1979 WR 250

I started getting the materials together to fix the egg shaped holes in a few of my Husqvarnas. I bought a 7/8" diamond hole saw with a pilot. I have some 1/4" steel plate left over from a motor mount project. I am making guide plates by spotting the guide plate from an identical frame using common locating holes to mount the plate to the frame. Drill the pilot hole in the steel plate. Then bolt the guide plate to the inside of the frame you need to repair. My intent is to cut the hole to find the actual size the diamond hole saw will cut. Then make hardened repair washers to fit the hole size and tack weld to check pivot fit before completing the weld. I got a quantity of 1" round A2 tool steel that can be turned and bored to fit and then be heat treated and drawn to 40 - 45 Rc to match the Husqvarna heat treat more accurately.

That husqvarna heat treat on those mounts is no joke. I put together some guide plates, then drilled M6 holes in the mounts to bolt the guide plates in. My M6 bit took two sharpenings to finish the 4 holes needed. The guide plates where then matched and drilled based on approximate hole centers on the oblong mounts (no 'other bike' of a similar year to compare to),I picked up one of those step-up bits with the idea that you step up until the entire edge of my hole is fresh, and promptly dulled the hell out of it without finishing one side. My left side will be round at M14 (probably could be at M13, but M12-M14 bushings are fairly common, where-as M12-M13 is a bit thin). Right side will probably need to go to M15 or M16. I will need to find better drill bits to do it with though, as the step-up bit is basically a joke.

do you sharpen your own bits? use lube?

I do throw on some light oil.
As far as the M6, I did sharpen it myself on my bench grider (the grinder has a slot for drill bit alignment/sharpening). Not exactly something I'm good at, but good enough to get the bit back cutting after it rounds off.

Try Champion drill bits they have been good quality for me and they sharpen better than any big box store brand. Believe or not try using water when drilling holes it cleans up easy and if your gonna be painting there's no oily stuff all over to clean before paint.

The swedes were the first to invent chrome moly steels. My dad being a prototype and repair machinest preferred the Swedish quality steels. I believe they also invented the electric furnaces to use in there foundries too. Every steel manufacturer followed soon after.

Verticle lines in a cylinder tells me that dirt got into the cylinder through a bad air cleaner possibly or in through the base gasket?

I restore tractors and I change every headgasket when I first get them home. Every scored cylinder I see I check the air cleaner and it's bad or missing. I add a new aircleaner plus the foam pre cleaner.

Every running bike I had which is very few in the past that crank seal on the tranny side or base gasket bites me sooner or later. So on every purchase I fight the desire to ride it and do the engine up with seals, crankbearings, gaskets don't forget a new air cleaner. Don't become a victim. Then we ride......

we use champion bits at work quite a bit. im not sure if they are good or not, as thats all we use..but sometimes i will get quite a few holes before resharpening. we drill quite a bit at work, i was surprised there is something of an art to it...along with sharpening them!

make sure its actual tapping/drilling oil..sometimes a good oil will make it tough to drill. my favorite is "tap magic"...there is defi itely an art to sharpening bits. too aggressive and they cut fast and chip, not enough and they wont cut. one day it will click and you will be bit sharpen champ. the key for me is to have a nice freshly dressed, flat stone on the grinder. if not, you are wasting time.

The best type of drill for drilling the frame is carbide first, Mo Max Cobalt second, The step drill being high speed steel will likely melt as the Husqvarna hea treat in 4130 Chrome Moly would likely fall in the range of 38Rc. That is why I bought a diamond hole saw in Ø7/8" and running as slow as I can drive it

Carbide drill? I have carbide drills that can drill out broken taps too.

I do have a full set of gaskets, seals and bearings for it. Not much bench space in the garage right now, so have been putting off the engine work.

I don't remember the brand, but my Metric bits are HSS (was a fairly pricey set to be honest), so sounds like I need to pick up something different. Admittedly my grinder's stone is a bit unbalanced, so that doesn't help on the sharpening bits piece. I could make it easier on myself and go with SAE sizing and get my old man to machine the bushings. Thanks for all of the background info on metals.

Note, if anyone is using tin coated drills keep them lubed with oil. They work great but lose the coating quickly. I keep the old Morse tapered drills with a straight shank to tapered adapter to hold them in my triple gear reduction craftsman 1/2" drill.

When tightening larger drills in a 1/2" chuck (includes silver & demoing too) tighten all three holes on the chuck with the chuck key. Make sure it's tight.

It is exceedingly rare that I put any drill in the Chuck without tightening all 3 holes.

Well, using .5mm step-ups with my HSS bits I've gotten both sides to 13mm (biggest HSS metric bit I've got). I remain certain that 14mm will be a clean hole on the left side. Right side will still need to go larger. Making slow work (oil, drill, cool, repeat), but I'll get there. Of course, there are only about 500 more challenges on this build.

Unrelated question, anyone have a good source for master links? I bought one off of Amazon and it doesn't fit right (on my '85).

Finally got the motor mounts drilled to my satisfaction. Melted the cutting edge on the step bits so finally gave up on them amd picked up some larger HSS bits. Plenty of oil, light pressure, pausing to cool, etc.
Looking over my parts to figure out what I need to pick up (or work with a machinist on) and noticed this:

I don't get the impression that the guy I picked the bike up from had any intention of looking too closely at things like suspension if he had gotten it going, so I'm thinking he may be lucky that he did not....

Frozen swing arm bearings or loose swing arm bolt?

keep in mind that I drilled out the motor mounts due to them being out of round. I would guess the bolt was loose. I haven't noticed the swing arm bearings being frozen at all. One of them moves a bit freely end-to-end. I'm hoping the sleeve is a bit worn, once I get a new one in, if it still moves around a bit I've heard that the inner surface can be knurled a bit to achieve a better fit. Otherwise I'll be looking for a replacement swingarm.

Good to hear! Sounds like you nearly had to resort to "persuasion."

My old man was visiting (for the first clamp and burn session), if I had played my cards a little better I think he might have picked up an oxy-acetylene torch for my garage. He really wanted to see that frame straight.