2001 cr250 rolling vibration

[shinerbock69]

Hi all,
After doing a chain and sprocket replacement, along with realigning the chain due to me going back to the stock tooth sizes I have noticed alot of vibration in the bike just rolling it in and out of the garage.

It was my first time doing the alignment and sprocket change; im looking for opinions as to what could cause this?

Before the bike rolled smoothly, even considering all the other issues it has. There is currently no oil in the motor, chain is lubed  

now rolling it back and forth there is a pretty noticeable amount of jitter coming up through the handlebars - I can only imagine this will be considerably worse once riding. 

[AMSinator]

If chain is new, stiff, o/x ring type and not broken in might create effect. 

Quality Sprockets??

Did you pump up tire PSI, or change tires, knobbies might be felt on hard surfaces.

I assume chain tension is correct according to OEM specs? 

[shinerbock69]

55 minutes ago, AMSinator said:

If chain is new, stiff, o/x ring type and not broken in might create effect. 

Quality Sprockets??

Did you pump up tire PSI, or change tires, knobbies might be felt on hard surfaces.

I assume chain tension is correct according to OEM specs? 

Its a renthal chain and sprocket.

The tires were at 30PSI and I dropped them to 15 per my internet reading (previous owner had at 30)

Tension is about 3 fingers worth, which was what all the videos I watched cited 

[Fred29]

Its a renthal chain and sprocket.


The tires were at 30PSI and I dropped them to 15 per my internet reading (previous owner had at 30)


Tension is about 3 fingers worth, which was what all the videos I watched cited 

Put it up on a stand or a five gallon bucket while in neutral. Spin the back wheel, you'll know where the problem is by the sound. You didn't put a new chain guide on the swing arm, did you? My master link (new chain, sprockets, slider, and guide) was catching on the guide and it freaked me out until free spun the wheel and figured it out. Also, make sure the "C" clip on the front sprocket is seated properly.

[shinerbock69]

3 hours ago, Fred29 said:

On 9/29/2019 at 10:15 AM, shinerbock69 said:

Its a renthal chain and sprocket.


The tires were at 30PSI and I dropped them to 15 per my internet reading (previous owner had at 30)


Tension is about 3 fingers worth, which was what all the videos I watched cited 

Read more  

Put it up on a stand or a five gallon bucket while in neutral. Spin the back wheel, you'll know where the problem is by the sound. You didn't put a new chain guide on the swing arm, did you? My master link (new chain, sprockets, slider, and guide) was catching on the guide and it freaked me out until free spun the wheel and figured it out. Also, make sure the "C" clip on the front sprocket is seated properly.

I hear the most towards the front. 
I did put a new chain guard, the old one was chewed up pretty bad
What do you mean by "C" clip on the front? Thats one thing I didnt check. Just put new sprocket on (had to buy impact gun because I took back tire/chain off first...whoops)

https://imgur.com/ZE4K627

[Fred29]

Ok, you only replaced the back sprocket? You wouldn't be able to get the front sprocket off without removing the "C" clip from it's groove on the counter shaft. Now we're getting somewhere. New chain and old sprocket(s) are no good. Even if it's not the problem, get a new front sprocket. While you're at it get a new clip ($2???). 

As you spin the wheel does the sound/vibration occur once per rotation? If so, your master link could be catching on the new chain guard. To make sure spin the wheel backwards and if the locking clip (not the "C" clip up front) on the master link flies into your eye, there's your problem.

Lastly, make sure the chain adjuster bolts in the tail end of the swing arm are exactly the same. Even a turn or two off can really throw off the alignment. If you can't turn them freely, STOP... Snapping one off is a nightmare to remove. The fix usually isn't MIG welding another nut onto it and then removing. I have a $230 bill from a machine shop because nothing but an EDM machine could get the MF'er out. I spent most of the Spring and Summer trying to remove it myself. There's a thread on here detailing my misery. If this is your case, PB Blaster and time are your only inexpensive choice. 

An impact gun??? Aluminum and pneumatic force don't mix. Use heat to remove stubborn bolts next time.

 

 

 

[shinerbock69]

12 hours ago, Fred29 said:

Ok, you only replaced the back sprocket? You wouldn't be able to get the front sprocket off without removing the "C" clip from it's groove on the counter shaft. Now we're getting somewhere. New chain and old sprocket(s) are no good. Even if it's not the problem, get a new front sprocket. While you're at it get a new clip ($2???). 

As you spin the wheel does the sound/vibration occur once per rotation? If so, your master link could be catching on the new chain guard. To make sure spin the wheel backwards and if the locking clip (not the "C" clip up front) on the master link flies into your eye, there's your problem.

Lastly, make sure the chain adjuster bolts in the tail end of the swing arm are exactly the same. Even a turn or two off can really throw off the alignment. If you can't turn them freely, STOP... Snapping one off is a nightmare to remove. The fix usually isn't MIG welding another nut onto it and then removing. I have a $230 bill from a machine shop because nothing but an EDM machine could get the MF'er out. I spent most of the Spring and Summer trying to remove it myself. There's a thread on here detailing my misery. If this is your case, PB Blaster and time are your only inexpensive choice. 

An impact gun??? Aluminum and pneumatic force don't mix. Use heat to remove stubborn bolts next time.

 

 

 

no, new chain, front & rear sprocket, chain guard.

For the front sprocket I removed the 12mm (maybe 14mm) bolt that held it on and replaced with new socket.

If you listen to the video you can hear the bike when rolling in neutral as suggested. The vibration isnt noticeable until off the stand and rolling on ground.

Still wondering if this is related to no fluids

I have my adjustors at the same distance per my measuring so I dont think thats the issue. 

Reading multiple sources it sounds like the impact gun is fine, its not really wanted to do but I couldnt find any other options. I made the mistake of taking the back tire/chain off first.

 

[Fred29]

no, new chain, front & rear sprocket, chain guard.

For the front sprocket I removed the 12mm (maybe 14mm) bolt that held it on and replaced with new socket.

If you listen to the video you can hear the bike when rolling in neutral as suggested. The vibration isnt noticeable until off the stand and rolling on ground.

Still wondering if this is related to no fluids

I have my adjustors at the same distance per my measuring so I dont think thats the issue. 

Reading multiple sources it sounds like the impact gun is fine, its not really wanted to do but I couldnt find any other options. I made the mistake of taking the back tire/chain off first.

 

I just listened to the video. I'm not hearing anything out of the ordinary. Mine sounded similar with the same new parts. If you did nothing internally, grease up the chain and put in your fluids. Run it.

[Motox367]

Looks like chain to short.  Sprocket hitting gaurd or chain is cause to short

[Motox367]

It's going to eat your chain guide up quick like that. Always good to buy 120 link chain and cut yourself 

[KcDavis]

I just listened to the video. I'm not hearing anything out of the ordinary. Mine sounded similar with the same new parts. If you did nothing internally, grease up the chain and put in your fluids. Run it.

I agree, nothing seems out of the ordinary. Mine also sounds similar. But, keep an eye on the chain guide... you don't want to chew through it and into your swing arm.