GS400/500 Gr650 Hybrid engine

[WolfTechnics]

Small update, I have decided on the way forward and have ordered the parts.

I'll be using GS1000 con-rods on the GS400 crank, the challenge here is the difference in big-end size. [TABLE="border: 1, cellpadding: 1, width: 500"]
[TR]
[TD] [/TD]
[TD]GS400[/TD]
[TD]GS1000[/TD]
[/TR]
[TR]
[TD]Stroke[/TD]
[TD]60[/TD]
[TD]64.8[/TD]
[/TR]
[TR]
[TD]Crank Pin[/TD]
[TD]28[/TD]
[TD]29[/TD]
[/TR]
[TR]
[TD]Big-End[/TD]
[TD]38[/TD]
[TD]39[/TD]
[/TR]
[TR]
[TD]Big-End Width[/TD]
[TD]20[/TD]
[TD]20[/TD]
[/TR]
[TR]
[TD]Small-End[/TD]
[TD]16[/TD]
[TD]18[/TD]
[/TR]
[TR]
[TD]Con-rod Center-to-Center[/TD]
[TD]Unknown[/TD]
[TD]Unknown[/TD]
[/TR]
[/TABLE]
Using the GS1000 con-rods allows me to use the GS500 pistons with GR650 head on a GS500 cylinder. I plan to use 32x39x20 bearings on a 28x32x20 needle bearing inner race.
I see this as an intermediate solution to get this setup going for as little money as possible, later I'll have con-rods made with a 38mm big-end diameter so I can use the stock GS400 bearings.

One issue I don't have data on is the center-to-center length difference between the 400 and 1000 con-rods. Due to the longer stroke of the GS1000 I'm gonna guess they are slightly shorter. this can be solved by shortening the barrels and skimming the GS500 cylinder to get proper C/R ratio.

Things I should mention:

• It seems to be impossible to find a 28x32x20 needle bearing inner race with oil groove, a hole should be made in the hardened steel to allow for lubrication.
• Centering the needle bearing inner race on the crank pin, also aligning the oil feed holes. Depending on fitment I will use a interference fit or shims.
• A suitable 28x39x20 bearing does not seem to exist, I have looked extensively.
• A GS1000 crankshaft, needle bearings and inner races have already been ordered.

Expect an update soon.

 

[GregT]

Have you looked through the rod catalogues from ProX and others ? It's much cheaper to use an existing rod and big end bearing than to have specials made.

 

[WolfTechnics]

Have you looked through the rod catalogues from ProX and others ? It's much cheaper to use an existing rod and big end bearing than to have specials made.

I have looked through multiple catalogues to find fitting rods for the GS400 crank, no luck. I also have a preference to use OEM Suzuki parts, hence the GS1000 rods. I managed to find a GS1000 crank for about 110 euros, which will yield me 4 rods, 6 bearings, 8 rod washers. Figuring it's not gonna get any cheaper then that. Just regarding the crank, the only issue is the 1mm difference in diameter of the crank pins. I plan on enlarging the GS400 crank pins to 32mm using a needle bearing inner race with an interference fit. I'll modify this inner race with an internal oil groove and a lubrication hole so its rotation relative to the crank pin won't matter. This 32mm dimension is much better for bearing selection and allows me to fit 32x39x20 bearings.

I don't like "adding parts" to the crank hence why I said I will have rods made in the future. I'll do that when ready for a performance upgrade and after the bike is finished and fully road worthy, which might be another 2 years...

In the meantime, a small update:

Out of 3 GS400 crankshafts there is one that seems to have fully intact undamaged crank pins, so I have started measuring some parameters to get a feel for the condition of this crank. Also I need to measure up tools for pressing it apart.

Measuring the run out first

RH side measures in at 0.04mm
LH side measures in at 0.12mm
Side clearance is 0.30mm both sides

Weirdly enough, a bolt seems to be stuck inside the LH web crank, I don't know what the person doing this was planning. I'll get this out after pressing the crank apart.

Both rods had a sideplay of exactly 0.3mm

 

[WolfTechnics]

Progress!

