127.5 Mikuni jets wanted.

[sharky]

http://www.streetfighters.com.au/forum/upload/5208559571791.gif


Is anyone that is going to Foxy's bbq at the w/e able to buy new 4 of the above jets for me ?
I need the large round head slotted type, 127.5

[devo]

I am picking up a few jets through the week ( well a Mate of mine is ) I don't know what sizes they are yet but I think we maybe wright any I dea roughly what sizes you may need , what jet sizes are you running at the moment.
I expect I should be getting these up to me by friday.
Let me know your plans.

[sharky]

The ones in the K&N jetkit were 122 and I have gone up to approx 130. I have checked the dynojet site and they use 124 mains for stage 3. Before I upped the jet I ran out of fuel at 180. With the 130's it pulled through. I don't know if I can go down from 130 yet...bit risky round here doing those speeds...
Be good to have a set in between for a rolling road run.
I have a set of drills so I can increase but obviously can't go back down.

[devo]

How soon do you need them I just have see what I get as they are a suprise bag at the moment.[:0]

[sharky]

I'm guessing at anything between 122 and 130. It runs ok'ish on the 130's but would be good to have some others to play with at the tuners, maybe 125/127.50 and 135ish.
If there's no sets of 4 in those sizes then just one or 2 in that range so that I can put the jet drills in to see what gauge size equals what jet size.
Won't need 'em for a week or 2....like towards the last week of the month.

[shift1313]

all jets arent created equal. Make sure you get the right jet for your style carb. Anyways, you dont need to run WOT in top gear to tune your bike. 2nd or 3rd gear roll on will do. Just feel/listen for problems on accel with hickups or lack of power. Everything above 1/4 throttle is going to be main and needle jet combo. 1/4 and below will be your idle circuit. Popping on decel means your pilot circuit is too lean. If your running out of fuel at WOT you might even just have a float level problem. If the bike runs smooth up until there then your floats might be too low so you are running them close to dry.

good luck

[sharky]

Matt, I checked float heights..they were as per manual spec. Are you saying maybe I should alter them from that or is stock correct ?

The jets I have are the larger head Mikuni's.

[sharky]

Been thinkin...surely if the float heights were too low the problem wouldn't go away with a larger main jet ??

[shift1313]

nope it wouldnt. Its hard to say if the stock height would be enough or not. How does the thing run from a 2nd gear roll on? What about hard decel? its just as easy to adjust the float height as to swap mains out so it might be worth a shot.

[sharky]

I'll go back to the beginning and try again, this time altering float heights. I still can't see it will be the problem though 'cos as I said (and you agreed) the float height/fuel level being too low would still cause a starvation problem, even with a larger main jet.

[Stocky]

Has anyone tried the Yoshi MJN needle/jets ?

There are a heap on ebay going cheap and they could be a good improvement for these carbs.

Totally different setup to normal.

Quote -

"YOSHIMURA-MIKUNI TMR-MJN

MJN Carburetor / Theory is simple!

The reasons are as follows;

1) MJN system can atomize fuel much better than ordinary solid type needles.
2) It is because MJN nozzle controls the amount of fuel in proportion to the throttle opening (the air), by numbers of accurately drilled small holes.
3) Better atomized fuel gives better throttle response as well as better fuel efficiencies.
4) Also, MJN system can supply the fuel through the MJN nozzle which locates at the center of the bore where air speed is the fastest. This also atomizes fuel even better! Another very important theory of MJN system is when the throttle is shut off for engine braking, very minimal amount of fuel is guided into the intake ports. Therefore remarkable recovering acceleration can be obtained. "

http://yoshimura-shop.netmove.co.jp/ap/lscat?p=6/7/0/3&c=4&s=39/114/24/59&t=/c_carb1_e/c_carb1_e/c_carb1_e/c_carb2_e/c_carb3_e&l=en

[shift1313]

doesnt help your starvation at top end but they sound cool:).

[Stocky]

It does,

They come as a set with new main jets , air bleeds and suggested settings.

Totally reprofiles the fueling.

[shift1313]

oh i see. that link took me straight to carbs for sale. what size mains do they come with?

[Ed74mnd]

Sharky,

i got some 125's (mikuni).

part number N100/604

let me know if these are ok

Cheers

Ed

[sharky]

They would be a great start mate. How much ? Or can I borrow 'em and try 'em ?

[Ed74mnd]

you can borrow 'em and if you like 'em you can buy them

send me your postal address etc.

