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Discussion Starter #1
Can someone link me the best threadfor jetting, my bike is a stock 1988 tw, the jetting is 40/114. Looking to make it start and run a little between as it seems to be kinda lean.
 

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Welcome!! Have you been in the carb already? Have you adjusted the pilot jet out to 2 and 1/2 turns or so? How many miles are on this bike, just curious...
 

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Discussion Starter #6
I ultrasonic cleaned the carb and used a torch tip cleaning tool to clean the jets, its jetted40/140 with the mixture screw out 2.5 turns, the bike has 5500 miles on it
 

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You mean a 40 and a 114, right?
 

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Does it make a difference if you go out a little more on the mixture screw? Bro, what makes you think it is lean in the first place? Hard to start? Long warm up time? Running ragged? Is the plug black? Is the air filter clean and oiled lightly?
 

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I would try opening up the pilot jet more. Do you have to use the choke a long time? How's the plug look?

I have a 87 and fiddled with the carb for a long time. I changed the pilot to a 42 from a 40. That gave it more gas and pep off the line as well as better starting and warm up times. I had a 114 in it and wanted to increase that also. I went to a 116 and it wasn't right, I went to a 118 and still not right, maybe worse, so I went the other way, back to the 114 and fiddled with it a little more...still not quite right...raised the needle a couple shims, ok, better mid range, but still lacking the smoothness I was wanting. As an experiment, I went the other way and went to a 112. Nailed it. The bike liked that. These carbs are a bit finicky; well...actually, a lot finicky. The littlest things make a difference even from day to day. The temp, the humidity, anything it seems. One day it runs like a race bike, the next day like a beat up mini bike... ;)
For year round riding, from 0* and snow, to the 110*s and heat, it's a little difficult, if not impossible, to have the carb adjusted in just one spot and have it run superbly. Either you live with it or you make tiny adjustments throughout the riding season.
 

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Discussion Starter #12
Good to know, yes choke for a long time. I'll try drilling the pilot jet out a bit and see what hapens but will try idle mixture first, the plug in it was new when I got and haven't ridden it much so I can't really read it yet
 

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I was just sharing what I did, not that you would want to do that. Try turning the pilot jet out another turn and see what happens...
Yeah, don't drill it yourself. Just buy another one if that's what you end up doing.
 

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....................I went to a 116 and it wasn't right, I went to a 118 and still not right, maybe worse, so I went the other way, back to the 114 and fiddled with it a little more...still not quite right... I went the other way and went to a 112. Nailed it.
Yes, yes, yes!!!! Richer isn't always the answer.

As I have said before, I replaced my worn #114 jet with a NEW #114 jet and my problems were over. The hole in the center of the jet erodes away and gets larger and runs richer. This bike here is a 1988 -- get a new #114 jet and use that as a starting point.

Often times a new #116 will run leaner than a worn out #114. People replace the worn out #114 with a new #116 and the bike runs better (though not perfect) and the assumption is the mixture needs to be richer when in fact it needs to be leaner. This was a lesson I learned the hard way! It seems littletommy learned it the hard way too. Convincing people of this is dang near impossible.

Good luck. Tony
 

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It really tests your patience sometimes. These are the finickiest little carbs...

The number 1 best carb mod that gains you the most benefits is just simply opening up the air/fuel mixture screw to 2 and 1/2 and leaving the rest alone!! Just that alone, gives you a whole different bike. ;)
 
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