During the last couple of days I took the time to create some tools to press both the GS400 crankshaft and the GS1000 crankshaft apart.
I made some exciting discoveries.

See the drawings below for what you need to make to press it apart.

And here is the final product with the GS400 crank inside, ready to be taken apart.

I started with disassembling the GS1000 crankshaft halfway. I didn't take it apart any further because I am waiting on tools to remove the bearing on the other side.
The bearings costs about 165 euros each so I am trying to remove them in such a way that I can re-use the bearings.
I had to elevate the tube with two metal blocks because I made it ever so slightly too short, should have cut it at 400mm, not 350mm.

This is how far I got with disassembly:

Like I said, I'm waiting on tools to remove the bearings, but getting this far atleast allowed me to take some critical measurements.
One mystery has, up to this point, always been if the center-to-center length of the GS400/1000 rods are the same, now I know they are.
Both rods measure in at 114.9mm.

The rods are 100% identical except the GS1000 rods are a bit beefier around the wrist pin area, and of-course the big-end is 1mm bigger

This is very exciting news, as it means when these GS1000 rods are put onto the GS400 crank you basically have a normal "stock" gs400 crank with 18mm wrist pins.

Now for the pistons, I believe it is best to use GR650 pistons and increase the C/R somehow.
A GR650 head with GS500 pistons is not optimal as the compression chamber is shaped differently.
GS500 pistons with a GS450 head is possible due to the exhaust angle, but it just doesn't seem ambitious enough, only 516CC
GR650 pistons with a GR650 head and the GS400 60mm stroke will give me 558.8CC or 573.4 if I go oversize +1.

From my initial measurements today it seems as you go up in capacity with the GS motors, the distance between crank center-line and piston crown at TDC increases slightly. [TABLE="border: 1, cellpadding: 1, width: 500"]
[TR]
[TD]Engine Type[/TD]
[TD]Piston Pin Height (mm)[/TD]
[/TR]
[TR]
[TD]400[/TD]
[TD]24.2[/TD]
[/TR]
[TR]
[TD]500[/TD]
[TD]26.1[/TD]
[/TR]
[TR]
[TD]650[/TD]
[TD]27[/TD]
[/TR]
[/TABLE]
. [TABLE="border: 1, cellpadding: 1, width: 500"]
[TR]
[TD]Engine Type[/TD]
[TD]Crank center-line to piston crown (mm)[/TD]
[/TR]
[TR]
[TD]400 (60mm crank)[/TD]
[TD]30+114.9+24.2=169.1[/TD]
[/TR]
[TR]
[TD]500 (56.6mm crank)[/TD]
[TD]28.3+114.9+26.1=169.3[/TD]
[/TR]
[TR]
[TD]400 with 650 pistons[/TD]
[TD]30+114.9+27=171.9[/TD]
[/TR]
[/TABLE]
.
From the information above it seems that the 400/500 motors are very identical, but this is deceiving as apparently the cylinders are of different heights.
It would be interesting to test if both engine types have their pistons flush with the cylinder deck, as that would mean the crankcases have different dimensions.
I am taking about the distance between the cylinder bottom gasket mounting surface and the crank center-line.
. [TABLE="border: 1, cellpadding: 1, width: 500"]
[TR]
[TD]Engine Type[/TD]
[TD]Cylinder Height (mm)[/TD]
[TD]Barrel Length (mm)[/TD]
[/TR]
[TR]
[TD]400[/TD]
[TD]81.6[/TD]
[TD]102.6[/TD]
[/TR]
[TR]
[TD]500[/TD]
[TD]83.1[/TD]
[TD]83.1[/TD]
[/TR]
[/TABLE]
.
The information above is not enough to make any good conclusions, but making some assumptions, at-least a plan is visible here, namely this:
If I use a GS400 crank, with GR650 pistons, the piston crown will be at +2.8mm over the stock GS400 piston.
If we then mount a GS500 cylinder, which is taller, we reduce crank center-line to piston crown by 1.5mm, taking us to +1.3mm crown height (you still follow?)
This +1.3mm might, or might not be, too much to increase compression ratio properly and not hit the valves, time will tell once I mock-up this combination of parts.
However, it's all terribly close to where it needs to be, and none of this can't be fixed with thicker gaskets and or milling the cylinders/heads.

