Jump to content

Knocking/Pinging problem? Help Needed :(

Recommended Posts

So here's my problem. I just rebuilt my top end (big bore kit) three tanks ago because my other piston had shattered it's skirt in two places. Had the bottom end rebuilt too with new bearings, new oil pump. I start riding it, and when I'm on the highway going 55mph, everytime i open the throttle >10%, i hear this rattling, knocking sound as if my valves were noisy. As soon as i let go of the throttle, sound goes away. Sound doesn't happen at idle, or even when cracking the throttle at idle. I suspected pre-ignition or detonation so i removed my spark plug and checked down my piston and here's what I found. Keep in mind the spark plug and piston are 3 gas tanks old. Bike idles super well, and bogs when I crack open throttle at 100% really fast, then recovers and revs up. Please any thoughts would be really aprpeciated. Maybe I'm just pannicking (hopefully)!!!

Pics:

VJiFXJQ.jpg

FsiBU4g.jpg

H6Z5ayQ.jpg

SPECS:

-Elevation: 540ft.

-2001 DRZ400S Converted SM

-Has manual cam chain tensioner and yes i know how to adjust it (idle and screw until click goes away)

-434cc Cylinder Works Big Bore kit installed 3 gas tanks ago

-3x3 Airbox

-Pro Circuit T4 Exhaust with spark arrestor

-Twin Air Air Filter

-Stock Cams

-Has FCR39MM Installed with following jets:

-I always use 91 octane fuel

===>Coast enrichener removed and the two nipples plugged together with fuel hose

===>160 Main Jet

===>200 Main Air Jet

===>65 Starter Jet

===>60 Pilot Air Jet

===>45 Pilot jet

===>My needle is a OBDXP and the clip is at position 5.

Spark plug: CR8E IX

Edited by Loreadarkshade

Share this post


Link to post
Share on other sites

I would suggest a EMN needle on clip 3.

Is there a throttle position sensor?  Connected?  If so, try disconnecting it.

Share this post


Link to post
Share on other sites

I think that is the question.  Is the noise ignition ping due to high compression, low octane gas, or advanced ignition? Or some other noise?  I'm running CW 434, standard 3 layer base gasket and don't worry much about what gas I use and never get any ignition ping.  However adding load to the motor with throttle is a sign of ignition ping.  So yes try a little more richness with jetting and the highest octane gas you can buy and see if that helps to cure the noise or isolate the problem.

  • Like 3

Share this post


Link to post
Share on other sites

that spark plug looks crispy white .. i wouldnt be afraid to go up a jet .. whats your gearing? if its stock or higher 55 is on the lower end of revs in top gear and even a stock bike will rattle with crap gas, you wont hear a ping, and yes it 'is' detonation .. i would never put anything but premium in the drz ..why would you put anything less? to save .25 cents a tank?

Edited by cowpie
  • Like 1

Share this post


Link to post
Share on other sites

I always use premium (91 octane is highest we can get in my local city). It's strange because with my stock cylinder this didn't happen. What size jet would you recommend?

Share this post


Link to post
Share on other sites

See above.  EMN-3.  Your main jet is fine and you are not on the main jet where you experience the ping.  You might actually try just opening the throttle to max to bring in the main jet and see if the pin goes away.  (Assuming it is ignition pin, I'm not totally convinced it is)  The DXP needle is the stock needle and it is pretty lean.  The EMN is a richer taper, richer diameter and a lot richer on the clip.  Until you get a EMN you can move the clip to DXP -7 (full rich)  It still will not be as rich on the clip as a EMN-3.

  • Like 1

Share this post


Link to post
Share on other sites

So i finally got my ocemn needle in the mail. I remove my old obdx needle and theyre virtually identical... my last needle was on clip 4 and still too lean so i put my ocemn on 5th clip to see what will happen. Im going for a ride now and will update you guys if the sound is still there with richer settings.

Share this post


Link to post
Share on other sites
On 4/29/2017 at 8:34 AM, Noble said:

I would suggest a EMN needle on clip 3.

Is there a throttle position sensor?  Connected?  If so, try disconnecting it.

 

On 4/29/2017 at 8:56 AM, Loreadarkshade said:

Tps already disconnected

 

:ride:

Share this post


Link to post
Share on other sites

Either piston skirt or big end clank, don't lug the engine.  Unless your CR is 12/1, 87 octane is fine.

Today's gas does not leave much to read on a spark plug.

Share this post


Link to post
Share on other sites

Yup, as predicted sound still there.

I'm at a loss. Brought it to a renowned suzuki dealer in my area and a supposed "competition winning mechanic" worked on my bike. He had installed my starter wrong too, the engine wouldn't even crank over because the washers were stuck between the crankcase, I had to fix it myself. Job cost me 1k >:( Let's just say I'm not bringing my bikes there anymore.

My engine has new bearings, new cylinder, new piston, top end redone.. I'm very disappointed. I've heard only good things about DRZ's but mine seems to be a pile of crap. Sorry about this rant, but I've reached a point where I'll just ride it 'till something goes wrong. I will make sure to update this thread whenever that happens.

Share this post


Link to post
Share on other sites
On 4/29/2017 at 8:03 AM, Loreadarkshade said:

So here's my problem. I just rebuilt my top end (big bore kit) three tanks ago because my other piston had shattered it's skirt in two places. Had the bottom end rebuilt too with new bearings, new oil pump. I start riding it, and when I'm on the highway going 55mph, everytime i open the throttle >10%, i hear this rattling, knocking sound as if my valves were noisy. As soon as i let go of the throttle, sound goes away. Sound doesn't happen at idle, or even when cracking the throttle at idle. I suspected pre-ignition or detonation so i removed my spark plug and checked down my piston and here's what I found. Keep in mind the spark plug and piston are 3 gas tanks old. Bike idles super well, and bogs when I crack open throttle at 100% really fast, then recovers and revs up. Please any thoughts would be really aprpeciated. Maybe I'm just pannicking (hopefully)!!!

Pics:

Try two things;

1) Put the stock plug back in.

2) Hook up the coast enrichener.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×