Browse Author: tore@grenasberg.no

Wiring diagram

I have started the process of drawing a complete new schematics in colour for the GT750 wiring harness. In the new document there will be links to different parts with photos showing the real component and its location on the bike. Until then, here is a wiring diagram I “stole” from the web ūüôā

As always on my blog, click on the images for a detailed view

GT750 wiring diagram in colour

Cover on the left hand side

Did the mounting of the cover on the left hand side today. The cover will also house the timing plate, points and capacitors.

I was advised to add some silicone gasket in addition to the new paper gasket, please see the pictures.

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Add silicone.

Don’t add silicone where I have the yellow marker. I did it wrong and had to wipe it off after the mounting.

 

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Mount the gasket. I had both alignment studs in the cover and therefore I put the gasket as shown.

 

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Add silicone gasket.

left side cover

To be able to align the side cover in its correct position the pin must hit the hole in the disk rotating the timing camshaft.¬†Be gentle and don’t use force. Rotate a bit to left and right until the cover snap on.

 

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I still had the original screws. Did some polishing on the heads before the mounting.

Done !

Cylinder in place

The difficult job is done, got the cylinder block down onto the pistons without breaking any of the piston rings. Got a helping hand from a friend, was too scared to do it alone.

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Hmm, rusty bolts. A new kit has been ordered from UK. The attempt to refurbish the old ones was not a success. Let’s hope I soon get the parts and can mount the cylinder head the next weekend.

Verifying the thermostat

Step 1. Remove the thermostat housing

Not an easy task, all of three screws were stuck. Applied some anti rust solvent and went ahead with the job the next day.

The housing were heated up by using a butane torch and in addition I used an impact screwdriver to get the screws loose.

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Finally I had the parts separated

 

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Cleaning of the parts using the ultrasonic washer

 

Step 2, verify the function of the thermostat:

According to the service manual the vale opening temperature is 82 deg C and wide open (8mm)  at 95 deg C.

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82 deg C and closed

 

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85 deg C and half opened

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90 deg C and almost fully opened

Good to go, the thermostat is functioning as specified.

 

Thermostat response time:

See how it’s closing only seconds after it is out of the boiling water.

 

Step 3, polishing the thermostat housing:

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Nice and shiny ūüôā

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Installing pistons

New parts to be mounted

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Part no

 

Step 1: Circlip

Circlip

Mount one circlip in all three pistons. Move the end position away from the cutout. Be gentle and don’t bend the circlip too much. Use a screw driver as a tool to flip it into the position in the groove.¬†Always new circlips, never reuse old one.

 

Step 2: Piston rings

Piston rings

Mount the piston ring as shown on the photo. Be aware of the pin locking the ring, see the arrows.¬†You don’t need any special tools for mounting the piston rings. They are quite expensive an if you are afraid of braking any of them, drink a beer before you start ūüôā

Step 3: Gasket and O-rings

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O-rings

Mount the gasket, don’t forget to mount three O-rings underneath the gasket.

 

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Before you continue, cover all holes so you don’t drop any parts inside the engine. Can be difficult to retrieve.

 

Step 4: Pistons

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Oil the bearing before and after it’s installed in the rod.

Piston mounting

Remeber the washers (31)

 

 

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Push in the piston pin and mount the last circlip at the end.

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Pistons

Make sure the right piston (label R) is on the right hand side and the arrow is pointing forwards. The left and center piston are identical and are both labeled L

Generator and front sprocket

Mounted the rotor part of the generator yesterday + the o-ring and the cover behind the front sprocket

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Use some pieces of wood to lock the crank.

 

 

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Mount the rotor part of the generator and torque to about 20 Nm

 

 

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Mounting a new oil seal in the cover behind the front procket.

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Mounting a new O-ring, use some grease to keep it in place

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Mounting the cover

Assembling the clutch and the kick starter

The photo below shows how I did the assembly of the clutch and the kick starter.

 

Step 1: Fit the oil guide plate.¬†Drive all three screws well home.¬†If you are to use thread locker or not depends on your religion. Do you believe in it or not. Someone says ” don’t use it, you will never get them loose”. Others say….And I’m not gonna tell you what I did .

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Step 2:

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Mount the shim ( no.16)

 

Step 3:

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Mount the spacer, chamfer side goes in back.

