i have the yosh trs slip-on installed on my bike and a k&n filter...it seemed to be running lean so i decided to order a 142.5 main an wasn't sure on what the secondary main (i guess mid main) was like so we (me and a bike mechanic) just put in the main and tried it out.  every time i got past 7k it would start to hesitate a bit so i figured since we never touched the secondary we would just take out the secondary main and hopefully he had a jet that was a bit bigger than that one.  he didn't have anything like it so he took out numbered drill bits, the really tiny ones, found which one fit it and went one size up and just drilled it.  he put the carb back together and i took it for a spin and seemed much better, there was a huge difference.  but it is still hesitating in the higher rpms.  in second gear it was really noticeable when i brought the rpms up to about 7k dropped the throttle and cracked it back on, like if i was trying to do a wheelie if i were on a more powerful bike , and as soon it hit 8k it seemed to almost do the same thing but by itself when i had the throttle pretty much wide open. my dad said it might be a "flat spot" which was the term he used.  when i am just going through the gears (not cracking the throttle) it does the same thing but not as intense. so basically the whole point of this write up is, what are the possible reasons for this and.....how the hell do i fix it??? i don't wanna bring it back to the shop because labour is extremely expensive, as i found out on my bill  so if someone could help me with this that would be greatly appreciated

thanks in advance,
Justin

help? anyone?

Jetting should be 40/142.5/1 #4 washer under each needle and 2.5 turns on the mix screws(this will need fine tuning).This is the same jetting as I use with K&N lunch box and D&D exhaust from a GSXR.

huh? do you have an older bike? i've got an '06 and stock it's jetted Pilot 17.5, Mid Main 60, Main 130, or are you saying that the mid main should be 40? and i did the rest with the 142.5 main and 1 washer under each needle but the mix screws i haven't really fooled with much i might just have to try that as well

I'm running a 06 with full Jardine Exhaust and K&N Lunchbox - 22.5 , 65 , 147.5 - 2.5 turns - 3 #3mm washers under the needles.
Runs amazing now, hopefully this will help you.  It sounds like your on the right track you just have to work with the numbers, its a must to raise the needles and turn out the air/mix screw. Chef

You cant run 142.5 mains with a K&N lunch box and pipe unless you run the float 4-5 mm too high.
That is just it. K&N and pipe is a minimum 147.5 and typically the 89-00 bikes have floats wear high, so it can sometimes mask the problems. Still even a 89-00 will run better with 150 mains and the float set right.
The 01+ series, has floats that dont go high with wear. So you deliberately set them 4-5mm higfh if you want to run 142.5 mians, or run the right mains (147.5-150).
Chef GS500 is absolutely correct - though I dunno what #3 wahsers are, we run #4, 1 or 2 #4's usually. 147.5 for an 01+ and 150 for an 89-00 with pipe and K&n.
Cool.
Buddha.

Buddha - I got the #3 washer idea from the wiki. Seems to work fine, i found them at Ace Hardware right next to the #4's. I bought both sizes just in case, but the #3 fit great. I don't know if there is much of a difference between the two in the final result. Chef

Ah, Good to know. I have ~1.2 gazzillion in 1 pack of #4 I bought. So, as soon as I am done I'll check out #3's, but if it works ... 
Cool.
Buddha.

Quote from: The Buddha on July 16, 2008, 09:45:42 AM
You cant run 142.5 mains with a K&N lunch box and pipe unless you run the float 4-5 mm too high.
That is just it. K&N and pipe is a minimum 147.5 and typically the 89-00 bikes have floats wear high, so it can sometimes mask the problems. Still even a 89-00 will run better with 150 mains and the float set right.
The 01+ series, has floats that dont go high with wear. So you deliberately set them 4-5mm higfh if you want to run 142.5 mians, or run the right mains (147.5-150).
Chef GS500 is absolutely correct - though I dunno what #3 wahsers are, we run #4, 1 or 2 #4's usually. 147.5 for an 01+ and 150 for an 89-00 with pipe and K&n.
Cool.
Buddha.