Also, I will put some GR650 barrels into a GS500 cylinder just to make sure I have enough wall thickness, Then modify the barrel length as needed, to make them fit.
If I go with oversize GR650 pistons or even big-bore custom pistons, I will just have a lot more barrel wall thickness to play around with.

Next update will be about pressing the GS400 crank apart further and how I plan on solving the big-end bearing issue.

 

[Chuck78]

Wow, very interesting and awesome news for those wanting to build a maxed out big bore 400/425! This also could mean the potential of running GS1000/1100G pistons in a big bore GS400...

I'd be very interested in the GR650 pistons and head, but am concerned about the modifications needed to the crankcase to move the inner cylinder studs to match the GS450/500/GR650 stud pattern...
The GS650 4-cylinder and the GR650 2-cylinderby far are the best head and piston design on any 2-valve per cylinder GS ever built... As they use the bathtub/kidney bean shaped combustion chamber to induce the modern swirl concept into the air/fuel mixture that the TSCC 4-valve per cylinder 16v GS big fours really pioneered - a drastically better combustion design.

 

[WolfTechnics]

Wow, very interesting and awesome news for those wanting to build a maxed out big bore 400/425! This also could mean the potential of running GS1000/1100G pistons in a big bore GS400...

I'd be very interested in the GR650 pistons and head, but am concerned about the modifications needed to the crankcase to move the inner cylinder studs to match the GS450/500/GR650 stud pattern...
The GS650 4-cylinder and the GR650 2-cylinderby far are the best head and piston design on any 2-valve per cylinder GS ever built... As they use the bathtub/kidney bean shaped combustion chamber to induce the modern swirl concept into the air/fuel mixture that the TSCC 4-valve per cylinder 16v GS big fours really pioneered - a drastically better combustion design.

The stud spacing has already been modified on the crankcase Chuck!, maybe one day I'll restore all the photo's in this topic but for now take my word for it. It involves machining aluminium plugs that are screwed into the stud holes using the strongest epoxy glue one can find and then re-drilling the holes. It will all be shown once I start building a mock-up engine.

I don't claim my solution regarding the studs is any good mind you...if the cylinder block is lifted during WOT I'll know it isn't.

 

[WolfTechnics]

Small update.

I received the parts I ordered.

I got SKF IR 28x32x20 bearing races, they will have to be modified.
Two oil feed holes will need to be drilled, as shown in the drawing below.
It's hard to measure accurately but they should be spaced 88 degrees apart from each other.
Diameter of the holes is about 2.6mm, with a small chamfer.

I did some math using a calculator and the press fit is a bit on the loose side, 0.008mm interference.
According to the calculator it should take about 26Nm to rotate the sleeve around the big-end journal, I think it will be fine.
The conrod doesn't really produce a torque around the journal, only a radial force aimed at the center-line of the journal.



Got myself some appropriate KT323920-C3-IKO bearings as well.

The next step now is to find a company that can drill into the bearing races, and figure out how I will press them onto the journals.
I need to think about how to put the sleeve o the journal lined up with the oil holes and centered between the counterweights.
And, then what to do about the brass washers that control the conrod sideplay?
Probably I will utilize small brass spacers with an 32mm OD in between the bearing sleeve and the crankshaft counterweights.
I will use the GS1000 32mm ID washers to control conrod sideplay.

 

[grcamna2]

Following along on your work.
I have an 81' GS450E which I plan to install a GS500E cylinder block w/ custom pistons.

 

[WolfTechnics]

Following along on your work.
I have an 81' GS450E which I plan to install a GS500E cylinder block w/ custom pistons.

Welcome!

The stock GS500e pistons should fit that motor, or do you plan to increase C/R ratio as well with custom pistons?
It's a real PITA that the exhaust exit angle is different on the GS500 heads, otherwise you could have used those.

If you are going to source custom pistons, might as well try to find a GR650 cylinder head...

