iame leopard hesitation

Beamed03

Member
I just picked up a tag kart with a Leopard MY09 engine on it and am hooked! Once I started to drive the kart harder into the corners I noticed a hesitation when getting back into the throttle. Just to get everyone up to speed, the motor fires right up, low end pulls good, mid power is good, and top end is good. I’ve played with the basic carb settings and have not made any progress on the “hesitation”. Runs great down a straight, and if you ease into the pedal around a corner you’re ok, but if you’re on the gas the kart will literally come to a stop. In my option it didn’t have the fuel after the long straight to match the air entering once back on the gas. Tried going richer on the adjustments but haven’t been able to get it resolved. Just curious if anyone has experienced this problem and or could steer me in some direction. Running 100 octane fuel, at 16:1... carb pop off is 11psi, fulcrum height is flush or (.085) below gasket face, new needle and seat (holds 8 psi), new diaphram and gaskets, low speed 2-1/4 out, high 1-1/8 out. Also to note, i have pulled the reeds and don’t see any cracks or gaps between cage and petals. This is beginning to frustrate me ?
 
low side passage may be blocked, under welch plug, if its plugged, no matter what you do to the needle will not make a change.. by choking, it builds up fuel behind shutter, so when you do wot, theres dual there waiting.. you can try it on stand.. the needle screw does no good if holes are plugged.. pop welch plug, and use oxygen/acely tip cleaners if you don't have small drill bits.

just giving ideas,, btdt.. this might not be the problem,... try changing plug, sometime they break down under load..

I do have a couple leopards I'm getting rid of if you know anybody looking for any..
 

Beamed03

Member
low side passage may be blocked, under welch plug, if its plugged, no matter what you do to the needle will not make a change.. by choking, it builds up fuel behind shutter, so when you do wot, theres dual there waiting.. you can try it on stand.. the needle screw does no good if holes are plugged.. pop welch plug, and use oxygen/acely tip cleaners if you don't have small drill bits.

just giving ideas,, btdt.. this might not be the problem,... try changing plug, sometime they break down under load..

I do have a couple leopards I'm getting rid of if you know anybody looking for any..

Completely makes sense, just because I had removed the Welch plug before doesn’t mean a passage isn’t plugged! We all know how small the passages are. I’ll definitely re-check that?. I do actually have a friend looking for a leopard tag setup as a matter of fact!
 
If you don't find any obstruction in the low speed circuit try lowering the pop off to 8 psi. One other suggestion, pressure check the motor to make sure you don't have an air leak. An air leak, particularly in the gaskets above and below the reed cage can weaken the pulse to the pump. I'm assuming you are using the HL334 series carb that came on the motor.... is that correct? The reason I ask it that the behavior you describe is very common for the HL360 gas carb and some people switched to the bigger carb if they are not running in organized races with tech inspections. If the carb is a 334 series carb it should run great at one to one and a quarter turn on the low speed needle with the HS needle at one turn. If you have to open the LS needle way out then something is wrong assuming you are running the Leopard spec pipe.
Steve O'Hara
PS.... I have a 2008 key start Leopard with 9 hours of run time for sale. I got it on a kart that had a Mychron 2T gauge that showed the engine had never exceeded 15,200 rpm or 950 EGT. It was used only for practice days by a family that had no karting experience at all. I've had the head off to look inside and the engine looks new. $1000 plus actual shipping for the entire engine package from air box to pipe, all plumbing, radiator and all electrical components except the battery. Excellent condition. The only part ever changed was the clutch guts as they wore out the linings.... that gives you a clue as to how fast it was driven!
 
steve is right, I know some that are running bigger carbs, some places allow that, so engines can run with newer engines.. if I render I started pop off around 10...

id take 600.00 for the two I have one is together, one is in box, (new crank and other parts, low bores,). no scoring, etc.. if you need rebuilt, I can do it..

602-741-7893
 

Beamed03

Member
If you don't find any obstruction in the low speed circuit try lowering the pop off to 8 psi. One other suggestion, pressure check the motor to make sure you don't have an air leak. An air leak, particularly in the gaskets above and below the reed cage can weaken the pulse to the pump. I'm assuming you are using the HL334 series carb that came on the motor.... is that correct? The reason I ask it that the behavior you describe is very common for the HL360 gas carb and some people switched to the bigger carb if they are not running in organized races with tech inspections. If the carb is a 334 series carb it should run great at one to one and a quarter turn on the low speed needle with the HS needle at one turn. If you have to open the LS needle way out then something is wrong assuming you are running the Leopard spec pipe.
Steve O'Hara
PS.... I have a 2008 key start Leopard with 9 hours of run time for sale. I got it on a kart that had a Mychron 2T gauge that showed the engine had never exceeded 15,200 rpm or 950 EGT. It was used only for practice days by a family that had no karting experience at all. I've had the head off to look inside and the engine looks new. $1000 plus actual shipping for the entire engine package from air box to pipe, all plumbing, radiator and all electrical components except the battery. Excellent condition. The only part ever changed was the clutch guts as they wore out the linings.... that gives you a clue as to how fast it was driven!

Thank you guys for all the help!, I come from the world of float style carbs so this pop off/diaphragm stuff is new to me but I’m picking up what you guys are putting down?. I do have the 334 carb and spec pipe. I’m going to pull the Welch plug and double check those low speed passages as well as pressure test the motor. Hopefully one of those will point me in the right direction. My pop off pressure seems a little high compared to what others recommend. Thanks for the motivation to figure this thing out! It’ll be a few weeks before I can get out to the track but will keep you guys posted as to what I find l! Also, I’m going to pass on your guys info on the motors for sale ?
 
Steve's right , drop the pop to 8 and also raise the fulcrum arm to .065 below the body with no gasket, which is normally an alky arm setting but it helps get that thirsty motor up off the turn.
 
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