Bobby Banshee Posted November 19, 2007 Report Share Posted November 19, 2007 OK fellows, I've tried everything I Know but still running lean on bottom end. I'm currently running the stock carbs, pilot-25, air screw 3 turns out, needle on 3rd clip position and 320 mains. I'm running a K&N filter in a air box with a K&N air filter box lid. The machine still bogs at low end with lid, with filter lid and lid removed all together. The middle and top end are good. Heres a list of mods: 4 Mil vito crank, bored 80 over, cool head with 19cc domes(190psi), port and polished trail port by Kevin Herr, delta 3 reeds, aluminum intake with built in cross over tube, pro motion twist throttle. The delta reeds are right up against the back of the engine(intake), then the aluminum intake with built in tubes, then the carbs. Do I need to put in spacers between the engine(intake) and the reeds so the gas will have time to burn. Would this cause a bog at low end. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
black sunshine Posted November 19, 2007 Report Share Posted November 19, 2007 Ok, you say rich in the header but lean in the first sentence of the topic? I am assuming you are concerned about the bog, try 27.5 and readjusting the air screw. Also try leaning the clip on your needle one notch. Don't know about the reeds, though :shrug: Quote Link to comment Share on other sites More sharing options...
Bobby Banshee Posted November 19, 2007 Author Report Share Posted November 19, 2007 Ok, you say rich in the header but lean in the first sentence of the topic? I am assuming you are concerned about the bog, try 27.5 and readjusting the air screw. Also try leaning the clip on your needle one notch. Don't know about the reeds, though :shrug: Ya i'm sorry, type ohhh. Its to rich. The stock pilot is 25, why would it be to rich... Quote Link to comment Share on other sites More sharing options...
afireblade929 Posted November 19, 2007 Report Share Posted November 19, 2007 I had a similar problem that sounded like this. My bike had crappy throttle response and was running really rich with stock pilots. Tried syncing carbs, adjusting air screw, nothing.... Pulled spark plug boots off and found that the tip of a spark plug somehow came loose and unscrewed itself from the plug, causing poor spark on the left cylinder. Try checking the spark plugs and little stupid things like that before taking stuff apart. 25 pilots with the clip in the middle position and 1 1/2 turn out on the sir screw should be fine, although 27.5 pilots will work as well depending on what pipes you have. Hope this was of help to you. Quote Link to comment Share on other sites More sharing options...
swrbansheeboy Posted November 19, 2007 Report Share Posted November 19, 2007 so is it blubbering and trying to fall on it's face or does it just act like theres no power there untill you hit the higher rpms? and have you tried doing a leak down test yet? since it's your bottom end have you tried swapping to a new set of plugs and doing a couple passes only using the first 1/4 throttle to see how it's burning? Quote Link to comment Share on other sites More sharing options...
Bobby Banshee Posted November 19, 2007 Author Report Share Posted November 19, 2007 so is it blubbering and trying to fall on it's face or does it just act like theres no power there untill you hit the higher rpms? and have you tried doing a leak down test yet? since it's your bottom end have you tried swapping to a new set of plugs and doing a couple passes only using the first 1/4 throttle to see how it's burning? I haven't done a leak down test, but i have checked for air leaks around the intake. I've changed the plugs serveral times to to them going bad because of the rich condition on bottom. Quote Link to comment Share on other sites More sharing options...
forumsearcher Posted November 27, 2007 Report Share Posted November 27, 2007 Also if the problem is mainly noticable on the bottom end you may have a reed valve stuck open. You may want to pull them and check them. By the way the title says rick and the first post says lean. Kinda confusing... Quote Link to comment Share on other sites More sharing options...
brian Posted November 27, 2007 Report Share Posted November 27, 2007 If it idles ok dont worry bout the pilot. Just move the needle clip up (towards the blunt end) one notch and do a plug chop at mid range (follow plug chop directions-- just run half throttle instead of WOT). I think that air box is prolly hampering the air flow. Have you considered goin with pod filters ? Quote Link to comment Share on other sites More sharing options...
FIRST BANSHEE Posted November 30, 2007 Report Share Posted November 30, 2007 OK fellows, I've tried everything I Know but still running lean on bottom end. I'm currently running the stock carbs, pilot-25, air screw 3 turns out, needle on 3rd clip position and 320 mains. I'm running a K&N filter in a air box with a K&N air filter box lid. The machine still bogs at low end with lid, with filter lid and lid removed all together. The middle and top end are good. Heres a list of mods: 4 Mil vito crank, bored 80 over, cool head with 19cc domes(190psi), port and polished trail port by Kevin Herr, delta 3 reeds, aluminum intake with built in cross over tube, pro motion twist throttle. The delta reeds are right up against the back of the engine(intake), then the aluminum intake with built in tubes, then the carbs. Do I need to put in spacers between the engine(intake) and the reeds so the gas will have time to burn. Would this cause a bog at low end. Thanks in advance. have you checked your float height? or for a stuck float? is your choke tube connected. good luck Quote Link to comment Share on other sites More sharing options...
fixitrod Posted November 30, 2007 Report Share Posted November 30, 2007 OK fellows, I've tried everything I Know but still running lean on bottom end. I'm currently running the stock carbs, pilot-25, air screw 3 turns out, needle on 3rd clip position and 320 mains. I'm running a K&N filter in a air box with a K&N air filter box lid. The machine still bogs at low end with lid, with filter lid and lid removed all together. The middle and top end are good. Heres a list of mods: 4 Mil vito crank, bored 80 over, cool head with 19cc domes(190psi), port and polished trail port by Kevin Herr, delta 3 reeds, aluminum intake with built in cross over tube, pro motion twist throttle. The delta reeds are right up against the back of the engine(intake), then the aluminum intake with built in tubes, then the carbs. Do I need to put in spacers between the engine(intake) and the reeds so the gas will have time to burn. Would this cause a bog at low end. Thanks in advance. Check some of these other things but after trying the needle and pilot screw try a leaner main... .I know Iknow... I must not know what I'm talking about. I'm not saying run the thing to death on the top end to test it but see if it helps. I am living proof and have see it for myself.... not just on mine.... the main and pilot can effect each other... it's usually a last resort because it's usually not noticable. You may have a lot more top end power to be tapped by going a touch leaner. This is if you mean the bike runs better with the lid off. 190 psi sucks hard and pulls a lot of fuel at once and for 2mm extra each way to boot on a trail port. I am running the same compression. I have to run everything way leaner than I ever expected. Give it a shot since you have tried a lot of things... it worked for me and I have a similar setup ... different carbs but still leaner than most. I got down to the smallest pilot made for k&n's and still sputtered and bogge. Went leaner on the main even though the plugs looked good and bang.... had to richen the pilot and pulled out some crazy ponies. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.