R1 Carbs (lots of pics)

[Stupid_fast]

@dangero,

 

 

I don't know what your issue is-

 

But I can say the stock datsun fuel pump -CAN- overflow the R1 carbs,  The stock R1 electric fuel pump turns off when there is back pressure(when the float bowls are full) so perhaps it could be getting too much?  Try putting at 3 turns mixture for an L18.  My 2 liter started with 3.5 turns.

 

Is it trying to fire at all ???  

 

 

Needles have holes in them ?!?! Perhaps some sort of lean needles for a bike ?  I would try replacing with stock R1 needles.

[spudly13]

does it cough and sputter at all? or just nothing? try squirting gas down each carb, it should do something no matter how the carbs are set up, that's how I would always get mine going instead of cranking on it forever after taking the carbs apart.

 

at least then if it does fire up it will help you narrow down the problem

[dangero]

Thanks dudes! it turned out to be super fouled plugs. I replaced them with bp5es (had 6 in there) and it fired first turn!!!!

 

I have the timing set to 10 deg in the video below and there is no vacuum advance. I will have to tap a manifold runner to add it. Its also running WAAAY lean as soon as you get into the needle so I think I am going to have to redrill the jets but wont know till I stick a wideband up there.

 

What static timing are you guys running if you are not running vac advance? 10 degrees feels fairly sluggish...

 

[HudsonMC]

air mixture hole on the throttle side blocked (the one that feeds airbox pressure to the main jet)

 

What's up with this? I haven't heard anyone talking about blocking mixture holes...?

 

another thing I have noticed is my needles are hollow with 2 rows of little holes in either side, they are not the tapered needles pictured everyone appears to have. The main jets laso had 135 stamped in them and I am wondering if these are the issues.

 

Those are MJN needles. Pretty cool, glad you were able to get them working for you. 

[PHANTOMa]

Manifold cut to the flange and waiting on runners to be fit and welded

[Stupid_fast]

Are you going to run EDIS/megajolt ?

[dangero]

What's up with this? I haven't heard anyone talking about blocking mixture holes...?

 

 

Those are MJN needles. Pretty cool, glad you were able to get them working for you. 

 I cant for the life of me find the thread that it was in but there was some excellent information on R1 carbs and if you are looking through the carb on the bottom there are  little holes. if you block off the main one the effect is like having a bigger main jet.

 

this is due to the main jen not mixing air with fuel before it enters the body of the carb. here is a link discussing the hole http://www.locostbuilders.co.uk/viewthread.php?tid=67564 I will try to dig up the thread with more information.

 

MJN Needles? cool I will look into them. I did notice in te process of cleaning the carbs I sprayed carb cleaner in the end of the needles and the mist that came out of the holes was VERY fine! The car is running well and apart from having to go up to a bigger size main jet it looks pretty good.

 

The L18's capacity has been rased to 1874cc with a 11.3 ish compression ratio and a mild cam so its going to need more fuel than your normal L18. I am going to drill out the jets step by step till I get it running right and then order jets n that size.

 

Currently 1.6mm but an going to go to 1.75 if i can get a drill bit that size or 1.8 if not

 

it does idle perfectly when warm at 900 rpm no carb cough or lope. the carbs have been messed with before I got them and I did not red th size of the idle jet so it may not be stock.

[Stupid_fast]

@dangero, edit, nvm 1.75's sound perfect for that build.

 

 

Why are MJN needles ???  I cant find any info on them ? 

[dangero]

I redrille the jets to 1.75mm and its now running sweet! the new motor needs some time to free up and I only drive up the street. didnt want to attract too much attention in a rlly car with no plates.

 

The MJN needles are short for "Multiple Jet Nozzle" Thanks HudsonMC for the heads up... they are pretty awesome design and are marketed as a kit by Yoshimura have a look at this video they are way cool!!!

 

http://www.youtube.com/watch?v=APq5jz4T_08

 

I scored a pretty good deal. I bought the carbs off ebay in the states and had them shipped to me here in Australia for less than the price of the the yoshimura kit!!! I think I am going to have some velocity stacks turned up for the carbs. I have a set on my clubman and they made a big difference to throttle response and peak power.

 

here they are on my clubman

 

 

this is what a clubman is

 

 

they were made by jnt performance http://www.jntperformance.com.au/ they will make any size you want but most importantly the profile has been designed correctly you give you the best flow.

 

in the right size for the R1 carbs they are about $18.50 us each and postage wuld not be much.

[VintageRice]

HATE U !  Dead sexy cars.   WANT ONE.

[Stupid_fast]

Soooo much want of those velocity stacks !!!

 

Do show how you mount them, I'd love to buy a set for mine. 

