Yamaha FZR 600 brake caliper seal sizes!! help!!

[Th3_V1k1ng]

calliper is an old fzr 600 front calliper. Unsure what year bike it came from, but theres an 94 UA stamped on the calliper.
I ordered some 43mm seals, good japanese ones. Come to strip the caliper, cleaned it, no solvent and no brake cleaner or brake fluid..
tiny bit of red grease to slide the piston in, wont go.
It seems like the new rubber seals are to small, to allow the piston to go back in. (piston is all nice and shiney, no marks, scratches or dents)

My Question is....  is this sumitomo calliper in fact 43mm as the man in the shop says.. OR... as my metal rule tells me 44mm, which means the inner bore of the piston hole.. might well be 45mm.

I've found on fleabay, some 45.3mm seals.
I cant remember where I put my vernier to measure, so eyeballed via the metal ruler, or else I'd have a much better idea.

Any ideas, suggestions?
These are only the old 2 pot callipers.. 1 either side. Grey sumitomo. I can take a pic, but if your a yammy guy, you'll know what I'm on about.

[Cynic]

Yep, know the ones your talking about. Seize riding by the chippy.

Your problem is that it may not be a 600 caliper. That caliper is on several bikes but with slightly different pistons. 

It was also fitted to 400's as well as the TDR and TZR again with different diameter pistons in each bike.

Me? Junk em and fit a pair of blue spots.

Unless you can accurately measure the piston and bore, then try someone like fowlers and see if they can help. They are pretty good that way in my experience.

 

[Th3_V1k1ng]

I have blue spots on the front of the divi 900, this is going on the back...AND... you cant chuck blue spots on in place of a lot of these as the centres are wider on the blue spots than on the old callipers.
I thought about a blue spot on the rear, as I have some spare, when I tried it, centre was out by about 20mm.
To fit blue spots to the rear of the divi 900, or the front/rear of the FZ750 1985, I'd need to get adapter plates, which I might well do for the FZ front.
Anyway, ordered some 45.3mm seal sets from powerhouse on fleabay.
Another guy on this forum has recommended them for seals for yammy brake callipers.
 

[Cynic]

Ah, well you didn't mention fitting it on the rear of a divvy 900 did you.

The blue spots are a straight swap to a lot of  bikes, like the 600's and the TDR/TZR 250's (although you need to change the mc) not all granted, but 100mm centres is very common across the yam middleweight range.

You might also consider, forum etiquette here is to post an introduction. Members are extremely cautious of answering first post questions because of the above. Just to say hi, what bikes you have etc. Not your life story, just enough to break the ice. Otherwise you may get very few responses.