1981 GS450S frankenbike rebuild

[steve murdoch]

I like the term "manually edit".
A very large hammer usually comes into play if i am using that term.

Are the shocks facing forward because of a frame clearance issue with the reservoir?

 

[Guest]

Excellent, that's always a great milestone to hit! I do have to second the question on the shocks though, the reservoirs typically face backwards... looking real good though!

 

[salty_monk]

I had quick measure after I had mounted the wheel. Its about 270mm.

That's about the same as stock. The CBR ones are 295mm. It's going to be pretty tight with those. You will likely need to space them out from the hub. What's the offset of the disc and how much space is there between your fork legs?

Congrats on getting to a roller!!

 

[Guest]

Yep, the shocks are facing forward temporarily. I loosely mounted the shocks and found there is a lot of length on the mounting studs left over.
Checking the diagram there are about 4 washers required on each of the top studs and I think 2 on each of the bottom studs. So it might still be able to work facing backwards.
They are a cheap ebay purchase I thought would be a good learning curve to the innards of shocks.
Turns out the piggy back reservoirs are purely ornamental; there is no path from the shock body to the reservoirs
So perhaps later on these will be used for something else and be replaced by another brand, preferably a version that can be rebuilt.

 

[Guest]

Today was an entertaining day fabricating some caliper adapters, or at least a template to use. More than just the adapters were worked on though. As a result of checking clearances I realised I had incorrectly assembled the front wheel axle spacers, forcing the fork legs to compress towards each other. After a lot of searching and trying various things I eventually fashioned an extra thick washer from an extra spacer I had. So now the forks are straight and not being forced together by clamping down the nut. As an aside what is the correct process for installing a fork like this? The version where the bottom of the fork leg can be removed and the whole axle and wheel can simply drop out? I took the approach of assembling the axle, spacers, speedo drive and wheel all together and clamping lightly into place with the fork legs. Satisfied the forks were clamping the axle in place I clamped down the axle nut, and then the fork legs.
Any thoughts?

Anyhow, once this was done I measured the distance from fork leg to disc and found a 1mm discrepancy, and thought but why? Remembering the spacer that is used with the one disc, I hauled it out and tried to insert it. Man: what a struggle. I recall dis-assembly was equally painful and ended up cutting off the portion that would sit between the disc and the hub center. With this editing done, the discs are now equi-distant from fork legs, so happiness ensued.

The caliper adapters were some fun to do. With some flat aluminium bar I had lying around I shaped and drilled some suitable brackets. So far I think they'll do, but would not mind some feedback. Doubtlessly there is something I have gotten horribly wrong. Sorry for the pics, but my phone really really doesn't like the dark.

Version 1

Some clearance visible in this shot. Pity I don't have new pads.

View from the back of the caliper

Caliper and adapter in a slightly better light

And the adapter plate as it stands now

I ended using a single spacer to bring the caliper a little closer to the disc. This gives me some measurements to work with.
From the inside of the fork caliper tab, I reckon about 11mm thickness takes me to the end of the nut you can see in the pics.
The caliper mounting plate is 6mm thick, so will need to offset the plate by 6mm to the outside to bring the caliper in line.

How thick should the plate be to provide adequate safety and rigidity? Any recommendations on material. Some brief internet searching basically came down to aluminium, but there are many voices yelling for a particular alloy. Help a numpty out here, too many opinions from too many folks.

And lastly had another go at mounting the decorative reservoir shocks on the traditional way, but no dice. The right side will foul on one of the tabs. Perhaps that tab will be scheduled for removal, but I'll just keep it for now.

Looking forward to this now. Much excitement in the air

 

[Guest]

Nice work! I can't really offer advice on how to ensure the brackets are safe, but when I researched what to use for my rearset adapters it came down to two types of aluminium being suitable which was marine grade 5083 or 6061 T6. Either of those are suitable for my application, but the 6061 T6 was easier to get and my understanding is the 5083 gets quite pricey.

For your application the 6061 T6 should be a good grade also (I believe it's good structurally full stop) but would definitely like some verification from someone else more "in the know" on that.

My rearset adapters use 12mm thick 6061.

Dan (salty_monk) will be your best bet there I think.

 

[Guest]

Some more work done yesterday, was to strip, clean and repaint the starter motor. As with previous items on this bike, some bits are broken, missing or worn out.
A new brush kit is absolutely required, and one of the bolts is missing. Any ideas where I could find a 5mm x 12mm bolt?

 

[Guest]

M5 x 12mm long? Any hardware store I would imagine...

 

[2BRacing]

Some more work done yesterday, was to strip, clean and repaint the starter motor. As with previous items on this bike, some bits are broken, missing or worn out.
A new brush kit is absolutely required, and one of the bolts is missing. Any ideas where I could find a 5mm x 12mm bolt?

Not sure exactly where you are situated, but in Paarden Eiland there is Bolt & Nut Centre, and Topfast Engineering Supplies. In Radnor Street, Parow there is Parow Bolt & Tool. Nesco Engineering is in Voortrekker Road opposite Sanlam in Bellville. In Epping there is Bolt Fast near the Cape Mail Centre.

