Which Emulsion Tubes to use with Ivan's Kit

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Blobber
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Which Emulsion Tubes to use with Ivan's Kit

#1 Post by Blobber » Thu May 28, 2015 9:39 am

I have removed my carburettors from my RZV500R and getting them ready for when I take delivery of my Ivan’s Needle Kit.

My dilemma is which emulsion tubes to use. The choice I have to hand is:-

• Use original n-6 front and n-8 back. I’m still not sure if these are restrictive to an extent that it will matter?
• Use Keyster pattern n-8 front and back (1GE repair kit). Unknown quality/size etc but do seem to function OK at the moment

I’d normally just try them but the carbs are such a pain to keep taking on and off any advice would be appreciated.

My favourite is to use the original Mikuni n-6 and n-8 where the quality is known but I don’t want to damage my engine with a weak mixture.

Thanks
Trevor
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Scbr1
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Re: Which Emulsion Tubes to use with Ivan's Kit

#2 Post by Scbr1 » Thu May 28, 2015 7:24 pm

Hi Blobber, I'm no expert by any means but think if you are jetting to 1GE spec I would try to use original mikuni n-8 14 hole needle jets in all 4 carbs (think this is what the last production bikes came out the factory with). Think you will find that the Keyster 1GE carb kits have o-0 size needle jets, far to rich. If you can't get the N-8 original ones Ivan sells a set he makes to same spec as n-8 think they are $180. He put about them on the email he sent me when I asked him the price on his needle & jet kit. Hope this helps m8.

Blobber
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Re: Which Emulsion Tubes to use with Ivan's Kit

#3 Post by Blobber » Fri May 29, 2015 4:33 am

Hi Scbr - I agree totally with what you say but dont have a set of original 14 hole N-8 and dont really want to spend another $185 on Ivans. Keyster did a 47x and 1GE kit, are you saying the same O-0 emulsion tubes were used in the two different kits?

I remember reading a post from someone a long time ago who claimed you could use the original 10 hole N-6 and N-8 which came with the restricted RZV but cant find it and cant remember their reasoning behind the claim.

Guess I just need to try them..............
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Re: Which Emulsion Tubes to use with Ivan's Kit

#4 Post by Scbr1 » Fri May 29, 2015 10:35 am

Hi Trevor yeah think you will find the needle jets are the same in both kits, sure I read that on the forum sometime. Someone may be able to chip in with more knowledge than me, but it makes sense if they can get away with o-0 in both kits = cheaper to manufacture. I got an RZV like you. My RZV is standard and I have jetted to 1GE spec with n-8 needle jets, 165 mains, 22.5 pilot & 1.1 pilot air jets. I have recently put in 1.4 pilot air jets as I think the latest production run came with them as standard ? Seems to bog a bit on low throttle / pull away. Thinking about 25 pilot jets but can seem to find a definitive answer if the last production RD/RZ's came with 1.1 pilot are jets & 22.5 pilot or 1.4 & 25 pilot. If anyone knows please let me know.

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Re: Which Emulsion Tubes to use with Ivan's Kit

#5 Post by Blobber » Fri May 29, 2015 10:58 am

Hi Scbr - I have 22.5 pilots, 1.4 and 165 and it runs great on start up, initial pull away and when under load with any throttle position - absolutely no bogging but may be its because of the O-0 needle jet making it overall a bit richer. As I said before the running of the bike is fantastic I feel its just over fueled and unstable when at low loads/small throttle openings trying to hold say 3 or 4k revs in traffic.

Changing the pilot air jet from 1.1 to 1.4 made a big difference as it leaned it out which ultimately made the bike crisper and more powerful at low revs. I have tried larger pilots up to 27 but things get worse which confirms that the bike is over fueled at lowish throttle openings.
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Re: Which Emulsion Tubes to use with Ivan's Kit

#6 Post by Scbr1 » Fri May 29, 2015 2:24 pm

Hopefully Ivan's needles will sort the low throttle issues for you. Think if I was you I would try to get hold of another 2 n-8 RZV 10 hole needle jets to go along with the 2 you got so you can put the same in all 4 carbs. Think I have a couple in really good shape in the garage. Let me know if you are interested & I will have a look for ya.
Steve

