[ryanc]

I bought a used 05 zx-10r with a milled head (down 0.015") and stock cams (I don't think they're "degreed"). Once the bike gets good & warm I notice it start to knock a bit. I think it's spark knock but not 100% positive. I'm filling up with 93 octane, even tried octane booster, and it's still there. It's not there when the bike is cold though. It is pretty consistent when cruising at lower speeds, and probably still there at higher speeds but I just can't hear it. It's not horribly loud or anything but it's enough to bug me. Can someone tell me what I need to do to correct this? The bike is mostly stock. Any help would be appreciated.

Thanks,
Ryan

 

[garth285]

could maybe mistake it for clutch basket chatter???

do you know if it had a power commander or ignition module???

 

[ryanc]

I do believe he did have a power commander and ignition module on the bike before I bought it. Once the bike is warm I can hear the sound when idling, cruising, in neutral, clutch in, clutch out. It isn't LOUD but I can hear it and if it is spark knock I do want to take care of it.

 

[nickalltogether]

If it happens at idle, chances are it isn't detonation, detonation normally only happens under load.

 

[ryanc]

Hmmmm I don't know I've heard spark knock before and this really sounds like it. What else could it be? I don't know if I could get a good clip of the sound with the video camera, maybe...

 

[edgeflyer]

Could have clearance problems. Metal expands when it gets hot. Get your squish and valve to piston clearance checked. If your having consistant detonation you'll probably be able to see it on the plugs. There will be specks on the porcilin (?) of your plugs.

 

[ryanc]

Could have clearance problems. Metal expands when it gets hot. Get your squish and valve to piston clearance checked. If your having consistant detonation you'll probably be able to see it on the plugs. There will be specks on the porcilin (?) of your plugs.

When he told me the head was milled I asked about the valve clearances and he said everything has been checked and is up to spec. I'll have to check the plugs sometime maybe this weekend to see if I can see anything on them.

 

[GoFaster]

The issue isn't "valve clearance" (the scheduled maintenance procedure), but rather the amount of clearance between the valves and the pistons. But, if it has stock cams and if the issue is happening at *lower* engine speeds, I doubt if this is the real issue. Valve to piston collisions are more of an issue at high revs - and if it happens, the engine won't survive long before going boom.

Detonation is a possibility. That amount of head milling will raise compression about 1 point, and it's already pretty high. Retarding the ignition timing a little should help.

BUT ... If the noise is happening at idle or no load at higher revs, it is *unlikely* to be detonation. Detonation happens from too-high cylinder pressure and temperature, and at idle, the cylinder pressure ain't there.

It is probably mechanical noise. These engines make a lot of mechanical noise, it's just the way they are. How does it sound compared to another ZX10R?

 

[ryanc]

I don't know anyone else with a zx-10r and I have never really paid that close attention to the other 10s I've heard in the past, so I don't have anything to compare it to. I hope it is just normal mechanical noise. I just don't want to ignore a noise if bad things could be happening because of it.

 

[garth285]

just one other suggestion since and it maybe a stupid suggestion but since you say it is happening at low speeds and high as well....

how is your drive chain looking???

 

[ryanc]

The chain looks really good. The bike only has like 4100 miles on it. It happens when I'm idling in neutral or just have the clutch in, so I don't think it's anything to do with the chain. It does get faster with RPMs, so even if I've got the clutch in and rev it up a little I can hear it get faster as RPMs increase.

 

[dsabat]

As was stated above, there's no way it's detonation if you can hear it at idle. Unless you are running the most volatile fuel on Earth, you'd need diesel-like compression ratios (>20:1) to detonate with no load.

Welcome to the noisy top-end that is the ZX10R.

 

[ryanc]

That's fine with me as long as it is supposed to be there. Hopefully that's all it is.

 

[sextaafondo]

I´d say don´t rely on what you were told and check the valve clearence out. They might be out of spec.
You´ll have the opportunity to see if the cams are degreed or not as well. If they are bolted to the round (non slotted) holes then they ain´t degreed.

 

[speeddemon]

there not degreed because it is my old bike.Read the stickys about the engine noises the zx10 makes.The valve clearance was checked and were set to the tight side.Why would i degree the stock cams???I had the race intake cam in there and i had that degreed, but took it out before i sold it.There is nothing wrong with that bike!!!

 

[ryanc]

Ok ok - I guess I'm just not used to that kind of noise from an engine. I will try to stop thinking about it now. The bike is awesome in every way - that noise just had me worried.

Thanks for the help,

Ryan