Just a little problem with my trusty XR 125

[adam2013]

Hi guys, I've posted on here a few times now and your advice is greatly appreciated and helpful.

So my 2004 XR 125 has done just under 30,000 miles and is still pulling strong in every gear and starts on the button every time regardless of climate.

So the problem is at around 25,000 the bike suddenly locked the back wheel at 20mph, saved it and no traffic so all good. Since then there has been a ticking noise, throughout the rev range. I have no idea what it could be but it is definitely coming from the cylinder upwards.

I fitted a new exhaust at around 27,000(old exhaust had a pen tip sized hole in the down pipe) with new gasket(copper) nuts are tight.
The reason i'm mentioning this is because when I put the baffle in the ticking noise is considerably quieter.

I change the oil every 1000 miles and clean the stainer every time
I use Motul 10 40w semi oil.



Just a quick second question. I bought the bike at 17,500 and I have never checked or adjusted the valve clearances. I was told by the mechanic "the bolts felt like they were going to snap." I would do it myself but he was charging me £10 and i would have had to but a set of feeler gauges.
so My question is should I risk it (but use some heat) and get them bolts of and do the much needed valve clearances check?

Thanks Guys
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Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC

[Ziggy81scott]

I'm no expert by any means but I think the tappets should be your first port of call.
Not really sure about heating the nuts up, it sounds like the right thing to do but of course you need to be careful about the petrol.
Perhaps someone else could advise you on this.

I don't really understand why the exhaust would quieten down the noise, and if the bike goes well the valve clearances can't be far out of adjustment.
Maybe try getting some feeler gauges and see what clearance you have and check the manual to see what there ment to be.

[Old Git Racing]

For the sake of the price of some feeler gauges and 10 quid I think I'd have had it done it if you can't. Probably too late now if the clearances have tightened up and shagged the engine. Buy a haynes manual, some tools and gauges and have a go, you don't have much to lose now.

OGR
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2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[KrisC]

Sounds like the piston seized on and has damaged the barrel.
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CBT pro.. City fly 125

[adam2013]

Thanks a lot for the help guys but the bike runs great its just the ticking noise is annoying.
I'm going to remove the rocker cover but as I said the mechanic thought they were going to snap(he tried when the engine was cold)
do you think if he uses oxy acetylene the will come out ok.
What are the chances of them snapping when they are glowing red?
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Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC

[piggoy]

Sounds like a piston seizure to me. A seizure is the only thing that would lock up the back wheel like you describe. The exact thing just happened to me on my CBF125, see my thread. The engine would run afterwards fine but with a very loud "tappety" sound under load. Currently rebuilding my engine. The piston seized and lunched itself due to a blocked oilway. The oil level was to the max but the lack of oil circulation meant that the cooling and lubrication of the piston in the cylinder was woefully inadequate. The sound is called "piston slap" and is basically a worn piston rattling about in the cylinder. In these small 125cc 4 stroke engines the piston and cylinder is the only metal on metal contact and the only think that can really seize. Camshaft, followers, big end and small end are all roller and needle bearings which are much more tolerant to lack of lubrication than shell bearings that you find in larger engines.

I hope that helps.

[adam2013]

This sounds just right so what do you think a new piston?

is this easy to do on these engines never really got to into the engine(I change the clutch once and removed a snapped exhaust stud)

Is there any way i can know for definite that it is the so called piston slap

Just been locking into engine noises on a cg125(almost the same engine) and found a few things about the exhaust

I have included a video of the ticking noise(sound a lot less tinny in real life)

The pictures are from my exhaust clamp which tried to tighten evenly(never looked until now) it did have a new gasket when fitted.(it is stainless but a bit dirty)

Could this issue with the exhaust clamp be the issue. As i said the old exhaust did have a small hole.
____________________
Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC

[adam2013]

pictures
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Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC

[adam2013]

Sorry forgot to mention in the video the ticking starts around 3 seconds in and is on and off(mostly on)

when riding the ticking noise is loudest at around 30mph in 4th

Thanks for all your advice
____________________
Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC

[piggoy]

It's hard to say I find it very difficult to diagnose sounds, especially from audio recording. In my case it was piston slap and I only know because I dismantled to the top end of the engine to find a knackered piston and cylinder. Until that point I spent forever (in denial) trying to convince myself that it was tappet, camshaft or follower noise. I found no problem with those so proceeded to dismantle the engine further. Eventually I found the problem. I managed to do all my work with a Haynes manual and with the engine still in the bike.

So here's what I would do if I were you, working downwards towards the piston and cylinder -
1.) Buy yourself a Haynes manual and a set of decent feeler gauges. The Laser 2481 is in my opinion the best since it has a good selection of thin blade sizes perfect for bikes.
2.) Check the bloody valve clearances! I cannot stress how important that is to the health of your engine. It should be done very 2500 miles without fail.
3.) Failing that - Check the rockers and pull rods for wear and play.
4.) Failing that - Take the head off and check the cylinder wall for damage. Replace the head gasket.
5.) Failing that - Take the cylinder off and check the piston and rings for wear. Check for play in the little and big end bearings. Replace the cylinder base gasket.
6.) Failing that - It's probably new engine time.

[adam2013]

[piggoy]

[adam2013]

Sorry for the late reply guys but got the valve clearances done to 0.08mm. Everything came off a treat with a little patience.
Now my problem is starting.
So got the valve clearances done, all back together started fine and ran great, AND NO NOISE. I went out for a ride and noticed after 2-3 mins of riding the bike struggles to idle then after getting fuel and 15mins later it was idling really high I'd say around 3000rpm and usually 1000rpm.
So I got home and turned her off and noticed fuel leaking out of the pipe at the bottom of the carb.
Tried to start it and no luck, so i zip tied the pipe and waited 30s to get fuel in and still no luck

It is getting spark and fuel and turning over normally.

Is the valve clearances to big/small? Did I do something wrong
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Current: '04 Honda XR 125L
Project: '86 Yamaha DT 125LC