It also needs enough kinetic energy to get it going to begin with… That’s part of what the discussion is about here… The starter motor and associated electrics.
You can also have fuel, spark compression and other factors causing it not to start… Leaking crank seals, cracked reeds. It’s still gets fuel… but it’s less likely to fire.
Sorry, but not in my experience.
I should have added “spark, at the right time”.
In 1975, at the IKF Nationals, I won the first heat of the 125 cc McCullough class. I actually got 2nd but first Place was disqualified for being too wide, so I started on the pole in the 2nd heat. It was running fine in lineups, and I led the first lap. Then I almost stuck, but finished. After the heat I put the pressure checker on it and found I had none. The PTO seal was bad and would not hold any pressure.
At my 2nd race ever, with a newly rebuilt Mac 20, it would start, but as soon as I tried pull away, it would quit. Turns out the builder did not install the stuffer right and it was leaking, real bad. Still, it did start. Wouldn’t run.
With the Yamaha, when starting up for a race, I learned very quickly to have a new spark plug and spark plug wrench close by.
None of those examples include an onboard electric starter though and yes it makes a difference.
I know 2T is a simple engine construction. I’m not new to motorsport. I raced in the SuperEnduro championship, won the all calendar, but still do not consider myself an expert. I also know that many people have problems with a faulty power pack. I have already found the whole working ignition system and the box in my country (it works now, it is not known for how long, the price of the new complete system is abstract, in terms of my currency) - but after discussing with some engineers from racing teams, I decided to convert the whole system to much simpler. swap from other engine model, there will be no full power pack electronics. Parts used today, so easily available and at a good price.
we’ll see what comes out of it, I think it’s the only solution that gives peace of mind for a long time,and eliminates the main source of many problems (power pack) - which is difficult to check and diagnose or repair.
You got it Working? That’s Great!!!
What system are you going to switch to? I may suggest the IAME MY-09. Everything is component and the Rev (RPM) limiter is the same for the 07 model. Only weak spots I have found on mine are the wires to the Key Switch connector are prone to breaking and I had a Starter Relay go bad. Both were easy to fix. Soldered Key Switch connection and just replaced Relay (sealed so no internal repair).
The engine is not running yet. I found people who have the entire Leopard installation in good working order, but as You know I decide to replace the cabling so I don’t buy any genuine parts.
Greg, I meant that the parts I found are working now (that tell me the owner), but I don’t know how long they are working yet.
When using the ratio and sprocket according to the table in the service manual, the motor should not exceed 15,000 rpm (recommended maximum speed by Iame)
Other old engines have only stator, and coil. Two switch to start and stop engine - its pure and easy ignition wiring 
Okay. Had to check. 07 Leopard has max rpm of 15K, 09 Leopard has max rpm of 17K. If no limiter on Rok 60, then you have to be careful on tight/twisty tracks that need a lower (edit) gear ratio to pull out of corners. On straight, you could over rev and cause excessive wear (edit).
One little point, and I don’t mean to sound condescending, or anything even near that, did you not mean “low ratio”? Think of a person pulling away from a stop sign, they’re in “low gear”! As they gain speed they shift to a “higher” gear ratios. There’s been a little confusion about that concept since I started karting in 1966. With a fixed driver, the bigger the driven gets, the “lower” the ratio. I.e., 10/70 is a lower gear ratio than 10/60. It doesn’t really matter, what matters is we all use the same terminology. A rose is a rose… and if you call it anything else, I won’t understand. Just in fun.
You are right. Typed in haste and did not check my grammar. Like a fraction, the bigger the bottom number (denominator) gets, the smaller the number gets with a fixed top number (numerator). Should have caught that as it is the basis for differential calculus. (As Y approaches infinity, X approaches “0”; X/Y) Thanks for the correction.
Does the leopard 07 have a limiter in the original installation? I did not find this information in the service manual. As I wrote earlier in the manual there are tables to choose the right gears and get the maximum possible engine RPM.
The 07 Leopard does not have a RPM limiter. IAME recommends not to exceed 15,000rpm.
You are right. They throw in a disclaimer below the part about Peak RPM.
Generally they’ll tolerate up to 17k. But I wouldn’t use that as a target. If you find the Revs are getting out of hand, choke the air box with a quick dab to shut it down.
Generally though I think you’ll be fine.
We had a track in St. Louis that had a bunch of tight turns and one long straight. If you gear’d to not get beat out of tight corners you saw 17 on the long straight. It was always uneasy, but that is what we did. I only ran the leopard for a year, but that was about 11 weekends. I do not remember anyone having problems. Except the guy that forgot to put oil in his gas. But that was another story
Pre 09 Leopards regularly saw 17k at high-level competition with not much worry. Most of the time we were between 16.2k and 16.8k with no issues.
The 15k recommendation is fine if you’re just using it for practice or not chasing lap times. From a competitive standpoint, if you race other Leopards you will be nowhere unless you’re in that 16k+ range.
Ok have replaced my old ignition two button system to a newer digital key start. Now the starter Bendix is kicking out which it didn’t do with the old system. Relay or Bendix ?
If the starter is still spinning and the bendix gear is not staying engaged, then could be a weak battery or some grit in the bendix. I would start by putting a good charge on the battery first.
Sounds like a weak battery.
+1 for the weak battery theory.
OK back to my starter issue, I have replaced the battery,bendix ( had a broken teeth) and the starter is new and still having a problem with the bendix kicking out. Starts great with an external starter but I got a Tag Kart for a reason. Thanks for your thoughts. Merry Christmas all.