 

Step 4:

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Mount the clutch

 

Step 5: 

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Mount the bearing assembly

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Step 6:

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Mount the spacer, chamfer side at the front.

 

Step 7:

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Mount the clutch sleeve hub (5),  locking washer (7) and center nut (6)

Always use a new locking washer, not the old one like I did on the photo.Why did I use the old one ? I didn’t know I had a new one until I had completed the assembly process. Can save the washer for the next time.

 

Step 8:

Torque setting for the center nut is about 50 Nm.

Before torquing up the center nut you need to some how lock the sleeve hub (5) Never use a screwdriver on the edges. You can make a special tool using old steel plates from a clutch. I had no such tool but did it in this way:

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Lock into one of the gears and do something clever to lock the front sprocket, like I did on the photo above.

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Don’t forget to bend the “new” lock washer. One of the edges¬†is enough.

 

Step 9:

Before mounting the clutch check the specifications of the cork plates and the springs

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STD lenght: 40,4mm. Spring setting limit :1,4mm

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STD thickness: 2,9-3,1mm. Wear limit: 0,2mm

 

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Let the cork plates be quite oily before you mount them

 

 

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Grind off any layers from the steel plates.

 

 

 

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Start with the cork plate, then the steel plate. The last plate should be a cork plate. The steel plate has a little radius on one side and a flat side on the other side. The flat side at the bottom and the radius facing  against the front.

8 cork plates and 7 steel plates.

And as you can see, I found the new lock washer after I had completed the assembly.

 

Step 10:

Mounting the clutch pressure disk.

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Remeber the mount the clutch release shaft (17)

Mount the bolts in a pattern for an even distribution of the force. When all bolts are driven home you just give it a tap . No torque settings

 

Step 11

Kick starter

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Mount the spring holder (and the plate behind if not already mounted)

 

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Mount the spring

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Competed !

 

 

Step 12

Mounting oil seals, gasket and side cover

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There are two oil seals in the cover, both should / can ( depends on age) be replaced. Add grease on the seal side.

 

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I found both mounting studs quite stuck in the cover, not at the case side. Therefore I put the gasket at the cover side.

 

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Done !

 

Case closed

Phuu, the crankcase is finally sealed and closed.

Please see the summary of how I did it: ( And this is not the time to say I did it wrong, not in a mood to undo, please let me stay happy )

Step1:

Cleaning the surface and do a test assembly to verify it’s all good.

I had a tube of the genuine Suzuki seal but I was afraid to use it. The first impression was a thin soup, looking more like an old oil leakage from 1976 ūüôā Therefore I bought something more modern from Loctite.

Loctite 574Suzuki seal

After some evaluation and testing of the Suzuki seal I think it’s might be good after all. After few minutes in air it changes to a more sticky paste. Totally different from the Loctite 574. The Loctite is curing after it is pressed against the alu surfaces, not in air. Then, what to use ? Since I had bought the modern stuff from Loctite and it’s made for this purpose I took the Loctite and applied the glue according to the instructions in the data sheet. It’s recommended to apply in one string and on only one surface.¬†On the bottom case I only took some glue around the o-ring connecting the water pump. Remember to add ¬†some silicone seal around the black plastic cover at the end of the gear shaft.

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Step 2

Mount the top case and install all the bolts on the top side. Secure the bolts but don’t use the maximum torque at this stage. ¬†Check to see the crankshaft is still movable.

Turn around the engine to the bottom side and mount all the bolts according to the correct torque settings. And now is the pay off time for using a carton to keep track of the placements.

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Please see the placement order and torque settings below. I have labeled 6mm bolts blue, 8mm green and 10mm yellow.

Click on the images for detailed information

Since I live in Norway I use Nm as tourque settings.
10mm bolts 32Nm
8mm bolts 15 Nm
6mm bolts 8 Nm

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Bottom torque sequence

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Bolt no 13 need a copper or alu washer + some extra silicone sealing

 

Top torque sequence

 

Step 3

Installing the tachometer drive.

Mount a 6mm screw at the top to secure the inner part.

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Tap the drive down to the position where you can see the mounting hole for the screw.

Step 4

Enjoy the work, dry off remains from the seal and do something clever to avoid parts falling into the engine.

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Am I ready ?

Hmm, what is missing before I glue and mount on the upper part of the crankcase…. Am I good to go ? I will double check up against instructions on the DVD. If anyone see something missing, PLEASE let me know.

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