Incoming new product, Piston Kits!

Superpacman13

Supporting Vendor
Vendor
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We partnered with JE Pistons to produce a race specific piston made for the 390's. This piston will be stock bore, single ring, coated, and fully boxed with the standard compression ratio. This piston will eliminate the weak pin boss of the stock piston and comes in even cheaper then the OEM options. My first production run will be done the end of March and there are only 8 available.
Pre order now https://grayareaktm.store/collections/rc-390-2015-2016/products/je-piston-ktm-390
 

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kostean

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Much appreciated the effort Superpacman13- finally, there are some real 390 engine performance internals becoming available again.
 

kostean

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Ordered the piston before the season and must say it really looks high quality made and has in comparison with the OEM one visibly stronger design.

Now further one, it got installed together with a new thin head gasket and got to be at the engine for maybe some 2 hours of track time before the head gasket went leaking on me. On what got collected during that time, at some reason (and I am not saying it must be because of the piston) the max rpm/speed of the bike dropped for 3-4km/h, so as I needed to open up the engine anyhow, I did go back for the OEM piston and OEM head gasket at that time.

Off season and if manage, probably would be interested to test on the dyno if that small top speed difference really might have anything to do with the +30g larger weight of the JE piston or just accounts from the wind during these few sessions it was installed. With increased compression though, I would go for that stronger design anyhow just for added reliability.
 

Clot

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在赛季前订购了活塞,必须说它确实看起来质量上乘,并且与原始设备制造商相比具有明显更强的设计。

现在更进一步,它与一个新的薄头垫圈一起安装,并且在头垫圈泄漏到我身上之前,它必须在引擎上运行大约 2 小时的跟踪时间。在那段时间收集到的东西,出于某种原因(我并不是说一定是因为活塞),自行车的最大转速/速度下降了 3-4 公里/小时,所以我需要打开引擎无论如何,当时我确实回去购买了 OEM 活塞和 OEM 缸盖垫片。

淡季并且如果管理得当,可能会有兴趣在测功机上进行测试,如果那个小的最高速度差异真的可能与 JE 活塞的 +30g 更大的重量有关,或者只是在安装它的这几个会话中考虑到风. 不过,随着压缩的增加,无论如何我都会选择更强大的设计,只是为了增加可靠性。
Have you found the reason? Is it too heavy
 
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