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Discussion Starter #1
Hey guys,

The main and pilot jets finally arrived :D
I have purchased this range
Main: 115, 118, 120, 122, 125, 128
Pilot: 38, 40, 42, 45, 48, 50

I know some are very very big but I had to purchase 24 of them lol

So I changed already my original main from 116 to 118 as said few months ago
No I do not remember what my carburetor has as Pilot One, but since I purchased them I will change of course, should I go with a specific size first because you guys already know it works best?
How about the main one? This tuner friend of mine said you should go 5 points more than your stock one, so I should go 120 or 122 (since I have no 121)

Also I should screw back in the fuel mixture right? Now mine should be at about 2,50-75 (between that)
Help guyzzz :D

P.S. assuming that the pilots will fit, but they should, I do not remember the stock size but when I dismounted the design was the same of the ones I have here as far as I remember
 

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Hey jannaruto, remind us what's been going on with your bike to make you want to rejet?

These new jets, are they OEM? If not, what are they, or where did you get them? Because, if not OEM, the numbers may not correlate at all. Different manufacturers have different numbering systems for the different orifice sizes.

Based on the sizes you mention, I'm assuming that you have a pre-2001 bike with the older slide carb. For the record, the stock settings are: 114 main, 40 pilot, 1 turn out on the pilot screw.

I think most go up 1 or 2 sizes (which are even #s) on the jets normally, with 2.5 turns out on the screw to get better performance, unless there is special circumstances like a pod air filter and an aftermarket exhaust, in which you'll likely have to experiment to get it right. Altitude and climate are also the other big factors when jetting.

I'm sure others with the old carb will chime in with their settings shortly. Good luck!
 

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Discussion Starter #3
Hey jannaruto, remind us what's been going on with your bike to make you want to rejet?

These new jets, are they OEM? If not, what are they, or where did you get them? Because, if not OEM, the numbers may not correlate at all. Different manufacturers have different numbering systems for the different orifice sizes.

Based on the sizes you mention, I'm assuming that you have a pre-2001 bike with the older slide carb. For the record, the stock settings are: 114 main, 40 pilot, 1 turn out on the pilot screw.

I think most go up 1 or 2 sizes (which are even #s) on the jets normally, with 2.5 turns out on the screw to get better performance, unless there is special circumstances like a pod air filter and an aftermarket exhaust, in which you'll likely have to experiment to get it right. Altitude and climate are also the other big factors when jetting.

I'm sure others with the old carb will chime in with their settings shortly. Good luck!
I like to play with my bike :D
Also I have a different exhaust that will be remounted sometime next month probably (we are modifyin for better grip on the tube that goes out from the engine and better grip on the chassi with new screws hole etc)

My bike when I opened the cabruretor was with a 116, not a 114, the pilot unfortunately I do not remember the size

The Jets are not oem, I purchased on aliexpress but I have my 116 jet here and it it identical, same shape, same threading and same hole on both side (the side that gets screwed in the hole is like a concave shape or something similar, dunno the english word) so it it 99% identical, just the size (the little number) is on top instead of the side
The pilot one I do not recall perfectly the shape, but my Carburetor is a TK, I purchased TK and so far they look identical, in a couple of hours I will go on the bike and change the jets, will see what happen ^^

As said I just want to have fun, worst case I spent 18 eur for 24 jets, not a big problem

The mixture screw I should set tighter like 1,5 because of bigger pilot?
 

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Discussion Starter #4
Guys question about Pilot Jet
the one that comes with my carburetor is like the one in the picture
as you know on the "tip" of the jet there are holes all around
mine one is like this scheme
: . : .

SO there are 2 holes then 1 hole, then 2 and then again 1
The one I purchased instead are like this
: : : :

There are two holes on each side

Is this normal? I tried to mount a 42 (mine origjnal is a 38) and sometimes the low end seems a bit empty, also I had to turn the mix screw to about 1 turn 1,15 max, otherwise it will be sooo rich the idle will be very low and sputter a lot

Any suggestions, argoument or whatever?


