Author Topic: Do i need a bigger main jet?  (Read 16861 times)

streido

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Do i need a bigger main jet?
« on: March 24, 2012, 06:25:49 PM »
Fitted a open cone filter today

Also upped my jet from 82 to 88. Started it up on the stand and revved it, it died down on revs when i tried to WOT and started kind of pulsing up and down the revs when i tried to hold it on throttle open.

Took some tape and sealed up about half the filter and tried agaim on the stand. It was better but didnt feel quite right. Went for a quick ride and it felt a bit lumpy or boggy when i opened up the throttle past half way. Stopped halfway and took a little tape off to let more air in, that made it worse. Got home and this time i taped up about 2/3 - 3/4 of the open filter and tried it on the stand, that felt pretty good so i went for a ride again. This time it was a lot better and almost felt as good as before i started messing with the stock filter.

So my question is do i just need to go even bigger on the jet? If im on a 88 now and only using 1/4-1/3 of the air filter how large do i need to go do you think so i can ride without tape on the cone? Im thinking at least 100 jet or 110-120 even? Does this sound about right?

Dont want to wreck my engine running lean so any help or advice would be good? I know Wordslinger usually ran 101 or 110 i think on his open filter so im guessing thats my problem, am i just using too small a jet? Checked my plug after my last run again and it looked ok, light tan,on the boggy runs before it was very light tan almost going white.
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #1 on: March 24, 2012, 07:36:24 PM »
I know Wordslinger usually ran 101 or 110 i think on his open filter so im guessing thats my problem

..yes!!!i ...it is indeed your problem!!!

..dont ride that thing without jetting higher!!..your taping experiments prove the point!!!

..start with a 100, and chop a plug...or just ride...

..most likely to wind up somewhere between 90 and 100...there's too many variables to be able to tell you any closer range than that..


...DON'T RUN LEAN!!!...


..btw...like that piping!

 :o
« Last Edit: March 24, 2012, 07:38:34 PM by wordslinger »
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streido

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Re: Do i need a bigger main jet?
« Reply #2 on: March 24, 2012, 07:46:42 PM »
Thanks man. Do you reckon i can ride it  the 18mile/day round  trip to work and back for a few days if i leave the tape on? Or will this damage it?

Only other option is that i put back my stock box and 82 jet tomorrow till i get some jets.

If i order jets mon morn i should have them tues afternoon with luck.
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #3 on: March 24, 2012, 08:10:41 PM »
..i would LOVE to say yeah, tape it and ride...i've done it myself...

...but if you REALLY want to be safe......................


 :-\
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streido

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Re: Do i need a bigger main jet?
« Reply #4 on: March 24, 2012, 09:31:40 PM »
Aaaargh  >:( Now i guess i should swap back to my old filter then till i get bigger jets, sh**!

Doubt i'll find anywhere open tomorrow since its sunday and the world stops on a sunday. I'll try find a shop but if i dont i reckon i prob should swap it back. Might leave the 88 jet in and see if it runs ok like that, it only going to be like that till tues at the latest so only be putting about 35-40 miles on it.

Im off to look for a local bike shop online thats got a parts dept thats open on a sunday. Good luck with that   ???

Think i'll buy a 100, 110 & 120 and try get it close with those. I can fine tune it perfect from that i think if its still not good enough. Thanks Word.
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #5 on: March 24, 2012, 11:39:40 PM »
...much over 102-3 will probably be a waste of money...

..i suggest 92, 95, 97-98, 100, 102...maybe a 102...

..where are you located?
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streido

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Re: Do i need a bigger main jet?
« Reply #6 on: March 24, 2012, 11:50:03 PM »
Hmmm. Maybe i should try 92, 95, 98, 100, 102 then. Think i'll need to order online tomorrow night unless i get lucky and find some tomorrow afternoon.

Im in Scotland, UK, weather is mixture of dry and damp usually, never warm very long apart from a month or so in summer if were lucky.
The 82 jet worked well after derestrict but i just thought with the 88 jet in and me needing to cover 65-70% of the filter to run it that if i used the same ratio i may need to up my jet by 65% or about .53 so that would give me a 130 jet. Guess the ratios dont work that way tho maybe. Ill try the sizes you suggest 1st. Ill order 4-5 jets i think.
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streido

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Re: Do i need a bigger main jet?
« Reply #7 on: March 24, 2012, 11:51:48 PM »
Also i just read online earlier someone said you need to oil the k&n type filters or they dont work properly? Is that correct? If it is what type of oil do i use?
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #8 on: March 25, 2012, 12:00:36 AM »
..never oiled my kn...been running it for 3 years...i dunno..lol...

..if it's mostly wet, damp air you ride in, then definately wont need the larger jets...

..damp air contains a lil less oxygen...which is what's mixed to fire in your combustion chamber...


..also have to think about your relative elevation...higher elevation might warrant smaller jetting...air is less dense at higher elevations...

..itsa trial and error, somewhat, process until you find your range...but it's always better to start out rich...not much worry in damaging ur engine that way...
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #9 on: March 25, 2012, 12:03:46 AM »
...also, if you ride wet, you might wanna think about something like this...
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streido

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Re: Do i need a bigger main jet?
« Reply #10 on: March 25, 2012, 12:13:48 AM »
Cheers. Like you say, trial and error, hopefully not too much tho  :)

We're not that high up just above sea level i think so i dont need to worry about elevation.
Quote
.. .btw...like that piping!

Believe it or not thats a piece of chromed 38mm copper pipe off a toilet urinal at work lol. Dont worry tho it didnt carry urine   :o , just water.
Seems to fit perfectly, just hope nobody minds the urinals not flushing anymore, the scoot seemed more important  ;D

Btw the filter i have has the plastic cover that goes over it to keep it dry(ish). I just havent fitted it yet cos i sprayed it bidy colour today and its still wet. This is the one i fitted http://www.ebay.co.uk/itm/270864360921?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #11 on: March 25, 2012, 12:17:57 AM »
Seems to fit perfectly, just hope nobody minds the urinals not flushing anymore, the scoot seemed more important 


..    ;D :D lmfao :D  ;D  ...


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wordslinger

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Re: Do i need a bigger main jet?
« Reply #12 on: March 25, 2012, 12:19:57 AM »
...thatsa good looking cover...

..on that filter, is the filter and mounting boot all one piece?
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streido

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Re: Do i need a bigger main jet?
« Reply #13 on: March 25, 2012, 12:24:24 AM »
Its 2 seperate pieces. I think it comes off if i was to pull it hard. I can spin the filter round on the boot. Is that better or worse?I hadnt even considered it? Maybe its a better quality item if its been made in 2 parts?
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wordslinger

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Re: Do i need a bigger main jet?
« Reply #14 on: March 25, 2012, 12:33:15 AM »
...well, i bought one of those spinning filters once...think it was a EMGO...something like that...

..after a cpl months, the filter part decided to divorce itself from my scoot..


..never did find it...

..it would be a good idea to go ahead and epoxy the 2 pcs together...lol..
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