Alternatively Suzuki South in Wynberg for OEM parts like the brushes etc and maybe the bolt as well.

Congrats on your progress so far. I second asking Salty Monk (Dan) for suggestions on the type of material to use for the bracket, he developed the twinpot brake upgrade conversion brackets.

PS: Those brake pads do look quite worn!

 

[Guest]

M5 x 12mm long? Any hardware store I would imagine...

Damnit. That was supposed to be M5 x 125mm
It's one of the bolts that runs through the starter motor and holds it together. Of course one is missing.
After having inspected the diagram for the starter I realise I have a few pieces missing. Notably washers/spacers internally, o-rings, bolt. And of course the brushes are well worn.
Think I will see what it would cost to rebuild or replace. Whatever makes economical sense really

 

[Guest]

Ah, I was picking my brain trying to remember where such a short bolt was on the starter motor! I'm not 100% sure but I've been led to believe GS500 starter motors will drop straight in. If that's true that should make it a little easier than finding a 450 one. Alternatively, most of those parts should be available from Suzuki still.

 

[Guest]

Not much progress made this weekend. Got a friend who knows a little CAD to mock up some caliper adapters on a 3D printer. Hopefully, that will happen in a week or 2 and I can see how the proposed solution pans out.
Tried to do a little electrical work, testing the stator and regulator. I am a little confused.

The regulator/rectifier is a 3 phase version; indicated by it having 3 yellow wires, 1 each of red, black and green. I should be able to do a diode test (positive or negative) and get a low resistance measure depending on which way I'm testing. I cannot get a reading at all. Just nothing, no matter how I test. Am I just incompetent or is it stuffed?

The stator is where my confusion lies. As I understand, if it were a 3 phase stator it should have 3 yellow wires that would plug into the regulator\rectifier.
This stator has 2 yellow and 1 green wire. Only 1 combination of yellow and green gives me a reading. The other 2 combinations give me no reading. is the stator stuffed too, or is it perhaps a single phase stator?

For reference, here are a quick pic I took of each, whilst unwinding the electrical tape that held everything together.
Regulator

Stator

As you can see the previous owner(s) did not believe in plugs. Electrical tape and twisted wire for everything.
That stator at least did not have carbon or burnt oil anywhere on it, so visually speaking it looks okay. Anyone in the know that might have a bit more info, could you let me know your opinion.

Otherwise I got on with some other bits. Mounted a digital speedo\tacho from Koso, some hand controls and switches, and started pottering around figuring out how I'm going to mount the battery and mUnit. Or more importantly where.
Tried to get the replacement ignition coil installed too, but it needs a bracket too, so will leave that for another day.

 

[Gorminrider]

That looks like a Honda R/R.

Green is ground, Red is regulated DC output. Black is the voltage sensor wire that tells the R?R when to "regulate" . You might as well twist it up with the red, though Honda would have it to the tail-light...Yellows are indeed for the stator.

if your stator is the Suzuki one, the wires are so dirty I can't see what colours they were but I could tell you what they should be- BUT it's moot. Ignore the colours and just attach the R/R yellows to the 3 stator wires. If it doesn't charge thereafter, you have a faulty R/R or stator.

 

[Guest]

phew! what a weekend of attempting an engine build. There I was thinking I would slap the engine together and I'd have it buttoned up and done on Saturday, and then installed on Sunday....

That didn't happen. I got the crankshaft and balancer reground to spec with new under size bearings, so I was super keen to get building this weekend.

Queue the optimistic photo of everything that needed to be put together:

So I got cracking, first peeling off all the painters tape on from all the parts. It had been left on so that the internals didn't get full of dust whilst waiting for all the parts to be ready.
Started putting everything the crankshaft, gearbox and cases together.
Gearbox works: check
Crankshaft spins freely: check
Balancer spins freely: check

Result: In business

Then I start clamping down the cases, tightening the bolts to finger tight all round, and then just what I can manage by holding a ratchet around the head.

Gearbox: check
Crankshaft: stiff (hmm -> possible because of new bearings?)

Crank it down to torque spec. Crankshaft doesn't spin for love or money.
Okay, I'm a noob. I did something wring, it was inevitable. Disassemble, double check. Lube all bearings.
Crankcases together, crankshaft spins.
Torque the bolts, crankshaft no spinnee.

And so proceeded the really annoying day of assembly/disassembly trying to figure out what had gone wrong.
Eventually started assembling with just one component at a time, and got to the point where the balancer shaft was the likely culprit.
Removed the new bearings and found the best of the old bearings. Re-assemble and torque...et voila! All is good with the world.
Right. Sunday is my day. This engine build is getting done.

Start buttoning up all the little bits: shift lever, oil pan, etc.
Time to move onto the pistons. Get the jugs oiled up and gasket in place, and try to lower onto the pistons. One piston won't go in.....
Eventually I realise the oil ring is not moving at all and seems to be an issue. And in trying to free it up, I break said oil ring. So now it really is an issue.

