Help diagnosing front end clunks and knocks

dooby · July 7th, 2013, 09:19 AM

Hi guys,

I wonder if you could help me diagnose a problem I'm having. My '11 250R is just coming up on 5000 miles so I took it to a local specialist for its 2nd service.

When it came back, they'd botched a few things - the front pads were changed but the reservoir was overfilled, causing it to weep some excess brake fluid. They also only left the sump plug finger tight, which might explain an occasional twitchy rear end (in both senses) during a quick welcome home blast through some twisties since it was dripping oil periodically.

So, given someone clearly botched a few things, what else should I be checking for if my symptoms are:

clunks or knocks felt through the handlebars when going over bumps, made worse if I'm on the front brake at the time, and seeming less bad if I use the rear brake instead over bumps.

I have tried rocking the bike back and forward on the front brake, and it seems to compress and damp as I would expect. I did not detect any other looseness, so I think whichever bearings are involved in that process are still good.

The (please excuse my ignorant terminology) main big nut on top of the triple tree seems tight, as do the 2 bolts each side attaching my stock handlebars. Looking from underneath, the clamp bolt each side holding the stanchion also seem tight. At the axle end, the castle nut seems secure, and is R clipped to stop it coming loose.

Could you help suggest other tests I should do to diagnose what is wrong? I'm handy with a spanner, but not good at motorcycle diagnostics.

I will be taking the failures up with the garage concerned but am understandably reluctant to trust diagnosis to them (plus it's another 30 miles I'd have to ride with it not feeling right).

Thanks, Pete

choneofakind · July 7th, 2013, 09:28 AM

Sounds like your steering stem is loose. Whenever you hit a bump or get on the brakes, your forks pitch slightly and get stopped by the bearings. That makes a clunk. Over time, this clunking on the bearings will dent them, causing slop that you can't get rid of and tight spots as you turn the bars.

Here's how you can test it. Hold the front brake hard, and rock the bike forward and backward. This should replicate the knocking in your stem. You can also put the rear on the stand, jack the front end up off the ground, and manually rock the front wheel forward and backward. Again, that should also replicate the knocking sound from you stem slop.

Here's how you can fix it. Loosen the stem bolt, remove the top triple, use your supplied spanner wrench (for the shock) to tighten the stem nut until the stem is snug without being too tight, reinstall the triple, reinstall the stem bolt. That will remove the slop in your stem and your knocking over bumps and braking should go away.

Remember, stem nut too tight = tight steering, stem nut too loose = slop and knocking over bumps. Find that happy medium.

Joshorilla · July 7th, 2013, 10:04 AM

Yep

dooby · July 7th, 2013, 11:23 AM

Thanks guys. Upon closer inspection, the triple tree bolt was not actually very tight at all, so I took it off and tightened the steering stem with the C spanner about 90 degrees. I re-tightened the triple tree bolt and tested the steering, still feels OK (not tight) but will feed back after a 60 mile commute tomorrow. At least I know what I need to be adjusting now.

Cheers, Pete

choneofakind · July 7th, 2013, 12:02 PM

Good! keep playing with it until it feels right.

dooby · July 8th, 2013, 02:27 PM

Hi Chris,

it did feel better today - I have tightened it up just a touch more this evening.

I wonder if it was related to the service - they swapped from stock pad compound to EBC HH but apparently didn't get a chance to bed them in (as I found out to my surprise when decelerating from 70mph to 30mph coming home). I read up on EBC's break in procedure, and took the bike back out doing controlled 40mph-5mph hard stops. After the 5th or so, the brakes started to really bite, and the rear wheel lifted which was a first for me.

I wonder if my new found appreciation for hard front braking has contributed to loosening the steering stem. Now I know what to look for and how to fix it.

Thanks, Pete

choneofakind · July 8th, 2013, 04:29 PM

Not sure if the braking would have that sudden of an impact on it. Likely, the braking is just what made you notice the knocking. Bearings wear over time, it's likely been gradually getting worse every time you hit a bump and/or brake.

