R1 Carbs (lots of pics)

[Stupid_fast]

:sneaky:

[captaingamez]

I am actually a yamaha certified technician so I can say that on the R1, I would drill out the hole on the slide. that will make it pull from the emulsion tube faster, thus giving you fuel quicker. then tune your needle accordingly.

 

you can try needles from different carbs to, but I would start with slightly enlarging hole, you can always seal it with epoxy and start over.

 

another fine tuning we would do is cutting the springs down a bit.

 

 

we used to do this alot when tuning carbs, at the dealership, and on the track. personally I always liked the old fixed slide carbs from the 70's but I digress.

[OkieRA29]

Okay, after reading the entire thread... took for ever!  I have a question.  Everybody is using the R1 Carbs, which I believe are for an 1100CC bike correct?  If so, since R1 carbs have nearly reached  the price of a set of dual webers(on ebay at least) I should be able to use any other carb as long as it is for around 1000cc correct?  I ask because I can find carbs for CBR900s, FZR900, heck even ZX900s for about half the price of the R1s.  Also, does this info translate over to the Keihin carbs as well? I am also finding those pretty cheap on Ebay as well.  Thanks for tolerating my stupid questions!

Oh yeah, will be going on a 2.2(20R) Toyota motor

[captaingamez]

the r1 is only 1000cc, but it revs all the way to almost 12,000 rpm, the intake volume flowing at that engine speed is tremendous, I dont have any figures on hand, but I would bet that it is close to a stock l16 or l20 at top whack. so for that reason it has large carburetors. anything with similarly sized carbs will be pretty close to the same. Yamaha doesnt even make the carburetors, they are made by Mikuni, and Mikuni makes carbs for everyone that Keihin doesnt make them for, so like half and half.

 

I havent seen somebody try fixed slide carbs, but I dont see why the wouldnt work, problem is that most fixed slide carbs are a bit smaller so probably not ideal.

 

I would look for early 2000s and mid 90's liter bike carburetors. Liter bike doesnt just mean 1000cc, it means 1000cc sports/racing bike (crotch rocket) a Honda cb900 cruiser likely wont be big enough

[OkieRA29]

Okay, that is what I was thinking.  I have found a bunch of mid eighties and 90s bike carbs as well.  Mostly GS1000 type stuff and they look the same, but I can't tell.  I have called around to some of the different bike shops around here and seems like nobody keeps spares on hand.  I will just keep looking

[Stupid_fast]

I am actually a yamaha certified technician so I can say that on the R1, I would drill out the hole on the slide. that will make it pull from the emulsion tube faster, thus giving you fuel quicker. then tune your needle accordingly.

 

you can try needles from different carbs to, but I would start with slightly enlarging hole, you can always seal it with epoxy and start over.

 

another fine tuning we would do is cutting the springs down a bit.

 

 

we used to do this alot when tuning carbs, at the dealership, and on the track. personally I always liked the old fixed slide carbs from the 70's but I digress.

 

 

A Yamaha Tech!? Cool ! 

 

Am I on the right track suspecting the needle jets(aka emulsion jets tubes whatever wrong name people call them) are causing my low end rich problem?

 

Drilling the slides?  Any baseline to start at? What effect does this have on AFR ? leaning or enriching ? curious about this.  Seems like it would lean the slide a bit?  Seems it would lean the low end were the slides aren't fully open? 

[captaingamez]

well it has been a few years but I was a Yamaha tech, just before the R1 went to the crazy big bang crank, so around 2008

 

to be honest, it might lean the low end a bit, it might not. I used to do this in very incremental steps, only enlarging the hole ever so slightly, then driving for a baseline and seeing where it is. sometimes I had to ride a bike 10-15 times before it was exact and its a lot less fun when you have to remove plastics, a tank an air box then the carbs, then make adjustments, then re-install.

 

the best way to do it is always on a dyno but obviously most of us dont have that convenience.

 

you have to physically change some parts of the carb to make it ideal though, and that is while the carburetor is on a Yamaha R1 still, big exhaust, and then big horns on the carbs mean big jet tuning. I can only imagine it would be the same putting them on a car engine. we used to buy DynoJet jet kits for the liter and 600cc bikes and they usually included a drill bit to drill the hole, different needles, different pilot and main jet, and lighter slide springs to make the slide raise faster.

[OkieRA29]

Ok, gonna do this after re-reading this thread.  One hurdle is out of the way.  After weeks of searching CL and Ebay I have decided to go with a local cycle shop for the carbs.  Prices on the bay+shipping are about what cycle shop will charge(150$+tax)  Mostly Harley stuff around here on CL and I searched all of Oklahoma and a bunch of the Dallas sites.  Thinking I can get a wideband either from CL or one of my drifting buddies.  Stock Fuel pump on the celica flows 6-8 Gph and I already have a FPR on there for the weber.  So really all that is left is fabbing the intake and figuring out the accel and choke cable.  Figure once I get everything together, I can sell the Weber(45 DCOE) to recoup some of my costs.  I will try to post pics and data here.  Planning on starting with a 190 and a 200 main jet as the engine is a 2.2 liter.

