Does anybody recognise this carb? Yoshimura RS

[xwhatsit]

'Lo,

I've been trying to nab a cheap Keihin CR33 in Japan for a while now, but people bidding at the last minute and my lack of funds keep getting in my way.

Anyhow, I've seen this pop up: http://page6.auctions.yahoo.co.jp/jp/auction/f61586500

Supposedly a Yoshimura carb for the CB250RS. WTF?! It's a Mikuni. And it looks like I could get it for cheap. Before I plonk down my readies, though, does anybody know what sort of Mikuni this is? I only really know the Mikuni VM series with respect to their roundslides, and it doesn't look like one of those (VM series pulls the slide with a cable from the top, there's no rotating throttle spindle). I'd like to do some research about the model first, so I know I can get jets and I know it'll be better than what I've got right now.

Cheers.

Oh, check the auction for more photos.

[Ixion]

It looks rather similar to the carbs on the RZ250. Just purely from memory. I'll dig one out tonight and have a closer look.

[xwhatsit]

Oh cheers mate. It does look rather generic -- actually a hell of a lot like the Keihin CR, except back-to-front. I suppose if your aim is to produce the cleanest-flowing round slide carb then you're going to approach some kind of aesthetic homology.

I doubt the Yoshimura claim somewhat, although a machine translation of the Japanese text seems to be promising it's the real thing.

[tri boy]

Hi Tom,
Going by the top right bracket, and the alloy body at the top left, I would say that it isn't a direct cable pull.
Probably a linkage/spindle type. No idea if it's suitable, (bore size etc)
but maybe a detailed search on the Yoshi site (if there is one) will confirm if it's suitable. Nothing wrong with Mikuni smooth bores.
Good luck, and don't over spend.

[xwhatsit]

Sorry triboy, in the original post I misphrased it -- I missed out a `doesn't' when referring to it not being a Mikuni VM. I meant to say it can't be a VM, as it's a spindle type (in the auction you can see photos from the other side) not a direct pull.

I'll have a look through some catalogues once I get uncorked from 64K connection. I'd like to compare it directly against the Keihin CR, they have such a good reputation, and it might be worth saving the extra money and not having to set it up twice.

P.S. Don't overspend?! Are you mad? It's an RS! Nothing's too good for it.

When I'm an old man, it'll have Öhlins, 350cc high compression, lumpy cam, fuel injection, aluminium tank and seat, TLS front drum, gusseted swingarm... *goes all dreamy-like*

[Wheeliemonsta]

Gidday,
It's a "Reverse Pull" Mikuni Smoothbore - most likely between 28 & 33 mm...

A crowd called Sudco in Canada http://www.sudco.com/mikuni.html#48 used to "kit" them for use on old air cooled two valve Kawasaki & Suzuki race engines...

The "kit" is very basically a glorified Dyno Jet kit supplied by Yoshimura R & D (hence the sticker)

There still available new, I believe

They are infinately more tunable in kitted form than the standard VM series smoothbore so it's probably a good choice for your project, provided you can get your cables to operate it correctly...

Think of them as a poor mans Keihin CR

Cheers

[xwhatsit]

Cheers mate! Really appreciate the info. As far as I can work out it's 33mm, which is apparently the defacto standard for these engines when using roundslides.

`Reverse Pull' -- something to do with the fact the spindle is on the opposite side to what I'm used to seeing?

EDIT: Actually, did the thread title throw you off? By Yoshimura RS I meant a Yoshimura-kitted CB250RS, not a Mikuni RS carb that is in that link. It does look damned similar though.

[Wheeliemonsta]

`Reverse Pull' -- something to do with the fact the spindle is on the opposite side to what I'm used to seeing?

Yeah, your on to it...

You'll be able to get bits for it through Northern Accessories as they are the master agents for Mikuni in N.Z

Happy to help mate...

Cheers

[imdying]

Cables are no trouble xerxes.

[xwhatsit]

It's at ¥5,250 ($US47), closes in 12 hours! Shall I do it?

EDIT: I still can't find any information on these carbs. The only Mikuni round-slides I can find are the VMs or similar (with the direct pull slide, no spindle). Anybody know the model name?

[xwhatsit]

Shit, I think it is a VM. VM33, to be exact. Constructed very differently from the normal VM carbs. Apparently developed for racing applications, to contest with the Keihin CRs (about the same time period). Compare with the first image. From the sort of stuff I'm getting (god I wish I could read Japanese sometimes ), it seems to be one of those Yoshimura/Mikuni collaborations like with the current TMR-MJN flatsides.

[tri boy]

Go for it dude. You know you want to. (you could always flick it on to Bonez)

[FilthyLuka]

do it, VM's are great

[xwhatsit]

Bastards. In typical fashion, it's blown out to ¥17,000 -- which is silly considering how I can get a brand-new Keihin CR33, velocity stack, set-up for the RS too, for ¥18,000.

Damnit!

EDIT: It closed for ¥20,500 -- unfuckingbelieveable. It seems that little Yoshimura sticker is worth a fair bit