I have have just bought an installed a 17.5 carb, it came with a 95 main jet. my original main jet in my old carb started at 54 and then i changed the exhaust so put in a 60. i put the 60 in the new carb and am wondering if this is correct the bike rides as before no performance gain. i have kept my standard filter as the noise was to much with a tnt open air filter with no gain so reverted back to stock filter. i have changed the clutch springs and torque springs. there are no other perfomance mods yet. maybe someone with the same bike and mods will understand if im correct with jet sizes. my exhaust is a leovince touring so the best performance pot but not load either. this is why i went to a 60 not a 62 jet as performance was diff.
The carby would have had the correct jet installed for the venturi size
It would have been better to leave it at that and then cut back in jet size
air filters do not affect performance unless they are blocked and it is a fact the so called high performance air filters let larger dust particles through and that cause a shorter engine life
mufflers can be changed to get better performance but it can be a trade off for noise
price is no guarantee of better so consider going to a bike shop that has a bike dyno and asking what muffler make and design will give the best increase in performance then have the bike tuned to get max performance from the muffler and new carby
the real way to get performance is not by guessing but by running the bike on the dyno so all performances can be graphed and improved upon
SOURCE: honda xr600r cutting out at 3/4 & full throttle
when you put on a new air filter you have to rejet the carb in order for the air/fuel mixture to be correct,because with a aftermarket air filter it is allowing more air in than before and not enough fuel. as the piston speeds up upon exceleration the air is not getting burnt off into exhaust because you do not have enough fuel in the mix
SOURCE: 81 xj650lh midnight maxim black exhaust, sooty plugs keep fouling
hi,fairly common problem with modified exhaust,start with the pilot screws,turn right in untill the screws are firm then back out 1 and 3/4 turns,this is a fairly standard rule of thumb that will get most things going,as far as the jets go,the original size would be a good starting point,but you should only need to go up 10-15 sizes to compensate for the exhaust mods(ie stock might be 127 may need to go to138 or 140 etc),the other thing that i would recommend is getting hold of a set of damped carb balancers these will enable you to get the mixtures and carb balance dead right,they are relitively cheap and easy to use and will have paid for themselves the first time you use them.(i regularly get 4-8 sometimes 10-11 extra hp over stock by tuning the carbs up properly).hope this helps
SOURCE: Which size Jet Kit for 800 Vulcan Classic?
general rule of thumb is to go up about 10 jet sizes,unfortunately it is a bit of trial and error,and you may have to swap out diferrent sizes to get the bike running right,(jets are quite cheap though)but first step about 10 sizes from standard,your local dealer should be able to tell you what jets are in it and supply replacements,if you change to a hgh flow aftermarket air filter you may have to change jet sizes again as changing the filter may effect the mixture ratio in the carbs,,hope this helps
SOURCE: 2000 Honda CR125 stock jet.
Here is a website to for different jets for the carb.
http://www.bikebandit.com/houseofmotorcycles/honda-motorcycle-cr125r-2000/o/m2176
Pull out the jet and it should have a number on it.
Now you can use this site to determine which jet you need.
http://www.keihin-us.com/list.htm
This page will help you determine which jet you need for your area.
http://www.4strokes.com/tech/howtojet.asp
I hope this helps
SOURCE: What jet sizes???? GS750.
i put 115 main jets in my 77 ge 750 and it will run but was told to jump up to 140 with pobs and 4into1 pipe (SM6) race pipe at the low side run 130 main and leave the stock pilot in. i rorde mine from NE to SD roude trip about 1300 miles got about 62 MPG with 115 jets jumping up to the 140 will drop the MPG but lets be real im not looking for MPG. hope this will help.
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