RS 38s on an 1100 slabside or 1200 blandit - which rubbers?

[Dezza]

Which carb rubbers are needed to fit RS38s (or even BST 38s??) to an 1100 slabside or 1200 blandit head? Swirl has some in the for sale section with pics but I am unsure if these are the ones I need. Any comments appreciated.

[mikeyd]

1990/91 Gsxr 750 or whatever year Gsxr 1100 came with 40 mm carbs. I think 90/91 also.

[nokturnal]

i did not know this... good to know. I am about to fit some RS38s to a 1052 myself. 

[Dezza]

Ok, thanks. But did a 750 ever come with 40s? I thought the last oilcooled (M) came with 38s. The BST40s were on the later 1100s (M,N). This is why I was asking as I am unsure as the extenal diameter of RS 38 when compared to the extenal diameter of BST 38/40. It seems to me that what is needed are the rubbers from a bike that was originally fitted with BST carbs of the same external diameter of RS 38s but whether this is BST38 or BST40 (maybe these are the same external measurement) I still do not know 100%

[Gixer1460]

38mm carbs have same inlet OD whether RS or BST so both will fit 38mm rubbers. They will easily go into 40mm rubbers (obvs) just need more clamping or stretch a bit of bicycle inner tube over the inlet OD to take up the gap a bit!

[Foz]

Rs36/38 carbs have the same inlet diameter I've fitted both into standard bandit 12 inlet rubbers . If the rubbers are really hard or awkward on one set I slightly chamfered the leading edge and then they went it with ease

[Dezza]

25 minutes ago, Foz said:

Rs36/38 carbs have the same inlet diameter I've fitted both into standard bandit 12 inlet rubbers . If the rubbers are really hard or awkward on one set I slightly chamfered the leading edge and then they went it with ease

That is most useful info, esepcially as I already have a stock set of Blandit inlet rubbers. Many thanks for your advice.

[Mole28]

If your inlet rubbers are hard, the best way to soften them up is get a Kilner jar( the type with the locking lid), buy 1litre of pure alcohol and 100ml of Wintergreen, put all of both into the jar along with your inlet rubbers and leave for a couple of weeks at least. The longer you leave them the better. The alcohol opens the pores of the rubber allowing the Wintergreen into it and they come out soft and pliable. Pure alcohol and Wintergreen are available on the bay.

[Dezza]

58 minutes ago, Mole28 said:

If your inlet rubbers are hard, the best way to soften them up is get a Kilner jar( the type with the locking lid), buy 1litre of pure alcohol and 100ml of Wintergreen, put all of both into the jar along with your inlet rubbers and leave for a couple of weeks at least. The longer you leave them the better. The alcohol opens the pores of the rubber allowing the Wintergreen into it and they come out soft and pliable. Pure alcohol and Wintergreen are available on the bay.

Interesting. Which type of alcohol?

[Duckndive]

I used this series to fit Lectron,s 1152 head and I had RS38.s in them before  that

 

 

[Mole28]

Isopropyl or Pure alcohol. It's about 6 quid a litre and the Wintergreen is abou 7 quid for 100ml. I've had mine for years and used it many times. Because the jar is sealed the solution doesn't evaporate. It really works well.

[Dezza]

Ok, thanks for that. I think Isopropyl alcohol is the main constituent of 'panel wipe.' There are a huge number of different alcohols, all of which are available in different forms of purity. Ethyl alcohol is definitely the most popular and easily available though.......