Author Topic: CB750 F1 front caliper  (Read 1455 times)

Online hairygit

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CB750 F1 front caliper
« on: February 23, 2012, 10:52:01 am »
I know these are almost impossible to source now :(, I draw the line at paying nearly £370 for one from Germany! >:( Is it possible to use the caliper swinging arm from a 400/4, 500/4 or 550/4, and then use a pattern 400/4 caliper from DSS with the standard disc? I suppose it could be possible, but I don't want to spend out on parts if it wont fit :'( Bryan J, your immense knowledge is needed! ;)
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Offline mick

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Re: CB750 F1 front caliper
« Reply #1 on: February 23, 2012, 12:09:50 pm »
Hi what's up with your old caliper?

Offline Bryanj

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Re: CB750 F1 front caliper
« Reply #2 on: February 23, 2012, 04:42:35 pm »
To be Honest i don't know, If the bracket will physicaly fit I see no reason why not, I could possibly find you used parts to try but not buy--too many "Projects" !!

Online hairygit

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Re: CB750 F1 front caliper
« Reply #3 on: February 23, 2012, 06:13:24 pm »
Mick, all the usual problems, corroding piston, seized bleed nipple, and I'm sick of paying 3 times the price for F1 specific parts such as caliper seal (even DSS is guilty of that one! >:() So I figure that if it will work, there will be plentiful spares for many years to come, I've seen several places doing pattern calipers, pistons seals etc for the other fours, so it should be a future proof conversion ;D Anyway, I've just managed to win a CB400F caliper arm and pivot for 99p on Flea-Bay, so when it arrives, I shall bolt it to the fork leg, and measure the distance between the disc and the arm, if they're the same, it should work :-\ What do you think Bryan?
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Offline mickwinf

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Re: CB750 F1 front caliper
« Reply #4 on: February 23, 2012, 08:21:12 pm »
so whats the difference on a F1 ? i thought they were all the same!
Love the 500/4 and 550 own 2 at the moment. Also 750f1 project

Online hairygit

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Re: CB750 F1 front caliper
« Reply #5 on: February 23, 2012, 08:28:44 pm »
The bolts that join the 2 caliper halves on the F1, K7 and A are spaced about 4mm further apart than all the other fours, the piston is about 30 though larger diameter, so you can see the problems getting parts! DSS said that there were not enough sold to warrant anyone making pattern calipers, they'd never recoup the set up costs, never mind make a profit! Sadly the same is true for most F1 specific parts, fuel tank exhaust etc :(. So switching to a more common caliper setup should make sense long term!
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Offline Bryanj

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Re: CB750 F1 front caliper
« Reply #6 on: February 24, 2012, 06:14:13 am »
If the caliper arm bolts on and clears the disc the caliper itself should be OK.

If you want to refurb the F1 one i can do a bleed nipple repair kit for about £5 and I'm sure Kevin (ttr400)  could turn you a phenolic piston if you have the sizes. OK you are stuck with the Honda seal and i know its dearer but you dont need them that often---even less with a phenolic piston

Offline mickwinf

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Re: CB750 F1 front caliper
« Reply #7 on: February 24, 2012, 08:47:19 am »
Bryan how does your bleed nipple repair work, i have a caliper with a bleed nipple that has sheared off, could this be fixed?
Love the 500/4 and 550 own 2 at the moment. Also 750f1 project

Offline mick

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Re: CB750 F1 front caliper
« Reply #8 on: February 24, 2012, 09:40:21 am »
Same here i have a F1 caliper the nipple sheared off and i attempted to drill it out  :-[, now it needs another type of fixing  ::), which i have seen on the net  ;),

Hairygit i have fitted an earlier style caliper ffom a k series 750 onto my F1 arm,

only thing i had to do was file the top of the caliper to match the profile of the arm as it stood proud, cheers Mick.

Online hairygit

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Re: CB750 F1 front caliper
« Reply #9 on: February 24, 2012, 12:24:59 pm »
Mick, I had a feeling the earlier K caliper would fit, but they seem to fetch silly money now, that's why I thought of the 400/4, 500/4 or 550/4 caliper, it looks the same as the original F1 caliper, and  complete pattern calipers are easily sourced ;D
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Offline Bryanj

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Re: CB750 F1 front caliper
« Reply #10 on: February 24, 2012, 10:34:43 pm »
The repair Kit is one i buy in but it's cheaper if you buy 5 or more.

You drill out the old nipple straight through then open out and tap 1/8 NPT, screw in a brass insert that accepts a bleed nipple and has the seat on the inside.

Somewhere on the US site is a write up with pictures, if i can find the pictures again i will re-do it for here.

Offline LesterPiglet

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Re: CB750 F1 front caliper
« Reply #11 on: February 25, 2012, 12:37:18 am »
Just pop this in guys. Don't use screw extractors. They are sh1t. They usually break off and leave a harder metal inside your nipple. OOer missus.
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Offline Bryanj

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Re: CB750 F1 front caliper
« Reply #12 on: February 25, 2012, 09:07:44 am »
OK if they attach there should be 3 pictures showing a very messed with 500 caliper sporting one of the "Kits" that i can get. They do come in 2 sizes for the different size bleed nipples but i see no reason the 500 one can not be used on a 750 as long as the caliper will take the 1/8 npt tap.

Offline Waggles

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Re: CB750 F1 front caliper
« Reply #13 on: February 27, 2012, 02:19:54 pm »
Cant help thinking there would be demand for re engineered calipers, I seem to see a lot of F1 owners in here ..... I for one would prefer I nice new one!

As a matter of interest for bore problems I noticed an ad in this months Classic Motorcycle Mechanics for a firm who seem to specialise in bike brake restoration and can re sleeve cylinders in stainless amongst other things. I have no connection with them and can't recommend them as I haven't used them but it might be worth an enquiry for anyone who is stuck?

They are called 'Past parts ltd' on 01284 750729 ( Suffolk )

Offline Spitfire

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Re: CB750 F1 front caliper
« Reply #14 on: February 28, 2012, 10:08:00 am »
F1 brake calipers are like rocking horse poo but they do come up on eBay now and again, The original one on my F1 is fine but I wanted a spare one so just kept an eye on eBay and one came up, it's now refurbished, bagged and boxed with all the other "insurance" spares in the loft.

Cheers

Den
1976 CB750F

1977 CB750F2

1964 BSA A65R