[PW80Dad]

I'm sorry if I posted this in the wrong place, I'm new to the forum.
I recently bought an ’06 CRF450X and have a substantial engine vibration at cruising speed and above. It’s enough to make my hands, feet and other parts numb after about 15 minutes. The bike starts easily, runs strong and compression is good. I’ve torqued the engine mounting and exhaust bolts and found no change. I’ve read about the counter balancer shaft and bearings causing a vibration. The top end doesn’t appear to have ever been off. I can see the stator cover has been off and I’m wondering:
A. Can the balancer gear be installed on the shaft in only one position or is it possible to install it incorrectly?
B. Has anyone here solved a major vibration by replacing the counter balancer shaft and bearings?
Thanks for any other thoughts.

First - welcome to the site. They guys here are great.
Second - I think the preferred method for this would be for you to start a new topic (but no worries - if it's a big deal someone that knows more than me will probably move it)

Third - and to your question. You say "at cruising speed". How fast are you going, and what surface are you riding on (dirt/sand, pavement, hard pack, rock, ...?)

Fourth - does the vibration occur at a certain RPM, or is it based on speed? Stated a little differently if you sit on the bike in neutral and slowly increase the RPMs by giving it throttle can you replicate the vibration without moving?

If you cannot replicate the vibration in neutral then it is (most likely) related to the post trans drive components. (FWIW my first thought when I read your question was if you were riding knobby tires on pavement)

If it can be replicated in neutral then it is (most likely) motor/trans.

I'm oversimplifying this a little bit, but I think folks here will be able to help if you can try to isolate the source a little. (so don't flame me guys)

[PW80Dad]

Update - carb has been rebuilt.

I pulled the carb and did the AP mod. Since I was having issues with the cables (another thread) and the carb will be off for a couple of more days I went ahead a pulled the bowl.

First - I'm certain the carb has been cleaned/rebuilt. Probably 30% of the screws are new, and the bowl has some gunk in the deep crevices that whoever went through it didn't get out (but that didn't come flying off when I tried to clean them off). Additionally the rubber gasket on the bowl was way too rubbery for a 10+ year old.

Question - I once had a carb screw assortment from Holley (used to race cars). Is there anything similar for these carbs? There are several of the screws I'd rather replace than strip next time.

Another question - Should I assume all the screws on this carb are JIS? I don't see the dots, but most are either somewhat or very corroded/surface rust.

As always - Thanks in advance for the help and advice.

[tucaz]

I'm sorry if I posted this in the wrong place, I'm new to the forum.
I recently bought an ’06 CRF450X and have a substantial engine vibration at cruising speed and above. It’s enough to make my hands, feet and other parts numb after about 15 minutes. The bike starts easily, runs strong and compression is good. I’ve torqued the engine mounting and exhaust bolts and found no change. I’ve read about the counter balancer shaft and bearings causing a vibration. The top end doesn’t appear to have ever been off. I can see the stator cover has been off and I’m wondering:
A. Can the balancer gear be installed on the shaft in only one position or is it possible to install it incorrectly?
B. Has anyone here solved a major vibration by replacing the counter balancer shaft and bearings?
Thanks for any other thoughts.

First - welcome to the site. They guys here are great.
Second - I think the preferred method for this would be for you to start a new topic (but no worries - if it's a big deal someone that knows more than me will probably move it)

Third - and to your question. You say "at cruising speed". How fast are you going, and what surface are you riding on (dirt/sand, pavement, hard pack, rock, ...?)

Fourth - does the vibration occur at a certain RPM, or is it based on speed? Stated a little differently if you sit on the bike in neutral and slowly increase the RPMs by giving it throttle can you replicate the vibration without moving?

If you cannot replicate the vibration in neutral then it is (most likely) related to the post trans drive components. (FWIW my first thought when I read your question was if you were riding knobby tires on pavement)

If it can be replicated in neutral then it is (most likely) motor/trans.

I'm oversimplifying this a little bit, but I think folks here will be able to help if you can try to isolate the source a little. (so don't flame me guys)

Thanks for the response. I specified cruising speed as I don't have a tach to call out an rpm range. The vibration is easily replicated in neutral by revving the engine and I'm confident the "buzz" is engine related. I've seen comments elsewhere that other owners of this model experience numbness caused by vibration and have considered it normal. Not being familiar with this model I'm not certain if it is normal or not.

[PW80Dad]

Thanks for the response. I specified cruising speed as I don't have a tach to call out an rpm range. The vibration is easily replicated in neutral by revving the engine and I'm confident the "buzz" is engine related. I've seen comments elsewhere that other owners of this model experience numbness caused by vibration and have considered it normal. Not being familiar with this model I'm not certain if it is normal or not.


That makes sense. And thanks for clarifying. If you don't have a tach where would you say you are at in the rev range in terms of %

I'll gladly tell you if I fell a buzz in neutral anywhere. I've not noticed one thus far, but I rarely keep it in the same rev range for more than a few seconds (wooded trails thus far).

I think I remember reading that the RPM limit is around 9.5 / 10k. So if you're feeling a buzz in the middle of the range it would be around 5k RPM.

Hope that makes sense. -Happy to help if I can.