Piston?

[thesheriff]

I am in the process of fixing my tranny and figured I might as well do a top end. I was wondering what piston I should look into getting (factory or aftermarket). I am looking for reliability more than performance. I was also wondering what premix I should use? I normally use castor 927 but I heard it burns really dirty and can clog up the powervalve. Any suggestions?

[TexTwister 393]

Use a factory piston if you want reliability and i like castrols fully synthetic 2 stroke oil..

[KRN15151]

I like the Wiseco Gp piston I got for my 01 cr125 and 02 cr250. It really seemed to pick up the performance while still being reliable. I have had the pistons in the bike for about a year now. As far as premix I love the Amsoil s2000. Amsoil also came out with a new oil called Interceptor and it seems to burn really clean.

Kyle

[FFRacing11x]

The bean oils are the absolute best lubes in my opinion, BUT they can be higher maintenance wise as far as the exhaust valves go.

[Keith 455]

Originally posted by FFRacing11x
The bean oils are the absolute best lubes in my opinion, BUT they can be higher maintenance wise as far as the exhaust valves go.

..........

I will agree,Castor based oils especially maxima 927 are excellent at lubricating, too many details to list,but I agree. Running 927 the head will be spotless, the crown of the piston will have black carbon deposits as thin as a newspaper sheet. Cylinder, piston skirt, exhaust and intake side wear will be excellent.The rod bearing, crank halves are beautifully coated with no rust whatsoever.927 is castor based with syntehtics so rust will not be a issue. I also have never seen a oil seal rings like 927. I would still be running 927 if it was not for the main exhaust valve collecting heavy charchoal deposits. The subs also get it pretty heavy,it can be a pain in the *** stripping them. Remind you I run kx's . The yz's I have torn apart were not as bad, the main valve pulls right out . They have the vent tubes for the powervalve,So it will be a little cleaner. I have been running KLOTZ R-50 (non castor) I am on my 10th bottle from a new top end,I pulled my pipe to have a look at the valve it has just a smigging of carbon on the edges (very impressed) the center is spotless. I will see how well the r-50 lubricates when I tear down the top end, cleanliness is not the only deciding factor for me .I chose the r-50 because of KLOTZ'S website, they give some decent information on each of their oil's.If the r-50 does infact lubricate like castor based oils I will be hooked.

[roadrash]

have you thought of just doing a set of rings??? maybe thats all you need?just my .02

[Keith 455]

Originally posted by roadrash
have you thought of just doing a set of rings??? maybe thats all you need?just my .02

............

I look at it like this,you have everything torn down, replace it all!!!!! I also like to have a fresh ring groove clearance on the piston. If I have a bad crank bearing, I would throw a new crank assembly in while I am at it.

[MATTXR250R]

I have been running Maxima Castor 927 in my CR250R as well. It does seem to lubricate VERY WELL. Keith might have a point about the head being clean and the piston just having a thin sheet of carbon..Because when i just tore my topend down the head was almost spotless and the top of the piston wasn't to bad. If I was going to re-use the piston I would just chip the carbon off the crown but I am putting a new Wiseco piston kit in it. Just be careful with the Castor 927 in cold wheather...On Maxima's site they say not to run it in temps 35 degrees F or lower as the oil seperates from the gas. I was using Pro Honda HP2 and it seemed to do a great job and it burned REALLY CLEAN. I can tell the 927 doesn't burn as clean as the HP2 but its not that much worse. When I get my new bike I will probably run the Castor 927 in the summer and HP2 in the winter.

[thesheriff]

I pulled the motor out yesterday. I took the head off today and am glad that I decided to do the top end also. The piston had a good amount of scoring on the skirt. There was also some aluminum transfer towards the bottom of the bore on the intake side. I don't know what the guy that had it before me has done but he sure did have his hand in the top end. The piston looked like it was ready to stick soon. I heard that golden spectro is a pretty good oil and one of the guys that I work with mentioned something about Klotz oil. Also, what gear lube do you guys recommend using. I am going to split the cases tomorrow and see where the shift problem is. Thanks for your help guys!

[Yardpro393]

tex
i am a hudge fan of the synthetics as well. i run mx2t in my brother in law's kx. it is so much less gunk forming on the overly complicated kipps exhaust valve system.

[ossagp]

I ran bean oils for years,,still would if I didnt live in cold country (separation). We found that if you are getting heavy varnish or carbon you can alleviate it by running more oil (just like with petroleum oils), the added oil keeps the formations wetter and moving rather than sticking in the case of an engine running hot, as a performance engine running at the upper end of its rev range will do. Wont help if you are riding slow and "sludging" it.

[Killer KX]

Bel-Ray H1-R with "Power Valve Formula" has been run in my 99 KX 250 from new @ 40:1. Gets a bit of spooge out of the pipe (but thats my riding skills) top end lasts 12 months easy (but thats my riding skills again )

Power valves are black brown with black oil on them but no carbon build up at all. The power valves have almost no slop or free play after 5 years so it seems to lubricate them well too.

Bel-Ray H1-R @ 40:1 for my KX

[hondageek]

I've read a few diff. threads where people state that they get a year or so out of a top end. How? I was doing a ring every couple of weeks and a piston every month and a half or so. I run straight C12 w/ 32:1 HP2, I'm maniacle about air filt. cleanliness, ride 2-3 times per week, usually 4-6 gal. of fuel per ride. Unless you ride very rarely I just don't see how a top end could last that long.

[ddfh_4_life]

GoldenSpectro lubes well, but is VERY dirty IMO...I think they all lube well, its just when it comes to tear down time, its not the same with other oils. I am running mx2t, and heard its a great oil, clean and lubes well...

[Blitz393]

Golden spectro lubes great, but it is the dirtiest oil i've enver seen. there was about a foot of carbon on my piston (exaggerating) and my powervalves were quite sticky. since i have put the new top end in, i used Castor 927 because of it being a non-synthetic (to break it in) and when i blew the thing up (almost) there is almost NO carbon deposits on the crown and the powervalves are perfectly stick-free and no free play. the 927 also smells REALLY good when burnt. use the 927 to break in the engine, then switch to Mobile 1 MX2T synthetic for winter riding (separation) or if you just want to run synthetic.

Rob

[Killer KX]

Yes you can easy get 12 months life from a 250 top end but if you race hard and practice 3 times a week no way will you get 12 months. Most average to intermediate riders (probably many of ATM members) would be lucky to get full throttle for 3 or 4 seconds on a 250 around an MX track, pro riders are on it the whole way round hence more load and increased wear on everything...

Honda synthetic 2 stroke race lube and race fuel mixed @ 32:1 will give you lube at least as good as anything else out their.

I guess getting 12 months out of my top end is one benifit of my average riding pace

[Keith 455]

Originally posted by Blitz393
Golden spectro lubes great, but it is the dirtiest oil i've enver seen. there was about a foot of carbon on my piston (exaggerating) and my powervalves were quite sticky. since i have put the new top end in, i used Castor 927 because of it being a non-synthetic (to break it in) and when i blew the thing up (almost) there is almost NO carbon deposits on the crown and the powervalves are perfectly stick-free and no free play. the 927 also smells REALLY good when burnt. use the 927 to break in the engine, then switch to Mobile 1 MX2T synthetic for winter riding (separation) or if you just want to run synthetic.

Rob

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Rob,927 is a certain% castor based,and synthetic formula.

[Aus_Rider_22]

Vertex Teflon Coated Pistons!

Geoff