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New to 35.... Carb help

Posted: Wed Nov 24, 2010 5:32 am
by cajun
Ok I've searched but got a few questions. So I just obtained a minty 35 with some carb work already done to it. Not exactly sure what yet so I took it apart today as the fueling as it sits is off. But what would be a generic base set up to start with. To my knowledge it has HRC Needles, Springs and the strangest part to me was that it has a longer velocity stack in the foward most carbs and short ones on the back. And also a Carbon undertray underneathe the carbs. So my question would be what would be a good starting point with basicall a half system twin pipe?

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Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 5:54 am
by J.B.
Congratulations on your bike, not many of them in the US. NC35's came with longer velocity stacks in the front 2 cylinders as standard. However these look shorter than OEM and could indeed be the genuine HRC stacks, someone here will know for sure. Likewise the carb tray is part of the racing kit, however the carb base has not been modified as per HRC manual (just involves grinding out those S shaped fins between the stacks). Are you gonna track this bike or ride it on the street? The reason I am asking is if you're gonna track it then I suggest taking it to a dyno and getting the jetting sorted properly. If you are going to ride it on the street then I suggest building up a set of carbs with standard or close to standard specs depending on the exhaust you're running. Oh, if it's gonna be a street bike I strongly suggest selling those stacks to me :-)

Jimmy

Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 6:02 am
by Cammo
The jetting will mostly depend on what sort of filter and airbox setup you intend to use. Once you know this it's quite simple to find a decent setup that works well.

It would also be worthwhile seeing for yourself what needles it has, the std and hrc needles have codes stamped on them. The hrc needles are also adjustable via clip position. I would also check the jet size, the previous owner might just be going off what the previous owner told them etc...

They are indeed hrc velocity stacks, nice find.

The rvf carbs aren't hard to sort out whatever sort of setup you choose to run.

Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 6:04 am
by Cammo
JB wrote:Likewise the carb tray is part of the racing kit, however the carb base has not been modified as per HRC manual (just involves grinding out those S shaped fins between the stacks).
Grinding the carb bracket is applicable to nc30's only, not intended for rvf carbs with their taller velocity stacks.

Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 11:23 am
by J.B.
Cammo wrote:
JB wrote:Likewise the carb tray is part of the racing kit, however the carb base has not been modified as per HRC manual (just involves grinding out those S shaped fins between the stacks).
Grinding the carb bracket is applicable to nc30's only, not intended for rvf carbs with their taller velocity stacks.
My bad, it's not in the RVF set up manual, I did it on advice from Harley at RB Imports. Not having the HRC stacks I used the OEM rear stacks front and back.

Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 10:00 pm
by Cammo
JB wrote:Not having the HRC stacks I used the OEM rear stacks front and back.
I use 4 of the standard short stacks on my rvf carbs, Rick Oliver sells them separately in the UK.

Re: New to 35.... Carb help

Posted: Wed Nov 24, 2010 11:19 pm
by cajun
Ok so a check revealed, 115 mains, HRC needles with clip in second position from the bottom, and mixture screws 2.0 turns out. I took the CF tray out as a friend of mine stated it was devolped to keep the carbs cool and from the looks of it, it actually blocks more air than it flows to the snorkle and makes it a pain to remove or put on the carbs. Only thing I did was put the AF screws 2.5 out. And has the stock airfilter with screen still in.

This will be a road bike as the 29 is my race bike.

Re: New to 35.... Carb help

Posted: Thu Nov 25, 2010 12:08 am
by Cammo
I think it would be better to use standard needles for your setup, the hrc needles are intended for much bigger air/fuel inputs (no filter, huge main jets etc), you will probably never be able to tune them adequately for a standard-ish road setup. These will be your problem. You should be able to get hold of some from the usual suspects on this site.

The hrc slide springs will be fine with some standard needles, and the 115 mains will be fine also with your intended exhaust system. When you've put some standard needles in, set the pilot screws to 1 & 5/8 turns out (standard setting). This setup is a good base to start from.

The air tray is overkill if you're using the airbox IMO!

Re: New to 35.... Carb help

Posted: Thu Nov 25, 2010 3:42 pm
by Neosophist
Cammo wrote:I think it would be better to use standard needles for your setup, the hrc needles are intended for much bigger air/fuel inputs (no filter, huge main jets etc), you will probably never be able to tune them adequately for a standard-ish road setup. These will be your problem. You should be able to get hold of some from the usual suspects on this site.

The hrc slide springs will be fine with some standard needles, and the 115 mains will be fine also with your intended exhaust system. When you've put some standard needles in, set the pilot screws to 1 & 5/8 turns out (standard setting). This setup is a good base to start from.

The air tray is overkill if you're using the airbox IMO!
+1 :)

The air-screw works backwards on the rvf... out is leaner (if i remember.. cammo?)

out of curiosity.. what size pilot jets were in there?

Re: New to 35.... Carb help

Posted: Thu Nov 25, 2010 10:00 pm
by Cammo
Neosophist wrote: The air-screw works backwards on the rvf... out is leaner (if i remember.. cammo?)

out of curiosity.. what size pilot jets were in there?
Yes, air screw is out for lean on rvf carbs. ;)

I'd be surprised if the pilot jets are different to the standard 35's, the hrc manual doesn't recommend anything biger than standard (unlike the vfr hrc kit). Worth checking though.