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Cuts metal like mad

R1 Carbs (lots of pics)

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Some of you are already familiar, but some aren't. I decided to give this its own thread to make it easier to find, and less clutter in the truck thread.

 

I decided to do something a little different, both for cost and just to be different, the R1 ITBs have been done... but as far as I know the R1 carbs are generally being utilized in the UK and Japan. A local shop I got talked to agreed to build me the manifold, this is the prototype and is little rougher than one that would be produced for anyone else but it will work just the same.

 

I toured the shop and to my surprise they own a 240z race car that they do very well with...

 

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Thats when I knew I picked the right guys for this sorta thing... They also have a EVO race car, and they do all the work on these cars...

 

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Another car they are building is a japanese RHD 180sx, though it wasn't at the shop for me to take pics.

 

On with the show...

 

Another reason I picked the R1 carbs is that they provide the benefits of and SU type carb AND a DCOE type carb in one unit, and you get individual carb per cylinder... they are really not very hard to tune, easier in fact than a set of SU's or DCOE's... they also don't tend to fall out of tune like a DCOE carb. I already found a way to make a carb sync'er using some very inexpensive pieces (this will be a seperate "build" of its own later). For jets, the easily obtainable weber DGV jets will bolt right in no mods necessary, or you can drill the original jets, although this is less than ideal, at least it will save you some money when choosing your jet size, get it close and then buy the right size instead of buying a bunch of jets you won't need.

 

The carbs have a variable venturi that is dependent on vacuum, so depending on how much vacuum you engine pulls is what determines how much fuel and air the carb will give you... kinda like a vacuum based fuel injection. The R1 carbs also have a Throttle position sensor already attached, and the carbs are 42mm with a 40mm choke... they are said to provide equal performance to a weber 45 or mikuni 44, and with the variable venturi will also give better low end than a weber or mikuni sidedraft. They are made by mikuni... can it get any better??

 

Heres the carbs and the new manifold. New flanges were made from 1/2" aluminum plate, and the tube is 1 7/5" OD, so 40mm inside, and 44mm outside.

 

Thanks for looking, glad to answer any questions.

 

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If you are interested in having a manifold made, contact Jason at

Forward Motion

 

http://www.turbo4g63.com

 

Jason@turbo4g63.com

 

253-324-6690

 

10313 B Lakeview Ave

Lakewood, Wa 98499

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Zoom, don't those look nice!!! What are they off of again? Do they need to be tilted up like that?

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Lookin' pretty spiffy Joe, you say that operation is largely vacuum dependant? I'm afraid to ask what those set you back too.

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trade you my 32 36 for them :D what DID it set you back? i might be interested in this if the price is right... now install and do some vids with sound :D

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Nice friggin work. Let's see them under the hood :D

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hell yea that is awesoem! am i right to say that you put them at an angle because thats the angle they would have been used at in the bike? it seems to me that makes sense, to spruce it up you just need some shiny hose clamps

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designed for streetrodders but sure would look good on there, about 8 bucks a piece i think

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the carbs are meant to be tilted but will run at almost any angle! 4x4 anyone?

 

I got this set for $115 shipped, the manifold is a prototype as stated so it's a little rougher than a "normal" one would be and let's just say I got an excellent deal.

 

As for those fancy hose clamps... Won't work, not enough room, barely enough for what's there, I am replacing the hose with some 44mm fuel hose after I get these tuned in. They come off of the 98-01 (I believe), yamaha R1.

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Mine are off a GSXR. After initial "close enough" tuning, they ran great. Only complaint is that I lost my ported vacuum signal for my distributor.

You are gonna love em. Throttle response is great. Sorry, photobucket isn't working for me right now but I think there is a pic in the 1200 section.

Edited by DRIVEN
pics won't post

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ima start looking for some then. any word on that manifold yet? the L16 one? i need to swap mine out asap, the gasket blew, lol.

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Guest DatsuNoob

Man, that's lookng good! I must say, I'm a bit jealous. I remember you showing them to me , but for some reason I thought they were Suzuki ITB's. Anyway, can wait to see how they work out. Those sure would look good on that KA of mine :D.

