1974 Kawasaki F7 175 Info Please...

Discussion in '2 smokers' started by Kelly_O, Feb 18, 2012.

  1. Kelly_O

    Kelly_O Been here awhile

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    I'm buying an old F7 for the wife to learn on. I don't have any sort of manual for the bike and haven't been able to find much info online. I need to know what to put in the oil injection tank. And how much of what should we put in the crank case? What spark plug? I'll be ordering a Clymer's shop manual for it, but we'd like to get the bike fired up. Any suggestions for locating parts for Ol' Blue? Thanks, Kelly.
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  2. JeffS77

    JeffS77 cheap bastard

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    injector oil in the tank. there is no oil in the crank case the oil is in the transmission..it is a two stroke..as for the tranny just about anything would work some 10/30 motorcycle oil would be fine..plug is probably a B7 to B9ES..what does it have now ?
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  3. Kelly_O

    Kelly_O Been here awhile

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    Thanks for getting back to me, Jeff. I haven't taken delivery of the bike yet, so I don't know what type of spark plug is in it. I haven't owned a 2 stroke for about 30 years. There isn't ANY oil in the crank case? This'll be a relearning exercise for me. I'll track down some sort of manual for it this morning. Thanks again, Kelly.
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  4. Shocktower

    Shocktower Long timer

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    Questions how long has the bike been sitting ?, as far as the injector drain the tank (oil tank) and put injector speific oil in it, not premix,
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  5. Kelly_O

    Kelly_O Been here awhile

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    The bike hasn't been registered since the mid 90's, but it's been ridden a few times on camping trips over the past 6 years. I saw it running about 2 years ago. As far as I know, it needs a good clean-up and a basic tune-up. The fork seals are also smoked. Those are still available. Thanks for your consideration, Kelly.
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  6. JeffS77

    JeffS77 cheap bastard

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    I may have been too literal or technical..but the crank/rod/piston is all lubed by the the gas/oil mixture coming in the intake.

    http://www.animatedengines.com/twostroke.html

    the oil in the "case" is just in the transmission half...thus when a crank seal goes out on a two stroke it starts sucking in the tranny oil and smoking very heavy..and if you run the 80wt tranny oil like i do in my older bikes the smoke has a more distinctive smell then the injector/premix oil.
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  7. lake_harley

    lake_harley Been here awhile

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    For what it's worth.....recently I bought three F7 175 Kawasakis. Two have titles and the other is a parts bike. I forget which is which, but they're all '74 and '75 models if I recall correctly. So......should you need any parts there's a chance I'd have something you need. Feel free to post other questions if you have any, since I have an actual Kawasaki manual for the F7 as well as some of their other "enduro" bikes.

    I got the nicest one running of my three, and intend to sell it when the weather gets a little bit nicer. The 2nd one with a title, is in process of re-assembly in sort of a "street-tracker" style. I plan to ride it for a while.

    Best wishes with your bike.

    Lynn
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  8. Kelly_O

    Kelly_O Been here awhile

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    It seems as though the intake charge should all get burned in the combustion process, and the bottom end would be out of luck as far as lubrication.

    Ah, the pleasant aroma of gear oil. That takes me back to my '72 Norton. Thank You, Kelly.
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  9. Kelly_O

    Kelly_O Been here awhile

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    Thanks Lynn. I ordered a Clymer's manual a few minutes ago. The battery on the bike is dead. I know the bike NEEDS to have a battery installed, but do I need a working battery? Isn't it basically a "current sink" in this application? I may need a factory front fender at some time in the future. Would you have one to sell? Thanks again, Kelly.
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  10. MacNoob

    MacNoob piney fresh

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    No, the oily intake charge goes to the bottom end FIRST - then transfers from the crankcase to the combustion chamber.
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  11. Kelly_O

    Kelly_O Been here awhile

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    I'm BUSTED! I had no idea how a 2 stroke engine worked. Jeff's animation cleared it up. Thanks Jeff. That explains why the carb on the F7 is buried inside the cases. Thanks guys, Kelly.
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  12. JeffS77

