R1 Carbs (lots of pics)

[Drummerboy4as]

So if you had an intake plenum you could pull the vacuum from the advance from there?

[datsunfreak]

So if you had an intake plenum you could pull the vacuum from the advance from there?

 

Probably not, not enough of a vacuum, too much turbulence, etc. There's only one ideal spot, sadly. :hmm:

 

If you disassembled one of the carbs it seems like you could drill/insert a nipple in the right spot?

[Drummerboy4as]

Would you need to instal a nipple just before the butterfly?

[datsunfreak]

Would you need to instal a nipple just before the butterfly?

 

Exactly. That's how all the OEMs did it, including Weber. That way at idle there's no vacuum, and it gets a lot of vacuum when you first crack the throttle, and has low vacuum at wide open throttle.

 

That's all the vacuum advance really does anyway, boost timing when you first open the throttle to keep it from stumbling. You can run without it, but acceleration and throttle response are better with it.

[Tristin]

Hmmm... not to thread jack, but maybe thats my stumbling problem. Im going to PM you John.

[VintageRice]

Not on my intake and carbs yet. But got a fantastic start on my header tonight. Quick cell pic. It's kind of a "shorty" style header. Cut up an old baja bug header for parts. Cost $30.

 

[pope_face]

Wow... So I come on a couple months back, find a link on how to install some R1 carbs, leave Ratsun for a while (due to school and working on my other car), and when I come back there's some three more pages on this topic, people already have R1 carbs installed (and running!), and VintageRice is working on a header... I love to see progress. :D

 

VintageRice: Didn't say this before, but you're welcome for the link. :) It was your comment on doing my own research that lead to it, so you're partially to blame... :P I still haven't gotten my carbs, but I don't have an engine yet either, so it probably doesn't matter so much. I'll make sure to look out for those other, top-secret carbs you may or may not have mentioned... ;)

[Drummerboy4as]

Just for clarification, when you say 1.6 or 1.8 "jet", which jet are we talking about? Main jet? Idle jet? If it is the main jet does everything else stay the same? Different clip on the needle?

I have a Mikuni flat slide carb on my bike so I know my way around these carbs, just not sure which we're talking about :D

[Drummerboy4as]

Anyone? Is it a .180 main jet?

[Stupid_fast]

Just for clarification, when you say 1.6 or 1.8 "jet", which jet are we talking about? Main jet? Idle jet? If it is the main jet does everything else stay the same? Different clip on the needle?

I have a Mikuni flat slide carb on my bike so I know my way around these carbs, just not sure which we're talking about :D

 

It is a weber DGV main jet which is the same main jet in the R1 carbs.

 

180 main jet = 1.80mm hole, you can use a 1.8mm drill bit and drill out the stock 138 jets if you want. 160 for 1.6liter, 180 for 2.0 liter. .

[Drummerboy4as]

Awesome, thanks for the clarification! So the needle and pilot jet and all that stay the same?

 

Reason I ask is I know the flat slide carbs are different from the CV carbs, but the flat slides use different jets based on throttle position. Main jet doesn't come on till 3/4 throttle.

[datzenmike]

"Drill out the main

jets. For a 2-litre XE,

use a 1.8 mm drill bit

(1.65 mm for a 1.6).

Alternatively, a set of

similarly sized main

jets from the Weber

DGAV can be fitted."

[VintageRice]

Well, I'm starting on my intake manifold. And I've been trying to do some research on the carb mounting angle. Seems like most people mount them pointing up to get the carb bowls level witht he ground. But it would be much EZier to build a manifold straight out rather than tilted up. This would also help with hood clearance. From what I've found, I heard both stories. Some say you mucst mount them so the bowls are level and others say you can run them at almost any angle. Even on page one of this thread the original poster said they run at any angle. The Bogg Bro's website shows them mounted straight up (vertical) so I'm thinking maybe they CAN be run straight. Side draft style. Any comments?? Heres a couple V8 pics with R1 carbs. They must run good at weird angles if Bogg Bros does it. Right???

 

 

 

[datzenmike]

They will only work if the jets are covered with fuel and the floats free to drop 'down' to let gas in. You may be able to run them at extreme angles as bikes seem to run just fine with the front wheel off the ground or leaning in a corner. I would run them as close to how they sit on a bike. I think the intake pipes should be close to horizontal perhaps tilted up slightly.

[VintageRice]

This is the angle they have to be to get the fuel bowl level. See mike. Pretty steep angle.

[Drummerboy4as]

Picked up a couple of sets "for parts" on the eBay recently. Spent a couple hours yesterday tearing em apart to make a complete set.

 

Now I just need to sell my Dell'orto twin side draft setup so I can buy the manifold :D

[datzenmike]

This is the angle they have to be to get the fuel bowl level. See mike. Pretty steep angle.

 

Oh yeah.... way steeper than I thought.

[VintageRice]

But because these bikes have a fuel pump and are under pressure(albeit low) wouldnt that keep the bowls full even when its tilted? I guess you get to a certain point and the fuel would just squirt out the needle jet eh? :)

[Drummerboy4as]

On the side of the carb in your picture there's a round "cap" with a "tube" running down to the float bowl. In between the 1&2 and 3&4 carb there's a connector piece. The tube runs down into the float bowl. Best I can figure its a bowl vent, but my setup came with fuel lines attached to a "T" so it could possibly be an overflow return line?

Would prevent overfilling the bowl. Unless you didn't have it connected to a return, in which case it was just spill on the road.

[sedition88]

I'm going to look at doing this on my L18 620. I work for a kawasaki, Yamaha, Honda, motorcycle shop so I'm keeping an eye out for carbs. Would the 1.6 or 1.8 jetting be best for this motor? This write up is great!

[VintageRice]

Well, gave it a go....

 

Tried building my intake today. it turned out pretty good. Got hood clearance....barely...

 

got a sloped up angle......barely.........hopefully its enough and they run good. Time will tell.

 

I'll probably shorten up the runners and the couplers so they are lower/closer to the block. Bought nice stainless t-bolt style clamps from egay and they were advertised as 2.25" and they clamp only down to 2.25" so they are going back.......lame.

 

Oics.....and some of my header, I got the welding finished and a collector flange put on.

 

 

 

 

 

 

 

 

 

 

 

 

[Z chopper]

I'm going to look at doing this on my L18 620. I work for a kawasaki, Yamaha, Honda, motorcycle shop so I'm keeping an eye out for carbs. Would the 1.6 or 1.8 jetting be best for this motor? This write up is great!

 

I would try both, but as seeing how 1.6 jets is best for l16 and 1.8 jets is best for l20b if there was a way to upsize the 1.6 jets to 1.7.................

[datzenmike]

Weber jets fit. Try weber.

[Stupid_fast]

Or drill the jets.

 

http://www.amazon.com/Jewelers-HSS-16-Piece-Micro-Bit/dp/B001D8SUY6/ref=sr_1_23?ie=UTF8&qid=1335724304&sr=8-23

[datzenmike]

Yes. Another trick it to fill with solder and drill them smaller also.