Willard's vintage Hotsaw Builds

[Bigmac]

Not trying to cluster your thread, here Is the 500 hill climb motor porting pics
BeforeAfter before
After

 

[Bigmac]

And the bike and pipe

 

[Willard]

Awesome pics, love the gnarly cone pipe.
Here's a CR500 hotsaw, DC built I believe or is it a 1984 CR250R?
Its head stud design looks like my '83 CR250R head and cylinder pictured here (mini CR500 ?)

 

[Bigmac]

It’s not a 500, could be a fl400 pitot motor

 

[Willard]

It’s not a 500, could be a fl400 pitot motor

Interesting motor from 1989 or abouts I see.

 

[Bigmac]

Interesting motor from 1989 or abouts I see.

Ya they are kinda rare, I assembled one a few years ago and had to get parts was difficult, crank bearings were weird and had to get them from the uk, and they were over $100! Seals were a pain too. There is a lot of potential in the cylinder, packard racing used to have a pilot cylinder r that was nasty fast back in the 90’s, the rotax 800 twin cylinder motor was a popular swap before all these new cylinders came out, 430cc pumas cam make some power and have the trx pattern, but still take a lot of work!
Word on the street is the linger cylinder for the 500 was developed for a pilot owner that had put a 500 cylinder on this pilot, pilots have the same Stroke a a 500, and its common-ish to do the 500 cylinder. So he paid cp to build that cylinder, or that’s what I heard

 

[Willard]

Yep that old engine looks old school up against the new billet engines out there now.

The fascination of the old TRX/CR250R is now carried on without the input of Honda which is becoming a specialized new and improved industry.

Kind of relates to the premier Stihl Timbersports ....they discontinued a super fast .404 high tooth chain and reduce the diameter of the competition log due to crazy high horse power capabilities now .
But now operated by more and more operators who can't handle them.

With the size of wood now with the reins pulled back a little a guy doesn't need a 60 horse plus hotsaw. 10 hp plus less power and a good chain will get more competitors qualifying.
Just the way it is.

 

[Billy Currie]

I would be of little help with suggesting horse power gains of a build this type. However, I can certainly tell you, when you get ready to cut the carbon fiber sheet, you need to have a good respirator and good eye protection. A dust mask is not sufficient.

 

[Willard]

I would be of little help with suggesting horse power gains of a build this type. However, I can certainly tell you, when you get ready to cut the carbon fiber sheet, you need to have a good respirator and good eye protection. A dust mask is not sufficient.

Sorry for the late reply guys. I lost my phone for the last 4 days while away down in the big city. Thought I lost it at the airport parking lot last week but found it on the floor when I got home tonight. Talk about relief and happiness!!!

Yup I got a dual canister respirator and a 5 hp shop vac hooked up to my scroll saw and sander with a high efficiency filter inside.
Googles and disposable paper coveralls also ready for the carbon fiber.

 

[Bigmac]

Glad you found you phone! That is a helpless feeling!


It’s not completely relevant here, but I Did find some cr/trx interchange info. Looks like 84-91 cases will accept a trx cylinder, the 84 is messy but will fit, the 85-86 are ideal and 87-89 will fit but have a case relief for an intake boost port, do not ideal. The 90-91 look like a good fit too, the k+s brand base gasket will fit 85-91. I

 

[Willard]

Just about ready to fit the carbon fiber sideplates. Doing both saw builds at the same time has its challenges.
If it wasn't for the CR250R's long stroke the YZ125 looks bigger in proportion.
Slabbed up a little down draft table...pylon, 2×4, expanded metal and a 5 hp Ridgid vac.

 

[Steve]

Just about ready to fit the carbon fiber sideplates. Doing both saw builds at the same time has its challenges.
If it wasn't for the CR250R's long stroke the YZ125 looks bigger in proportion.
Slabbed up a little down draft table...pylon, 2×4, expanded metal and a 5 hp Ridgid vac.
View attachment 212358 View attachment 212359

I like that table!

 

[Billy Currie]

That down draft table should be perfect!

 

[Willard]

That down draft table should be perfect!

It's just the right size for the motors when I'm sanding grinding whatever.
Should work good for spray painting parts too but probably better to install a dry wall dust bag to backup the expensive filter I put in it.

 

[Willard]

Cutting 5mm carbon fiber wears out metal cutting jig saw blades like cutting with your chainsaw in sand.
Bought a diamond composite blade and works really good. Good clean cuts. Couldn't wear it out.

 

[Steve]

It's just the right size for the motors when I'm sanding grinding whatever.
Should work good for spray painting parts too but probably better to install a dry wall dust bag to backup the expensive filter I put in it.

I would be careful spray painting with it. Hate for the sparks in the vacuum motor to ignite the aerosol. Would be a pretty cool flame thrower though?

 

[Willard]

Thanks, good point Steve. I'll have to do a little more research on that.
Seeing the vac motor is external best to leave the vac outside, run the hose with extension into the shop.
I'm worried sucking grinder sparks into the vacuum so making sure paper or other burnables aren't in there.

 

[Willard]

Only problem putting the vacuum outside is it's -33 below outside and dropping.

 

[Willard]

Things are finally taking shape with the CR250R and YZ125.
Engines are now hiding behind their unfinished sideplates held on with titanium fasteners.
The top handle support profiles will be cut when everything is put together with bar/chain's installed and fuel/oil tanks are filled. Then I'll know where my final balance points will be by hanging them from the rafters.

Next is to build both saws aluminum fuel tanks with built in oil tanks. These tanks will also have sideplates to attach to the carbon fiber pto sideplate . The mag side aluminum tank side plate with be the other top handle support. The 7/8" aluminum 6061 rounds will be the top handles. One end bolted to the CF support and the other end welded.

The rear handle will need lots of sanding to get to my preferred profile. A buddy of mine who makes custom knives has an idea to make some exotic wood pistol grips for both rear handles.
A full length 20" long 1.5" wide 6061 chain / chip guard will cover from over the sprocket curving down to the back bottom of the rear handle to give it more support plus act as a hand guard.
From under the cylinder head to the end of the rear handle will be another guard with a curled up lip to aid in leg support for doing up cuts.
I'll stay tuned.

 

[Bigmac]

Looking good! How did your dust collection go?