Engine noise

[kiwisuzuki1100nz]

Hi,

1987 GSXR 1100 - Engine has Wiseco pistons bored out to 1109. Done maybe 6000 kms since rebuild.

Std Cam and springs. Head had a bit of work with ports cleaned up. Idles fine, performs fine. But a bit of a rattle with revs, sounds like top end, maybe cams?

Popped rocket cover and checked and set valve clearances, all good.

Any clue on the noise?

Plan on doing a compression test later this week.

 

 

Edited January 10, 2021 by kiwisuzuki1100nz

[colinworth79]

I would have a look and see if the cam chain is loose . 

[bluedog59]

I'd give the cam chain tensioner a service including a new spring, check for any exhaust leaks at the head and balance the carbs. Slide carbs also tend to "chatter" a bit at low revs.

[Dezza]

As said above but when you removed the cam cover did you also check the bolts that hold the cam sprockets to the cams? I am guessing these are probably fine as you checked the valve clearances but if these work loose/fail it can all end in tears

[dupersunc]

Difficult to tell from the video, but I'd be checking the oil for bearing material.

 

Edited January 10, 2021 by dupersunc

[kiwisuzuki1100nz]

Thanks for all the suggestions, appreciated. The rattle is easier to hear with the 2 revs at 32 33 secs.

Ill do the compression test rule out ring and values, drop the oil and check,, pop the cam cover again and check cam chain tension and cam bolts.

I think this time ill actually pull the cams out checking the bolts and the bearing surfaces. Typical as  I have a race in 4 weeks.

[Nik]

My guess would be piston slap. How much was the piston to cylinder clearance when it was assembled? 

Edited January 10, 2021 by Nik

[kiwisuzuki1100nz]

9 hours ago, Nik said:

My guess would be piston slap. How much was the piston to cylinder clearance when it was assembled? 

Hi @Nik  Bored and honed and 1109 piston kit fitted 6000 km ago bang on clearance. Very unlikely piston slap

[kiwisuzuki1100nz]

Compression Test Results:

Manual Std Compression: 142 - 199 psi

Min: 114 psi

Max Variable: 28 psi

Bike Results       Initial psi / Final psi

Cylinder 1: 140 / 178

Cylinder 2: 140 / 180

Cylinder 3: 140 / 170

Cylinder 4: 140 / 175

Keeping in mind it is an 1109 with high compression wiseco pistons. Also I haven't ever done a compression test on a slabbie but followed manual instructions

Diagnoses:  Initial of 140 psi I will assume is great on first crank? If so valves are sealing well . Built to max pressure quickly so rings good. Variation within 10 psi so within spec and less than 10% variation.

So looks like rings and pistons fine and values sealing which leaves the possible noise source as maybe

• Cam shafts loose in caps - cap bolt loose or snapped
• Cam chain - Probably not - wrong noise

I'll drop the oil out of the engine next and then tear down the top and and check camshafts and cap journals etc...

Sweating that I have buggered cam journals

Anything else to check or consider?

 

Edited January 15, 2021 by kiwisuzuki1100nz

[Hanma-shin]

The bearing in the cam chain guide wheel.

[kiwisuzuki1100nz]

21 minutes ago, Hanma-shin said:

The bearing in the cam chain guide wheel.

@Hanma-shinDo you mean the wheel in the cam chain idler? Number 3 in the parts diagram

[Hanma-shin]

Yes

[bluedog59]

The tappets are fine, compression is good and it performs fine. You can hear it is not running smooth at low revs so balance the carbs, check the cam chain tensioner is working properly and you have no exhaust leaks. With the carbs out of balance the load will cycle as it runs through the firing order and everything will "chatter". Even if it doesn't stop all the noise, at least you will be left with what is causing it and got rid of the background noise. Do the basics first before you go looking for doom and gloom ( I think we've all heard the one about the full engine rebuild when it was the keys rattling on the top yoke all the time ).

[Pudzrx]

Have you checked cam timing ? Not a valve just clipping a piston ? Can yo borrow a bore scope and have a look inside , would be easiest.

Puddy 

[kiwisuzuki1100nz]

4 hours ago, bluedog59 said:

The tappets are fine, compression is good and it performs fine. You can hear it is not running smooth at low revs so balance the carbs, check the cam chain tensioner is working properly and you have no exhaust leaks. With the carbs out of balance the load will cycle as it runs through the firing order and everything will "chatter". Even if it doesn't stop all the noise, at least you will be left with what is causing it and got rid of the background noise. Do the basics first before you go looking for doom and gloom ( I think we've all heard the one about the full engine rebuild when it was the keys rattling on the top yoke all the time ).

@bluedog59Thanks good advice. The carbs are flat sliders and chatter at idle, they have been balanced but will check again

[Gpz1100_Convert]

given the speed of the rattle.. it does sound like the cam chain to me as well. Hard to tell but carb rattle is different on the rs carbs and it doesn't sound like an air leak to me.

Mark

[kiwisuzuki1100nz]

Cam chain was tight and not loose. Idler sprocket bearings fine. All cam caps still tight no bolts broken. 1 cam bearing showing some blue so possibly a bit tight wit cam cap and binding and overheating.

No major galling on cam surfaces. Bit at a loss.

Any concerns looking at the photos?

Will look to spruce the cam chain tensioner.

Have a few cam caps to helicoil as cylinder head cover threads stripped on a few.

 

Edited January 18, 2021 by kiwisuzuki1100nz

[TonyGee]

get yourself a mechanics stethoscope, makes life a lot easier to pin point an engine noise.  i swear by mine. 

[coombehouse]

Sounded like tappets to me. Are you sure you've not mixed up metric & imperial measurements or feeler gauges or maybe the gauges were not narrow enough to actually sit on the top of the valve stem. 

 

 

 

[Dezza]

Something loose in the clutch? It sounds a little like a Ducrappy with a dry clutch but maybe it's my imagination instead.

[kiwisuzuki1100nz]

So still trying to figure this out.

Torn it down and removed the head, going to check valve springs ok, Cam chain is fine and tensioner and guides. Having a look at the camshafts again the cam lobe profiles arent very even, one side is very steep. I am not familiar with how the cam lobe profiles should look.

Any thoughts on below? Do they look ok?

No ridges on the lobe faces

 

Edited February 27, 2021 by kiwisuzuki1100nz

[Jaydee]

15 minutes ago, kiwisuzuki1100nz said:

the cam lobe profiles arent very even, one side is very steep.

Perfectly fine. The lobes aren't meant to be symmetrical.

[dupersunc]

Check the big ends.

[kiwisuzuki1100nz]

8 hours ago, dupersunc said:

Check the big ends.

Dang, hope I don't have to as haven't done it before. If I dont get anything with valves and springs I will look at that adventure

[Dezza]

When the engine was rebuilt, did you replace the cam chain?