Cheers

Ed

[Cruisecontrol]

Maybe...

http://cgi.ebay.com.au/SUZUKI-GSXR750-CARBY-JETS-HEAPS-FIT-OTHERS-MIKUNI_W0QQitemZ320082582891QQihZ011QQcategoryZ352 32QQrdZ1QQcmdZViewItem

[devo]

I just spoke to the guy that owns these jets they were the ones I am getting so I will be getting them soon so sharky whats doin do you need them straightaway or are you now all sorted.

[sharky]

Still lookin mate. I've found a drill that is mid way between 122 and 130 (digi vernier) so I am gonna try that. As long as I can get it running reasonably I'll be happy (ie not running weak).
I am now getting the 38's off Benz so thats when I will look at dyno's.
I'll still be interested to see what you get though as I will need to rejet the 38's. Ed74 is running them and has given me the sizes and settings he is using on his GSX11 so that will be a good start point.

[devo]

I have 38's on the 1100 race bike and it is running 37.5 pilots and 160 mains.
Now as I haven't had it dynoed yet I thought the safest thing to do is run with the airbox but remove the filter.
Finally got it started today and took it for a run and Fuck me it has got some fucking grunt let me tell ya.
Anyway the bike was running Avgas but with 40mm GSXR750RR carbs
Jetted to suit so if it does not perform well at the Barry Sheene
race meet at first qualifying we will use the 40's and I will bring some Avgas.
Ideally it will eventually be jetted to suit Avgas running the 38's either using the original air box and utilising the powerjet feature or we will set it up to run my Yoshimura still air box.
We will see.

[sharky]

Whats this 'Powerjet thingummy ? Do all 38's have it ?

[devo]

Here is a link to teach you a little more about them top Carbs for racing.
http://oldskoolsuzuki.info/index.htm
When you use this link go to seven eleven on the left hand side of the page click on it and scroll down to FAQ & DIY on the left and you will see Journey to the centre of Mikuni BST38SS Carbs click on that and it will explain it to you.
A definate must read.

[sharky]

Cheers mate...off I go to old...choke ...skool....cough su....zu....ki.....

[sharky]

Mmmmmm interesting reading.....'cept my redline is 9500rpm....Guess I won't be needing to change it :)

[sharky]

Devo, Any luck on those jets ? I am after a set of 127.5's if you got any ??

[devo]

Picking up the jets on Saturday Mate.
The jet sizes you need are Std jets for the 1100 by the way.

[sharky]

Were you able to get the jets mate ?

[devo]

Sorry Mate a bit of a slacker I is,
The bad news is no 127.5 but if 132.5 is alright
cause there the smallest jets there are let me know if ya
want em and i will send to ya just give me your addy.
Cheers Mate.

[sharky]

Unfortunately not mate. The 130's I have are too big.
I'll try the 125's I've got from Ed74 (and if they work I'll pay ya, Ed :)). If they don't then I'll have to order some.

[xjrjack01]

Hey Sharky when you got your dyno jet kit did you drill out your slide diaphragm vacuum port?

[sharky]

Yes mate I did.

[Ed74mnd]

what's the story with the slide holes?

some recommend epoxying one up some rec drilling out?

does closing the hole make the slide rise faster and conversely??

Cheers

Ed

[sharky]

As far as I'm aware its the air rushing past the hole that causes the vacuum around the diaphram which then makes the slide rise.
Same way that the air in a paint gun passing the pick up pipe sucks up the paint, or air passing over bonnet vents draw out the hot air around the engine.......[^]

[Ed74mnd]

ahh yeah.. think you're onto something Sharky.
;)

cool analogy for simple folk like me.

Cheers

Ed

[xjrjack01]

quote:Originally posted by xjrjack01

Hey Sharky when you got your dyno jet kit did you drill out your slide diaphragm vacuum port?

I only ask as I'm thinking about doing this to My xjr, just wondering when you drilled yours out did it cause any adverse effects on performance? Oh and what size in mm is a #28 or #29 drill bit?

[sharky]

I give up mate...What size is it ???

I'll have a look later and measure the drill that came with the kit.

[xjrjack01]

I dunno myself, but it seems this is the drill dynojet supply in their kit. It might be like their jet sizes, just made up to suite themselves and bare no relation to any standard size chart!

[xjrjack01]

Ok so after some research I came up with this
http://www.streetfighters.com.au/forum/upload/729797270109413.jpg

http://www.streetfighters.com.au/forum/upload/72979727085982.jpg

So a #29 drill is 3.454mm & #28 is 3.569mm.