I'm not the only 1 here running the same set up without problems. 

OK Ben. Why do you think he's having trouble at 7K and up.
Cool.
Buddha.

Quote from: The Buddha on July 16, 2008, 11:43:20 AM
OK Ben. Why do you think he's having trouble at 7K and up.
Cool.
Buddha.

He maybe lean but I didn't catch that he had the newer bike.I had just roused from my peaceful slumber. 

Quote
He maybe lean but I didn't catch that he had the newer bike.I had just roused from my peaceful slumber. 

i dont think it's because i'm running lean because i didn't have this problem before i rejetted, it was after i got the new jets in it started to happen, but besides that problem it seems to be running a lot better in the lower rpms and the higher...when it doesn't have that little hiccup in there

He is lean, and the newer bike does not have floats that need adjusting every month ... which may be at work in yours. Also you need to jet on the coldest, wettest day you have in your town. This heat will let a lean bike run a lot better than it will in winter. I would guess your bike, ben is either running high on floats, or is going to act up and run lean when it gets cold and wet. Old or new will not run right except some unique issues with 142.5.
For max power on a old GS, 145-147.5. Several years ago, there was a guy racing a GS in atlanta called well his store was called Buzz's pscycle. He said that the bike acted lean as hell till 147.5. Which was what he run in his race bike.
For driveability on an old GS almost regardless of weather, elevation, temperature etc etc 147.5 to 150. I toss in 150's and usually the bikes never have a problem. I have been once or twice told that someone had to run 147.5's. I have heard of 1 152.5 from 1 person. All else 150. I'd guess I have jetted 100+ carbs so far, maybe 50+ was 150.
If 142.5 was maximum driveability, at 145 the bike will turn into an undriveable mess. You over do just a little on the rich side and the thing will go down hill very very fast. However you can jet it 3-5 sizes lean and still work OK. 1-2 sizes smaller it will actually make great power and run well, except when you try to hold steady throttle but past that it will act up more and more everywhere especially as it starts to get cold.
Cool.
Buddha.

Quote from: jdecaire on July 16, 2008, 12:09:23 PM

Quote
He maybe lean but I didn't catch that he had the newer bike.I had just roused from my peaceful slumber. 

i dont think it's because i'm running lean because i didn't have this problem before i rejetted, it was after i got the new jets in it started to happen, but besides that problem it seems to be running a lot better in the lower rpms and the higher...when it doesn't have that little hiccup in there

You ran fine with the stock jets and the washers only
Maybe go back to that setup then.
Cool.
Buddha.

Quote

You ran fine with the stock jets and the washers only
Maybe go back to that setup then.
Cool.
Buddha.

it was running lean acceleration was way worse than it is now and the engine seemed to be running hot and it was getting harder to start...i want it to feel the way it is now just try and somehow get rid of the hiccups in the higher rpm...but i don't know how   

OK in that case dont touch anything else, just put 147.5 mains in it and post back. If it dont work, heck I'll buy the 147.5's from you.

However you have to make some runs and post back with your observations before you toss them.

No GS is going to run without symptoms with less than 147.5 in it if everythign else is set right. People may disagree, but usually there is some huge misadjustment with somehting else if it does run with smaller than that. I ran 1 up size at a time for a year to arrive at this observation. Agreed its a 89-00 type, but the new carbs are too close to those for it to be different.

Cool.
Buddha.

Quote from: The Buddha on July 16, 2008, 12:52:57 PM
OK in that case dont touch anything else, just put 147.5 mains in it and post back. If it dont work, heck I'll buy the 147.5's from you.

However you have to make some runs and post back with your observations before you toss them.

No GS is going to run without symptoms with less than 147.5 in it if everythign else is set right. People may disagree, but usually there is some huge misadjustment with somehting else if it does run with smaller than that. I ran 1 up size at a time for a year to arrive at this observation. Agreed its a 89-00 type, but the new carbs are too close to those for it to be different.

Cool.
Buddha.

k i will try this but i won't be able to get to it till this weekend i don't think then i'll let you know