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Discussion Starter · #1 ·
Pilot screw=3 turns out
Pilot jet = 35
Main jet =170/180/180/170
I got new needles and seats and the jets and screws are soaking right now.



So does that sound OK or all fucked up?
I know how to tune carbs very well ,if it's a Jetski or Superjet ,but dont know much about these settings. The bike has a D&D pipe with stock air filter if that helps. So, will it run like that or do I need to go up in sizes? I have only ridden this thing around the block so I have not had it at high speeds yet. It's a 98 7R.
What to do? What to do?:eek:hno
 

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Did it run properly before? If so leave it alone.

You might be way rich with those pilot screws like that, although if everything else is stock they may be compensating for it breathing easier. With the 500, the only modification you do after installing an aftermarket exhaust is to turn the pilots out a bit extra.

Now, the 7R is likely not the same... but if it ran before...
 

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Discussion Starter · #4 ·
I traded a shitty Dakota for this 7R. It didn't run but had hot spark and compression.
i gave it a "quick" carb clean and it ran pretty good but not a good steady idle and it was leaking fuel. Not to brag but I am a damn good carb tuner on most marine engines like skis and boats.
So I bought the kits and I would like it know what it should have, then I can guage it myself.


My Yamaha Superjet is a 701cc twin cylinder with twin 44mm Mikuni SBN's ,big compression head, a big pipe with water injection, MSD with lightened flywheel.
These ski carbs have a diafram that's a tunable part and "YES", we do have to change the main jets when there's a pipe change. Those 3 turns out sure seems like someone did something wrong but I dont know these bikes. Thanks for any help.
 

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I traded a shitty Dakota for this 7R. It didn't run but had hot spark and compression.
i gave it a "quick" carb clean and it ran pretty good but not a good steady idle and it was leaking fuel. Not to brag but I am a damn good carb tuner on most marine engines like skis and boats.
So I bought the kits and I would like it know what it should have, then I can guage it myself.


My Yamaha Superjet is a 701cc twin cylinder with twin 44mm Mikuni SBN's ,big compression head, a big pipe with water injection, MSD with lightened flywheel.
These ski carbs have a diafram that's a tunable part and "YES", we do have to change the main jets when there's a pipe change. Those 3 turns out sure seems like someone did something wrong but I dont know these bikes. Thanks for any help.

Glad to have another carb tuner on board.

3 turns sounds a bit rich. Normal is around 2 turns out, stock is 1-3/4. Many on here have had good results within the range of 2 to 2-1/2 turns out from lightly seated.
 

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3 turns out is too much. Mine were 3.5 turns out before I cleaned them and the bike ran so rich it would pop like crazy on decel from up in the rev range & shoot flames out of the exhuast during burnouts. I'm now running 168/178 @ 2 1/4 turns out, with a D&D can and K&N air filter and she ran MUCH smoother today when I took her out for the first time. I'm gonna experiment with the different jet combos I got with the Factory Pro jet kit to get her tuned just right over the next couple of months.

Those are the stock jets and the stock settings for the pilots are 2 1/4 turns out. I would start there. Because you haven't had a chance to really ride her hard, I would stick with those jets, adjust the pilot screw to 2 1/4 turns and go from there.

One other thing to consider while you have them apart is we have #35 mains. ZX7rJoe switched to #38 mains and reports that his starts like a champ every time. I'm seriously considering that switch if this recent change in jets doesn't help the cold/hot start issues I was having with the stock jets and mains.
 

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Everything these guys are saying is correct. Also make sure your floats are set within 1MM if you can. Picky picky these carbs are. The 38 pilots would be a good change and bring in the pilots to about 2.25 and work from there.
 

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Just be glad it wasnt as effed up as my carbs.
 

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You might be way rich with those pilot screws like that
Glad to have another carb tuner on board.

3 turns sounds a bit rich. Normal is around 2 turns out, stock is 1-3/4. Many on here have had good results within the range of 2 to 2-1/2 turns out from lightly seated.


Stock carb settings on my mint bike were 3 turns out... i know because i had to drill the plugs out and confirm jet settings... :smile

just as an FYI most bikes coming from kawi back then were adjusted at factory... not just a bolt on the carbs and go out the door.... if you find yourself a copy of the kawi manual it explains it a bit, that all idle screws are set appropriately. :rolleyes



so with a stock set up 3 turns out could be completely normal :squint
 

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Stock carb settings on my mint bike were 3 turns out... i know because i had to drill the plugs out and confirm jet settings... :smile

just as an FYI most bikes coming from kawi back then were adjusted at factory... not just a bolt on the carbs and go out the door.... if you find yourself a copy of the kawi manual it explains it a bit, that all idle screws are set appropriately. :rolleyes



so with a stock set up 3 turns out could be completely normal :squint

That's weird. Never ever heard of a zx7r with 3 turns out on the pilot screw that was running well but who knows?:dunno

There's a first time for everything.:smile

Guess we'll have to wait to hear back about how she's running and go from there.
 

