Willard's vintage Hotsaw Builds

[Willard]

that pipe is a beauty!

I can adjust this pipes 2003 tuning to to my 1983 engine. Ports besides one being case reed are very similar in both engines.
Stock 2003 CR250R is running around 188° exhaust and close to 130° transfers.
I'll have the '83 at 190°/130° so just some minor header pipe adjustment should get her right on.
This brand new FMF fatty went for undet $200 US so price was right.
The 2002-03 CR250s were busting cylinder exhaust flanges big time . No more OEM and aftermarket are getting just as rare. Probably reason why these pipes are getting blow out prices.

 

[Willard]

I will get lots of use from this Chinese Foredom. Price was right and no complaints with how it runs.
All I need for it is a right angle handpiece.

 

[Willard]

So recently I acquired some extra gearing for the CR250.
This 261cc 72 stroke will be making some good top end so this will be the tallest gear I want to put on it.
The little YZ125 will be happy I'm sure with the 12T .404 .063 harvester rim.
Zoom in close to that sprocket and you'll see where my machinist tried to drill mounting holes for the rope spool he's making.
Change of plans the spool will be bolted to the rotor on the mag side.
Good choice I say for cold starting that little pup with a 18" roller bar.

 

[Deets066]

So recently I acquired some extra gearing for the CR250.
This 261cc 72 stroke will be making some good top end so this will be the tallest gear I want to put on it.
The little YZ125 will be happy I'm sure with the 12T .404
Zoom in close to that sprocket and you'll see where my machinist tried to drill mounting holes for the rope spool he's making.
Change of plans the spool will be bolted to the rotor on the mag side.
Good choice I say for cold starting that little pup with a 18" roller bar.

View attachment 254029

One off builds are fun. Time consuming as hell, but fun.

 

[Willard]

One off builds are fun. Time consuming as hell, but fun.

Yes I'm definitely taking my time with these two projects and it's nice to have one to work on if the other gets a bit frustrating.

Hopefully this time next year I'll have run both in a few competitions.
All I can say is "come on winter I'm ready for you!"

 

[Willard]

My machinist making my YZ125 rope pulley today mounted on the Mag side rotor. Milling the knot slots for counter clockwise rotation.

 

[Willard]

All done and back on the work bench

 

[Willard]

The little YZ125 will be in the wood very soon, the Honda CR250 will have to wait as it's a new build.
My machinist did a great job with the YZ's sprocket and rope spool.
I got the PTO side dust seal perfectly centered to the crank on my own.
Still in the plans to have the YZ powerhead to the weight of a 3120XP.

 

[jacob j.]

Looking good, Mr. W...

 

[Willard]

The YZ125 rim sprocket didn't exactly turn out the way it should have.
I originally planned to bolt the starter rope pulley to the sprocket but the sprocket was too hard to drill and tap the 4 mounting holes.
So pulley was mounted to the mag side rotor.
If we originally known that outcome I would have had the rim sprocket's chip exhaust ports facing outwards.
There is 3/16" inch clearance between the rim and crankcase sideplate so exhausting chips should still work some what.

 

[Willard]

Guys never buy a used crankshaft off ebay. I bought 2 last year for the 1983 CR250R and their both junk. Brand new OEM CR250R main bearings both fall off the journals.

I recently bought a PRO-X connecting rod kit thinking I could rebuild my best crankshaft.
Not impressed with the kit and sending it back.

Ordered this NOS OEM 1983 crank tonight. Should have ordered it in the first place last year!

 

[Willard]

My above crankshaft may not be a full circle crank but it has no tin can covers like the '84 and newer Honda cranks.
Plus the '83 design must have been a good one as it's very similar to the very fast '95 TZ 125.

 

[Willard]

Profile foundation on the YZ125 is done, now to carve out to balance the top handle side plates. Then on to fabricating bolting on finishing parts.
Honda will be done also at same time.

 

[Willard]

My welder did a nice job tig welding the YZ125 pipe back together to this mockup profile pic.
I'm making the mounts for him to weld on after this labor day long weekend.
He'll bend the stinger pipe away from the rear handle also.

 

[Willard]

Too many saws jumbled together making a poor picture if you don't look close. Daylight through the window not good either.
Little better house keeping here to make a better mockup pic.

 

[Willard]

I got a little dilemma with making the top handles for these two bikesaws.
Try 10° angle handles like the saws have that I work with every day or go 90° straight like the old Jonsereds I used to use.

Is the 3120XP and MS880 top handles 10° or 90° straight?

 

[Canadian farm boy]

I got a little dilemma with making the top handles for these two bikesaws.
Try 10° angle handles like the saws have that I work with every day or go 90° straight like the old Jonsereds I used to use.

Is the 3120XP and MS880 top handles 10° or 90° straight?

I’d say the MS880 is 90*. I’m not sure about the 3120
(Ignore the ms880 in the top left. It got smacked by a tree)

 

[Willard]

They must be a 90° handle for a reason same with my old 090.
Big wood big bars making square bucking cuts. Heavier bars make the saw side tippy heavy, straight top handle would offer more leverage I'm thinking....

I looked at 3120xp pics and they look straight too, not sure.

 

[Willard]

It's official I now have a third bikesaw project.
This morning I won the auction on Ebay for a 1984 Honda CR500 cylinder, piston and complete reed cage assembly with intake boot manifold.
This engine with a 139mm short rod bottom end and the only year the CR500 had a open oval exhaust port is claimed to be the most powerful CR Honda has ever built.
The works bike was really crazy.

With a modern ignition, carb, pipe and squish tuning 60+ h.p. is easily attainable.
I got my line up covered now
125, 250, 500.

 

[Willard]

Myself thinking we're going for the long haul with the Covid 19 thing, here is the start of my 3rd bikesaw project to keep me occupied.
514 cc 91mm big bore 1984 Honda CR500R . Air cooling fins will be milled off after running in the bottom end bearings and new rings. Will save alot of weight there.
Engine profile will be cylinder leaning ahead like how it is in the bike.
Big heavy engine. No problem getting 60hp at the crank with the right squish, ignition, pipe and carb with porting tweaks.