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Re: Which Emulsion Tubes to use with Ivan's Kit

#7 Post by Blobber » Mon Jun 01, 2015 4:51 am

Hi Steve - Ivan's kit arrived on Saturday and looks really nice. Professionally packaged and clear instructions. He does still recommend drilling the pilot hole out to a 1/16 for smoother fueling but think I will possibly try that at a later date see how just changing the needles, main jets and float height works out first.
Thanks for the offer of two 10 hole n-8 tubes. If you can find them I would be interested in them as I still think that the 10 vs. 14 holes is not that critical. I could always get them drilled if it proved to be a problem. See if you can find them for me and let me know what I owe you.
Out of interest I have tried the needles in the Keyster emulsion tubes and the n-8 10 hole and the needle definitely is a slacker fit in the Keyster kit which points to them being o-0. Not very scientific I know.......however I dont have any suitable measuring gear.
Ivan makes no mention of the emulsion tubes in his instructions which I find strange.
Cheers
Trevor
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Re: Which Emulsion Tubes to use with Ivan's Kit

#8 Post by Scbr1 » Mon Jun 01, 2015 10:55 am

Hi Trevor

Glad you kit arrived safely & is looking good. Yeah I don't think the 10 hole or 14 hole thing will make any difference to be honest. If you PM me your address I will send you the needle jetts, no charge m8 there yours if you want them.

Cheers

Steve

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Re: Which Emulsion Tubes to use with Ivan's Kit

#9 Post by Blobber » Mon Jun 01, 2015 11:24 am

Thanks Steve - very kind I've emailed you and PM
Cheers
Trevor
PS - are you waiting for your needles to arrive?
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Re: Which Emulsion Tubes to use with Ivan's Kit

#10 Post by Scbr1 » Mon Jun 01, 2015 11:53 am

Hi Trevor yep still waiting for them. Cant wait for them to arrive (not lol) as it's so much fun getting the carbs off these things. Whatever were they thinking. Will stick the needle jets in the post today or tomorrow for you as sure your itching to get them carbs back on.

Steve

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Re: Which Emulsion Tubes to use with Ivan's Kit

#11 Post by Blobber » Mon Jun 01, 2015 12:13 pm

Yeah cant wait will initially try the type A needles clip in middle with 175 mains and n-8 10 hole tubes, hopefully all will be good and carbs can finally stay on the bike where they belong! I have already readjusted the floats and was surprised that the fuel level prior to the readjust was around 5-5.5mm below the gasket surface so a bit low really and it was me that had adjusted previously to the 3.5mm. Not sure why this had changed as I spent ages setting them up to what I had thought was spot on. The float tang had to be bent quite a bit to bring the fuel level back to the 2.5mm Ivan specifies.
Trevor
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Re: Which Emulsion Tubes to use with Ivan's Kit

#12 Post by Blobber » Wed Jun 03, 2015 11:45 am

I've just got two more N-8 series 487 emulsion tubes from an RZV and they are different to the two taken from my RZV!
Both types are stamped N-8 series 487 but the 10 holes are in different places.
I'd be interetsed to know what other RZV owners have in theirs.
Does it matter where the holes are?
I'm guessing it does but.........
May be best to get all 4 tubes drilled with the additional 4 holes
Anyone any advice as I'd rather not go to the hassle of having them drilled.
Cheers
Trevor
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Re: Which Emulsion Tubes to use with Ivan's Kit

#13 Post by nzminis » Wed Jun 03, 2015 4:21 pm

after the testing i did your right , 10 vs. 14 holes is not that critical
and i had the aftermarket tubes measured and they are 0-o far to rich to be of any use really

hard to say if the hole lay out would change anything . but do remember there are 2 Rzv models . 51x and 1gg , even know the 1gg is still marked as 51x

if i recall all the 6 bikes i have had apart had the tubes like your 2nd picture
i will also be interested in anyone else running the 1.4 air jets on your setup
and what the very last bikes used in them . i think i had a parts manual for the last bikes but i cant find the info again

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Re: Which Emulsion Tubes to use with Ivan's Kit

#14 Post by Blobber » Fri Jun 05, 2015 7:40 am

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OK guys just had a chat with one of the Mikuni distributor in UK regarding all my emulsion tubes:-

His view regarding keyster is that the accuracy is unknown and best to avoid using them.