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Before everybody gets a big hard on!!!!!!

Will it fit in the engine compartment and not hit the side wall or brake master.

So I guess no airfilters will be used.

 

why I say that it looks too long. This was a common prople on the Nismo Mikuni intakes as the rear airhorn would hit the master cly and no aircleaners.

Then Mikuni made the short tube intake for most applications

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Looks like he can trim the manifold to fit if he needed to. Especially if those will run at any angle.

 

I still wanna see them in the engine bay :D

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Yeah, looks like there is room to trim the runners back if necessary. My runners are kind of an S shape and the UNI filters I used just barely clear the brake master. There's probably more room under the hood of a 521 than a 1200.

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There is plenty of room actually, and yes theres enough tube there to cut back... 3"-4" as a matter of fact. This setup looks long in the pics, but its actually shorter than a weber sidedraft attached the "normal" cannon manifold most people run, I wanted the runners as long as possible and still be able to buy some airhorns... no filters will be used, just screens.

 

Its not going on the 521 anymore... LOL I know I know... its going on a 510! Stay tuned, will need to get the 510 running on either the hitachi (that I finally RE-disassembled and fixed) or a weber 32/36... I just don't want to be diagnosing the carbs AND a timing problem at the same time.

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I used to run 40mm mikuni round slide carbs on a lz2.2 in a 620 I had back in the day I had quit a bit of $ into that mikuni brass to get my midrange correct finnaly found the correct slide cutout and needle and needle jets that worked right took a lot of trial and error. I guessing you might run into the same problems. If you have a mikuni tuning manual might be a good idea to look and see if all those above parts are avaliable for those style cv carbs. Ya might need them. cause just changing pilot, main jets, and air jets will not work well. Especially when about 80 percent of driving the carbs will be in that midrange circuit

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I used to run 40mm mikuni round slide carbs on a lz2.2 in a 620 I had back in the day I had quit a bit of $ into that mikuni brass to get my midrange correct finnaly found the correct slide cutout and needle and needle jets that worked right took a lot of trial and error. I guessing you might run into the same problems. If you have a mikuni tuning manual might be a good idea to look and see if all those above parts are avaliable for those style cv carbs. Ya might need them. cause just changing pilot, main jets, and air jets will not work well. Especially when about 80 percent of driving the carbs will be in that midrange circuit

 

 

 

Don't know what you mean by slide cut out... The needles are adjustable... These are very popular elsewhere, I got the idea from everyone using the itb's... StRted searching and found tons of these done, most of the info is coming from the UK. Can't remember the website but check google for hogg brothers fabrication... It's even been done on ferraris. After I get my set running I'll share a bit more of the info I have... It's great stuff.

 

Even if it only works moderately well... It would have still been worth the price!

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Ok well I'll keep it short I've tuned jap bikes for a lot of years. If you look at the back of the carb notice the slides are half mooned shaped on the bottom, that's a cut out. Their are different degrees of cut out,or shallow or deep cutouts that controls air flow into the throat of the carb usually measured in numbers such as, 1.0 1.5 2.0 etc etc. 1.0 being very shallow or a richer cutout. I think??? Been a while lol! Yes the needles are adjustable but a lot of time you cannot adjust them enough then you have to go to a different taper, and the needle jet has to match that particular taper of whatever needle you choose. Like I said if you order a mikuni tuning manual it will g show you what I'm talking about. I really can't see these carbs being just a straight bolt on kinda thing. also I'm guessing being a cv carb, you might have to get some stiff springs (if they have em??) so the slides do not just slam open with the kinda vaccumm a l motor has compared to a small CC bike engine. But I could be completley wrong about this these are just thing I've gone through in the past. Even have to do this when swaping carbs from one bike to a different bike. Bike carbs are very picky everthing has to all work together. Every circuit from idle to full throttle overlap each other to provide smooth acceleration. If their not tuned right you'll wind up with serious bogs, idle problems all sorts of weird stuff.

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