 

[GregT]

If you are going to source custom pistons, might as well try to find a GR650 cylinder head...

Don't. You'll drop a huge amount of compression with a 650 head on a small motor.

There's nothing wrong with the 450 head. A mild port job and a recut of the valve seats is all that's needed.

 

[WolfTechnics]

Don't. You'll drop a huge amount of compression with a 650 head on a small motor.

There's nothing wrong with the 450 head. A mild port job and a recut of the valve seats is all that's needed.

True, but that issue is mitigated with custom pistons. Hence, why I said "if you are going to source custom pistons".
I take it, "custom pistons" means having them made by CP Carillo or equivalent.

 

[grcamna2]

True, but that issue is mitigated with custom pistons. Hence, why I said "if you are going to source custom pistons".
I take it, "custom pistons" means having them made by CP Carillo or equivalent.

Yes,I plan to have a pr. of custom pistons made;I want to have the piston maker form the dome to be exactly the same shape as the OEM Suzuki dome(considering the low quality of pump gasoline out here in Ca.)and going from 71mm up to 74.25mm using the 450 head and the same dome shape(and stock 450E exhaust)may give me almost 10:1 CR?,which is enough for this street bike.
I was quoted a price by Terry Stewart(CP Carillo)of around $1600 for 4 pistons,but I just need two.. I'm considering calling JE Pistons also.

 

[WolfTechnics]

Yes,I plan to have a pr. of custom pistons made;I want to have the piston maker form the dome to be exactly the same shape as the OEM Suzuki dome(considering the low quality of pump gasoline out here in Ca.)and going from 71mm up to 74.25mm using the 450 head and the same dome shape(and stock 450E exhaust)may give me almost 10:1 CR?,which is enough for this street bike.
I was quoted a price by Terry Stewart(CP Carillo)of around $1600 for 4 pistons,but I just need two.. I'm considering calling JE Pistons also.

Thats a good plan, Can I follow your progress somewhere?

 

[grcamna2]

Thats a good plan, Can I follow your progress somewhere?

I haven't started a thread.
I see now that I should;during the process of getting the $ to have the machinist do the cylinders(pistons first) & head,get the pistons made,and the $ to get a pair of mild Mega-cycle camshafts($600+),the ones that are good for stock pistons and valve springs.
My goal is to have a good running '500' in a GS450E(450 bottom-end)frame that will hold together for many years w/o needing constant tweaking;I have a set of carbs. from an 83' GS450E,or I might get a set of GS500E carbs?
I'm thinking that I can use an OEM Suzuki GS500E head gasket on my GS450-head/GS500E cyl. engine?

 

[WolfTechnics]

A small update on the GS500 guys, mostly as a proof that I'm still alive and working on this, and as a distraction from the fact that NOTHING has happened with the hybrid engine of late.
I promise, progress will be made this year, I just want to get this GS500 out of the way first .

I did a mock fit of the rear swing-arm, good thing that I did. The chain doesn't clear the swingarm, I ran into trouble mounting the brake caliper upside down, and some other minor issues.
Anyway, here's what it looks like right now:

As you can see, the brake caliber has moved back to its normal location again, it was just gonna be...eehh...less headache to do it this way.

I'm proud of this one, the brake line goes through the reaction arm!

That's it for today, I'll be working on this another day tomorrow, so who knows, maybe another quick update if I get something done.

peace.

 

[Buffalo Bill]

Looks like you way overbuilt that swingarm. Remember you're using steel not aluminum.
Here's how I did my steel Katana swingarm.

 

[WolfTechnics]

Looks like you way overbuilt that swingarm. Remember you're using steel not aluminum.
Here's how I did my steel Katana swingarm.

Very nicely done!

I don't even consider it "build", it's purely for looks. This GS500E is gonna be a fun backroad bike, nothing serious about it.
But I understand your sentiment, to be honest, the whole thing was an experiment, I wanted to see what this idea would look like.
I have run into some issues fitting this swingarm and had to cut and modify it, it isn't worth it in the end and on my Hybrid bike I will do it differently.