Honda xr 125 to set tappet clearances and adjust timing chain 03 model thanks

Question edited for clarity

I use to ride a very modified SL125 in Enduro!

Yes you are correct

Engine and gearbox specs..... Piston ring to cylinder bore clearance: New: 0.010 to 0.040mm / Max 0.100mm Valve clearance (inlet): 0.05mm (when cold) Valve clearance (exhaust): 0.05mm (when cold) Idle speed: 1,300rpm (+/- 100) 25 more rows •
Feb 16, 2011

Honda XL125S Specs and Info (1979 to 1985)

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ThumperTalk https://www.thumpertalk.com > forums > topic > 899863... Jul 22, 2011 - (removing plug makes engine easier to turn over by hand) Rotate crank (under that left side cover) counterclockwise until the T lines up with a ...

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Here is the Service Manual for it

https://kjaer.com/wp-content/uploads/2019/06/XL125-XR125-XR150-Service-Manual.pdf

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Should be the same as Honda 125

What is the valve clearance of a 125? The intake valve clearance should be 0.08mm (0.003 in) and the exhaust valve clearance should be 0.12mm (0.005 in). There should be a slight resistance as you slide the feeler gauge between the adjusting screw and the top of the valve stem. If there is no resistance the clearance is too large.

This actually says on Bajaj CT100 doesn't tell you and suggests 0.007mm.

https://www.team-bhp.com/forum/motorbikes/203868-diy-setting-tappet-clearance-motorcycle-bajaj-ct100b.html

https://www.google.com/search?q=bajaj+xcd+125+valve+clearance

They could put it here!

https://www.bajajauto.com/images/maintainance/XCD_125dtsi.pdf

Service Manual, says Free, but doesn't like my Ad Blocker!

https://www.google.com/search?q=bajaj+xcd+125+service+manual+pdf+free+download

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The most common setting for those engines is 0.14mm for Both valves.

If you need to remove the cylinder head, here's how. To remove the cam chain, you've got to also remove the left crankcase cover and flywheel.

First, you need to turn the engine over until the piston is at top dead center (TDC) of the compression stroke. Begin by removing the two round covers from the left side of the crankcase cover. Also remove the four tappet hole covers from the cylinder head cover. Turn the engine (in the normal direction of rotation) and watch the intake valves open - and close, then see that the exhaust valves open, then close. Now align the 'T' on the flywheel with the notch in the inspection hole. With all of the valves closed, the engine is at TDC of the compression stroke. Do not begin removal of the cylinder head cover until this is done - to avoid damage to the cover.

With the cylinder head cover removed, you will find two bolts attaching the cam chain sprocket to the camshaft. Turn the engine until you can get a 10mm socet onto the heads of the bolts and remove them. The sprocket will come loose and slide down onto the camshaft, enabling you to remove it an the camshaft.

Upon reassembly, set the cam timing by first setting the engine at TDC. Then, align the two marks on the cam sprocket with the gasket surface on the cylinder head. With the engine at TDC and the marks lined up, the cam timing is properly set.

Before calling the job done, make sure to adjust the tappet clearances to .002" on the intake and .003" on the exhaust valves.

Remove the spark plug, put the piston on TDC compression. Now, with engine cold, set the clearance on the intake to .004 to .006. Now set the exhaust to .007 to .009.

It won't be a bad spring if the bike runs well. It is probably just a tappet out of adjustment. Set the valve clearances. Use only premium gas.

sounds like it could be 2 things. the valve tappets, meaning valves need adjusting and or loose cam chain which may need adjusting.

I would recommend you , if there's no problems at all to the engine of your bike..like missing ,hestation or idling or tick over and speed and or any kind of noise, thn you need not worry about anything.
Just remove the spark plug examine it to its condition and gap , reset the gap if needed or best replace it.
Check too the air filter, pressure blow it and if its in worse condition replace it.
Check to the battery if it has one , if its a non-maintenance free check the acid level and if low fill her up to the level with distilled water.
Check the brakes and adjust as necessary.
Check the drive chain and adjust as necessary.

Once done.... your service is done!
Have a nice and safe riding!
Good luck.