1967 Yamaha DS-5 250cc Rebuild

Always wear old close fitting clothes when polishing, don't let anything get caught by the wheel.

Did a bit more today. Zinc plated some small bits and fitted them, polished and fitted the second hand guard I bought.

Will have to leave it for a while now to fix a few other things that need some attention.

 

Have started on the engine rebuild. The cases came apart easily enough.
The generator/starter rotor gave a bit of trouble getting off. I snapped off the 8mm bolt being used as a puller (Oh shite) leaving the threaded bit still inside the rotor.

Using my left handed drills I was able to get the broken bit out. I tried again with a new bolt and it pulled the thread out. I re tapped to 3/8th Whitworth as this is a 'deeper' thread and finally it let go.

There has been a bit of moisture in the bottom end at some stage and had to replace all the main bearings.

The gear shaft bearings were good, just took them out to bead blast the cases and put them back when clean.



The chain had been thrown and damaged the cases, so a bit of weld was needed to repair that.
The kick start and gear shift shafts had been 'chewed' on the splines and the levers arc welded to them.

I cut them off to get the shafts out of the cases. I built up the worn areas with the mig welder, ground the rough bits off and trimmed them round in the lathe.

Then to respline I locked the chuck with the back gears and turned a suitably ground tool 90 degrees and moved the carriage back and forth along the lathe bed to slowly scrape a spline. It is a slow process but it saves buying a many thousand dollar machine or paying through the nose for someone else to do it.

Two done, many to go.

A clean up with a file when they are finished and it will be ready for another 40 years service.

 

Thanks fellas. Yep big job but doing a bit each day will get me there in the end.
Blair, bought from Repro Decals in Canada.

 

Finished the spline work today. I cleaned the burrs off the splines with a triangular file and wire brushed them.

Fitted up the gear lever just lovely.

 

Another 40 years maybe?

 

Started on putting the cases together (bit distracted after ST1100 BBQ) but had a binding issue. Pulled apart again today and found I had a shim on wrong side of a circlip. Fitted to right side and all turns freely and selects all gears.
Loctited the bolt that Risky said he had trouble with. If get time tomorrow will be fitting clutch and ignition.

 

Today got the side cases painted and fitted.

Found one broken brush in the generator, others still have plenty of life yet.

Had some brushes from an Ozito angle grinder that I wore out a when I was building racing cars, and with a bit of sanding and soldering was able to fit it.


Now the young ones will be wondering why I bother with all this 'old ****'. Well, its because I CAN FIX IT. I don't know how to fix an injection computer or electronic ignition, but I can set points and clean carbs (they are things that make old engines go).

 

Been doing a bit the last few days. Have engine fitted, timed, carbs set, oil pump primed, new chain, new plugs, cables fitted and adjusted, wiring complete, oil in gearbox and oil tank, cleaned and fitted pipes and welded broken baffle.
Waiting now on fuel tap and tank badges from yankland. Need to buy a battery next week.
Nearly ready for the Blue Ribbon show.