pug 103 bearings

Anyone know how to remove the bearings on a pug 103. I have already split the case, and the bearings and seals are still in each half of the case. Do i need to let it all cool and reheat each half for a short period of time and they will fall out or is there a special tool that i need. Any help would be appreciated.


Re: pug 103 bearings

I have found the best way to do this is to use a MAPP gas torch.

1.Get a wood board, place the carter half on the board face down (inner portion of case is facing down) this will allow the bearing to drop out downward.

2. Light the torch and put on some leather gloves.

3. With the torch on a low setting while holding it an inch or two away from the case. Heat the outside of the carter in a circular motion where the bearing is located. This will help evenly heat the carter around the bearing.

4. as you get the case to approx. 225-250 deg ( i think) the bearing may drop out on its own. If it does not, you can grab the carter with gloved hands and tap it on the wood board to help drop the bearing. You dont have to get crazy with slamming it down as hard as you can. Remember it is just aluminum.

Good Luck!

Re: pug 103 bearings

thanks will try that tomorrow and will let you know how it goes

Re: pug 103 bearings

Adrien Pearson /

nick could not say it any better. a week ago i replaced the bearings and seals on my pug. pretty much did the same thing he did. it wasnt that hard either! Mabye have a bud to help out!

Re: pug 103 bearings

bearing puller.

Re: pug 103 bearings

Thanks, guys the bearings fell out with the blow torch method. Last question, i was curious if the case gasket, is just yamabond, or if there is an actual gasket, that needs to be cut or bought? the gasket that was on there looks like it was an actual gasket and not sealant. Thanks for the suggestions.


Re: pug 103 bearings

actual gasket

Re: pug 103 bearings

You need to use a real gasket. They sell them at Treats for $3. You need to also get intake gaskets, base/head/exhausts as well.

im going to be honest with you Dan. You need to do a little research before jumping into a pug motor reassembly. They can be frustrating and you need to make sure you have it all staged out before doing it. French motors require heat/freeze methods to get things together. The tolerances are very tight. I wish the bottoms ends were as easy as puch's but there not. If you got to the "moped riders association" you can download shop manuals to get torque specs, assembly steps and a breakdown of parts. there is a lot to these little motors/variators/ignitions.

Here is a QUICK breakdown of steps.

1. clean all gaskets surfaces of old gasket residue

2. press seals into carters, springs facing outwards

3. place crank in freezer over night

4. make a wooden jig that will go in a bench vise (2 pieces of wood screwed together. One on top wider than the bottom for vise gripping.) *Note. drill hole in the jig to allow for the smallest of the two bearing to fit into it.

5. heat first bearing (Smallest) with torch to Approx. 225 deg (making sure you put it on the right side of the crank)

also if you are using FAG bearings make sure you dont hit the nylon ball guides in the bearing with the torch. With these bearings, you may want to boil them in oil on the stove or something

6. quickly place frozen crank in jig with the correct side facing up.

7. with gloves, grab hot bearing and drop it on crank. Should slide down to the crank counterweight cheek.

* Note: have a piece of clean PVC pipe about a foot long on hand and a mallet just in case you need to persuade a little. Make sure the pipe is thick walled to take a mallet blow and that it is just large enough in diameter to allow the crankshaft to slide into it and allow it to contact the inner race of the bearing. It is best not to put alot of stress on the outer race.

8. Place crank and one installed bearing back into freezer

9. Heat next bearing to same temp.

10. pull crank out of freezer and put the side with the small bearing installed down into the jig.

11. grab bearing and drop on crank. Persuade if need be.

12. Place crank in freezer overnight with bearings installed.

Next Day

1. Take case gasket that you purchased and put some oil on it with your fingers and sit it aside close to the vise. This oil will allow the gasket to swell a little so you get a better seal when you compress it.

2. Get your case bolts laid out properly near the vise. Number them if you need to keep their locations right.

*Bolt head should be on the variator side and nuts should be on ignition side I believe for clearance reasons.

3. Take carter half that will receive the large bearing first, place face down (inner part of motor down). Rub some 2 stroke oil on the seals to help protect them. Heat the carter half with the torch in a circular motion where the bearing sits to around 225 or maybe more.

*Note: make sure you keep the flame away from the SEALS! it will destroy them.

4. Grab crank from freezer and place it on the jig SMALL bearing down into the jig first.

5. Grab heated carter half with Leather gloved hand making sure it is still hot and slide it on top of crank in jig. Make sure the crank connecting rod is located where is should be in the carter half so it doesnt hit. Put the carter on straight in relation to the bearing! You dont want it to bind up and not go in completely. Also make sure the crank doesnt catch the seal wrong and damage it either.

6. flip your "so far" assembled bottom end in the jig over so that the next receiving crank side is facing upward.

7. DONT FORGET TO PUT YOUR CASE GASKET ON NOW. Just lay it on top of the carter half that is currently in the jig.

8. Grab the second carter half and oil the seal. Heat the carter with the torch like before.

9.Grab the heated carter half and slide it on the crank like before making sure the connecting rod is still properly located in relation to the case. Hopefully the case halves meet up. Make sure the crank doesnt grab the seal wrong!

10. grab a few of your case bolts and put them in as stated earlier. Start to tighten them down evenly around the carter so that it doesnt stress out the aluminum.This should help pull the case together to its final location while making the gasket in between seal like it should. Put in the rest of your bolts and tighten to the correct torque.

Your bottom end is now finished. whew! I need a beer stat!

There maybe easier ways to do this, ive just found this works best for me. I literally have a freezer right beside my vise in the shop:)

Good Luck! Do your research!

Re: pug 103 bearings

Wow, First let me say thanks for all the advice. This is my first french bike and i really appreciate the advice. I have been reading up on it, but getting advice from people always makes it a lil easier. and i definently dont want to damage anything. Thanks again and will let you know how putting it back together goes.


Re: pug 103 bearings

I'm doing a rebuild as well. Lots of good info there.

Re: pug 103 bearings

i'd like to jump in here and ask a question...

had a soft seize last week...cleaned up everything...ordered a new piston, seals/ bearings/gaskets from treats

now i'm wondering if i should replace them or just send 'em back...if i grab the crankshaft and rock it side to side i have a tiny tiny amt of play...

now i'm wondering if i should even bother given the info here...really? is it this involved?

i figured i had the engine out might as well replace but really?

any input is welcome.


Re: pug 103 bearings

btw, i'm just talkin about the seals/bearings here...


Re: pug 103 bearings

Always good to replace the crank. If not at least replace the bearing in the top end of the conrod.

Yes rebuilding a pug is kind of difficult because you need a case splitter that is not sold. You have to make one. You can use heat to split it also but be careful not to damage the case

Also bearings go in the case first, then you press the crank into the case.

Re: pug 103 bearings

† CH∆D † /

Aaron what your saying doesnt jive with what is written out above?

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account