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carbs(help)

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2.6K views 10 replies 4 participants last post by  motorhead87  
#1 ·
ok i replaced the floats now the bike revs up but when im driving the bike the throttle dosent open all the way it will run fine but heavy throttle will bog down i need to have this running asap any help will be appreciated
things ive done
cleaned the carbs
new floats do new floats need to be adjusted?
clutches
tires

i dont know y it bogs down its only when i try accelerating
 
#2 ·
motorhead,

Some things to look for:

Throttle cable(s) snagging on something. Try turning the handlebars side to side with the bike stopped, engine running. Does the engine rev any when moving the bars?

Check the carb boots. The rubber part between the carbs and cylinder head. Are they in good condition and clamped properly?

New floats need to be adjusted. The setting is 17mm (plus or minus 2mm) with the carb partially inverted (i.e. on a 45 deg angle where the float is just touching the needle but not compressing the spring) from the carb body to the top of the float.

The bogging could be from restricted fuel flow, restricted bowl vent(s), fuel tank vent, or missing parts from the airbox (such as the 'snorkel' or air filter)

Good luck.
 
#3 ·
the cables are fine no reving when i put them side to side the baffles are tight and sealed all the way i have new floats when you look at them should the tab be slightly down or up when they are on the table tab up
 
#4 ·
The tab may be either direction, depending on manufacturing tolerances. Measure the float level while holding the carb at about a 45 deg angle upside down, look across the float from the side of the carb. The float 'tang' should just touch the valve needle but not compress the spring pin. Measure from the top of the round part of the float to the carb body. It should be 17mm (plus or minus 2mm)

If you want to try something a little bit more exact and easier, use a bit of clear tubing connected to the bowl drain. Move the fuel tank valve to PRI and open the bowl drain. Holding the tubing against the side of the carb (open end pointing up please) slowly move it downwards while looking at the fuel level inside the tubing. It should be near the top of the bowl mating surface. (spec is +.5mm to -1.5mm) Repeat on the other carb. If it's close I don't think your problem is with the float level. Oh, the bike must be vertical when doing this test, NOT on the side stand.

Did you put all the jets back correctly? A missing or missized jet would cause problems.
 
#5 ·
ok i took off the carbs and looked at the jets thier fine put the carbs back on (not sure what to measure the floats with) the engine will rev all the way up no prob get into gear and the rpms break up from half to 3/4 thorttle then power returns if i keep it at 1/4 throttle it drives fine just not a lot of acceleration untill i pass that point with the throttle in that space of no power it almost seems like it looses all power then snaps back up after i gently roll the throttle up (sorry im on a cheap budgett or i would have taken it to a shop and the closest one is 30 miles away) thanks for the help
 
#7 ·
motorhead87

I went back and read your last thread and it sounds like you might have gotten the main jet needel and spring seat in wrong . these are in the diaphragm , the needel goes in first, then the plastic spacer (spring seat)large end first, then the spring and cap.

hope this helps
 
#8 ·
ok when i pull the carbs what would i measure the floats with and ill check the spring and seat but i think they seated when i put them together ill have to resyncronize them cause my friend gave me some gauges and i cant get then to work they move to much im used to working on cars not bikes thanks fo the help
 
#10 ·
My bike does something similar when it's been sitting a while. Will start and idle fine. You go to accelerate and it bogs down then takes off like a banshee. I'm assuming it's just varnish build up in the small carb passages. I just ran some Seafoam or other carb cleaner thru a couple tanks of gas. This eliminated about 80% of it and then after about 3-4 more tanks of gas the rest cleared up and now it's smooth as butter.