Break-In Method
Moderator: Rob Voska
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Dennis Detweiler
- Posts: 65
- Joined: Wed Nov 14, 2007 9:35 pm
- Vintage Karting items owned: 1961 Simplex
1974 Margay Concept Sprint
1984 Margay SR-16
Mc91b1 - Location: Iowa
Break-In Method
What is a standard break-in method on a rebuilt?
Re: Break-In Method
I only track run mine. Easy for 10 minuytes to seat the rings pulling harder out of the corners the longer I'm out there. Then the next sesion I run it rick where it burbles out of hte tight corner nad at hte last part of hte straight. Then the third session I tune it in and it sould be good to go. But lots of guys jsut break them in on a stand. It has never worked for me. The only way I can get a good runnign engine is the break them in under load. When I break in my Yamaha's I run them direct drive.
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Gordon Duax
- Posts: 134
- Joined: Tue Oct 09, 2007 4:39 pm
- Vintage Karting items owned: Lots!
Re: Break-In Method
When My son was running Jr. Sportsman in the Texas series, and every tenth counted, the engine (Yamaha) had a new ring in it for every race.
We run super tight clearances, nothing over .0015", and break-in was critical.
The engine was spun with an electric motor for no less than 1 hour, without the plug, and with pre-mix running through it.
The jug was then pulled, and the ring was inspected to make sure it had developed a wear pattern the full 360 degrees around it.
Then it was put on the kart, and fired up for another hour (3-20 minute stints) at a fast, rich idle (about 5000 rpm) with a hot plug.
The jug was pulled one more time to check for high spots on the piston.
If there were no strange rub spots on it, the engine went back together, and was ready for the track.
At that point it was ready for anything we could dish out.
We never had a seizure, even with the high head temps we were running.
But my Mac engines that I run for fun, I just put them together & run them......
Two scenarios,
one for points at any cost,
and one for fun, where I run the engines fat & happy.
We run super tight clearances, nothing over .0015", and break-in was critical.
The engine was spun with an electric motor for no less than 1 hour, without the plug, and with pre-mix running through it.
The jug was then pulled, and the ring was inspected to make sure it had developed a wear pattern the full 360 degrees around it.
Then it was put on the kart, and fired up for another hour (3-20 minute stints) at a fast, rich idle (about 5000 rpm) with a hot plug.
The jug was pulled one more time to check for high spots on the piston.
If there were no strange rub spots on it, the engine went back together, and was ready for the track.
At that point it was ready for anything we could dish out.
We never had a seizure, even with the high head temps we were running.
But my Mac engines that I run for fun, I just put them together & run them......
Two scenarios,
one for points at any cost,
and one for fun, where I run the engines fat & happy.
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Bill Johnson
- Posts: 85
- Joined: Wed Jun 20, 2007 2:26 pm
- Location: Hickory, NC
Re: Break-In Method
For a Mac.....One easy lap on and off the throttle (running rich) and on the second lap get on it hard then lean it down. One lap for me is about 2.25 miles on a road course.
On a yamaha crank it on the stand and let it fast idle for 5-7 minutes when you can hear it speed up about a 1000 rpm and at that point the ring has seated and you are good to go.
No need baby these engines.
On a yamaha crank it on the stand and let it fast idle for 5-7 minutes when you can hear it speed up about a 1000 rpm and at that point the ring has seated and you are good to go.
No need baby these engines.
MacDaddy