Also I changed the main jet from 118 to 120
 

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I would do some research and see what oem looks like and then go from there. looking at two different pilot jet port patterns I would feel lost from a tuning perspective. I just got mine in today too as a set I pieced together for mains, couple jets each way from stock, and went from a 31 stock to a 34 pilot jet as recommended several times on here for my newer 2016 style carb. I found a company selling all oem parts on ebay so I put them all in a cart and done one pay and saved some shipping. Search the site here for exactly the info you need, it is here for sure. I just recently found the best way to search is to just use google ex: "tw200 forums carb tuning" and the threads will come up. works great compared to the little search box. Be aware that 87 to 200 was one carb and 2001 to current is a different carb and they take different jetting sizes.

P.S. I would bet the 114 and 40 suggested as original for the older slide carb was correct. If you want to use the aftermarket jets I would just go by the #'s and try it, keep what came out as a reference. Is it running poorly, you never did comment of what it was doing wrong ??
 

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On my 1993 with a TK carb, I tried an aftermarket carb rebuild kit. I had to go back to the oem pilot for best starting and performance. I also tried only one size bigger than stock main jet and had to go back to oem on that one also. On mine it just looks like Yamaha did a good job.
 

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Discussion Starter #7
My bike actually stock (when I opened) was main 116 and pilot 38 so... quite different from a real stock one
The main jet I went from 116 to 118 some weeks ago (I purchased an used tw125 and the cabruetor was basically using the same exact jet so I took it) and the pulling at higher gear was awesome
Now I changed again to 120, still need to decide if it is pulling more, but I can probably feel something in 4th and 5th gear, like the "pulling feeling under the butt"

The thing that bothers me now is the pilot jet which is smaller than original as far as you guys are telling me, and my bike as mentioned in some other topic is quite faster than other TWs I've come across
I bet with the proper 40 or 42 pilot one my bike would start wheelies without even wanting them hahaha
But I need to search a Pilot like that one :S
 

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Discussion Starter #8
I was thinking
Since my bike has a pilot of 38 with the style I described
: . : .

Maybe if I put a 38 of the new style I purchased
: : : :

It could be like increasing the flow, right? Like going from 38 to 40-42, but I will be using the same number since it has 2 more holes

Does it make sense? the jets are identical, just that 2 more holes are different
 

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Discussion Starter #9
OK I opened another cabruretor of a TW I own (part of a TW actually, it miss the front fork) it is a very new 125 cabruretor TK
I took the pilot jet, it is a 40 one, same pattern as mine 38
: . : .
Only difference is in the "top" where you put the screw driver, this new one the edge is a bit sharper than the original one, dun care, bike seems to run very very good so far, but it is raining so can't test properly on the street, also I am sure I will have to check the mixture screw to make it run properly

One thing still concerns me
My bike came with a 116, i switched to a 118, runs great, yesterday I switched to 120, is that too much fuel and should I go back to 118? I am asking this unrelated to what my body could feel as improving performance, pull or whatever, is maybe too much? I am basically at sea level (Neaples, south italy which is a sea city)
 

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If it feels good and running good you are close. Some top speed comparisons to check power output from one jet to the other can somewhat answer your question, also don't forget you can install a new spark plug and do a plug check for color.
 

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Discussion Starter #11 (Edited)
If it feels good and running good you are close. Some top speed comparisons to check power output from one jet to the other can somewhat answer your question, also don't forget you can install a new spark plug and do a plug check for color.
Top speed feels somewhat the same like 115-120kmh
Is hard to tell EXACTLY how much it improved or lost since wind varies a lot on the highway and it affect a lot this bike
One day the front wind was so damn strong I could barely hit 100-105kmh

I should definetely check the spark plug tomorrow tho or maybe in a couple of days where I will run the bike in mixed situations (low-mid-high speed) but my impression is MAYBE rich, I don't know why but I have this weird impression

Also I should check carefully in every single gear the 1/4 throttle which I guess is where the pilot jet has an effect mostly, I want to check very very carefully for "holes" misses or whatever that could be, if any of this happen (even after carefully adjusting the mixture screw and making sure everything is fine) I will have to decide if I want to go back to 118 main from 120 or back to 38 on the pilot from the actual 40 (which as said has slight different head, but the design on the rest is identical)

P.S. if I change the air filter with a more "permissive" one, will it also effect my low throttle air/fuel mix?
 
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