Topic: wont pull after 4500 rpm

[jbrick28]

got my 74 on the road and it runs great, idles great and pulls good till about 4500rpm. it does have a 4 to 1 and i took the airbox out and im running individual air filters. it ran 25 years ago with the header just fine so im guessing the airbox may be the candidate and he ran a different plug than stock. im running stock plugs. any suggestions on the first step i should take?

[OldSchool_IsCool]

Are you running stock points?  Is your advancer working properly (check with a timing light).

[jbrick28]

Are you running stock points?  Is your advancer working properly (check with a timing light).

everything there seems to be fine according to my friend. we believe its running lean because of the header and no more air box. im tryin to see if there is anything i can do to keep from re jetting or see if anyone knows the jet set up i would need

[Trav-i]

If you've gone to pods your're gonna have to rejet (which will require larger slow jets, larger main jets and some tuning of the needle height).  I had the same problem with my bike when I ran pods, the only way I could get full rev out of it was to install larger slow jets, and a slightly larger main jet.  FYI I had 115 main jets, and drilled out slow jets (I'm not sure of the actual size).  Then I recynced it, but never got it quite right, those larger slow jets resulted in a serious drop in fuel economy (like 20 mpg) since crusing speed is mostly done on the slow jets.  So I actually just put an air box back on and saw a noticeable difference in it my fuel economy it is back up (to around 40 mpg, without a speedo I can't tell for sure), and it is a lot smoother then it used to be.

All in all I know the air box is ugly, but it works (really well for that matter), if I were you I would put it back on and go ride.  The amount of time you will spend on tuning pods is not worth it, I'd rather ride.

Just my 2 cents.

Travis

P.S.  If your're gonna toss the air box let me know I'll buy it from you.

[jbrick28]

If you've gone to pods your're gonna have to rejet (which will require larger slow jets, larger main jets and some tuning of the needle height).  I had the same problem with my bike when I ran pods, the only way I could get full rev out of it was to install larger slow jets, and a slightly larger main jet.  FYI I had 115 main jets, and drilled out slow jets (I'm not sure of the actual size).  Then I recynced it, but never got it quite right, those larger slow jets resulted in a serious drop in fuel economy (like 20 mpg) since crusing speed is mostly done on the slow jets.  So I actually just put an air box back on and saw a noticeable difference in it my fuel economy it is back up (to around 40 mpg, without a speedo I can't tell for sure), and it is a lot smoother then it used to be.

All in all I know the air box is ugly, but it works (really well for that matter), if I were you I would put it back on and go ride.  The amount of time you will spend on tuning pods is not worth it, I'd rather ride. ;)in the morning im going to put the airbox back on and give it a shot. i wanna ride. ill play with the jets and stuff later. thanks for talking some sence into me

Just my 2 cents.

Travis

P.S.  If your're gonna toss the air box let me know I'll buy it from you.

[bender01]

Who cleaned the carbs? I didnt seat a jet once in one carb and it fellout in the bowl. Similar symptom. Also if your floats are set to low it would starve for gas under a load but run and rev fine in the garage. Just some thing to think about.

[jbrick28]

im gonna try putting the the air box back on to see if that helps just to see if its some sort of carb problem. if it runs good with it then ill first look at jets. Im kinda likin Trav-i's thoughts, i wanna hit the streets.

[Tretnine]

My first thought was timing also, so I say check that first because it's a lot easier than carburetor work. Then, follow the advice of these knowledgeable fellows and do all your carb tuning. 

[Inigo Montoya]

Pods = rejet. No way to get around that, not on the older CBs.
On the 77/78 you can get away with it but that is because those carbs use fuel screws with a much more flexible metering system. Your 74 though needs jetting.

[jbrick28]

after some messin around i had another set of carbs layin around and seen that there were 105 main jets in them and those carbs were clean too so i slapped them on. ran pretty good and pulled good till about 6500. i opened the carbs i just took off and it seems the petcock let loose of some nastyness and clogged the jets. come to find out they were 110 main jets. ill put those jets in the new carbs and tomorrow ill let everyone know how it goes. thanks for all the help.