XR650R Lower Knocking Noise


13 replies to this topic
  • Billahjack

Posted April 15, 2007 - 09:41 AM

#1

My bike is making a bunch of knocking noise and I'm looking for a few pointers on which way to head here. I am pretty sure that the noise is from the bottom end versus valve noise.

The bike started out pretty quiet until after the first ride with the new cam. It sounded fine right after I installed the cam and putting around the neighborhood. About 100 miles later when I returned from the first big ride, I noticed the knocking. It has since become louder. During that ride, I rode conservatively for the first 3 hours for cam break-in and then raced my buddy on the ride home. We were hitting the rev limiters at around 100MPH (stock gearing). :thumbsup:

I have since changed the oil 4 times and logged another 600 miles on the bike. I have a magnetic drain plug and use the paper filters (Honda or K&N). I carefully install the filter the correct direction and they have been clean every oil change. I have not seen any brass shavings.

My 2001 XR650R has low hours, I'm guessing less than 200 and was in great condition when I bought it. The rims were still shiny like at the dealership. Anyway, I put in a Hotcams Stage 1 and a Moriwaki Exhaust along with the cut-out side panel. The carb was rejetted and I have a 185 Main in there.

Any thoughts on where to look first?

  • focallength

Posted April 15, 2007 - 12:27 PM

#2

Have you adjusted your valves? They need to be readjusted after installing a new cam as they will be set for the old cam and could be off. the only knocking I can think of on the bottom end is worn bearings, but valve tick can echo big time and sound like its coming from everywhere. Also check the decompressor if this is misaligned it will bump on the lifter and make a ticking sound. Good luck

  • Billahjack

Posted April 15, 2007 - 02:07 PM

#3

Thanks for the tip. I readjusted the valves a few times. I followed the link on Fourstrokesonly for the XR650R valve adjustment. I can barely slide a .009 in the exhasut and a .007 in the instakes but the .008 and .006 shims fit easy. The decompressor lever seems to be working fine and there is not an auto-decompressor on the Hotcam.

I'm pretty sure this is much louder than valve ticking. I also removed the valve cover last night (last valve adjustment) and verified the cam-chain tensioner was working correct.

I'm wondering if I fried something in the lower end running at high RPM for sustained periods.

  • philipstjohn

Posted April 15, 2007 - 04:04 PM

#4

Dude- It sounds like your engine is fried! :ride: :worthy: Not, remember it is a Honda XR650R, just go back and re think your last few steps...:thumbsup:

  • Hondathumper450

Posted April 23, 2007 - 11:03 AM

#5

A different noise,
Does the XR650R get noisier as it gets hotter? I have become accustomed to the normal knocking noises for the XR650R Engine but does the engine get noisier as it warms up? I notice a buzzing???? noise and a bit more knocking when the engine warms up and gets hotter. The oil is fresh and full, plenty of coolant and it does nto boil over unless I let it sit idleing for 10 minutes standing still and shut it off. Just trying to make myself feel better that the noise getting a bit louder the hotter it gets is still normal for these engines. COmpression is still very exceptional and power is still outageous.
Runnign it uncorked witht he 175 and 68s jets and running a K&N Filter.
I am running a 13 tooth front now for the seriously tight trails I sometimes get on but thinking about going back to the stock 14. Anyone have a sound clip of the xr6650r engine with quite a few hours on it so we can all listen to what is a bad engine, a tired engine, an engine with a lot of hours on it and a fresh engine?
This would be an excellent post-it sticky section so everyone in question about engine noises can be rest assured that it is bad or normal

