New 36mm Round Slide on Suzuki RM 400

RCN4HIM
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RCN4HIM
Edited Date/Time 9/4/2015 11:19pm
I'm new to the old school moto stuff. Just picked up a 79 RM 400 which was supposed to be rebuilt and it runs horrible. Pulled the carb off and opened it up and the thing is hideous inside with lots of corrosion and can't even belive the bike ran at all. Anyone try to run one of these new Mikuni 36mm spec type carbs that can be found on ebay? Also, anybody have baseline jetting for this bike... Not coming up with much, Thanks.
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RiV
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RiV 9/4/2015 11:56am
9/4/2015 11:56am Edited Date/Time 9/4/2015 11:58am
More experience w/78 250/400 but the jetting looks to be very similar.
Should be able use 250 carb as well, 77,78 & 78C2 carbs will work,
C2 does not have an idle screw...as I recall. 370/400s too, just make
sure the slide is the same cutaway since their pricey. Get a new needle
jet, they tended to oval out at the top. Lists an R-6 which is pretty rich,
they should be a 159 series which I'm sure WPS stocks them. Reference
the jet needle as well, std is:NEEDLE, JET | 6FJ6-3.

The bikes I jetted back in those years ran quite a bit leaner than delivered,
we also ran 50:1 mixture adding to their richness. Usually 2-3 sizes
smaller mains and I ran as small as a #35 pilot on many of the bikes to
get them to run cleanly. Pretty vague info but hope it helps, always err
to the rich side!

https://www.rockymountainatvmc.com/oem-schematic/7?PID=6147458&ref=cj
newmann
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newmann 9/4/2015 12:28pm
9/4/2015 12:28pm
About the ones on eBay....are they Chinese knock offs or real actual Mikuni's? Got a link to one? Reason I ask is I bought a Mikuni from a vintage supplier out of Florida (I think it was Florida, long time ago...) and it looked kinda weird, a bit different in appearance from the ones I buy direct from Sudco. Not only that, but everything was reversed, mirror imaged so the slides will not interchange and the jetting was pretty far off in all respects for my CR125's. My advice is to buy a pre jetted Mikuni direct from Sudco. They are always extremely close on jetting and you get a quality carb that you don't have to spend an extra $75.00 to jet and slide correctly.

Did the RM400 use a 36 or 38mm carb?

http://www.sudco.com/mikuni.html#vm
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Hasletjoe
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Hasletjoe 9/4/2015 12:41pm
9/4/2015 12:41pm
You can also use some of the online sites to get the stock jetting. My site-de-juor (All the French I know) has been Rocky Mountain.

Shows:

50 Pilot
270 Main
R6 Needle Jet
6FJ6-3 Needle
2.5 slide

I agree with Newman, I bought one off eBay for an XR and the thing weighed more than a real Mikuni. Way More.
1980 model I confirmed ran a 36, no date on 79 at hand
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RCN4HIM
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RCN4HIM 9/4/2015 1:08pm
9/4/2015 1:08pm
Well I called Sudco and they quoted $221.49 for the carb jetted... I said the carb is $100 with free shipping on ebay (Did verify that it was a Mikuni) and their reply is that they have there own jetting specs?

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newmann
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newmann 9/4/2015 2:49pm
9/4/2015 2:49pm
RCN4HIM wrote:
Well I called Sudco and they quoted $221.49 for the carb jetted... I said the carb is $100 with free shipping on ebay (Did verify that...
Well I called Sudco and they quoted $221.49 for the carb jetted... I said the carb is $100 with free shipping on ebay (Did verify that it was a Mikuni) and their reply is that they have there own jetting specs?
Is this the one? I see it has MIC on the side and top cap but I don't see Mikuni on it.
http://www.ebay.com/itm/Mikuni-Round-Slide-VM-Series-Carburetor-36mm-Bo…



This is what they look like when I get them from Sudco.




fookyoo
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fookyoo 9/4/2015 3:22pm
9/4/2015 3:22pm Edited Date/Time 9/4/2015 3:35pm
Fuck Sudco!
Carb parts Warehouse in Ohio
send email with the stock suzuki specs from your bike manual
ask for quote
should be 50 plus less than sudco
and with be at your door in 2weeks

buy the time you buy a carb and all the parts
to jet, slide etc, your well over $200.00

This was on another web site a while back
and the person who posted the info about
Carb Parts Warehouse was correct!

Sudco prices are crazy high!
Dick Trickle 9/4/2015 11:19pm
9/4/2015 11:19pm
Recently i purchased two genuine Mikuni carbs, a 28 and a 36 from an authorized Mikuni dealer in Australia. I also purchased the jets separately to suit the bike from the same authorized dealer. I was tempted by the ones on Ebay. They say MIC and look the same etc.. but are too cheap and there are fake ones out there, just like fender guitars.
I would recommend you only purchase a carb and jets (there are also fake Mikuni jets) from an authorized dealer. Its the only way you will know you don't have a Chinese copy.

Here is the RM400N owners manual. You should get all the info you need out of it, and here are the carb specs from the manual..

Cheers,

https://onedrive.live.com/view.aspx?resid=407D7EF0965D3991!4478&cid=407…





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