R1 Carbs (lots of pics)

[crewy]

They turned out sick looks like there were casted.

[blackmarkit]

Nope 3d printer. It's my birthday/Christmas present. It takes along time 8 hrs each side. but it's amazing for prototyping. And it would have been very difficult to try and make a mold to cast any other way.

[Farmer Joe]

how resistant to heat is that plastic? 

[uberkevin]

Good question..

 

How big is your printer? You made the Mani in what program?

[blackmarkit]

My printer is small 8 x 9 x 10".

Pla is extruded at 410 degrees F

Abs is extruded at 482 degrees F

I drew it in rhino 3d. I thought about leaving plastic but the print is actually mesh inside not solid. I sure I could change a setting but I know alinum will work

[MantisX620]

So I have some sorta good news/bad news for guys running 1.8mm mains and are about 3.5 turns out on the screws. I got my wideband installed and heres what I observed so far. This is without me touching a thing yet.

 

Idle:  14.7 - 15.2 AFR

Part throttle under load : 15.1 - 16 AFR

Part throttle cruise: 14.9 - 15.4

Full throttle: 13.7 initially but the closer to redline I get it starts to lean out to 15.8 -16 AFR territory.

 

Based on the reading ive done, ill need bigger mains possibly to get that full throttle AFR down. I also heard that the needles can also cause this increasingly lean effect as they arent letting in enough fuel fast enough. Before I drill my mains, I think ill try raising the needles to see if that richens it some.

 

To reiterate, my engine is virtually stock. I have 2 and quarter exhaust and elec ignition. Stock cam. 

 

Overall though, it seems like the base settings are about right. I intend to richen up part throttle some just for the sake of keeping things cooler but I think I found why my truck gives out of steam up top. Its running oh shit lean!

[ap72license]

Does anyone have a ka24e manifold for sale still? I saw it listed on this thread several times.

 

Also, it seems 210 mains would be a good baseline for the ka24e?

 

Also, does anyone have a good timing curve for this engine with itb's?

[datzenmike]

This is the engine forum, for the discussion of anything engine related.

 

All buying and selling is done in the proper classifieds section and not on this forum..... http://community.ratsun.net/classifieds/category/4-engine/?sort_key=date_added&sort_order=desc

[datzenmike]

 

how resistant to heat is that plastic?

 

 

 

My printer is small 8 x 9 x 10".

Pla is extruded at 410 degrees F

Abs is extruded at 482 degrees F

I drew it in rhino 3d. I thought about leaving plastic but the print is actually mesh inside not solid. I sure I could change a setting but I know alinum will work

 

 

How resistant is it to an explosive back fire without splitting?? Maybe it could be much thicker?

 

 

 

So I have some sorta good news/bad news for guys running 1.8mm mains and are about 3.5 turns out on the screws. I got my wideband installed and heres what I observed so far. This is without me touching a thing yet.

 

Idle:  14.7 - 15.2 AFR

Part throttle under load : 15.1 - 16 AFR

Part throttle cruise: 14.9 - 15.4

Full throttle: 13.7 initially but the closer to redline I get it starts to lean out to 15.8 -16 AFR territory.

 

Based on the reading ive done, ill need bigger mains possibly to get that full throttle AFR down. I also heard that the needles can also cause this increasingly lean effect as they arent letting in enough fuel fast enough. Before I drill my mains, I think ill try raising the needles to see if that richens it some.

 

To reiterate, my engine is virtually stock. I have 2 and quarter exhaust and elec ignition. Stock cam. 

 

Overall though, it seems like the base settings are about right. I intend to richen up part throttle some just for the sake of keeping things cooler but I think I found why my truck gives out of steam up top. Its running oh shit lean!

 

 

This is fine................................................................................................... Idle: 14.7 - 15.2 AFR

Must always be lower than 14.7 and decreasing with load and throttle........  Part throttle under load : 15.1 - 16 AFR

This is fine................................................................................................... Part throttle cruise: 14.9 - 15.4

Should be 12s perhaps dip into 11s, never 14.7......................................... Full throttle: 13.7 initially but the closer to redline I get it starts to lean out to 15.8 -16 AFR territory.

[ap72license]

11s is way too low for decent power, unless your engine has issues you want to be right below 13:1 for max power.

 

Many of these engines are pretty worn though and you may need to get closer to 12:1.

 

Also, I didn't mean to start trouble, I just saw a ka manifold listed on this thread and it's not in the classifieds. I looked.

 

Related to the itb's, I was planning on running ms to control the timing, but I'm considering just running the l20 distributor. How much are people spending to run the l20 dizzy in a KA, I can't find the right used parts anywhere and the salvage yards by me mostly have stuff from late 80s and newer.

[datzenmike]

11s would be better in a modified engine yes.

 

No trouble. The reminder is mostly for others to see and remember.

[ap72license]

Not "modified" so much as "burning oil". A very well done modified engine will actually want a slightly leaner af ratio as it SHOULD be burning the fuel more efficiently. Oil burners and mismatched builds will require a slightly richer mixture but 11:1 is still pushing it for all but the worst NA engines- assuming you're running standard pump gasoline.

[uberkevin]

I originally started welding a intake together but they need to taper for the head and carb to have a nice transition.

Any more work on this?

