What to look for during motor break-in?

[MAYDAY]

Grenaded my 98 701 motor last season(bad crank let go) and following a complete rebuild I have started the break in process. Yama lube 32:1 half throttle or less 10 min rides with 10 min breaks. Does this sound ok? What should I be looking for when I pull my lid during breaks? So far it seems to run good and be really responsive. Can't wait to be able to really grip and rip a little. Thanks in advance. Mayday.

 

[crazy4sand]

Splash some water on it make sure it's not too hot, I usually do the 10 on ten off for 6-10 times. Them the rest of the first tank i do 30-60 minute half throttle rides , first take of brake I'm I usually double up on my oil mixture i do 40:1 so 16 oz, so break in I do 32oz on both my dirtbikes and jetskis

 

[shadowrider]

I am new to jet skis world, but other 2 stroke engines I have always been told by the engine builders to do a couple heat cycles and then you are good to go. What do the jet ski engine builders recommend? Its interesting how little HP per CC these engines make. I am use to 800cc making well over 200hp. (stock 150hp) 701cc makes like 70hp........kind of weak..........but they are super fun!

 

[Hallie]

I run motors in at 40:1, same ratio I use after it's run in, but I run it a fairly rich so it gets plenty of fuel and oil. If your too heavy on the oil, you actually have less fuel (as oil is taking up the volume the fuel would) being metered in, hence you are running leaner.

I pull the plugs after each run to confirm she is a bit rich. After a few cycles I start to lean out the carbies till I get them right. A few WOT runs, pull the plugs each time. A dark brown coffee colour begins to develop on the plugs when the mixture is right.

I check the plugs every ride, to make sure no lean condition is beginning to develop, which would show up as a lighter colour on my plugs.

A lean condition could develop if your bottom end isn't sealing properly. Reading plugs can nip this in the bud. Better to replace some seals than engine rebuild.

A stock 701 motor properly cared for should do hundreds of hours between rebuilds.

 

[Sanoman]

I run motors in at 40:1, same ratio I use after it's run in, but I run it a fairly rich so it gets plenty of fuel and oil. If your too heavy on the oil, you actually have less fuel (as oil is taking up the volume the fuel would) being metered in, hence you are running leaner.

I pull the plugs after each run to confirm she is a bit rich. After a few cycles I start to lean out the carbies till I get them right. A few WOT runs, pull the plugs each time. A dark brown coffee colour begins to develop on the plugs when the mixture is right.

I check the plugs every ride, to make sure no lean condition is beginning to develop, which would show up as a lighter colour on my plugs.

A lean condition could develop if your bottom end isn't sealing properly. Reading plugs can nip this in the bud. Better to replace some seals than engine rebuild.

A stock 701 motor properly cared for should do hundreds of hours between rebuilds.

Good advice....

 

[MAYDAY]

I run motors in at 40:1, same ratio I use after it's run in, but I run it a fairly rich so it gets plenty of fuel and oil. If your too heavy on the oil, you actually have less fuel (as oil is taking up the volume the fuel would) being metered in, hence you are running leaner.

I pull the plugs after each run to confirm she is a bit rich. After a few cycles I start to lean out the carbies till I get them right. A few WOT runs, pull the plugs each time. A dark brown coffee colour begins to develop on the plugs when the mixture is right.

I check the plugs every ride, to make sure no lean condition is beginning to develop, which would show up as a lighter colour on my plugs.

A lean condition could develop if your bottom end isn't sealing properly. Reading plugs can nip this in the bud. Better to replace some seals than engine rebuild.

A stock 701 motor properly cared for should do hundreds of hours between rebuilds.

Hallie thanks for the great reply I appreciate it. I put 5gal of 32:1 premix in my tank and unfortunately did not check my plugs while riding. I am away from the ski for a few days so I will do that ASAP. At this point I am thinking the best thing to do is drain my tank and use that fuel in my daughters sn Start over with some 40:1 and check those plugs. Thanks again everybody. Mayday.

 

[MAYDAY]

Splash some water on it make sure it's not too hot, I usually do the 10 on ten off for 6-10 times. Them the rest of the first tank i do 30-60 minute half throttle rides , first take of brake I'm I usually double up on my oil mixture i do 40:1 so 16 oz, so break in I do 32oz on both my dirtbikes and jetskis

This is what I did but only had time to ride for about 30 mins total. Gonna take all suggestions and get this baby broke in right. Thanks again. Mayday.

 

[crazy4sand]

Taking the time during break in prolongs the life of the motor, everyone has a different method or theroy

I do a 10gallon break in on my cr500, then I pull it apart and sand down any possible score marks or imperfections then put it back together and rip the hell out of it, I usually get 4-5 hard years out of it

 

[mike b]

First tank 32:1 2nd tank 40:1. I did 15 minute idle only. Then first hr checked motor 2 or 3 times and splashed water and gave 5 or 10 minute breaks. After I got first hr in I opened to about half and up to three quarters. Second tank of gas same on throttle. Ran 11 gallons so far and have 6 or 7 hrs of ride time on it and hope to get open to full throttle brapps this week so I can get some more rotation for spins taking it easy pays for itself. Would rather spend an extra hr or 2 for break in rather than a week or two for rebuild and new parts. Slow and steady wins this race!