1975 Kawasaki F11 - Fork Oil Quantity - Kawasaki Motorcycle Forums
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post #1 of 8 (permalink) Old 05-15-2016, 04:31 PM Thread Starter
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1975 Kawasaki F11 - Fork Oil Quantity

Hello All.

i'm replacing the seals and doing general fork maintenance on a F11 i recently picked up.

it has a Hatta fork, but i don't think it's the original F11 fork. So, when i replace the oil, i don't want to rely on what the manual says for quantity.

is there a general rule of thumb for figuring out fork oil quantity in these older forks if it is unknown?
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post #2 of 8 (permalink) Old 05-15-2016, 08:33 PM
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You are correct the Hatta forks DID NOT come on the F11 from the factory. However the F11 "stock" forks are nearly identical in terms of the internals and fork tubes sans the 3 position pre-load adjuster fork caps. The Hatta's that came stock on the F8, F81M, F5, F9. As a matter of fact the later Hatta (F9) forks did not have the 2 (3 when the lower fork leg is flipped) position axle mounting, but still retained the 3 position pre-load adjuster. However because the inner fork tube and lower leg axle mountings are the same the forks from the aforementioned bikes fit your F11 as well as other bikes from other brands that use the same inner tube diameter.

Just to be clear for others that may stumble onto this thread the Hatta forks found on the F7 (175) are a different size (smaller) but function and have the same type of internals.

Anyways to answer your question. 175cc of oil is standard but you can alter that 5cc's more or less for slightly different damping action. One thing I would have done when you had them apart is to better chamfer the oil passages in the damper rod to aid in oil flow and reduce the tendency to hydraulic lock when the forks are moving fast in the stroke. OR even better yet put some cartridge emulators from Race Tech in them. This is one of the best mods you can do to these old conventional forks.
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post #3 of 8 (permalink) Old 05-16-2016, 04:47 PM Thread Starter
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Thanks Junkman! Exactly what i needed...the fork is still dis-assembled, so i can still chamfer those damper holes.

And yes, the non-stock HATTA fork on this F11 is exactly the same as the fork on my F7, except this one is larger (the inner tubes are a larger diameter).

Speaking of which, i'd like to replace at least one (or even both) of chromed inner tubes for this F11 fork...off the top of your head, do you know a few of the non-Kawasaki bikes that used this HATTA fork (so i can broaden my search a bit)?
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post #4 of 8 (permalink) Old 05-16-2016, 05:18 PM Thread Starter
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Also Junkman...can you tell me what RT emulators will work with this fork? I'm coming up a little short finding proper fitment info.

thanks!
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post #5 of 8 (permalink) Old 05-16-2016, 05:32 PM
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I do not know what other makes of bikes use the exact same tubes, if any. Only Kawasaki used HATTA forks from the factory.
Here is a list of bikes that use the exact same fork seal and thus the triple clamp mounting would work, in this case 34mm forks are the same across other makes and models but this would not necessarily mean the tubes were interchangeable as the internals might be different. For instance the overall length, damper rod length or retention might be different. However you could buy a pair of used forks from this list and see if they measure up identically. It is quite possible some might as various parts like this were made by a third party and sold/bought buy all the manufacturers. Similarly like today where KYB and Showa build most of the forks for the manufacturers with only subtle differences in internals.

Your best option is to just have or originals repaired and re-chromed. It doesn't really cost that much compared to hunting for suitable used ones which could take time. Just call up a few chroming places and ship/drop them off. I will only be a couple hundred dollars and will protect those fork seals and with a new smooth sliding surface they will work a lot better with less stiction.

A word to the wise on chamfering the holes, do not make the hole bigger, all you are looking to do is eliminate any "burs" from manufacturing, a set of my F9 forks had strings of metal from the machining process still attached when they drilled the hole, as well as making a smother transition rather than the 90 degree bend the oil has to move around.

Race Tech Emulators, if you have questions about them give them a call http://racetech.com/ProductSearch/1/...11B%20250/1975

