GT750 J Front Drum Brake

For those wanting to keep their bike the way the factory made them.

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oldjapanesebikes
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GT750 J Front Drum Brake

Post by oldjapanesebikes »

I'm trying to gather additional information for an update to the GT750 Field Guide about the front drum brake. This follows on from a discussion thread on the KC board in the UK. To make it interesting, I'm running a small contest of sorts and you can read about it at this link on my OJB Facebook page. If you have a GT750 J with a frame number lower than about 12000 then I'd like to hear from you ! 8)
Ian

If at first you don't succeed, just get a bigger hammer !
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jabcb
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Re: GT750 J Front Drum Brake

Post by jabcb »

Interesting. This is more complicated than I was suspecting.

I didn’t use a washer on my GT550 cafe build. Vaguely remember it having a single washer when I disassembled it but there was no room for a washer when I put it together.

I bought a 4LS via eBay some years ago. Used it on my 72 GT380 cafe build. Was a tight squeeze but it fit fine. Didn’t use a washer.

Do you have any measurements so we can figure out if we have an early or late 4LS?
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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oldjapanesebikes
Moto GP
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Joined: Sat Feb 07, 2009 12:43 am
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Suzuki 2-Strokes: GT750(Jx3,L,M,A,B),T500
Location: Ontario
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Re: GT750 J Front Drum Brake

Post by oldjapanesebikes »

jabcb wrote:Do you have any measurements so we can figure out if we have an early or late 4LS?
The later style drum brake assembly using no 5mm spacers (these are part number 09180-15019 by the way) measures 165mm across the full width with the brake plates in place. The only difference between the the early and late drum assemblies seems to the the side plates - the later ones have a raised centre boss. The drum itself appears to be the same. That then would indicate an earlier style assembly must measure about 155mm across. 8)
Ian

If at first you don't succeed, just get a bigger hammer !
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