[dangero]

on R1 carbs

 

inner = 42mm

outer = 46.5mm

 

you could get them made up and use a small sleeve to go over the outer of the carb and over the straight section of te velocity stack with just 1 band clamp holding the assembly on the wal thickness of the stacks is 1.2 iirc giving you a total of 44.5mm.

 

infact with a really thin rubber shim wrapped around both and then the clamp it would work perfectly, if you did it neatley and had the clamp at the bottom and the stainless band at the top you wouldnt even see the rubber or bolt, just a neat stainless band then the stack.

 

I just bought a pipercross filter and backing plate. In the end I am sacrificing power for reliability. The car is going to be driven on dirt and I want the best filtration I can get, so the pretty stacks wont fit under the filter :(

 

Stupid Fast, I can call the dude and see if he can make an interference fit if you like, I will give him the dimensions and ask a price and post up his reply.

 

Vintage Rice, Thanks I think!!! Mine is the red one. I have had it for 3 years and love it to bits, it drives like nothing else you can leagally drive on the road and brings a smile to my face every single time I drive it. Not sure what your regulations are like in the US, they are so rediculously strict here and registration is a real nightmare but people still build them from scratch and go through an enineering process to get them on the road.

 

check out:

 

http://www.locostusa.com/forums/ really good bunch of people and a great recource!

 

sorry for the OT post!

[Stupid_fast]

@dangero, I thought of that using a clamp or rubber sleeve to attach the stacks, it seems like the best solution short of welding them on.  

 

I am also running a pipercross filter on mine, I was thinking a small stack could fit under them, but I have not measured anything yet.  Would even a short stack not fit? 

 

An interference fit would be nice, but would it in any way effect the air flow ?  I'm not sure if I care as I just crave that sweet velocity stack sound.  

 

At $20 a stack it seems like a great option, the only aftermarket R1 stacks run for $250+

[HudsonMC]

If you're running them under a pipercross filter, looks shouldn't be a problem. Why not use the OEM yamaha rubber stacks. They have a little angle on them...dunno what for though. I would assume something to do with the yamaha airbox fitment. 

[Stupid_fast]

@HudsonMC, I didn't get stock stacks when I bought the carbs, if I see a set up for sale I'll buy em but I figured it would be more worth it to upgrade them. 

 

They seem to be about $40 on ebay ...

[dangero]

Righto! I have done some measurements and the 42mm diameter stacks that are 50mm long will fit under the pipercross and itg filters perfectly. they have a 68mm bellmouth and the radius is perfect for both the carbs and the filter.

 

With CV carbs, there is less importance in the length of the stack due to the slider/piston helping to create velocity. What is important it the rate of curve and the bell shape. so to 50mm under the filter is a perfect combination I spoke to JNT and they said the method of clamp over hose would be the best method as it would centre the stack and there would be a perfect transition line between the carb and the stack.

 

Having said all that, I already have the rubber stacks and they will JUST fit under the filter at 65mm long VS the 50mm alloy stack. I will upgrade to the alloy ones once the car is ready for tuning for $80 you can't go wrong!!!

[Stupid_fast]

Well yeah, for only $80 I'm definitely interested in a set !!!

 

Sounds great !  Where do I throw my money?

[dangero]

http://www.jntperformance.com.au/ :)

 

here is the exact part you are after

 

http://www.jntperformance.com.au/index_i6515573.html?catId=269035

 

postage would be about $19

 

cheers!

[Stupid_fast]

Ah right you already posted that, I was sleepy at the time I posted. :P

 

Thanks, hopefully I'll have those in a week or two.

[dangero]

i had a problem with cam timing that has now been resolved thanks to datzenmike!

 

I took the car out for a drive and it pulls HARD all the way to 7,000 rpm. I have to raise the needles 1 clip higher as its pinging slightly in the transition from part to full throttle but appears to be perfect on full throttle. I wil do this and see if its right, otherwie it will have to be a step up to 1.8 jets and lower the needles.

 

idle is perfect and it does not backfire or run rough anywhere.

 

Before fitting the R1 carbs I had a pair of genuine 1.75 SU's and the R1 carbs pull a lot harder and run smoother. The plan from here is to dyno the car in the next month to see if I have cracked 100hp. seat of the pants dyno tells me the car is making good power. I m really glad I fitted these carbs and ot was honestly a really easy job, the hardest part was making the manifold followed by throttle assembly.

 

I used bike cables for both choke cable and throttle, just had t grind down the round end slightly smaller to fit the bike carbs.

