high speed in the dark isn't something you'd be likely to forget….

I seem to remember a journalist for Motorcyclist magazine blowing that fuse at high speed at night in Nevada. It happened to me, luckily on a straightaway; a few seconds later and it would have been very dramatic. Even if a 10 was stock, going up to at least a 15 may be safer.

I'll also issue a caution to those who might run with the high beam after the low beam burns out. The other filament is [was] your plan B. I carry a spare bulb on the bike.

[Gorminrider]

15 amp, from the Owner's manual for 450s. and gsx400s too. Very likely for 250s and 300s without looking it up.

[John Park]

15 amp, from the Owner's manual for 450s. and gsx400s too. Very likely for 250s and 300s without looking it up.

That's good to know, and is pretty sensible. OTOH, if you've added any watts to your headlight or would rather not have the experience of going dead at speed maybe 20 is a better choice. I seem to recall blowing the original 15 and replacing with a 20 way back when. But you do want the fuse to melt before the wiring does. A fuse is just a calculated and replaceable weak spot - an electrical shear pin.

[Oldman99]

That's good to know, and is pretty sensible. OTOH, if you've added any watts to your headlight or would rather not have the experience of going dead at speed maybe 20 is a better choice.

I converted the stock glass headlight to a plastic one that takes a 35w H4 bulb. Did not want to use anything higher powered that would use juice faster than the bike could make it and kill my battery.

[Oldman99]

Before anyone gets upset about how I "ruined the gas tank" will truck bed liner. I used high build primer first. This way when I'm ready to have a proper paint job done, I can use a scraper and it will come off in chunks. I did the same thing to a mazda miata. Came right off.



Cleaned up the fuel cap area. Had layers of paint that never fully cured because of the gas. I guess they never taped it off to paint. Rinsed the inside out with paint thinner and got more paint out that way. Filled with vinegar and water. Let it set for 12 hours and gave it a shake every now and again. Had alot of nasty brown water come out.



Sanded and painted the bottom.