Time to gap the valves

[Dust Buster]

I have a 2004 Suzuki GSX-R 1000 with 79k kms on the clock, but with no history of adjusting the valve clearances every 24k kms.

So, I better check the valve clearance. I usually measure the gap, then the thickness of the shims. The intake gap should be between 0.10 and 0.20 mm cold. The exhaust gap should be 0.20 and 0.30 mm cold. Then, via a spreadsheet, move the shims around and purchase the missing shims to set the gap back to the factory range. I assume that after sorting the gaps to within tolerance, I should do a compression (minimum 1000 kPa and 200 kPa between cylinders) and leak-down (maximum 14% and 10% difference between cylinders) test to verify there are no burnt valves.

If it fails these tests, I suppose that I can take the head to have the seat and valves grounded. If several valves need replacing, then I need to make some decisions.

In the following year(s), titanium valves were used, which allowing revving higher than current redline of 12,500 rpm, ~1,000 rpm more (for more hp). They also started increasing the size of the intake valves. If I do both, I will probably need to remap or the more common solution is to get a Power Commander and program that on a dyno.

As the oil ran dry once (ceramic nitride lining saved scoring the cylinder walls), I could bore or add a liner (with ceramic nitride lining again) for larger pistons and increase the torque as well.

What's next? Larger throttle bodies... Do mods ever end?

[Dust Buster]

Sorry guys – the gaps were all within spec.

I do hear a “ticking” noise when I stand behind the bike at idle. I wonder how close the piston crowns are to the spark plugs.

[Schurkey]

The ticking on my Honda (ancient, CB1100F) was/is the clutch dampers.

Which kinda explains why the dealership service department got nowhere trying to fix the valvetrain.

[BLSTIC]

Wasn't 2004 roughly when they were discovering that small ports increased overall performance and before charge motion was seen as so important?

What I guess I'm trying to say is, your head is good but there's more on the table. What's the latest model head that fits your block and frame? Can you apply the modern porting techniques to it?

[Dust Buster]

The ticking on my Honda (ancient, CB1100F) was/is the clutch dampers.

Which kinda explains why the dealership service department got nowhere trying to fix the valvetrain.

Thanks, I'll get this checked.

If I apply the front brakes, I can't do a weight off, burn-out as the clutch slips. However, as it is acts like a slipper clutch in high rev downshifts and doesn't slip on normal weight on launches, I have not replaced it.

[Dust Buster]

Wasn't 2004 roughly when they were discovering that small ports increased overall performance and before charge motion was seen as so important?

What I guess I'm trying to say is, your head is good but there's more on the table. What's the latest model head that fits your block and frame? Can you apply the modern porting techniques to it?

2004 - sounds about right

Shortly thereafter there were problems with the frame cracking, but it was probably unrelated.

The silly EXUP valve kept giving F1 codes (not really trouble codes). So, I removed the activation mechanism and blanked the ECU sensor. By partially closing, it was supposed to have provided more low-end torque, which to me, must have acted like a reduced port size.

As at the same time I defeated the first, second and third gear nannies (preventing full power at launch), I didn't notice any loss of low-end torque by leaving the EXUP fully open.

[Schurkey]

If I apply the front brakes, I can't do a weight off, burn-out as the clutch slips. However, as it is acts like a slipper clutch in high rev downshifts and doesn't slip on normal weight on launches, I have not replaced it.

Honda and others have incorporated a "slipper clutch" feature to prevent chattering the rear tire on downshifts...however, I thought that was controlled via a one-way clutch so that you should have full friction when engine drives tire, but slipper only when tire drives engine.

You might want to look into that. I think something's wrong/worn-out on your machine if it slips under acceleration.

[Dust Buster]

Correct – I don't have a back-torque limiter / slipper clutch like later models of super bikes for engine braking. My clutch is starting to go as it does slip like a slipper clutch when I downshift a couple of clicks going into a tight corner. It's nice not have the rear tyre chirping.

When I sit on the seat properly, it launches with a vengeance, lifting the front wheel and again with each shift. However, I note that the clutch is going as when I stand / straddle the seat and grab a handful of front brake, I cannot accelerate and pop the clutch to smoke the rear tyre any more.

For now, I'm enjoying the cheap downshifting “slipper” clutch, even if I can't play the hooligan at the lights.

[Dust Buster]

GSX-R_ex_pipe_back.jpg

I finally got a chance to take my bike to the local Suzuki dealership workshop. They listened for the ticking noise around the engine. Then applied the front brakes while partially engaging the clutch. They confirmed that the clutch was fine, but also wanted to put the engine under strain to see if the ticking noise changed. Then they pronounced that the exhaust was the problem. I asked them to explain further as the system was at temp from riding there and not ticking from cooling.

I have a Yoshimura tri-oval slip-on exhaust can. They pointed to the hole in the bottom of the built-in tip as the culprit. They said that I can install a flat screw [shallow self-threading bolt] to cover the hold and eliminate the ticking noise.

GSX-R_ex_pipe_hole.PNG