Seal size 34mm x 46mm x 10.5mm

Kawasaki
1975 Kawasaki F11 250
1974 Kawasaki F11 250
1973 Kawasaki F11 250
1973 Kawasaki F12-MX 450
1971 Kawasaki F5 350 Bighorn
1970 Kawasaki F5 350 Bighorn
1972 Kawasaki F8 250 Enduro
1971 Kawasaki F8 250 Enduro
1971 Kawasaki F81M 250
1975 Kawasaki F9 350
1974 Kawasaki F9 350
1973 Kawasaki F9 350
1972 Kawasaki F9 350
1973 Kawasaki H1 500 Mach III
1971 Kawasaki H1 500 Mach III
1970 Kawasaki H1 500 Mach III
1969 Kawasaki H1 500 Mach III
1978 Kawasaki KH400A
1977 Kawasaki KH400A
1976 Kawasaki KH400A
1976 Kawasaki KT250
1975 Kawasaki KT250
1974 Kawasaki KX450
1975 Kawasaki S3 Mach II
1974 Kawasaki S3 Mach II
Suzuki
1973 Suzuki TM250 Champion
1972 Suzuki TM250 Champion
1972 Suzuki TM400 Cyclone
1976 Suzuki TS250
1975 Suzuki TS250
1974 Suzuki TS250
1973 Suzuki TS250
1977 Suzuki TS400 Apache
1976 Suzuki TS400 Apache
1975 Suzuki TS400 Apache
1974 Suzuki TS400 Apache
1973 Suzuki TS400 Apache
1972 Suzuki TS400 Apache
Yamaha
1971 Yamaha DS7
1971 Yamaha DT1 Enduro 250
1970 Yamaha DT1 Enduro 250
1969 Yamaha DT1 Enduro 250
1968 Yamaha DT1 Enduro 250
1970 Yamaha DT1C-MX
1971 Yamaha DT1MX
1969 Yamaha DT1S
1979 Yamaha DT250
1978 Yamaha DT250
1977 Yamaha DT250
1976 Yamaha DT250
1975 Yamaha DT250
1974 Yamaha DT250
1972 Yamaha DT2MX
1974 Yamaha DT360
1978 Yamaha DT400
1977 Yamaha DT400
1976 Yamaha DT400
1975 Yamaha DT400
1975 Yamaha MX250
1974 Yamaha MX250
1973 Yamaha MX250
1974 Yamaha MX360
1973 Yamaha MX360
1975 Yamaha MX400
1975 Yamaha RD250
1974 Yamaha RD250
1973 Yamaha RD250
1975 Yamaha RD350
1974 Yamaha RD350
1973 Yamaha RD350
1978 Yamaha RD400
1977 Yamaha RD400
1976 Yamaha RD400
1970 Yamaha RT1
1971 Yamaha RT1B
1970 Yamaha RT1M
1971 Yamaha RT1MX
1972 Yamaha RT2
1972 Yamaha RT2MX
1973 Yamaha RT3
1974 Yamaha SC500
1973 Yamaha SC500
1974 Yamaha TX500
1973 Yamaha TX500
1974 Yamaha TX650
1973 Yamaha TX650
1977 Yamaha TY250
1976 Yamaha TY250
1974 Yamaha TY250
1975 Yamaha XS500
1976 Yamaha XS650
1975 Yamaha XS650
1977 Yamaha YZ100
1976 Yamaha YZ100
1975 Yamaha YZ250
1974 Yamaha YZ250
1975 Yamaha YZ360
1974 Yamaha YZ360

Last edited by thejunkman; 05-16-2016 at 05:38 PM.
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post #6 of 8 (permalink) Old 05-18-2016, 02:42 AM
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'can't say enough good things about the cartridge emulators. I appreciate them every day.
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post #7 of 8 (permalink) Old 05-18-2016, 12:21 PM Thread Starter
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Also!

I read a suggestion somewhere about using a heavier weight oil for these forks (assuming i don't use emulators). What you suggest i use, specifically?

The manual for the F7 says to use a SAE #10W oil. What are your opinions?
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post #8 of 8 (permalink) Old 05-18-2016, 03:12 PM
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Quote:
Originally Posted by s_tiber View Post
Also!

I read a suggestion somewhere about using a heavier weight oil for these forks (assuming i don't use emulators). What you suggest i use, specifically?

The manual for the F7 says to use a SAE #10W oil. What are your opinions?
It is best to experiment, however unless you are doing some serious riding and setting it up for VMX or some type of vintage competition, it is really not going to matter nor will you probably notice much difference in damping action (without emulators). In my trail/play ridden vintage bikes I just run 10w (or what ever the manual calls for) in them. Some guys have good luck with ATF fluid which I have been told works somewhere around a 15-20w type oil. You also might want to experiment with fork oil level/qty most forks (including yours) can accept a range of +/- 10cc This will change the amount of air space in the fork creating either a plusher or harsher initial stroke (think small bumps or when the fork is only moving a little bit)

Again these forks are not the best and there is only so much you can do without going to emulators to help with damping. And even then they are still going to be a little floppy just by their nature, a fork brace helps here as well. But again it all depends on how hard you are going to be pushing those forks.

Just for fun, here is some vintage film of me and a friend racing around my home MX track. Me on my F11 and my buddy on a DT250.

Here is some Kawasaki F11 performance information I have gathered over the years that you might find interesting.

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