reborne cr500. breakin oil?

hey guys, just rebuilt my 01 cr500. went out, brought it, rode it once then stripprd the whole thing down. replaced every bearing, swingarm to engine and rebored it too. my question is sholud i break it in on synthetic engine oil at the recomended ratio of 32-1 or use a cheaper oil? on four strokes your ment to use cheap oil or you can damage the engine. does the same apply to smokers? its a steel bore with a vortex piston.

You need a castor based oil, not synthetic.

I run Maxima 927 in my 500. Castor-based oils are perfect for a CR500, since our bikes don't have a powervalve. I broke mine in on 927 after a rebuild, no issues whatsoever.

Rings seat almost immediately...for the break-in you're more worried about heat cycling the piston for the first time.

well i *****ed it.... i took off my exhaust, looked into the port, and sure enough, the piston has melted and scuffed on the exhaust port and scuffed on the inlet. only 1 hrs riding on 3 seperate rides on a new vortex 1mm and rebore. so i pulled the piston out, sanded the marks out of the bore and piston with 180 grit then 1200 grit to smooth it a little. there are still a few deep scores in the bore.... im kicking myself.. never had this happen before to me on a 2stroke. used full synthetic at 25-1 and broke it in gentle but think ive ruined this bore and bruised my ego in the process. put it back together and gonna try running castor based oil in it for a while at 30-1. see how that works..

Using synthetic premix oil for the break in wouldnt have caused the piston to melt, sounds like you have other issues like lean jetting or perhaps an air leak that caused a lean condition.

I personally break in my 2 strokes with the oil im going to be using for the full life of the piston and have never had any issues with using synthetics..i actually don't like castor oils..they smell great but are a dirty oil in comparison to ester or synthetic based oils.

well i found cracks in the boysen reeds and heard that that can cause them to run lean, the bike came with a new carby and im not sure which jetting to use cos the numbers on the carb dont match anything in the manual. so i set the needle from 2nd position to third position(to make it richer on the safe side) and kept the slow jet to 55 i think it was(same jet size for all cr500s) and upped the main from 170 to 175. the bike has boysen reeds and a fmf gnarly pipe. i hope it works better this time.

You really don't need to do anything to break it in short of a 2-3 warm ups and cool downs. No special oils, just take it easy for the first few minutes so if something does break it happens at low rpms and does less damage.

1200 grit is too smooth for a cylinder bore. The ring manufacturer will spec a hone grit, usually 180-320 grit range. The moly coated rings in dirt bikes use a hone towards the fine grit end of the spectrum. I still don't recommend using sand paper. Run it by your local machine shop they'll touch it up for you. Make sure you chamfer the ports afterwards or they'll grab a ring and break your piston.

I've always broke mine in using Bel-Ray synthetic at 32-1 and never have had any problems. However, I've always used OEM pistons and rings; don't know if the Vortex pistons require a specifc break-in procedure.

well now im thinking the machine shop might of screwed the rebore and made it too tight. should take it back for a re measure but too late now. its all put back together. ill just go really easy on it for the next 2 hours ride time

If the exhaust port has been made wider by a porting process, the aftermarket piston very well can be allowing the transfers to communicate directly with the exhaust.

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On my 125/500 conversion, I used the Maxima Super M. 4 rides later everything is perfect! Castor is good stuff for high load, high temp dune-type riding. But since mine is trail/trial bike, no need for the messy castor. End of season one must fog and clean motor well as it attracts moisture.

If I were to go a castor route, no doubt 927 is the shiznet.

No! i also have a cr 500 an 85. i have been riding and rebuilding top ends on to strokes for alot of break it in with the same synthetic you run in it just go a little more then 50:1 on the first tank and ride it easy dont get it on the pipe until you have ran a tank througt it.You dont have to run a synthetic.but especially in the newer bikes i have found it to run better and the top ends last longer i live in phoenix its hot here and in the cooler months i take mine down to adout one and a half ounces to a gal of gas.50:1 is 3 onc to a gal hope ot works for you

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