Need Help! 07 Cbr 125r Vibration. Annoying vibration

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

Hi, I am new to bikes and just got a 07 cbr 125r from my friend, around 7k km. It was running smoothly before I dropped my bike at pretty low speed in a small accident.

Then I found my bike got some annoying vibration.

Below 7k rpm, neutral or running, I can feel a bit vibration from foot pegs and hand bars, tolerable but definitely more noticeable than before. Vibration gets worse when rpm gets higher. After 8k, I can feel very obvious vibration in hand bars and foot pegs and most annoyingly, between my legs and under my seat which gives me itchy balls. I have checked mounting bolts - tight. Oil and spark plug were replaced. Vibration gets better but itchy balls are still itchy at high rev. Now I suspect that it is something inside engine got out of balance. Might it be an out-phased balancing shaft? Please give me some advice! Thanks!

If it is the engine problem, Getting this fixed by some professionals might cost up to half of bike. but if I want to open it up myself, is there some sort of guide for beginners like me? thanks in advance!

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

I had vibration on my CBR125 from 7k-9k rpm. Engine died soon after.

Usual vibration causes are the fairing, but the brackets are minimal on the 125.

My engine issue was the cam bearing which are noted as being weak points.
If you need a working engine minus engine cases I have one in my garage with 9500 miles on it. Its a carb 05 model. PM me if you want it.. looking for £50 as it has no cases (can use your own.)

Does your engine sound a bit tappy near the top of it? The cam issue is quite noticeable.

I take it you checked engine mounting bolts, footrest bolts and the like? How about your wheel bearings? Might not be anything to do with the issue but might as well check Thumbs Up

:Edit: Opening the CBR engine is a piece of cake. Checking the cam is simply rocker cover off but you need to remove the air pipe on the top. That and the CBR is an absolute ball ache to do work on. Tank has 4 pipes that need to go on the right way, MANY wires under the tank...just meh.

Where abouts are you based? If you are close I don't mind having a look, owned so many of the buggers Laughing

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

Take the fairings off and grab a flat head screwdriver, put the handle against your ear and the blade against various parts of the engine. Will hopefully help see if there is a problem in the engine.

Tappy noise. Like a clicking or knocking noise from the top.
When mine got really bad it sounded like this (bear in mind this was over a 3 month period and me not bothering to check it)

https://www.youtube.com/watch?v=gvwjwYJY_u4

Sydney is a bit far Laughing

Opening up the engine, top end is simple, never had to do the bottom end, they seem fairly robust.

You have a choke near the left handlebar, CBRs are notoriously annoying to start and keep running (especially in the UK)
I have to leave it on choke for around 5 minutes then ride with it slightly on for a few miles until the temp gauge starts moving. Unsure why, but hey...its a quirk Thumbs Up

bwprice100 · Borekit Bruiser Joined: 11 Dec 2011 Karma :

.
Hi Courak

If it has started after your off then give the bike a really good check over.

Whilst ridding are the vibes linked to a certain engine revs or speed?

When the vibration happens does it disappear if you pull the clutch in?

Brian
____________________
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My bikes 1956 BMW R26 250cc, !981 BMW R80 (was a TIC ex plod), 1994 R100RT, sold my 1981 Yam XS 250

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

mab · Nitrous Nuisance Joined: 24 Jul 2011 Karma :

Does it sound like this?
https://www.youtube.com/watch?v=9ZwmqGIjTj8

If so check your cam. The cause of mine was the bearings on the camshaft disintegrating

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

mab · Nitrous Nuisance Joined: 24 Jul 2011 Karma :

Could you upload a video of the bike whilst its running?

Is the vibration there when the bike is stood? Reving up to 8k in neutral?

Are the wheel weights still on the wheels?

Have you had your tires changed recently?

What is the condition of the tires?

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

bwprice100 · Borekit Bruiser Joined: 11 Dec 2011 Karma :

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

If it wasn't fucked it is now Laughing

Just curious... how long was your engine running before you revved it like that?

When it was idling it sounded ok... but you can't really tell much from far away, might need to get it ticking over a little faster with the idle screw or choke and get the camera closer to the top of the engine for distinctive noise.

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

It would be an idea to let your engine warm up completely before revving it that high... like have a decent 30 minute ride or something rather than when its like that.

What big screws?

Also, the FI wont be an issue unless it comes back on. The noise of your engine from the video sounds fairly ok... just I wouldn't be revving it that much at all..

Courak · Derestricted Danger Joined: 21 Dec 2011 Karma :

mab · Nitrous Nuisance Joined: 24 Jul 2011 Karma :

Sounds a little rattly to me.

Whats your oil level like? Is it between the low and max lines on the dipstick?

Check the function of the cam chain tensioner. They are known to be a little dodgy on Hondas.

The two big screws are for setting the engine to top dead center. The larger of the two reveals a large nut for a socket which will turn the engine. The smaller will have a small mark on the side. You will be able to see the edge of the flywheel which will have a mark on it that lines up to the mark on the case when you hit top dead center.