If any of you have read my previous posts you will remember my SP 35mm carb cast got damaged. Trying to source replacement was impossible. Nothing on ebay UK, DE, US, JP...

In the end I bought some 33mm carbs from a 1994 GSXR 400.

The good news is that the casts (apart from no.1 - see next paragraph) are identical apart from the bore on engine side. My vernier gauge report them as 31mm on the 33's and 33mm on the 35's. Surely my gauge isn't out by 2mm!? It wasn't a cheap one

The first 33mm carb actually has the screw mounts for the SP's TPS. There is a difference here tho and that is the first carb (33mm) does not have an opening into the butterfly for the TPS.

The main jets (100) and pilot jets (47.5) are the same on both types of carbs. Butterfly is the same... Mikuni only made very slight changes and perfomance wise I don't think there is anything in it

So I have 2 options:-

1) Run the 33mm's with TPS by having an engineering company drill into carb cast. Easier than what it sounds.
2) Have engineering company bore out to the SP's carb diameter on the engine side.

I'm looking to go with option 2.

Thought this may be helpful should some else find themselves in the situation I had.

Yup it was 2mm out

I'd personally get the one bored out if thats possible.

Hi guys, so just a quick one, u saying that if i get a hold of a 33mm carb I can use the internals for my 35mm carb (non TPS Enabled) Pre SP (1991 RM)

Hi,

I can only offer advice on standard 33mm's against my SP 35mm's that have TPS.

When I had the banks apart on both sets of carbs there are some small differences -

- 35mm has an extra drilling into side of cast for more fuel. Therefore the 35mm carbs have additional hoses.
- Although the 33mm carb has the mounts for TPS on the 35mm one sticks out further (approx 5mm).
- 35mm has a drilling into cast so the TPS can see the position of the butterfly.
- 35mm carb on airbox side seems to have one bigger jet that screws in. 33mm Carb seems to have one same size as 35mm but one smaller that cannot be unscrewed?
- Butterfly, needle, main jets, pilot jets all seem to be the same

I hope that this helps.

Thank you so much for your reply, I found a local distributor here in South Africa that sells Mikuni kets for most grey bikes, carb float bowl kits from R145 each (about 9 Pounds)
Main Jets for R30 (about 2 Pounds) each

http://www.mcomp.co.za" onclick="window.open(this.href);return false; - they do mail order aswell .!