Honda XL 125R Engine Rebuild

[Mikey_F7]

Hi I’ve recently purchased a 1984 Honda XL 125R (Front Drum Brake Model) this is my first restoration and I’ve got it to a rolling frame (Swingarm, suspension, Wheels) and I’ve just started on the engine. I wasn’t there when I purchased the bike but was told it had compression and started but was a little boggy so was doing a full engine rebuild build on it but wasn’t sure how to go about it whether I should strip it down in to every piece, label it clean it and reassemble from there or do the top end then the bottom end and also what I would need for the rebuild e.g. piston kit, head gasket kit any information would be great thanks

[Snod Blatter]

If it runs at all and there are no awful noises then I'd start with a full service and a carb clear out (checking for blocked jets in particular) and see how it goes from there.

[fastbob]

Hi I’ve recently purchased a 1984 Honda XL 125R (Front Drum Brake Model) this is my first restoration and I’ve got it to a rolling frame (Swingarm, suspension, Wheels) and I’ve just started on the engine. I wasn’t there when I purchased the bike but was told it had compression and started but was a little boggy so was doing a full engine rebuild build on it but wasn’t sure how to go about it whether I should strip it down in to every piece, label it clean it and reassemble from there or do the top end then the bottom end and also what I would need for the rebuild e.g. piston kit, head gasket kit any information would be great thanks

 

I'd remove the whole top end first before deciding whether you need to open up the bottom end . If there's no play in the big end and the bike changes gear well enough , you can just leave it alone . The top end might just need a light hone and new rings depending on the condition of the bore . I'd pay some attention to the camshaft bearings and measure the wear on the camchain and guides while I have it apart . So perhaps there is no need for a total strip down . You might as well buy a full gasket set anyway. Good luck .

[hawkeyefxr]

I had an earlier model of this bike but i think they are about the same.

As Fastbob says remove the top end, thats the camshaft head and barrel, don't drop the cam chain do in the crankcase. When thats done stuff rags into the hole in the crankcases so that nothing falls down there. Grab the conrod in you hand and see if there is any VERTICAL movement, there will be a little side to side play but thats ok.

Also as Fastbob says check the play with the camshaft in the head that there is no vertical play there, leave it all oily as to do it dry can cause damage to the bearing surfaces. When you rebuil it you will need a torque to tighten the head down toy the correct torque, that very important.

Not sure what oil filter type you have, Hondas used to have spinning one that spun the dirt out to clean the oil, they are very good but people neglect to clean them right out. The dirt in there is pure dirt dont get it on your hands.

Also get yourself a book, a proper workshop manual will be quite expensive so the second option is the Haynes book of lies.

They are great little engines and are normally bullet proof unless and animal had it previously.