[OkieRA29]

Welp, got me some carbs from a local shop.  The counter gal was super cool and ended up letting me have 2 sets for the price she quoted me for one.  The R1 carbs she had were not complete so I grabbed what I thought was another set.  Turns out they are 38mm so nothing will swap over.  Headed back tomorrow to swap them out again.  She said I was more than welcome to.  Any rate, they had a ton of the Keihin carbs for liter bikes.  I know that I can use them, but will they take the Weber jets like the mikuni?  I am bringing my calipers tomorrow so I can verify and make sure I am getting the right sized carbs.

[Stupid_fast]

So I received the replacement needle jets.

 

I pulled out one of the needle slides from the carb, and slid it down into the new neeldle jet .... it doesn't seal !! it has a ton of play around it, so it seems that my needles are at such a rich setting that they don't seal at low rpm/low throttle. 

 

I took the air filter off and watched it at idle ... sure enough all four are pouring fuel into the carbs at idle !!  I can imagine the pilot tune is all kinds of screwed up with this happening.

I probably have to get some different taper jet needles.  I'm going to measure mine and figure out what I need for this motor.

 

For anyone else with the low end rich problem, check and make sure your jet needles are properly sealing against the needle jets with the slides closed.

[captaingamez]

you are talking about just the needle right? the "needle jet" or "main jet" is the jet in the bowl at the bottom of the enrichener tube, the Needle is in the slide, which did you replace?

 

you can try changing the main enrichener air jet, that may help, its located in the intake side (the small holes in the bell) the needle and enrichener tube/main jet shouldnt be sealed at idle, but they shouldn't be pouring fuel either, there should only be a tiny bit coming out at idle.

 

what kind of needles did you get? I would possibly try Vmax needles....maybe.

[Stupid_fast]

you are talking about just the needle right? the "needle jet" or "main jet" is the jet in the bowl at the bottom of the enrichener tube, the Needle is in the slide, which did you replace?

 

you can try changing the main enrichener air jet, that may help, its located in the intake side (the small holes in the bell) the needle and enrichener tube/main jet shouldnt be sealed at idle, but they shouldn't be pouring fuel either, there should only be a tiny bit coming out at idle.

 

what kind of needles did you get? I would possibly try Vmax needles....maybe.

 

 

The jet needle and needle jet are two different parts.  I'm not talking about anything in the float bowl.

 

The jet needle attaches to the vacuum slides, it is the thing that is a real needle.

 

The needle slides into the needle jet, wich is a port at the bottom of the bore, the needle slides in and out of this controlling the flow of fuel from the main jet as the RPM and throttle increase/decrease.  

 

At idle the needle jet should be sealed by the jet needle, and not flowing fuel from the main jet.  

Idle fuel is metered and supplied by the pilot hole and pilot jet circuit.

 

THIS is a needle jet.  I have not replaced them yet, I'm not sure if I even had to.  Expensive to replace if worn, Dynojet $20 each. 

 

 

Depending on fuel, driving conditions, and many other variables the needle jets can wear in an oval shape and cause the issue I'm having, they won't seal properly at idle and need to be replaced.

 

Though in my case, I simply have the needles backed so far that the needle taper is not steep enough to function properly.  

[captaingamez]

I was going under the assumption that You had them in the down most position in the slide.

[Stupid_fast]

I was going under the assumption that You had them in the down most position in the slide.

I have them raised a bit over half, they're some aftermarket needle thats not stock to the R1.  If I lower the needles it runs nice at the bottom, but its way too lean at the top, 4-6k popping and lean AFR's at part throttle. 

 

The tops are 2.5mm, and the needle jets are 2.6mm diameter... this is probably the cause of my issue.

 

Going to buy new needles now and see where the tune ends up.

 

edit, apparently the 6-clip no-marking needles I have are a dynojet kit ... 

 

 

I'm having a BAD time finding the right needles online ... I'm going to go to a cycle shop and see if they can help me out.

Anyone know where to find a good selection of needles ???

[OkieRA29]

Hey, after searching and searching all 54 pages, I have a question.  Are there any good online sources for info on stripping and rebuilding the R1 carb?  I am looking mainly for float height specs and the like.  I have found a couple of online tutorials for rebuilding the BS series, which is pretty much what these are, but no specs on float height.  Also stupid stuff, like which is the pilot and main jet etc..  Am I going to have to buy a mikuni manual to get this stuff?

[Stupid_fast]

@OkieRA29,  All I had to do with my carbs was disassembly the visable parts and clean everything out.  Blow jets with carb cleaner, clean the vacuum slides, and put new float bowl gaskets.

