stumped

[Anonymous]

Hi guys thanks for such a great site, it has been a great help. Now the problem, I have an 81 750L with a V&H 4into1 pipe, got it real cheap, it was no virgin. After I replaced the ignition mod. and had spark to all four. I cleaned the carbs(tore down and dipped) when I pulled apart no#4 the main jet and washer were lying in the float bowl, I set the floats at 23mm from the carb base to the flat area on the float closet to the pin.
With carbs reinstalled the bike starts and idels fine,(left airbox off) but would not pull past 4000rpm (would just spit and sputter untill the throttle was lowered) so I installed the air box, now it will pull up to 7000 in the lower 3 gears but only 4 to 5000 in 4 and 5 gear(just spits and sputters), so to me this sounded like it was running lean, because of the pipe, so I pulled the carbs apart to rejet, the mains have no numbers on them just a (R and a square with a smaller square inside) so I got out the drill bits to see what size the mains are and a number #55 fits perfectly(1.397mm), the plugs do look like it is running rich, but at this point I'm out of Ideas.

[first timer]

well this is how your carbs work



what do your plugs look like, they will give you a idea of what condition is going on white= lean, black = rich. almond= good

what is you air filter like ?

unfortuntly i have no idea what size mains you are supost to have and what that would be if you used a drill to measure the hole.

maybe some of teh 750 guys can post the oem carb settings for you and you can go from there.

-ryan

[earlfor]

Re: stumped

Most 750's are stock jetted with 102.5 mains. Vance and Hines recommends for installation of their 4 into 1 exhaust and if keeping the stock airbox and filter, that jet size be increased to 115.

Earl

Hi guys thanks for such a great site, it has been a great help. Now the problem, I have an 81 750L with a V&H 4into1 pipe, got it real cheap, it was no virgin. After I replaced the ignition mod. and had spark to all four. I cleaned the carbs(tore down and dipped) when I pulled apart no#4 the main jet and washer were lying in the float bowl, I set the floats at 23mm from the carb base to the flat area on the float closet to the pin.
With carbs reinstalled the bike starts and idels fine,(left airbox off) but would not pull past 4000rpm (would just spit and sputter untill the throttle was lowered) so I installed the air box, now it will pull up to 7000 in the lower 3 gears but only 4 to 5000 in 4 and 5 gear(just spits and sputters), so to me this sounded like it was running lean, because of the pipe, so I pulled the carbs apart to rejet, the mains have no numbers on them just a (R and a square with a smaller square inside) so I got out the drill bits to see what size the mains are and a number #55 fits perfectly(1.397mm), the plugs do look like it is running rich, but at this point I'm out of Ideas.

[Anonymous]

Just to follow up, I put in a stage 1 K&N jet kit today I used the 116 jets and now the old girl runs like a scalded cat, I was surpised to find out that the Dynojet jet kit cost $120 something and the K&N kit was only $35 thats quit a difference. Thanks for the help, you guys are great