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Old 03-26-2013, 07:18 AM   #16
dan-c
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Quote:
Originally Posted by supershaft View Post
The oil tank?
All Kaw two-stroke enduros and street bikes were oil injected too. In fact all Jap enduros were.
Since the 60's?
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Old 03-26-2013, 08:30 AM   #17
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Originally Posted by CharlieT View Post
The F81m , which of course came with no lights, had a very small internal flywheel, that is, internal to the coils. Yes the bike was a faster and when it came up on the pipe it was explosive. TO the point it was difficult to ride at times. At the same time I also had an F8 enduro. Working on the bikes one day, we pulled to ignitions off and replaced the F81m's rotor/ignition with the larger, heavier F8 ignition. Remember, this was in the days before flywheel weights.

The heavier weight smoothed out the ferocious hit and though the bike may have been a bit slower, I was actually faster on it. Ended up ordering another complete F8 ignition to leave on the F81m. THe other thing it did was provide the needed lighting coils which enabled me to install barely legal lighting, thus enabling me to ride the F81M in some enduros.

As for rotary valves, as I recall, the Bighorn stayed a rotary, but the 250 changed from rotary to piston port in either '72 or '73.
good info on all counts, charlie... you are correct about the 250/350 differences. the 250 bison was a rotary valve motor for only a couple years before being superseded with a piston port motor, while the 350 bighorn went from being called f5 to f9 but remained a rotary valve intake for the entire span of production.

regarding the flywheel, i had done some digging around on f81 magnetos, and the consensus was that they were generally a drastic difference. the stock flywheel, meanwhile, weighs somewhere around 5 pounds. the klemms shave about a half pound off the outside of them to make things a bit more snappy and to decrease load on the left crank bearing. i'll probably go for that latter route when/if i get around to digging into this motor. for now, the only thing that NEEDS to be done is slap some new clutch plates and discs and springs in and call it good.
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Old 03-26-2013, 12:11 PM   #18
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OK, you made me go dig around in the few photos I have from back in the old days.

Here's the F81M and F8 together;


Notice the additional air intake on the case cover right over the carb. If I recall, we ended up blocking that off as it wasn't as effective as the up top filter....and also significantly lowered the depth of water crossings you could handle.

And here is some young skinny guy () on the F81M



Should have held onto that F81M.
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Old 03-26-2013, 03:17 PM   #19
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wayback machine!

awesome pics, thanks for posting them!

i found the F5 race kit booklet online in the kawasaki singles yahoo group, and noticed the super sketchy modified air "filter" cover. wow. dramatic increase in power coupled with dramatic reduction in top end lifespan, one might surmise...

might have to try and get a chamber rolled up to the race kit specs though.
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Old 03-26-2013, 04:40 PM   #20
supershaft
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Quote:
Originally Posted by dan-c View Post
All Kaw two-stroke enduros and street bikes were oil injected too. In fact all Jap enduros were.
Since the 60's?
Enduros? TM's were injected. At any rate. I think the injection had long since been removed from the ones I remember being around. That or I just never noticed the tanks. I never checked them out otherwise.
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Old 03-26-2013, 05:04 PM   #21
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Also notice on the pic of me on the F81m that there is no silencer on the end of that stinger. And my wife asks me why I have the TV volume up so loud......???????
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Old 03-27-2013, 08:41 AM   #22
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Originally Posted by charliet View Post
also notice on the pic of me on the f81m that there is no silencer on the end of that stinger. And my wife asks me why i have the tv volume up so loud......???????
what? Did you say something?

mtothef screwed with this post 03-27-2013 at 08:42 AM Reason: how dare this format try to reduce my attempt at humor?
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Old 03-31-2013, 08:52 AM   #23
Foot dragger
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Originally Posted by mtothef View Post
i wish. i can't leave well enough alone though... took the beast for a good shakedown ride in the twisties on saturday. clutch slips, parts are already on order. the engine was rebuilt to stock, jetting is close to stock, i think previous owner actually leaned out the main a bit. i did a couple plug chops and things looked okay, but there were a couple moments where i heard some detonation rattle. according to los hermanos Klemm, who have to be THE brain trust on these engines, that is kind of par for the course with these bikes and what passes for gas these days.

aaanyway, the expansion chamber hits pretty bad when you try to go around any corner that isn't a left hand corner. and the bike has no discernible hit. grunty, easy to ride, mellow and fun. feels almost like a four stroke. the itchy part of me wants to pull the top end off, send it to Klemm for some porting and squish mods, then cut the rotary valve, then weld up a proper chamber, then get a slightly bigger carb and jet it for angry riding, then shave a bunch of eight off the flywheel. all of which will probably make it a whole lot faster but also less reliable, and will considerably unweight my bank account.

for now, i'll ride it as it is. it's quirky and fun, and not likely to make me try and do anything heroic. and i need a runner for the time being. at least until the RD moneypit gets finished...
Could run some race gas,trim the rotary disc a little and run it that way for awhile.
I know guys had amazing results back in the day just changing the disc.

