1971 Kaw F8 Bison 250 goin' down.

runmikeyrun

New Member
Well. Finally scored one of these. I've been looking for years for either the 250 or 350 (F5/F9). Why?

Back in the day my dad had a 350. Sold it after a few years to a guy. Fast forward to when I was 12 (late 80s) and dad bumps into said guy. Guy sells the bike back to him, which has been sitting almost since my dad sold it to him. My dad rebuilds the bike in our basement that year. I watch and I'm hooked! At 17 I bought my great uncle's RD250 and promptly restored it a couple years later. I've been a vintage bike nut ever since.

About the project: the bike is an oil injected two stroke. instead of going for a full restore my goal is to have a reliable and safe machine with the current "patina" that it has. The tank and fenders are straight and while there's some of the usual scrapes, surface rust, tears in the seat cover etc its in pretty good overall shape for a bike that's 45 years old. Besides I'm already balls deep in a cb350 frame off and two full restorations at the same time would be too much. One good thing about the Ohio winter: lots of time to build.

I'll be working in two phases.

Phase one includes getting it on the road before the Ohio winter. Amazingly, the tank is spotless inside and it runs pretty strong! Shifts nicely too. So some quick safety upgrades are in order so I don't immediately die- check/clean brakes, replace tubes in tires, lube cables, fix trans oil leak, replace the crusty chain. The petcock leaks like crazy. Needs some bits to get back to street legal too: gauges, head/tail light, signals etc. It never ceases to amaze me the number of people who strip enduros of all these things! Just buy a dirt bike. Also, it needs a title so I'm working quickly to get the paperwork to Vermont BMV.

Phase two (next year) is a motor tear down for new gaskets, seals, clutch plates, etc. Electrical upgrade (modern ignition and addition of regulator) and new tires. The tires are workable in phase one and putting around town but for the sake of longevity they need replaced. I'll probably replace all the control cables, fork seals, brake shoes, etc. Wiring needs TLC. Shocks are stock units and suck bad.

At some point I'd like to swap the 250 cylinder and piston for the 350. From what I've read the bottom ends and most of the rest of the two bikes are the same. The 250 makes ~23 hp, the 350 ~34 hp. Kind of a no-brainer. I'll probably do this when I tear down the motor.

I decided to name her Buzz Bomb. She actually has a deep grunt for a two stroke but still retains the buzzy quality they all have.

I'll post updates as I make progress!

Bike as she sits fresh after delivery- the beginning!
 

runmikeyrun

New Member
jimmer said:
I hope you keep the stock tank/seat combo with the original patina! Cool bike.
Yes, absolutely am! People pay money to have their bikes relic'd like this.

Update: coincidence or fate that I start vacation a week after getting the bike?



Tore into a couple things today. First, I sent the bill of sale and DMV paperwork to Vermont to get a registration so I can get an Ohio title.

Second, wanted to start addressing some issues and get the ball rolling on parts. Ordered a battery, petcock and gauges online. The Local vintage Kawasaki shop had a few items in stock- tail light lens, engine seals, and a chain. I'm glad I bought a chain for one extra reason that I found when I got home:



Seems as though a previous owner thought metal spade connectors would make good master link clips. God, that would have ended poorly!

There's a transmission oil leak and a little investigation revealed it was coming from the clutch side cover. Wouldn't you know, the bolts were loose. Tightened those up, we'll see if it will address it enough until I tear down the motor. While I was over there I inspected the carburetor which is under this cover:



Everything was ok. Replaced the fuel line while I was in there. There's a plug missing that I'll have to find, because that's a direct line of unfiltered air to the engine!

Speaking of unfiltered air- the air filter element was long gone, so I oiled a piece of filter foam and wrapped the expanded metal cone. I'm not sure how the bike was running, some doofus had installed the air cleaner lid so that it sealed the air cleaner assembly!



The tail light socket is crusty because it's been missing a lens and bulb for who knows how long.


So I picked up a new center contact and will be installing that. I couldn't find any 6v tail light bulbs locally, so I'll have to order some.