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That's weird. Never ever heard of a zx7r with 3 turns out on the pilot screw that was running well but who knows?:dunno

There's a first time for everything.:smile

Guess we'll have to wait to hear back about how she's running and go from there.
Here is my stocker running with 3 turns out.... keep in mind that this perticular bike hasnt run since 2002... the carbs were so bad I had to replace them and rebuild another set i had with all the stock components....

This is the second run... she had been runing for a 2 hours straight as a break in... then a shut down and cool followed by that start up there...


ZX7R SECOND RUN SINCE 2002, ONLY 5,600KM!!!









:crazyloco
 

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Discussion Starter · #12 ·
Thanks guys.
3 turns out still sounds way rich for stock. This bike has a D&D can. The diameter of the pipe after the collector looks pretty big and if the D&D is kinda free flowing then I might have to go up in pilot jet size.
The low speed screw is only for the "off idle" throttle chop and has nothing to do with any kind of RPM. I will start at 2 and 1/4 turns and see what she does.



I should post an introduction thread so you can see this bike and the story of how I got it, huh?
 

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That's weird. Never ever heard of a zx7r with 3 turns out on the pilot screw that was running well but who knows?:dunno

There's a first time for everything.:smile

Guess we'll have to wait to hear back about how she's running and go from there.
Here is my stocker running with 3 turns out.... keep in mind that this perticular bike hasnt run since 2002... the carbs were so bad I had to replace them and rebuild another set i had with all the stock components....

This is the second run... she had been runing for a 2 hours straight as a break in... then a shut down and cool followed by that start up there...

:crazyloco
Thanks guys.
3 turns out still sounds way rich for stock. This bike has a D&D can. The diameter of the pipe after the collector looks pretty big and if the D&D is kinda free flowing then I might have to go up in pilot jet size.
The low speed screw is only for the "off idle" throttle chop and has nothing to do with any kind of RPM. I will start at 2 and 1/4 turns and see what she does.

FROM THE FACTORY PRO TUNING SITE:

"The problem with about 80% of the 750's is that they are normally on the lean side at low rpm and the emulsion tube needs to be changed and then the stock needles work well, even with no shimming (WITH the different Factory Pro needle jets / emulsion tubes.
This kit is also available from Muzzy's.


Note that we said "80%" of the zx7r's.....
About 20% of the zx7r's are "different".
Those are usually the "7's" that were too rich, even when all stock
.
On THOSE bikes....... we suggest to install the carb kit and follow the kit float height settings. If that's too rich and stumbly at low rpm and you DID(!) properly set the float height, then, lean out the float 1mm to try to lean the lowend."



So "3 turns out" isn't out of the question as a stock setting at the factory. Having said that, my manual suggests 2 1/4 turns as the recommended setting:

(See Below)

[/IMG]

Also, piggybacking ZXgreen7's reference to what the manual says about the pilot screws:

[/IMG]
 

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Tips for tuning:

Important notes about CV carb tuning!

To properly tune, you MUST:

1. Have selected the BEST main jet for full throttle power (not just a "good" main jet - we mean "the BEST main jet" for power at high rpm).
That eliminates the common severe tweaking of the midrange and lower tuning ranges to compensate for a "wrong" main jet.

2. Then - select the BEST needle height / clip position for power at FULL THROTTLE / MIDRANGE after selecting the BEST main jet -
That almost eliminates weird problems at cruise caused by tweaked needle heights that were required because the main jet wasn't correct.......

3. Then, adjust the BEST Float Height for BEST FULL THROTTLE / LOW rpm (many Honda's excluded because floats are not adjustable) -
You should be able to apply FULL THROTTLE at LOW RPM in TOP gear without ANY misfire of bogging or stumble.......

If you follow that order, you will have:
1. Best topend.
2. Best midrange.
3. Best low rpm power.

Then - all you have left is dialing in the pilot circuit - i.e. mixture screw and pilot jet size - That's IT - Don't tweak needle heights and throw away full throttle midrange to try to fix a cruise issue (Unless you want to)

Perfect Carb Kit TUNING requires patience and perseverance and "reasonable" feel to feel the changes - of which - most motorcycle riders have a good ability to do.


Yeah...you guys (ZX7rJoe, ZXgreen7, Turbo329, MastaSuidge, Christikitty, 57x, ******, etc.) have me hooked on carb tuning now :lol

I fault you guys for getting me addicting :thefinger
 

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Discussion Starter · #15 ·
Wow, I guessed right 2 1/4 turns. not bad for a marine engine mechanic. When i run it I will test the low speed circuit in the first few weeks. I might just try this motorcycle tuning thing.


My superjet hates the attention this Ninja is getting. Everything's been done, well not everything.
 

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Since google dug this back up for me, 11-14mm float height?

And here I was thinking 13mm was running pretty damn rich. Maybe I should try raising it further to 12/11?
 
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