Predator 212 not enough fuel at startup?

M

mallardsx2

New Member
#1
#1
I have a stock carb with a .37 main jet and a .22 idle jet. I have my idle set where it needs to be at but for some reason I keep having to give it gas on startup. Should I try a bigger idle jet? .24 or .26?

I have a cam and billet connecting rod and billet flywheel and 18 pound springs and the lash is set correctly. I don't like giving it any gas to start it up because it about came out from under me yesterday while working on it... (Not smart enough to put it on a crate)

Just wondering what to do since there is not much adjustment on these carbs.

Any help would be greatly appreciated.

Really impressed by this motor on my Coleman Mini bikes. Super fast and very powerful from mid range on up. I wish I has a little more bottom end though. I guess I could change sprocket size to help that out a little bit.
 
C

Camjamsdad

Active Member
#2
#2
I'm in the same boat. Although I haven't messed with the idle jet yet. I solved the part where the bike flys across the yard riderless. I put a bigger spring in the clutch so it engages at about 3000rpm.

If I can't solve it with the idle jet I'm considering another option. If it ends up working I will post up the result.

You can play with the gearing to find a nice compromise. Go too low, and you'll have a wheelie machine. Go too high, and you'll cook the clutch. I'd recommend first punching in numbers in a ratio calculator then buying a sprocket adapter and a few split sprockets. This is assuming the Coleman sprocket is drilled the same as a doodlebug or motovox. If it's different you could run a PMR jackshaft and be able to change ratios fairly easy
 
M

mallardsx2

New Member
#3
#3
I may end up going to a bigger clutch...This is starting to drive me nuts. I cannot figure this problem out. I think it may be a matter of ignition timing or something. Does anyone have any suggestions?
 
creia

creia

#4
#4
mallardsx2 said:
I have a stock carb with a .37 main jet and a .22 idle jet. I have my idle set where it needs to be at but for some reason I keep having to give it gas on startup. Should I try a bigger idle jet? .24 or .26?

I have a cam and billet connecting rod and billet flywheel and 18 pound springs and the lash is set correctly. I don't like giving it any gas to start it up because it about came out from under me yesterday while working on it... (Not smart enough to put it on a crate)

Just wondering what to do since there is not much adjustment on these carbs.

Any help would be greatly appreciated.



Really impressed by this motor on my Coleman Mini bikes. Super fast and very powerful from mid range on up. I wish I has a little more bottom end though. I guess I could change sprocket size to help that out a little bit.
Click to expand...
What do mean by stating " I keep having to give it GAS at startup"? If what you mean is that you have to open the throttle (suspected), you are actually giving it more AIR, not gas. This suggests an overly- rich condition (too much gas). Have you tried putting the stock idle jet back in and trying it? Personally, I have found that you really do not need to mess with the stock idle jets in this engines, and reading other past posts by members here seems to support this as well. I have read about many more problems when changing the idle jets than any benefits gained.
Michael
 
M

mallardsx2

New Member
#6
#6
I have to open the throttle a little bit to get it to start.
When it idles the plug has just a small amount of soot on it.

Running 22low idle and 37 main jet
 
C

Camjamsdad

Active Member
#7
#7
Mine is a 36 jet. Personally if I run the 140 etube the bike runs bad. My forays into the idle jet never worked out well. I always think just a little more.
 
M

mallardsx2

New Member
#9
#9
My main problem is that I need a low idle because my clutch engages at about 2K rpm. I don't have the luxury of idling higher unless I buy a 3000 RPM clutch and then the bike will come out from under me when it kicks in.
 
C

Camjamsdad

Active Member
#10
#10
I had to put in the stiffer clutch spring for the riderless trips across the yard. The hopped up bike idles at 1860 too close for a clutch that was engaging at 2000 rpm
 
creia

creia

#11
#11
mallardsx2 said:
My main problem is that I need a low idle because my clutch engages at about 2K rpm. I don't have the luxury of idling higher unless I buy a 3000 RPM clutch and then the bike will come out from under me when it kicks in.
Click to expand...
What brand clutch are you running? If it is a standard Max Torque, you can purchase JUST the higher-engaging spring- CHEAP. No need to buy the whole clutch.
Michael
 
M

mallardsx2

New Member
#12
#12
If I set the idle that high I would have no problem getting the bike to start. But a clutch that engages at 3000RPM is a bit much. Also, At high RPM going down road I feel the bike cutting out. I am wondering if I am having a fuel delivery issue... When I let off the gas it is still backfiring a little bit. apparently I am the only person with this issue. Both engines are built to the same specifications.

ARC Billet flywheel
CAM CL-1
18 pound springs
Billet connecting rod
Stock Spark Plug
140 E tube
.22 low idle jet
.37 top end jet
KNN intake
Header pipe
 
SnakePliscan

SnakePliscan

New Member
#13
#13
Parking brake

mallardsx2 said:
My main problem is that I need a low idle because my clutch engages at about 2K rpm. I don't have the luxury of idling higher unless I buy a 3000 RPM clutch and then the bike will come out from under me when it kicks in.
Click to expand...
My ATV has a gizmo on the brake lever that i can swing over and holds the lever in the applyed position, essentially a park brake.
Maybe you can fab something like that or you can just jam a cloths pin in there,
be as sophisticated as u wish.
 
Dragbikemini

Dragbikemini

#14
#14
Yup your engine is modified. It would be hard to expect it to idle normal. Your mods would rrequire a loose clutch also. Idle jet Richens or leans the idle circuit. You only run on idle circuit when butterfly is closed. As soon the instant you crack throttle it goes to main circuit. (Tube and main jet) you have choke?
 
M

mallardsx2

New Member
#15
#15
I have a factory choke from Predator. I choke it to get it to start but I still have to crack the throttle a little bit. Define a loose clutch? Meaning tighter clutch springs and higher RPM at idle? I need to get bigger clutch springs and let it idle around 2500 RPM? If that's the case then I should be good. I just need clutch springs and ill turn the idle up.
 
M

mallardsx2

New Member
#16
#16
I have a factory choke from Predator. I choke it to get it to start but I still have to crack the throttle a little bit. Define a loose clutch? Meaning tighter clutch springs and higher RPM at idle? I need to get bigger clutch springs and let it idle around 2500 RPM? If that's the case then I should be good. I just need clutch springs and ill turn the idle up.

I guess a better question should be with my mods what should the idle be set at? Im trying to have it idle at 1500 RMP so that must mean that I am expecting too low of an idle. I need to idle around 2500RPM?
 
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