Classic Bike Engine Overhaul

CalamariFritti

Hi Everyone,

I have a 40+ year old enduro in pretty good nick and more or less original condition but the engine would need an overhaul at this stage. I'd be happy and able to do some of that myself but she needs probably a new bore and the valves done and that would be beyond me. I wouldnt even have the tools for it. So I'm thinking I better have a professional do it.

Would anyone know anyone who's still does that kind of stuff? Expertly too?

Cheers

C

H_Lime

CalamariFritti wrote: »

Hi Everyone,

I have a 40+ year old enduro in pretty good nick and more or less original condition but the engine would need an overhaul at this stage. I'd be happy and able to do some of that myself but she needs probably a new bore and the valves done and that would be beyond me. I wouldnt even have the tools for it. So I'm thinking I better have a professional do it.

Would anyone know anyone who's still does that kind of stuff? Expertly too?

Cheers

C

Kida hard to say really. If it's an r80gspd it will need quite a different approach to a bultaco pursang wont it!
Are we to guess what she is, and what if I guess correctly do I win a prize?

CalamariFritti

H_Lime wrote: »

Kida hard to say really. If it's an r80gspd it will need quite a different approach to a bultaco pursang wont it!
Are we to guess what she is, and what if I guess correctly do I win a prize?

Sorry you're right of course. She's a 79 Yamaha XT500.

H_Lime

CalamariFritti wrote: »

Sorry you're right of course. She's a 79 Yamaha XT500.

Ah cool��What's the plan, oem, resto mod or just a good tidy up.
Either way engines out of the by the sound of things so maybe blast the frame. Paint it or powder?
How are the wheels, respoke?

Very simple engine to work on. How game are you on stripping it?

CalamariFritti

I'm handy for a layman. Done a lot of work on this bike.

She's not in showroom condition she's in use, but she's in good nick and original unless there was a good reason not to. Did a 12V conversion and the fork and clutch and gearbox and carb and new shocks and restored loads of bits and bobs.

Compression isn't great and she burns a bit of oil and she has a lot of years on the clock. So I'd say new bore with a slightly oversized piston or a sleeve or something. And the valves need a new cut and that. Not sure im using the correct technical terms. The only weak spot on the bike is the engine really. Sadly its also the most important bit and the one I can't do myself.

Currently looking at some guys in Germany who send you a basically a new engine in exchange for your old one plus cash. Just wondering is there something closer to home.

Del2005

It's a 4 stroke it most likely just needs new rings, valve's and maybe valve seats if it's burning oil. You should be able to see when you remove the head.

H_Lime

CalamariFritti wrote: »

I'm handy for a layman. Done a lot of work on this bike.

She's not in showroom condition she's in use, but she's in good nick and original unless there was a good reason not to. Did a 12V conversion and the fork and clutch and gearbox and carb and new shocks and restored loads of bits and bobs.

Compression isn't great and she burns a bit of oil and she has a lot of years on the clock. So I'd say new bore with a slightly oversized piston or a sleeve or something. And the valves need a new cut and that. Not sure im using the correct technical terms. The only weak spot on the bike is the engine really. Sadly its also the most important bit and the one I can't do myself.

Currently looking at some guys in Germany who send you a basically a new engine in exchange for your old one plus cash. Just wondering is there something closer to home.

If theres no need for splitting cases then it's top end off which is pretty doable. Do you have the manual?
In the latter stages of something similar to what you are talking about and what I did was strip the head and barrel. I'm in Cork so brought them to Murphys Engineers and have them give the head a light skim and hone the barrel as my piston and ring end gap checked out when I measured em. I had previously bought valve stem oil seals so had them install them and decoke the head. They also ground in the valves as per the manual. All in I think it was 150 euro. Very worth while as you've covered a lot of bases there.
Wherever you are there's a place who will do likewise. I like to do as much as I can myself as I like learning new skills but fir me to buy all the kit to do those jobs wouldn't pay me, I why reinvent the wheel?
Based on the jobs you've done so far I'd say your more tha than capable of managing this.
Bang up a rebuild thread! Love to see the project unfold.

Zebbedee

I had an XT600 rebored recently through LME motorcycles in Windy Arbor in Dublin.
I couldn't fault the work.

The guy he uses to do the engineering is a genius.

newmember2

Zebbedee wrote: »

I had an XT600 rebored recently through LME motorcycles in Windy Arbor in Dublin.
I couldn't fault the work.

The guy he uses to do the engineering is a genius.

I'd say Liam uses Loftus Farell in Harold's Cross.
As said, new rings might be all that's needed. What's the mileage on the engine and can you do a compression test?