That's it for the moment, more to come!
 

jimmer

New Member
Get on amazon.com and buy a 12$ JT countershaft sprocket for that new chain. I'm sure it needs a rear too. You are getting things done! Have a great and safe vacation.
 

runmikeyrun

New Member
I think that's a great idea. They look ok, bike's odometer says just under 3,000 miles. But yes, I think sprockets are a solid idea
 

runmikeyrun

New Member
The tail light lens is reproduction, looks kinda funny all brand new and stuff. Maybe I should hit it with a scotchbrite pad? Lol

 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
runmikeyrun said:
The tail light lens is reproduction, looks kinda funny all brand new and stuff. Maybe I should hit it with a scotchbrite pad? Lol

Just throw it on the ground a couple times, that's the look I'm going with on the XL

JT is pretty good about getting you sprockets that will work, if they don't have your model just grab the measurements they show on the website and call them up. You can get em cheap if you shop around, I found the best prices for front and rear on eBay.


Sent from my iPhone using DO THE TON
 

runmikeyrun

New Member
Back from vacation. I actually dreamed about working on the bike while I was away. Two nights in a row.

Psychological issues aside, I got down to some stuff today. I was smart enough to order a bunch of stuff before I left so I had some parts waiting for me. I replaced the mangled gauges with some eBay units.

The new gauges came with the dash lights, which was nice because mine were corroded to all hell. Stuck them inside some loom.

Also lubed the cables and replaced a broken brake lever. One of those fancy upside down units...

Speedo cable is shot. Adding that and some gauge light bulbs to the list.

Found the source of my oil leak wasn't just a loose clutch cover. Seems the shift shaft runs all the way through to the right side of the motor and out of the clutch cover. The only reason I can think of this would be flat track, moving the shifter to the right side and removing the rear brake. I've never seen anything like it before. Anyways, the seal is shot so it's going on the list.
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Interesting setup with the shifter spline. Never seen that before either. Going to be able to save those forks?
 
A few early Japanese bikes had gear change shafts like that so that the gear change could be on either side for different markets, the rear drum is usually on a cable as well so that it can be either side.
 

runmikeyrun

New Member
julian.allard66 said:
A few early Japanese bikes had gear change shafts like that so that the gear change could be on either side for different markets, the rear drum is usually on a cable as well so that it can be either side.
Makes sense!
 

runmikeyrun

New Member
No photos, but I pulled off the front wheel. The front brakes and drum look good, reassembled and adjusted. I left the fork oil alone; I am going to do the seals at a later date and I will change it then.

Done for the day. Waiting on a petcock and battery and I need to find a headlight and signals as well.
 

runmikeyrun

New Member
Not too much today. Put on the new petcock (heh heh) and since the screen doesn't fit in the tank I installed an inline filter. I forget if it was Klemm's vintage or Junkman adv that had a link to the right petcock. Anyways, it's a Biker's Choice chrome petcock for HD #011411 so I'm pretty sure it made my bike louder and lose 10 horsepower . I also rinsed the inside out thoroughly as there was quite a bit of rust on the old petcock screen.


Painted my recycled chrome turn signals with some plastidip. I love this stuff.


Horn was weak at best, so I checked the switch and it was crustified. Sanded the terminals and spring and now works great.


Ordered some headlight bucket ears, a 6v halogen bulb which I will Frankenstein into the existing sealed beam headlamp, and I'm working on clutch cover items- cover gasket and shift shaft/Kickstarter seals. Oil leak was too bad to continue. Will replace clutch discs and springs while I'm in there too, if I can find replacements. I'm finding that there aren't many parts left out there for these.
 

runmikeyrun

New Member
Tried to replace the crusty tube inside the 45 year old front tire today. Tire itself was ok enough to ride out the last of the season but I at least wanted to have legit tubes in there. Well the tires are as hard as you can imagine and the iron slipped, smashing my finger into the end of the axle. As soon as I finished throwing the tire irons and swearing I broke down and ordered two new tires and tubes. I will let a shop handle the swap!


On a positive note, all turn signals are installed and working.
 
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