We’ve been running a 5 degree Odenthal ez set. At first my daughter had issues with hitting her elbow on it, but she hasn’t said anything the last few times out. I also have moved the motor as far back as the sprockets will allow.
I use a 0* mount and modified the clutch cover to allow clearance. Put it on the mill to cut out a U, then dremeled the bottom side as thin as possible to allow the chain to have enough room. I gained about 1” from the steering wheel to the leading corner of the engine. Not super noticeable, but every little bit helps.
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Thank you for the feedback.
Depending on your size I think hitting your elbow on the head is going to happen no matter which mount you use. I will say mine feels no more more than warm to almost hot when it hits.
Try using an elbow pad.
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How can you tell which needle is which on the carb? took mine apart to clean it but didn’t mark which is which. one point looks a bit longer then the other.
The needle with the longer point is the low speed needle.
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follow up on my post from earlier, Builder said I didn’t get it too lean, what actually happened was the retaining pin for the ring pushed into the piston allowing the ring to rotate and it caught on the exhaust port causing carnage from there. That somewhat puts my mind at ease from a carb tuning standping, I’ve def seen issues where I got it a little lean but that resulted in a bog, that was not the case when the piston gave up.
Top end had 9 hours on it, we regularly spin them pretty high on a tight technical track. Hopefully this is a fluke and not something more people run into.
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Did they mention anything about the ring possibly siticking? Sometimes the ring groove gets gunked up with carbon, especially with castor based oils. Something to ponder.
he was pretty certain the locating pin for the ring was the issue.
I go in after every other race and pull head / cylinder / ring and clean the carbon off of everything including ring land.
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Tell me about your experience with castor oil sticking a ring in the groove.
I ran 2 seasons in the Stock foreign class, with direct drive (won the championship one year in Norcal) and never once experienced any problem with gumming up the ring groove.
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He has a valid point, My brother and I ran Yamaha’s for a couple years with caster and had to keep after the ring land on those or they could get sticky, that’s why I keep after the KA the same way even though running synthetic now.
All customers will get the new Kennesaw rabies and repairAre you 800s in 604 800s in 604I tried running Super Klots in a KT100. I had taught the driver how to use the EGT. He got really good at it. At our first big IKF race, he came in from the first heat and everything was fine. The 2nd heat was a different story, HP was way down. Check the compression, very little. Pull the head, the piston look good. Pull the barrel, ring was stuck in the groove so tight we couldn’t get it out. New piston time. Where’s the castor oil? I said. The synthetic just wouldn’t take the heat.
I’ve found the ring locating pin to be one of the main causes of seizure.
Anecdotally it happens more than anything else.
I think that it is a “best case” seizure in that when it catches a ring it doesn’t do a lot of damage to anything and can be fixed reasonably easy. Perhaps the locating pin wearing is a type of planned obsolescence failure that prevents barrels from getting massive score marks in them from some other failure. I have nothing to back that thought up with though.
9hrs does seem a bit low for it to happen but then that’s about the time the top end could be coming due to.
The other failure I’ve seen a bit is main bearing cage failure.
When KA’s first came out they had a metal ball locating cage in the bearing and they have since shifted to a plastic one. The plastic can heat up enough to melt, then the bearing collapses.
The air cleaner needs to be cleaned and oiled at least every event, to keep dirt out of the bottom end, and the seals on the crank need to be kept clean somehow, the bearings that fail are always seem to have dirty seals. Whether its because the dirt is coming in through the seals or the air cleaner I don’t know.
Can you or anyone elaborate what happens to the pin? I assume it is pressed in, does it just work itself loose? I would think if this is an issue why wouldn’t be installed in a way that it can’t be removed. Sounds like a ticking bomb just waiting to ruin your day.
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I have not had it happen on my old leopard, but if the pins are the same they are made of steel. Looks to be either cast into the piston during manufacturing or pressed in from underneath at the factory. What Bill is describing is the pin just gets worn through as the ring wiggles slighting on each stroke of the engine. The ring is also steel or some form of it and thicker than the pin. Over time, the pin is likely etched away by the rubbing of the two surfaces. Not really a big deal in four strokes if the pin rotates, but in two strokes, the gap in the ring can potentially line up with one of the ports and pop out slightly. When it does it catches the opening of the port and either snaps off the tip of the ring or grinds into the bore of the piston or both. Not good, but not necessarily total destruction either.
The Locating pin looks like either a short rod or a ball bearing that has been pressed into a hole on the ring seat. I may one day cut one open to see which it is.
Either the pin or the ring itself wears over time, which could be due to any number of factors- Heat, fuel oil mix, excessive RPM, there could even be manufacturing faults playing a part. I have always excepted it as something that happens, about when I should have changed the piston anyway.
If an engine is running at high RPMs (KA should max around 15K), lean A/F mix, lean oil mix, tight tolerances - all the things that make engines fast something is bound to break and having a pin wear early then jam a ring in the port, is better than any number of other types of seizures.
It is generally a quick hone and another piston to fix, so reasonably “cheap” fix
There are guys in this thread saying that the regularly spin their engines to 16K RPM, and I can’t outright say they are doing something wrong, because it obviously works for them, But that has got to be shortening the engine life.
Which may be fine for them and their budget.
However peak power is well below 15K and running lower rpms "richer’ A/F mixtures, and 5% oil in the fuel will keep engines running at their best for longer, which I think is better for the “average” club day karter.
The KA is an excellent platform with hundredths separating the good from the bad engines, and I think it’s important to separate what people are wanting to achieve.
For a person wanting to race at club level, be competitive and have fun, ringing the absolute neck out of this motor wont do anything except increase your engine builders bank balance.
If a person wants that championship, that is a totally different conversation that needs to be seperated from what is “best” and what is actually achievable for the majority of us, that are never going to win that major event, but are going to have a shed load of fun along the way.
Sorry, got up on that soap box…
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I do wonder if the pins dislocating is more of a manufacturing thing.
15-16k should really not be much for these engines in a mechanical sense.
They’re derived from engines that would turn anything from 19-21000 on the high end and these newer ones have a more durable bottom end.
Based on that I’d have no hesitation to spin the motor up to 16k if needed.
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dumb rookie question, I read the manual like 19 times when re-assembling my KA after the broken piston, looks like I made one mistake.
Do you guys use a feeler gauge to set the gap between the ignition rotor and the stator? I could find nothing in the manual in reference to it. The stator basically sits in a cage on the engine case and it all looks like it is basically pre-gapped, unfortunately it looks like my stator and rotor were coming in contact with each other slightly under running conditions this last weekend. Thankfully the thing ran great, but I noticed it in going over things after the fact and it doesn’t look healthy that way.
Thanks,
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I’ve personally never set a gap with those, but that’s not to say it shouldn’t or can’t be done.
Recommend you check the crank for radial play though. Ie up/down/front to rear movement. There should be essentially none. If you find there’s play, you’ll need to consider replacing the main bearings.
/note to self
It would be useful to be able to upload a short video here 