  • philipstjohn

Posted April 23, 2007 - 01:51 PM

#6

A different noise,
Does the XR650R get noisier as it gets hotter? I have become accustomed to the normal knocking noises for the XR650R Engine but does the engine get noisier as it warms up? I notice a buzzing???? noise and a bit more knocking when the engine warms up and gets hotter. The oil is fresh and full, plenty of coolant and it does nto boil over unless I let it sit idleing for 10 minutes standing still and shut it off. Just trying to make myself feel better that the noise getting a bit louder the hotter it gets is still normal for these engines. COmpression is still very exceptional and power is still outageous.
Runnign it uncorked witht he 175 and 68s jets and running a K&N Filter.
I am running a 13 tooth front now for the seriously tight trails I sometimes get on but thinking about going back to the stock 14. Anyone have a sound clip of the xr6650r engine with quite a few hours on it so we can all listen to what is a bad engine, a tired engine, an engine with a lot of hours on it and a fresh engine?
This would be an excellent post-it sticky section so everyone in question about engine noises can be rest assured that it is bad or normal


This is my first XR650R, and I thought it made alot of "knocking noise" when I first rode it. I guess I was expecting it to be a little smoother sounding considering the dependibility and reliability reputation the bike has. But I can not complain when it rips as it does and it is very fast from 0-95+ mph. Think about a pig, it does not purr, it snorts and makes wierd noises! Its a BRP!
That would be a good post to have an audio of a great sounding bike and a bad sounding bike, but then the exhaust debate may come up...:applause: :excuseme:

  • Nailpounder

Posted April 23, 2007 - 04:29 PM

#7

It could be the wrist pin an the small rod end. They might be out of spec.
If the pin rocks in the rod end it's time for a crank rebuild.
Pull the jug an wiggle the piston to see if it rocks in the rod end.
Why your in there check your bore for excess clearance with a bore gauge.
One more thing, check your cam bearing too. The new cam might be out of spec. Does the cam bearing feel loose on the cam ends.
My 2 cents worth.

It might be to lean also causing knock.

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  • jetski701

Posted April 24, 2007 - 05:36 AM

#8

I'ts possible to have the valves hitting the piston from lack of clearance. I just had that happen after a stage 2 cam install. It started about 30 seconds after startup, and sounded like a rod knock or piston slap. I checked valve lash and cam timing and they were dead on, so I pulled the head, and found marking on the valves and the piston from hitting. I had the piston machined for valve clearance and will be putting it back together on thursday.

  • KShow

Posted April 24, 2007 - 08:55 PM

#9

Just a thought about the knock, other than having a normally noisy bottom end on a 650r, if you have a skidplate it can reflect more of the knock back up to you. I have a full Baja skid plate and the engine knocks quite a bit,, untill you take the skid plate off,, much quieter. Probably not your issue, but just a thought

  • Billahjack

Posted April 24, 2007 - 09:24 PM

#10

Thanks for all the input. I will be installing a HRC cam this week to see if that makes it quieter. I'm running the stock plastic skid plat on this bike for the moment. I'm not going to tear the head off anytime soon unless I get metal in the oil or it siezes up.

If I can, I'll try to get a sound clip of the motor via video. I'm not sure if the camera microphone will fuzz out from the loudness.

  • captb

Posted April 25, 2007 - 12:55 AM

#11

Most of the noise in big thumpers is the balancer gear lash, there is no adjustment. If they would have used a scissor gear it wouldn't make so much clatter.

  • Nailpounder

Posted April 25, 2007 - 05:26 AM

#12

I dont think anything is wrong with the motor, ride it like you stole it.
If it breaks then fix it.

Take care............

  • Hondathumper450

Posted April 25, 2007 - 06:55 AM

#13

CRAP!!!!!!!!!!! You Already know I stole it!!!!!!!!!!!!!

  • Billahjack

Posted April 27, 2007 - 06:25 PM

#14

So I figured out the noise....

I installed my cam chain tensioner incorrect and did not wind the spring to retract it. I realized this when putting in the new HRC cam.

BTW, the HRC cam has a autodecrompressor and the sprocket flange already assembled. It also has an interesting lobe profile where the lobe is not symmetrical looking down the rotaion axis. There is more of a ramp on one side than the other.





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