 

here is the breakdown of costs

 

R1 carbs $196 delivered

manifold materal $36 + some tig rods and a stock manifold I used for the flanges

radiator hose 44mm diameter $16

8 hose clamps $31

bike cables $22

1.75 and 1.8mm drill bits $5

 

Total $306 :w00t:

 

pipercross air filter & custom back plate for R1 carbs $175 :no:

 

I could have bought the cheap ass chinese filter stcks for 15 bucks and would have if the car was only used on the road but its going to be used on dirt 90% of the time and I didnt want dust to kill my new motor... cheap insurance!

[dangero]

I spent a bit of time stuffng around with a wideband 02 sensor today and have the car running properly. it starts and idles perfecty once warm with an AFR of 14:1 any leaner and it pops slightly.

here are the AFR's for rev range

hard pull in socond gear
2000 - 13.5:1
3000 - 13.2:1
4000 - 13.8:1
5000 - 14.2:1
6000 - 13.7:1

 seems to taper off quite quickly from about 5,700rpm

Here is the jetting and carb settings for the engine (wont really help anyone as the needles are MJN yoshimura needles and will be different to standard R1 needles.

1.75 main jets
17.5 pilots
air mixture screws 3.75 turns out
needles in the RICHEST setting I may have to step up to a richer main jet and lower the needles target AFR should be no leaner than 13.5:1

This was all done with a static timing of 15 BTDC using 98 ron fuel. there is no pinging but as soon as I connect the vacuum advance it detonates like hell!

I thought about the idea of using a restrictor in line with the dizzy vacuum line to reduce the amount of vacuum seen by the dizzy in effect reducing the rate of advance. This is easily done. I have used restrictors in all sorts of applications in turbo cars before. You can use a MIG welding torch tip inline. I will play with this if I do end up putting it on the dyno.

The car pulls pertty hard for a 1.8 NA engine and sounds pretty mean! using my mobile and racechrono, punching in the cars weight as an estimated 950 kg's with me in it and doing 0 - 100 takes 8.4 seconds... I thought it would be faster than this! I guess its got to loosen up a bit. it also estimates the horse power at 166hp. minus 20% for drive train loss and its a pretty respectable 132hp or almost exactly 100 rwkw! sounds a bit high to me, perhaps my guess on the cars weght is wrong or the software is nt that accurate.

puncing the nubers into olline calculators give very close results so its possible!

Will not know till I put it on the dyno in a few weeks.

[Stupid_fast]

Sounds like your L18 is running nice!  Vac Adv gave me a ton of trouble as well, static timing seems to run just fine. 

 

I'm surprised it runs out around 5700, must be the cam profile?

 

My AFR is too rich on the bottom(around 10:1 at 2000rpm) and too lean at the top(13.5 at 6000), yours looks like a much more flat AFR across the rev range.  Could it be my needles ?  I don't think they're stock R1 needles.  From reading about tuning, I'm not really sure what parts effect this range of tuning.  

[DADZSUN]

Going to go back through the thread for tuning info, just wondering if anyone has some tips for me !! 

 

Have you set your float levels? Changing the float height and hence the fuel height (within the bowl) can alter how the jets behave, either more rich or lean. Factory fuel height is 4.1-5.1mm below the line on the float chamber which apparently equates to approx. 6-7mm float height.

 

Good to see your notes on the wide band. Please be sure to continue sharing your data. How far downstream on the exhaust did you mount your O2 sensor? I've got a new Innovate MTX-L that was originally planned for a R1/KA24e build this winter but ran out of time due to work relocation - so I reinstalled my L20 and will use the wideband on it this summer. I'll be sharing my info as well, once I get the carbs working right. After running great for 4-5 months last summer, my R1 carbs have been gradually getting worse (random RPM hanging issues and dieseling on shut-off) and I suspect a new needle valve set is required.

[Stupid_fast]

@DADZSUN,  No ! Float level were the first thing I was going to try when I get my motor back together.  

 

I have the innovate LC-1, I'll continue sharing AFR data as I mess with the tune. 

 

The o2 is mounted right at the end of the header next to the steering box.

[DADZSUN]

Is anyone running ethanol mix on their R1 carbs?

 

So when I picked up my R1 needle valve set (P/N 4km-14107-15 includes full needle vavle seat with screen and O ring along with new needle vavle), the technician told me not to use high octane gas than includes ethanol mix on the carbs.

 

I'm aware of the potential rubber degradation issue but apparent the problem goes beyond that with ethanol, like fuel mixing/atomization. 

 

 

After some thought I realized that many of my issues on the carbs appeared shortly after running then on my l20. It's a high compression engine and I was forced to run high octane (confirmed to have ethanol mix) compared to my low octane L16 which ran flawlessly with the R1 carbs. 

 

Anyone else running ethanol mix? I would assume so since it's pretty much everywhere but I thought I'd ask.