All the emulsion tubes I have in the photo below are specials made for specific applications and probably specific bikes and are not available. He did however think it likely that many of the bike manufacturers will start making things like this available as it is a good money maker particularly as most manufacturers are struggling with new bike sales at the moment.

Now to the main question of which tubes should I use? His view was that I should keep everything the same as factory as Yamaha knew what they were doing although as we know these bikes are inherently rich but having said that what combination of jets/tubes is this view based on – all of them? We examined the various hole patterns and he confirmed they are put in the various locations for a reason. The holes allow the air to pass into the emulsion tube bore controlled by the needle position and mix with the fuel which is drawn through the main jet.

When the throttle is opened the needle move up the emulsion tube and exposes bleed holes allowing more air into the tube to mix with the corresponding additional fuel. If the needle is passing an area where there are no additional holes being exposed then more fuel is provided to the carb throat but not a corresponding additional amount of air. This will cause the mixture to be richer than if there were holes being exposed. As it passes areas where there are additional holes being exposed the mixture will be weaker than if there were no holes being exposed.

Ultimately the answer lies with me to just try the various tubes. What I do know for sure is that the Keyster so called N-8 (475) 1GE spec tubes I have are O-0.

Another thing that has always baffled me is why the rear cylinders of the RZV were given richer tubes but not the full power RD/RZ. The Mikuni guy reckoned it was logical to richen up the rear cylinders and I do know that when I bought my RZV it came de-restricted from Japan but not with 4 emulsion tubes all the same or even the RZ/RD items. It came with N-8 (345) in the front cylinders and O-0 (345) in the rear cylinders. As you can see in the photo they also did not have 14 holes like the RZ/RD series 475 tubes had. I kick myself but never rode the bike as bought – I straight away serviced the carbs and installed some of the Keyster bits including the emulsion tubes.

What bike do these 345 series tubes I have come from? Where they an RZV derestriction kit available from Yamaha?

Based on where the holes are drilled I’d guess that the N-8 (345) arrangement will be weaker than the N-8 (475) particularly during the initial stages of opening the throttle based on the needle not having passed any holes. This I guess is a good thing.

Anyway the top and bottom of it is that I am initially going to try the following settings:-

Pilot Jet – 22.5
Air bleed – 1.4
Main Jet – 175
Emulsion tubes – N-8 (345) front and O-0 (345) rear
Float height 22mm – 22.5mm
Needles – Ivan’s A

My pilot and air bleed work really nice at the moment with the Keyster O-0 and hence don’t intend to change this, however it may need to change using the 345 series tubes and Ivan’s needles as it may cause the initial small throttle opening to be weaker.

An interesting problem but a bit frustrating when you are unable to buy all the tubes you may want to try as I have no OEM N-8 (475) which would have also been interesting to try.

Any comment welcome - I'm no expert but above seems logical to me
Cheers
Ttevor
Last edited by Blobber on Wed Jun 10, 2015 10:44 am, edited 1 time in total.
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Re: Which Emulsion Tubes to use with Ivan's Kit

#15 Post by Blobber » Fri Jun 05, 2015 11:00 am

I've just been doing some more research and read that instead of using RD/RZ needle jets people fix the 10 bleed hole RZV jets by
putting in a larger main jet.
I can understand the theory; larger main jet less restrictive fuel supply into the carb but more fuel requires more air through the
bleed holes. This modification will surely just create an unrestricted fuel supply into the carb but overly rich due to the restrictive air
supply through the 10 holes.
Am I talking bollox?

What I am realising is that it is no surprise that people have massively different jetting in these bike because it doesnt just depend on
which emulsion tubes you are using. Its not as simple as I'm running N-8 or O-0 its also dependent on which series (or hole pattern
the jet is;
(i) 475=7 hole spaced equally along the tube
(ii) 487=5 holes one at the top and four equally spacing towards the bottom or
(iii) 345 with 5 holes equally spaced towards the top of the tube

There may possibly be other series numbers as well
Does anyone else have series 345 like me?

What a f****** nightmare................
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