Fine. Remove piston and inspect. Looks like the wrist pin orifice has been damaged somehow and is clamping the oil ring in place.

As an aside any idea what causes such a burr in the piston? Looks almost like someone used a blunt drill and the metal was pushed out of the way instead of cut.

Lovely. Whip out the files and start working away at the burr of metal that's causing a problem. Eventually work it away enough to have a smooth surface and allow the oil ring to move freely.

Okay, Well top end build halts here. So now I have a conundrum: what is the appropriate move next? Clearly a new set of rings. I assume it's not a good idea to match new and used rings, even if you could get just an oil ring. And I'm guessing I will need to know what size the current rings are? I checked for numbers, but only the 2nd ring had a number 11575782. Does that mean anything to anyone?
Is there any merit in building the engine to test compression? I imagine the compression would be less without the oil ring, but could it be a useful measure? Let me know some thoughts.

As the top end is effectively stalled, it's still possible to continue elsewhere. Let's look at the clutch. Maybe I can at least finish off that side. Examine clutch basket. Oh look, so many notches from the clutch plates.

Out with the files again! After a bit of work got them flattened out okay.

And that's it for today. Not the finish I had envisioned, but I guess some progress was made.
Now to figure out what all the loose little bits are for..

 

[Guest]

So whilst I still have a little daylight left, I thought I would try out some style options on you folks. The basic idea is a street tracker from this old GS 450.

The colour scheme has not been cast in stone yet. Initially I was going with a majority white on the tank, with some green and gold strips, but seeing the white tank in the daylight is making me rethink it. For the moment I'm going to park the colour scheme and just imagine the lines. To that end see the pics below:

Clearly there are some bits on the frame that need to be modified. Much as I hate to just take a grinder to everything and start hacking, the seat definitely needs to be lowered down to the frame tubes. And a little of the excess frame lopped off the back. At this stage no idea is a bad one, so go ahead: tell me I'm 20 years out of date.

 

[steve murdoch]

Since you asked....do you have room for the rear shock reservoir to be facing the back?
The angle of the muffler should be about halfway between the two photos, definitely lower the seat and lop the tail off the frame.
Green paint should only be on a Kawi.

 

[Guest]

There is a tab on the right hand side of the frame that the shock will foul against, otherwise the reservoir would be facing backwards.
When I get to the point of finalising the layout I may cut the tab off if it isn't necessary for anything.

 

[Guest]

So this project took a bit of a backseat for a few weeks whilst many things were going on. South Africa is under lock down now, so while I am at home every day, I have assembled the bottom end.

Right:

Left:

the top end will have to wait until I receive the new pistons. I took some measurements of the state of the engine, see below (in mm)

[TABLE="width: 500"]
[TR]
[TD][/TD]
[TD][/TD]
[TD]Left[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]Right[/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD]Gap[/TD]
[TD]Width[/TD]
[TD]Height[/TD]
[TD][/TD]
[TD]Gap[/TD]
[TD]Width[/TD]
[TD]Height[/TD]
[/TR]
[TR]
[TD]Top Ring[/TD]
[TD]1.35[/TD]
[TD]2.66[/TD]
[TD]1.2[/TD]
[TD][/TD]
[TD]4.42[/TD]
[TD]2.7[/TD]
[TD]1.2[/TD]
[/TR]
[TR]
[TD]Middle Ring[/TD]
[TD]0.2[/TD]
[TD]2.96[/TD]
[TD]1.2[/TD]
[TD][/TD]
[TD]0.35[/TD]
[TD]2.9[/TD]
[TD]1.2[/TD]
[/TR]
[TR]
[TD]Piston Clearance[/TD]
[TD]0.4[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD]0.4[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[/TABLE]

This is the first time I've delved into an engine and measured anything like this.
That the engine is worn is no surprise really, but what is surprising is the ring gap on the right top ring: 4.4mm.... That is huge (to my mind). How does it even get that big?
Never mind measuring with feeler gauge, not enough meat for that. Had to go to the vernier to measure.
Anyway, I kind of like the mostly silver with black and gold highlight. I will be honest: the clutch actuator adjustment cover I painted black by mistake. Still, I think it actually looks okay

 

[Guest]

It's been pretty quiet for a month or 2 since the country wide lockdown. Now that things are finally opening up, it seems most stores don't have any supplies yet.
So I've been playing at painting the tank. I'm pretty much making it up as I go along.

I'm trying out a green base coat and some white highlights to break it up a little.
At first blush, that's a lot of green

With a bit of highlighting it looks much better. Just some clean up required, looks like the rookie that taped it up didn't do a bang up job.

We'll see how this goes with a cleanup and re-assess.

Will likely need something on the sides of the tank. Still a ways to go before that becomes an issue

 

[Guest]

That green is lovely. I think some early seventies Suzuki's were in green. Was it a GT125 twin colour? Ignore the kwaker jibe. Colours do not belong to any bike company. Colours were around before motorcycles. And it's your bike, your choice. Enjoy.