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gt550 fork tubes

Posted: Sat Feb 12, 2011 7:11 pm
by stlrocker
i need to know if the fork tubes for a 550 are the same for all years, or if they changed along the lines somewhere. i have a 72 that i need to replace the tubes on. i know the lowers changed, but i am hoping they kept the same tubes. it seem like it may be hard to find a set without rust on them.

Re: gt550 fork tubes

Posted: Sat Feb 12, 2011 8:24 pm
by Jughead
try http://www.frankmain.qpg.com/ for new reproduction tubes.

Re: gt550 fork tubes

Posted: Sat Feb 12, 2011 11:34 pm
by stlrocker
yeah, i know about franks. it seems i heard they have gone up a bit since i last got some tubes from them. i havent contacted them yet, but heard that tubes were close to 300 with shipping these days. thats a good amount more than i remember, and more than i really want to spend if i can avoid it. if other year tubes fit, it will really give me a lot better chance of finding a decent pair.

Re: gt550 fork tubes

Posted: Sun Feb 13, 2011 11:16 am
by Buffalo-guy
As far as I know, the 550 and the 750 in 1972, used the same front end to accommodate the 4LS brake. On E-bay, check out "cruisinimage" out of Japan, as they have replacement tubes for those forks, for $80 a set. That is good value in anyone's book. I've bought a set, and so has Mr. oldjapanesebikes, and they are the real deal. The later forks are totally different internals, so will not inter-mix. The early forks have a slipper ring at the top of the leg, and a piston at the bottom of the tube. The later ones have neither, with total tube contact in the leg. Hope this helps. Cheers.
Fred
PS. The new tubes are hard chromed all the way to the top, so the old problem with corrosion under the headlight ears should be eliminated.

Re: gt550 fork tubes

Posted: Sun Feb 13, 2011 12:31 pm
by oldjapanesebikes
According to the Zedder index, the front fork inner tubes were not the same for the GT550 and the GT750 - 51111-34030 and 51111-31030 respectively :( Not sure what the difference is - they are both 35 mm (I posted a link to a handy list of fork tube diameters which can be found here) but perhaps the lengths are different ? I haven't checked if the internals have the same part numbers.

At any rate - as Fred says I'm happy with the Cruizinimage fork tubes, and I actually bought two pair ! :D One pair for my '73 GT750 K and a set for the '72 J I'm collecting parts for 8)

Re: gt550 fork tubes

Posted: Mon Feb 14, 2011 4:40 pm
by stlrocker
thanks, that sounds like a nice price. the sellers name looked familiar, so i checked and it turns out i just bought a gasket set from him. came pretty quick from japan. he listed the length of the tubes, so im gonna go check mine to see if they match.

Re: gt550 fork tubes

Posted: Mon Feb 14, 2011 8:56 pm
by stlrocker
my tubes check out the same on length. 62.5cm. so they are the same length and diameter, but the different part numbers have me wondering. does anyone know for sure they will interchange? the price is good, but if they dont fit, it aint so nice afterall.

Re: gt550 fork tubes

Posted: Tue Feb 15, 2011 11:01 am
by oldjapanesebikes
stlrocker wrote:my tubes check out the same on length. 62.5cm. so they are the same length and diameter, but the different part numbers have me wondering. does anyone know for sure they will interchange? the price is good, but if they dont fit, it aint so nice afterall.
I suspect your best bet is to just sit down with the parts lists and cross check to see what is common and then make a decision. On-line parts lists are available at lots of places. 8)

Re: gt550 fork tubes

Posted: Wed Sep 13, 2017 8:35 am
by jabcb
Need inner tubes for a 72 GT550.

GT550 original part # is 51111-34030
Compared GT550 & GT750 fork damper assembly part #s & found two difererences: spring & inner tube.
GT750 original part # is 51111-31030

Options include:
Frank’s
eBay seller Legend Motorcycles (made in Japan by ???): https://www.ebay.com/sch/m.html?_ssn=le ... uzuki+fork
Tarozzi for GT550: http://www.fastfromthepast.com/05-0701 (listed as 35mm OD & 625mm long)
Tarozzi for GT750: http://www.fastfromthepast.com/05-0494 (listed as 35mm OD & 624mm long)

eBay seller CruzinImage only lists fork tubes for late GT750s

Has anyone used the fork tubes that Legend Motorcycles sells?
Any thoughts or suggestions?

Re: gt550 fork tubes

Posted: Fri Sep 15, 2017 7:24 am
by jabcb
Bump -- no input?