How many revs for a CR125

Todd Kageals · Joined: 15 Jun 2012 Posts: 271

Guys,

I will be taking two fresh CR125s out for practice on Friday. I know what I am supposed to do to break them in. After break-in, how many revs are generally considered to be safe? I assume I should gear so that I am hitting the max at the end of the front stretch but I have no idea what redline would be. They are both '99s.

Thanks,

Todd

Tyson Henry · Posted: Mon Mar 11, 2013 7:44 pm Post subject:

Rev till it wont rev anymore?

Randy Mckee · Posted: Mon Mar 11, 2013 7:53 pm Post subject:

Michael Taksa · Posted: Tue Mar 12, 2013 8:11 am Post subject:

So what do you do for break in? Stand, slow, faster, even faster with castor oil? Also, how do you know when "the ring has seated"?
Thank You.

Todd Kageals · Joined: 15 Jun 2012 Posts: 271

Below is copied straight from the SRS Engines website. I have seen lots of different procedures. I'm sure most of them will work. I plan to follow what SRS says!

Written by John Sefcik

BREAK-IN PROCEDURES

Sprint Instructions:

■The engine should be broken-in with starting with part throttle runs through the gears with light loading and low rpm. Gradually increase the length and loading of the pulls through the gears over a period of 5 minutes. Do not apply full throttle or rpm above 11,000 during this period.
■Cool down for 3 minutes and check for leaks and loose connections.
■For the next 5 minutes apply short bursts of full throttle in all the gears. Gradually increase the length of the full throttle bursts until full throttle is constantly applied in 1st thru 4th gear and intermittently thru 5th and 6th gear.
■Go racing.

Road Race Instructions:

■The engine should be broken-in with starting with part throttle runs through the gears with light loading and low rpm. Gradually increase the length and loading of the pulls through the gears over a period of 5 minutes. Do not apply full throttle or rpm above 11,000 during this period.
■Cool down for 3 minutes and check for leaks and loose connections.
■For the next 5 minutes apply short bursts of full throttle in all the gears. Limit the rpm to 11,000.
■Cool down for 3 minutes and check for leaks and loose connections.
■For the next 5 minutes apply full race power and rpm in 1st thru 4th gear out of each turn. Use part throttle and limit rpm to 11,500 in 5th and 6th gear until the next turn.
■Cool down for 3 minutes and check for leaks and loose connections.
■Go racing

Randy Mckee · Posted: Tue Mar 12, 2013 11:05 am Post subject:

The ring needs pressure to seat against the cylinder, so that means load. (Don't do break-in on the stand) I just put it on track and race it most of the time because that builds the most pressure immediately. If I'm feeling really anal about it, I follow Swedetech's advice because it's easy and I'm sure they know what they are talking about.

Here's the link to their break-in procedure:

http://www.swedetechracingengines.com/tech_tips/tech_tips_cr125.html
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Randy
#123 TonyKart - S4 Stock Honda

Sam Zavaglia · Posted: Tue Mar 12, 2013 2:35 pm Post subject:

To break-in, especially with new piston and new jug, the hotter the water the better, make sure it is hot before loading the motor....try not to leave the pits unless it's hot already.....this is all you need to know. Wink

Take note of this from the Swedetech site.
"Break-in water temperature should be 140 to 145 degrees, with the normal running water temperature at around 130 degrees"
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www.samzavaglia.com

Randy Mckee · Posted: Tue Mar 12, 2013 3:00 pm Post subject:

Oh yes, thanks Sam for clarifying that. I don't mean let 'er rip when it's cold -- that would risk a "cold stick." Warm it up real good, then run it on track.
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Randy
#123 TonyKart - S4 Stock Honda

Michael Taksa · Posted: Wed Mar 13, 2013 8:31 am Post subject:

Thank You guys, I see a lot of tape on my radiator in near future:)