    JeffS77 cheap bastard

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    Actually the carb is off the side of the case because it has a rotary valve intake..and not the more common reed valve or piston port.....but thats a whole nother thang.

    http://www.freeengineinfo.com/two-stroke-induction-1.htm
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  13. Kelly_O

    Kelly_O Been here awhile

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    Damn straight, it's a nuther thang. I'd wondered WTF a rotary valve was all about. Thank Jeff. I'm enjoying 2 stroke 101, Kelly.
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  14. lake_harley

    lake_harley Been here awhile

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    I may have a front fender, but I don't think it's "show quality". I'll try to remember to see what I have and send you a PM.

    As far as having a battery....my understanding is that they'll run without one but it'll burn up the ignition module or something. Sorry for the lack of specific info.....just part of a memory of something I read.

    Lynn
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  15. lake_harley

    lake_harley Been here awhile

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    Ah, rotary valve! The one of three of the bikes I got running would start and kinda idle when I first tried it, but it would spit back through the carb if you tried to rev it. Finally took a good look at the rotary valve's opening and closing, with relation to the direction of piston travel and position. I had been told the valve was replaced, and sure enough it was off by about 180 degrees. Actually the Kawasaki manual seemed a bit unclear/vague about what mark(s) to use to "time" it. Finally decided on a position that seemed close to the degrees of opening and closing according to the manual. Movements, spline to spline, are quite a few degrees at a time because of the relatively course splines on the crank where the rotary valve slides on. Must have gotten it good. Bike ran when I got it back together:D Honestly I don't know how the bike even started before I re-timed the rotary valve. It was open on the piston downstroke.

    To say the valve is a job to get to is an understatement. About all that was left to do yet was split the cases. Even had to make a special tool to hold the clutch basket to remove the nut that retains it on the trans input shaft.

    Lynn .
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  16. Shocktower

    Shocktower Long timer

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    Hey ya know what would help some of the n00bs is you guy's post some of this info here :evil
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  17. Euromad

    Euromad Been here awhile

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    I have a donor '74 175 and a running '73 175. What do you want to know?
    Here's a brief overview:
    -Kawasakis were the main user of the rotary valve engine of the Japanese bikes but CanAm's used them with great success.
    -My Clymer lists 80-350cc models from '66 t0 '94

    -The rotary valve opens to allow the fuel mix into the crank cavity and then closes until the down stroke is complete. Thios keeps the charge in the crank instead of spitting back through the carb.
    For early two strokes this was a great way to broaden the powerband. The exhaust pipes didn't use the exhaust pulses to scavenge the spent exhaust very well. If you look at a modern two stroke pipe it is fat and thin in different areas to make the best use of this exhaust pulsing to suck the spent gases out of the cylinder.

    Yamaha used reed valves for a similar effect. The flexible reed opens when the engine sucks in the fuel mixture and closes when the exhaust back pressure pushes back. It's located in between the carb and cylinder.
    The reed valve works best for increasing the low end power and becomes useless at higher rpms as it stays open.
    The main disadvantages of the rotary valve are complexity, and increased case width.
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  18. lake_harley

    lake_harley Been here awhile

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    Would it then be inaccurate to think that a rotary valve engine (F7) wouldn't benefit as much from a "performance" expansion chamber as a reed valve or port timed engine? I want to build a low mount expansion chamber for my "street tracker" 175 instead of the high mount stock pipe, but really don't know the first thing about expansion chamber design. I wouldn't want to build something that looked pleasing but it actually hurt performance/power. Then again, I'm not looking to squeeze the last bit of power from the otherwise stock, almost 40 year old engine either.

    Lynn
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  19. JeffS77

    JeffS77 cheap bastard

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  20. Kelly_O

    Kelly_O Been here awhile

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    Oh, I get it. Jeff the Instigator! How the hell am I going to keep Tracy happy with her stock exhaust if she knows there are expansion chambers for her F7?
    #20