Then of course go full boat later.
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Old 04-01-2013, 08:29 AM   #24
bogieboy
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Quote:
Originally Posted by CharlieT View Post
The F81m , which of course came with no lights, had a very small internal flywheel, that is, internal to the coils. Yes the bike was a faster and when it came up on the pipe it was explosive. TO the point it was difficult to ride at times. At the same time I also had an F8 enduro. Working on the bikes one day, we pulled to ignitions off and replaced the F81m's rotor/ignition with the larger, heavier F8 ignition. Remember, this was in the days before flywheel weights.

The heavier weight smoothed out the ferocious hit and though the bike may have been a bit slower, I was actually faster on it. Ended up ordering another complete F8 ignition to leave on the F81m. THe other thing it did was provide the needed lighting coils which enabled me to install barely legal lighting, thus enabling me to ride the F81M in some enduros.

As for rotary valves, as I recall, the Bighorn stayed a rotary, but the 250 changed from rotary to piston port in either '72 or '73.
The 250 enduro switched to piston port with the 73-5 f11...which i happen to have one of in my garage...LOL
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Old 12-10-2013, 09:00 PM   #25
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Bighorn Badass

I was 13 when I first laid eyes on one, I purchased mine for $250.00 fairly well used. I loved on it and rode the shit out of the thing, that was 1984. I had 1 friend on a CR 480, he ran off and left me, another on a new RM250 and another friend on a brand new XR350. Ate those boys up on that old bastard. Sold it that fall. No Suspension, comparably, but horses's that counted when needed, had to be careful on the water crossings, due to the fucked up carb location. An Animal in its day.
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Old 12-10-2013, 11:18 PM   #26
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Neat looking lil smoker!!! You probably know this but in case you didn't,Wattsonville airport has 110 Low lead at 6 bucks a gallon. How's the RD project coming along?? If you need any RD parts shoot me a PM. To say i know a few local RD hoarders would be an understatement.
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Old 12-11-2013, 01:28 PM   #27
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rd from satan's footlocker...

Quote:
Originally Posted by bykpimp View Post
Neat looking lil smoker!!! You probably know this but in case you didn't,Wattsonville airport has 110 Low lead at 6 bucks a gallon. How's the RD project coming along?? If you need any RD parts shoot me a PM. To say i know a few local RD hoarders would be an understatement.
that RD broke my heart. i apparently didn't pay enough attention when i had the gearbox apart, and failed to notice some worn dogs on 4th gear. pops out of gear as soon as any hard load goes onto it. sooo, it has to come apart again. basically stalled out when i discovered that, too many other projects in the hopper. i will tear into it again over the holidays and see if i can get it sorted. otherwise, the ol' beast is looking pretty and mostly rideable (well, aside from not having 4th gear, and also needing to chase down the usual timing and jetting spooks):







oops, sorry for the hijack. back to dual sports, yeah!
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Old 12-11-2013, 05:52 PM   #28
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Super sexy!!! Sorry to hear about the tranny woes. Who's swinger is that? I think the pipes/rearsets may be Moto Carrera? Careful with the right handers with those " GP style " pipes. I ran a pair on one of my RZ's and like my fav' kinna woman..........They go down easy!! Love the vented rear hub as well!!
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Old 12-11-2013, 09:24 PM   #29
flinders_72
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My second bike was a Bighorn. It was like your wrist was connected directly to the rear wheel. You turned the wrist and it just pulled like stink. Awesome torque!

Handling was non-existant.
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Old 12-12-2013, 09:50 AM   #30
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Originally Posted by bykpimp View Post
Super sexy!!! Sorry to hear about the tranny woes. Who's swinger is that? I think the pipes/rearsets may be Moto Carrera? Careful with the right handers with those " GP style " pipes. I ran a pair on one of my RZ's and like my fav' kinna woman..........They go down easy!! Love the vented rear hub as well!!
pipes and rearsets are new moto carrera parts. swingarm is an old motocarrera piece. yeah, the pipes hang low on the right, but aren't too bad. the rear end ride height is substantially jacked up from stock (increased shock length to get the head angle more toward td3 geo, instead of the more commonly practiced head angle chop), so there is a bit more ground clearance, and the pipes took a fair bit of creative denting ti fit as close as possible together. it is still not ever gonna be able to wear the right edges off the tires, but it isn't terrible.
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