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Hi Everyone, I am very new to motorbikes, and I am currently trying to get my Dad's old Honda XL125 1982 in running order so I can learn to ride, however, the engine is making a strange sound when applying the throttle. It idles fine and starts like champion. I took it to a garage and they said they would need to take the engine apart, however they weren't sure and I didn't want to spend the money they were asking for. Was wondering if anyone on here would be able to help me narrow down my search for the problem. https://youtu.be/EF7hd61_MgU Its hard to explain the sound, but it sounds very hollow and doesn't seem to have much power. Any suggestions would be appreciated, I have had the carb cleaned recently.

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Diagnosing engine sounds via recordings is always tricky......they rarely sound like they do in real life,


pull the plug and put a pic up here, did it have problems before you had carb cleaned?


Did you clean it or a Pro?


Hello BTW

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Welcome.

Was it running ok before when your Dad had it?


Does it have points ignition or cdi?

If the former,clean them up or replace points,change condenser.

Check advance mechanism.

Set points gap and static timing

Check valve clearance

check air filter not blocked

check exhaust not blocked

Replace spark plug.


Seem to recall old Hondas wearing out cam bearings if the oil level was low or not changed regularly?

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check that the plug is tight and its not missing the sealing washer .

my old xl100 had a similar issue but because thread had started to go on the head for the plug and was leaking past .... had to helicoil eventually when thread fully went and popped plug( did ride bike with a leather belt holding plug in place to get home )

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I had a listen with headphones and I think I'll take a guess at a worn out overhead camshaft bearing . This would explain the rattle and the lack of power. It probably runs in plain bearings so a good engineer might be able to turn down the shaft and insert some bushes. Usually in these cases both the steel shaft and the plain bearing will be damaged . Only a guess though.

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Thanks everyone, I appreciate its hard to diagnose stuff without being here and it doesn't help that I'm not really a bike person! I'm working my way through all he suggestions, the exhaust is connected properly and does have a gasket, and I don't think its blocked. Its had oil relatively recently. I have also ordered a new spark plug. I have found that it had no air filter so not sure if that could be the cause? I didn't think it would effect it that much! The carb was cleaned by a professional so I don't think that is the problem. It has a CDI unit, but that seems to be working ok? I mean it starts every time even when its been stood for 6 months (but im no expert). I don't have a lot of money to spend on it, and I would like to try and do any of the work myself so I could learn for the future, but I'm quite reluctant to attempt to take the engine apart as I fear I will bugger it all up! is it as hard as I imagine? or could a beginner do it, using youtube?

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Thanks everyone, I appreciate its hard to diagnose stuff without being here and it doesn't help that I'm not really a bike person! I'm working my way through all he suggestions, the exhaust is connected properly and does have a gasket, and I don't think its blocked. Its had oil relatively recently. I have also ordered a new spark plug. I have found that it had no air filter so not sure if that could be the cause? I didn't think it would effect it that much! The carb was cleaned by a professional so I don't think that is the problem. It has a CDI unit, but that seems to be working ok? I mean it starts every time even when its been stood for 6 months (but im no expert). I don't have a lot of money to spend on it, and I would like to try and do any of the work myself so I could learn for the future, but I'm quite reluctant to attempt to take the engine apart as I fear I will bugger it all up! is it as hard as I imagine? or could a beginner do it, using youtube?

Forget YouTube, people on it don't necessarily know what they are talking about and unfortunately you are not in a position to decide who's right or wrong. By far the best thing to do is buy a Haynes manual, and please don't take this the wrong way,READ it . 😉 If you get round to telling Megawatt whereabouts you live he may offer to visit you to sort it out . https://m.ebay.co.uk/itm/Honda-XL-125-RC-1982-1984-0124-CC-Haynes-Workshop-Manual/360754808850?hash=item53fea98812:g:wVcAAOSwyTFaiD0s

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Hi Everyone, I am very new to motorbikes, and I am currently trying to get my Dad's old Honda XL125 1982 in running order so I can learn to ride, however, the engine is making a strange sound when applying the throttle. It idles fine and starts like champion. I took it to a garage and they said they would need to take the engine apart, however they weren't sure and I didn't want to spend the money they were asking for. Was wondering if anyone on here would be able to help me narrow down my search for the problem.... Its hard to explain the sound, but it sounds very hollow and doesn't seem to have much power. Any suggestions would be appreciated, I have had the carb cleaned recently.

 

It would be really helpful if you were to tell the forum where you are located. If you click on your name and go to the user control panel you can put your location in the profile tab.

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Hi again everyone, Ive noticed that the bike is running rich, could this be a big issue? or would it not cause the problem im having?

 

Megawatt is asking where you’re based as he wants to help.

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Best advice i can give, is that if you dont know exactly what you are doing leave it with a professional as you could potentially make it worse. If you do try to fix it yourself firstly try to find exactly where the noise is coming from eg gearbox, top end, bottom end, exhaust. Then take it from there.. hope this helps.

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I had a listen with headphones and I think I'll take a guess at a worn out overhead camshaft bearing . This would explain the rattle and the lack of power. It probably runs in plain bearings so a good engineer might be able to turn down the shaft and insert some bushes. Usually in these cases both the steel shaft and the plain bearing will be damaged . Only a guess though.

What lack of power? Don't recall OP mentioning that....apart from "doesn't seem to have much power". Has anybody given it a good thrash up the (private) road? I would bet valve clearances or piston slap. Anyway, Honda single ain't gonna be much hassle to strip & fix. Haynes time, I'm afraid......

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Hi guys, I fixed it! Ive had the carbs cleaned again and there was a hole in the underside of the exhaust pipe where it had rotted away, I should have noticed it before!! Started it up and the throttle is back in business!! thanks everyone for the advice, really appreciate it!

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I had a listen with headphones and I think I'll take a guess at a worn out overhead camshaft bearing . This would explain the rattle and the lack of power. It probably runs in plain bearings so a good engineer might be able to turn down the shaft and insert some bushes. Usually in these cases both the steel shaft and the plain bearing will be damaged . Only a guess though.

What lack of power? Don't recall OP mentioning that....apart from "doesn't seem to have much power". Has anybody given it a good thrash up the (private) road? I would bet valve clearances or piston slap. Anyway, Honda single ain't gonna be much hassle to strip & fix. Haynes time, I'm afraid......

 

Forgive me but the phrase " doesn't seem to have much power " indicates to me a lack of power.

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Hi guys, I fixed it! Ive had the carbs cleaned again and there was a hole in the underside of the exhaust pipe where it had rotted away, I should have noticed it before!! Started it up and the throttle is back in business!! thanks everyone for the advice, really appreciate it!

 

Great ! Would you say that it now has more power ?

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