July 7th, 2013, 09:19 AM	#1
dooby ninjette.org member Name: Pete Location: UK Join Date: Aug 2012 Motorcycle(s): '11 250R SE (FI), '14 Daytona 675, '14 Sprint 1050 GT SE Posts: 121	Help diagnosing front end clunks and knocks Hi guys, I wonder if you could help me diagnose a problem I'm having. My '11 250R is just coming up on 5000 miles so I took it to a local specialist for its 2nd service. When it came back, they'd botched a few things - the front pads were changed but the reservoir was overfilled, causing it to weep some excess brake fluid. They also only left the sump plug finger tight, which might explain an occasional twitchy rear end (in both senses) during a quick welcome home blast through some twisties since it was dripping oil periodically. So, given someone clearly botched a few things, what else should I be checking for if my symptoms are: clunks or knocks felt through the handlebars when going over bumps, made worse if I'm on the front brake at the time, and seeming less bad if I use the rear brake instead over bumps. I have tried rocking the bike back and forward on the front brake, and it seems to compress and damp as I would expect. I did not detect any other looseness, so I think whichever bearings are involved in that process are still good. The (please excuse my ignorant terminology) main big nut on top of the triple tree seems tight, as do the 2 bolts each side attaching my stock handlebars. Looking from underneath, the clamp bolt each side holding the stanchion also seem tight. At the axle end, the castle nut seems secure, and is R clipped to stop it coming loose. Could you help suggest other tests I should do to diagnose what is wrong? I'm handy with a spanner, but not good at motorcycle diagnostics. I will be taking the failures up with the garage concerned but am understandably reluctant to trust diagnosis to them (plus it's another 30 miles I'd have to ride with it not feeling right). Thanks, Pete

July 7th, 2013, 09:28 AM	#2
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Sounds like your steering stem is loose. Whenever you hit a bump or get on the brakes, your forks pitch slightly and get stopped by the bearings. That makes a clunk. Over time, this clunking on the bearings will dent them, causing slop that you can't get rid of and tight spots as you turn the bars. Here's how you can test it. Hold the front brake hard, and rock the bike forward and backward. This should replicate the knocking in your stem. You can also put the rear on the stand, jack the front end up off the ground, and manually rock the front wheel forward and backward. Again, that should also replicate the knocking sound from you stem slop. Here's how you can fix it. Loosen the stem bolt, remove the top triple, use your supplied spanner wrench (for the shock) to tighten the stem nut until the stem is snug without being too tight, reinstall the triple, reinstall the stem bolt. That will remove the slop in your stem and your knocking over bumps and braking should go away. Remember, stem nut too tight = tight steering, stem nut too loose = slop and knocking over bumps. Find that happy medium.
	1 out of 1 members found this post helpful.

July 7th, 2013, 11:23 AM	#4
dooby ninjette.org member Name: Pete Location: UK Join Date: Aug 2012 Motorcycle(s): '11 250R SE (FI), '14 Daytona 675, '14 Sprint 1050 GT SE Posts: 121	Thanks guys. Upon closer inspection, the triple tree bolt was not actually very tight at all, so I took it off and tightened the steering stem with the C spanner about 90 degrees. I re-tightened the triple tree bolt and tested the steering, still feels OK (not tight) but will feed back after a 60 mile commute tomorrow. At least I know what I need to be adjusting now. Cheers, Pete Last futzed with by dooby; July 7th, 2013 at 01:08 PM. Reason: It's a bolt not a nut...

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Diagnosing possible electrical issues	simook	2008 - 2012 Ninja 250R Tech Talk	5	January 29th, 2015 02:01 PM
Upgraded front suspension, front end tuck	Ginganinja	1986 - 2007 Ninja 250R Tech Talk	12	October 30th, 2014 10:27 AM
WTB 08+ Front Brake lever/Bar End/ Front Turn Signal	1LoneWolf	Items Wanted	3	July 8th, 2013 02:50 AM
Help diagnosing electrical issue	Lvr	2008 - 2012 Ninja 250R Tech Talk	6	June 16th, 2011 02:41 PM
Need help diagnosing: Bike keeps dying	altomista	1986 - 2007 Ninja 250R Tech Talk	6	July 14th, 2010 06:58 PM

July 7th, 2013, 10:04 AM	#3
Joshorilla Bass Master General Join Date: Aug 2012 Posts: A lot. Blog Entries: 24	Yep

July 7th, 2013, 12:02 PM	#5
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Good! keep playing with it until it feels right.

July 8th, 2013, 02:27 PM	#6
dooby ninjette.org member Name: Pete Location: UK Join Date: Aug 2012 Motorcycle(s): '11 250R SE (FI), '14 Daytona 675, '14 Sprint 1050 GT SE Posts: 121	Hi Chris, it did feel better today - I have tightened it up just a touch more this evening. I wonder if it was related to the service - they swapped from stock pad compound to EBC HH but apparently didn't get a chance to bed them in (as I found out to my surprise when decelerating from 70mph to 30mph coming home). I read up on EBC's break in procedure, and took the bike back out doing controlled 40mph-5mph hard stops. After the 5th or so, the brakes started to really bite, and the rear wheel lifted which was a first for me. I wonder if my new found appreciation for hard front braking has contributed to loosening the steering stem. Now I know what to look for and how to fix it. Thanks, Pete

July 8th, 2013, 04:29 PM	#7
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Not sure if the braking would have that sudden of an impact on it. Likely, the braking is just what made you notice the knocking. Bearings wear over time, it's likely been gradually getting worse every time you hit a bump and/or brake.