Burned Need Help - Bog After HC

I took another test ride this weekend and I definetly have the bog. It ran perfect before the HC install. I can't ride it like this for long.

It occurs from a low RPM, say less than 12 mph in first, when I quicky open the throttle to about half or 3/4 open. It stumbles along for a while, then gets over it and runs great, or so it seems to me. I don't know how to tell if it is rich at high RPM.

Here are my settings for 2003 S model with CV carb - I ride at 2000-5500 feet

134 main

25 pilot

Klien Extend. Fuel screw - Adjustment does not fix bog or affect idleing

DJ Needle and Spring

3rd clip

Stock E exhaust

HC intake only.

I have done some searching and it appears to be running rich. I don't understand why it only affects it at jumps off idle but it seems to run storng once it gets the RPM's up.

Here are my questions:

1. Do you think it is running rich at all RPMs?

2. If I add a full yosh exhaust, will it fix the problem. I like this option :naughty: Seems like it should since opening up the exhaust flow more air thus, less rich.

3. What jetting do you recommend?

I have searched and some people fix it by using the 3rd clip, but I already on the 3rd clip. Other says the stock spring is the fix. The pilot is probably too big at 25 since the fual screw has no affect. What do you suggest?


try the stock slide spring and or needle clip 2.

try the stock slide spring and or needle clip 2.

Thanks. I changed out the spring to the stock spring last night. Easier than I thought it would be since the carb can stay on the bike. I am going to research about the clip position so I understand what it is doing if I move it. I could put in the stock fuel screw, but if you are suggesting changing the clip it must not be the pilot/fuel screw circuit that is off.

I also checked the valve clearances after the HC install, Everything is still the same after 130 miles. :naughty:

I will test ride on Tuesday night and report back and then try clip 2 if it still bogs with the stock spring. Thanks again.

I did a test ride last night after changing back to the stock spring. It is slightly improved, but still bogging. The bog is not as pronounce or as deep of a stumble, but still there. If I roll on the throttle very slowly from 0 to 1/4 while rolling at 7-12 mph, it does fine, but if at the same speed, the throttle is opened to half throttle or above too quickly, then it bogs. I have run the fuel screw in an out and changed the idle speed and no change to the bog.

I will try the 2nd clip position (2nd from the top) next and report back. :naughty:

I gave a quick test ride last night with the stock slide spring and the clip at the 2nd position from the top (moved from 3 spot). Pretty easy to move the clip position, just gotta keep an eye on that little spring. So far so good. :naughty:

Based on my limited test ride, I would say it is 50% better. Still bogs, but not as deep or as long. I thought I noticed some surging though and a bit less power in the mid range. I don't want to make any conclusions or changes at this stage without taking it out again on a longer test run. I want to test it again step by step and at a few diff. altitudes, re-clean the air filter, new gas and take some notes.

During my test I am going to

adjust the idle,

Adjust the fuel screw

maybe try the stock fuel screw if I can swap it easily.

Does it seem like I am on the right track? Anything else I should try next or watch for?

Thanks again for your help.

i had the same problem after my hotcams install.

i can happily say i have finally got it crisp off the bottom! :naughty:

going from the 4th clip to the 3rd got rid of most of it.

then i went from a 25 pilot, 2.5 turns f.s. to a 22.5 pilot, 2.5 turns f.s..which seemed to help a little more.

today i finally got to ride it with the clip in the 2nd postition. it ripped off the bottom & stayed that way throughout the ride. before it seemed to always run good till it got good & hot.

you probably need to go to the 1st clip. i am not sure if you need to drop the pilot jet, but if you still have the bog after 1st clip, it might be worth a shot.

thanks to burned for his help.

Thanks for the suggestion. It is good to know that it is fixable. I want to do what ever it take to get it running right. I may have to try a different pilot, but if I have to get into the bottom of the carb I will be tempted to change the main and install the yosh exhaust. I will be interested to see what my next test ride reveals.

I agree, Burned's advice is extremely helpful.

if the 2nd clip doesnt clean it up,try a 130 main jet.

if the 2nd clip doesnt clean it up,try a 130 main jet.

does that mean i should not have dropped my pilot from a 25 to a 22.5?

should i just leave well enough alone or would i benefit from a smaller main also? i'm running the 142.5 now. thanks

I was curious If you did the 3x3 airbox mod, If you didn't and added the new jet's it will of course run rich and would explain the problem you are having, The yosh exhaust will not cure this problem, you sound like you are running rich. I'm not going to mess with my bike for awhile, as my Friend Darius Died yesterday after being in a coma since sunday.. yes he was riding on the street, and no he didn't have his helmet strapped on sucurely,check and double check your safety equipment the life you might save might be your own, Dave....

I was curious If you did the 3x3 airbox mod, If you didn't and added the new jet's it will of course run rich and would explain the problem you are having, The yosh exhaust will not cure this problem, you sound like you are running rich. I'm not going to mess with my bike for awhile, as my Friend Darius Died yesterday after being in a coma since sunday.. yes he was riding on the street, and no he didn't have his helmet strapped on sucurely,check and double check your safety equipment the life you might save might be your own, Dave....

I should have included that I have the 3x3 hole.

I did a lot more testing and the second clip did did help the bog, but the bog is still there but I think I am now lean at 1/2 throttle and maybe wide open. It surges at 1/2 throttle in second and 3rd gear and runs hotter than a blast furnace when at 1/2 throttle or more Does this sound lean?

Thing is, it still rips in the mid range during accelation with the cam though so I don't want to take the cam out. The bog is a drag though but makes life suddenly interesting when it comes out of the bog. :naughty:

Since it is going to take getting to the bottom of the carb, I am trying to order a full yosh from the TT store. I feel a little guilty about spending hte money, but you only live once and I don't spend much on other stuff. Figure that since it is going to take some more fine tuning I ought to just get it working with the exhaust. I will keep you posted. Thanks for everyone's help so far.

go back to the 3rd clip.

does it still pull good at high rpm?

if so,start coiming down on the main jet.

Don just called from TT, my yosh pipe is in. :D They are fast. Plus, they had all the info regarding the inserts for the yosh, which recently changed. I first called yosh and no answer so I e-mailed yosh to get insert info and two days later and no response. TT gave me the info I asked for within 8 hours. :)

I will pick it up tomorrow. Last night I reinstalled the clip to the 3rd spot and re-intalled the DJ spring so I am back to base line jetting before the pipe and HC. I will install the pipe and see how it does over the weekend.

Here is where I am going to start at with the new pipe.


dj spring and needle

3rd clip

hot cam intake

full yosh pipe with 96 db insert

134 main

25 pilot

klien fuel screw adjusted per Burned's method

2000 to 5000 feet elevation

I will report back on Monday.

Well, I finally got the pipe installed. Somewhere between the HC intake and the exhaust, this bike picked up some speed. I really think the bike is faster with the new exhaust. Sometimes the sound makes it seem faster, but it revs faster and things get scary quick. Front tire does not steer as well now though. :) Exhaust looks too nice for my bike.


The bog is somewhat better, but still there. Before the pipe, it would actually stop making power, but now it makes power during the bog, but it is still hesitating. It rips in the mid range and pulls into the top end. May be a slight surging, but much better than at 2nd clip. I also have control over idle with the fuel screw, which I did not have before the new pipe. If I screw in the fuel screw less than 1/2 out, then it startes to hesitate.

I am going to try the stock spring and adjust the clip position to see if that helps. I will let you know. If that does not help, I will need some advice. THanks all.

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