 

A few pages back you'll find someone posted float height spec is suppose to be around 6.5mm from gasket surface.  Seems to be a fine baseline.  you can play with the setting after your jetting is mostly dialed in.

 

 

 

 

 

Anyone know where to get needles to fit these carbs ??? 64.7mm length (Mikuni #6), I need one with a 2.60mm straight section and more aggressive taper.  Mine are too rich in the low end.   Having a hard time finding the right fitment for BDSR40's. 

[OkieRA29]

That is what I figured.  I will look again for the float height post. Well, Duh! don't I feel like an idiot.  The float height was posted two pages back...

[OkieRA29]

Okay, some confusion on my part...

 

I know the labeled stuff, main, needle and pilot jet, but I need to know if and how I remove the needle jet.  Do I need to remove the needle jet if I am just cleaning and reassembling the carbs.  Should I get a bigger hammer to remove it.  I know that it is supposed to come out the top but it doesn't want to seem to budge. 

 

TIA

 

Oh yeah, the parts circled in red and yellow, do I need to remove those as well?  If I do, any advice on how to do it.  This is a parts carb, so don't worry about the dirt and stuff.  The real carbs are much cleaner.

[Stupid_fast]

The needle jet is removed from the other side of the carbs, its attached to the vacuum slides with a little clip thingy.

 

Two screws to remove the top cap, the slides slide right out.

 

 

Ignore the parts in red and yellow.

 

Blow any holes out with carb cleaner or compressed air if you have a compressor.

 

 

you should never have to hammer anything on these carbs to remove them. 

[OkieRA29]

The jet needle and needle jet are two different parts.  I'm not talking about anything in the float bowl.

 

The jet needle attaches to the vacuum slides, it is the thing that is a real needle.

 

The needle slides into the needle jet, wich is a port at the bottom of the bore, the needle slides in and out of this controlling the flow of fuel from the main jet as the RPM and throttle increase/decrease.  

 

According to your own post, I have the needle jet correctly identified.  The jet needle is already out and clean.  Most cleaning tutorials I have looked at tell you to remove the needle jet to clean it.  I know they come out from above, most of the tutorials show this.  If I can carb dip the sucker without it coming out, that is fine by me.

 

Oh yeah, I might be able to run by the shop I bought my carbs from and pick up some extra slides and needles if you want.  They would be the stock needles out of either 37 or 39mm carbs if those will work.

[Stupid_fast]

@OkieRA29, I must have misread your post ... looks like you have everything properly identified. 

 

It depends, I need to know the measurement of stock needles at the straight section(top) and it has to be a 64mm length needle. 

[OkieRA29]

In reading your prior posts, I am guessing that you will need 2.5mm needles?  I will bring my calipers with me this weekend when I run over.  On another note I discovered something for those searching for a vacuum source with these carbs.  Here is the R1 carbs  See that dimple at about 11 o'clock on the carb body?

 

 

Here are the GSXR carbs I have.  They are about the same size as the R1s.  They measure 39.7mm with my dial calipers. 

 

See that capped brass fitting.  It is for the vacuum assisted enrichment circut that Suzuki had.  Most people with GSXRs just cap these and move on.   I am thinking, that rather than tapping all four runners and going to a vacuum manifold, I can tap in there.  Here is the thing, I am using the R1 carbs and not the GSXRs.  I am planning on measuring the brass tube on the GSXRs and getting something that size.  I am going to drill into the R1 carbs at that dimple and insert the brass tubes.  I will then plumb that to my vacuum manifold.  Any thoughts. warnings?

 

Oh yeah, I haven't checked, but I am guessing that the hole on in the inside of carb is present on both sets, will confirm in the morning

[Stupid_fast]

 I'd like the measurement of the straight section of the stock R1 needles, and/or a 2.6mm straight section needle with an aggressive taper.  That'd be about 2.6mm straight section all the way down to a 1mm or less at the end measurement to keep the midrange/high range about the same as it currently is. 

 

This would lean out the low end while keeping the top end rich enough. 

[OkieRA29]

Sorry man, no joy on the needles so far.  I do have this complaint to make though,  Who uses blue loctitie on brass screws????

 

 

 

All the screws on the intake side of the carbs had loctite on them.  Of course, this was only noticed after I had stripped two of the screw heads.  After two days, I finally got one out, but will have to tap the hole for bigger screws.  The other, I broke the extractor off in it... I have since snapped three drill bits trying to get the extractor out...

[Stupid_fast]

Oh thats always fun.  Who would do that? just put loctite on something serviceable ...

 

 

Needles... no problem. it seems these are really hard to find a specific needle.   I ordered some random #6 (60mm) mikuni needle from a Yamaha dealer, I'm gong to measure it and see if I ID'd the part number correctly.  Next step is to go to a performance bike shop and see what they have to say.