[MantisX620]

Today, I installed 205 mains. I also found I had 175 jets in the carbs and not 180s like I thought. This changed my afr from 15.4-15.8 afr to 13.1-13.3 at full throttle. Wow! It pulls freakin awesome for what it is! I still want to add a cam but for now I'm very happy with the performance.

 

The only thing it does is go really lean when I get back on the throttle from a coast. Then it smooths out to around 14.5 or so. I'm not sure which jet or needle controls this so I'll need to research.

[zachariah768]

Does anyone have a picture of the bogg bros intake installed on an l20? I noticed there's a piece connecting the two pieces the looks like it might interfere with the exhaust manifold?

[Kirden]

I do not have one for the L20, but I have one for the A15. On the A15, that middle section needs to be removed prior to mounting. It is only there to provide proper spacing between the posts during manufaturing and prevent possible scratching or blemishes on the manifold during shipment. I'm fairly certain that this is similar for the L20 manifold design, but you would have to try a test fitment to be sure.

[DADZSUN]

Bringing this thread back from the dead - I'm almost complete a MegaJolt ignition swap on my KA24e/R1 setup.

 

I'd provide links to the YouTube clip and my build thread but this site seems to freeze when I hit the 'Link' icon. :confused: What a PITA...

 

As expected, the stronger spark appears to be leaning out the A/F so I'll have to consider playing with the jets once complete.

[MantisX620]

Mine is still running well, but I still have a lean spot up top (full throttle) where the AFRs climb a bit over 14. I have size 210 jets in the carbs, so I dunno if I accidentally bought a built engine or if something else is at play. It appears to want way more gas up top.

[ap72license]

Mine is still running well, but I still have a lean spot up top (full throttle) where the AFRs climb a bit over 14. I have size 210 jets in the carbs, so I dunno if I accidentally bought a built engine or if something else is at play. It appears to want way more gas up top.

May need to adjust your air bleeds as well. Just throwing more jet at it may cause it to run overly rich. Need to look at part throttle operation too, could just need a needle or spring adjustment.

[MantisX620]

I installed .215 main jets in my carbs today. No more leaning out up top and pulls way better. My afr gauge has me in low 13 afr. Are you guys sure .180s are the way to go?

 

MantisX

[Greensleaves]

Hello, is this thread still going? I've been reading all 63 pages... Fascinating! One thing I was wondering is if anyone has managed to succesfully drill and tap into the carb bodies for vac advance take offs? I few pages back it was touched on it but wasnt resolved. Am I right in thinking the best area to do it would be before or after the butterfly valves closing point .... That way at idle it won't advance all the time like it would if you were to tap off the inlet manifold? I'm just cautious of actually doing it for fear of it screwing the running of the carbs up.
By the way I'm from the UK and there is another company other than bogg bros .... http://www.danstengineering.co.uk And no I don't work for them It's not an advertising campaign.
Thank you in advance.

[datzenmike]

Good question. On a ported vacuum advance the port is just above the closed, at idle, throttle plate. Some that I have seen have a very small vertical slit down to, and probably below the plate. So, there may be a very small advance present?? shrug?? Generally there is none until the throttle plate moves up and exposes the port to intake vacuum.

 

R-1s (just like SUs) are constant velocity carbs with a sliding venturi ahead of the throttle plate. I don't know it that would affect the vacuum signal or not. One port would be subjected to strong vacuum pulses from cylinder suction however at 1000 RPMs that 500 sucks per min. or 8.3 per second... I doubt very much the vacuum advance could react that fast and the length of the hose would tend to be tend to act like a reservoir to smooth it out.

[Greensleaves]

Good question. On a ported vacuum advance the port is just above the closed, at idle, throttle plate. Some that I have seen have a very small vertical slit down to, and probably below the plate.

Thanks for your reply. Just to clarify when you say above and below the throttle plate do you mean that it's on the side closest the engine or the side toward the air intake? Or literally directly above or below the sliding throttle plate?

[datzenmike]

The slide is designed to provide a constant velocity across the needle valve, by opening and closing by a vacuum signal and why they are called a constant velocity carb. A vacuum signal sucks the slide up, keeping pace with the demand for air. It doesn't open all at once. The air speed below the slide stays constant no matter how open or closed it is.

 

 

I have a set of Hitachi SU carbs and the front one has a vacuum advance port but how it works I don't know.

 

I did find this...

 

On many cars it is found desirable to use vacuum operated ignition advance to obtain optimum part throttle consumption figures. The take-off point for this vacuum is arranged slightly to the air intake side of the butterfly, and in such a position that opening the butterfly allows the throttle disc to pass over the vacuum take-off point so that it then communicates with the manifold depression. By this means the vacuum is small at the distributor during idling and full throttle conditions, and is large at part throttle, being at a maximum when the throttle is open a few degrees.

 

Here ... http://sucarb.co.uk/technical-su-carburetters

about 1/5 th the way down. Now this applies to the British SU and by association the Hitachi copy of the SU. Bike carbs are probably another matter???

[Greensleaves]

Good info!

On the underside of the carbs there is a brass plug? Which is directly in line with 3 little holes under the butterfly valve (see pics) I wonder if that might be a good place to tap into. Take the brass plug out maybe. Do you know what lies under this plug? Maybe more pathways from other points? I which case I'll leave it be.