DT125R FORUM

Not a good weekend for projects sadly. Today felt like a good time to tackle the the gearbox rebuild. [image: AP1GczON28f-2MsafJeD5d-5vpCddgE_F7wvwMw4mUgLb2qd4IhmX86P39IsZ82b_iWLEnwRqePbVAtntY2GH_ynSVKF-Pj2PWn_o11HKdPfEkiASpdPOuL8lcdFL_PBfKHjAhmRSBCEGtLjRGsR2fvnMhUA=w1341-h1083-s-no?authuser=0] Input shaft stripped ready to lay the gears onto the 1st gear conversion. [image: AP1GczOIOkdYg_118U84DE74bmnWa2tQKSoRjs7q2MOk0Q5fzTisZFT3fIl-MQKf_FuyjrvEYTMzvxMkhDYxFqDSyI7_TcHsUlsHK2RMHJcIgquU3WpNel8Fhugb5EeV3yOXCvv07VUZmQfQuSEcscoq6L-0=w1920-h901-s-no?authuser=0] [image: AP1GczOalIT8UP8GvsIu6oaCiebY2y1koDXD4F2rR4NZNUMeZhXVep5MHVKU92rHWzH24zPCUFbygSgL6E50bZfOwWG7Jm06MIV3hEjj8kd54GM1CLMGcMtcyoZvWKled2_dqcZEUpRv4ArxwKagYBJ8p_au=w813-h1083-s-no?authuser=0] All rebuild, new bearings, shims and circlips. [image: AP1GczO0QU9H7znj-nhFz4Cy18H8C6M08FS17ilL7ci8C9UVT24jFQ3yAVfARsbqKWkbHVAmy-v82EmVU1LFPcYTp0BPrMOdINfIRPttvzDjPvQfG7TyEwS_t2lEg_DFnWm_IVWg1en5V51sbSJk1a2LyzbB=w1920-h956-s-no?authuser=0] So far, so successful. Next tackling the output shaft. [image: AP1GczM5AdnAIDxi9C0cdm6iB-EQHGx1JXF0L7cjDoDM0JZsEhucD3y83x0wSP59PILgj3EGebFH0sLD02_NWCU3n4QVScZlhIonncHAx9tsflH_A6oXPv8Z_lS381ccF8N9qaGcmDhGjs_Kk5859zBhub4l=w669-h1083-s-no?authuser=0] Was going extremely well...until it came to dismantle third. [image: AP1GczO2Xjf9Y9WDogyaSfLEhfo_IP15jgPuKi_7M_zm2hUgacLm0cejxlpzFvdjoRv-F2aEkWNmIHKT0OSxbMPm9edFoMeWjJ1NMlepxIUHz8myGNfoxzAHBacbnRjoXDwnuAeFOCrppphFla0WHSMRzuRy=w556-h1083-s-no?authuser=0] This was not coming off and the prognosis wasn't good. Rough running third gear with swarf coming out of it. [image: AP1GczM62rE4VM-9MSlHtq3hT_6tAjAGc24wkdjOxyvjaJynqnqa5B8AwuSffkKGCxUp8L6uAOtp4AhpDkOswpwC8IH-SWsKlEzs7co4o5C1LtMxj1aklyd7e86f6J2AmzKg1jLQaMLcTIvSvdvjOrAyIzXO=w890-h1083-s-no?authuser=0] The layshaft's damaged beyond repair and so was third gear. Luckily the layshafts can be had brand new and I managed to find third gear. So sadly that's the cost of a used gearbox, but then that tells me for scrimping on the gearbox. The layshaft's coming from Japan so I'll have to park this rebuild for now.

@calum said in Athena 170 porting: @lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is... Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one. I have compared Athena 170 kit vs 3MB P (and 2RH) cylinders, the only 2 things that's off the athena kit is the piston taller than the stock,the ports are exact copy off the 3MB just a bit wider and the c port is little lower and matches more a 2RH cylinder The 170 is a mix between the 200cc casing (for the cooling canals and ypvs location) and 125 portmap internally.I searched for a piston that has the dimensions of the 56mm and with bore of 65mm but there is not,only some aftermarket forged that are max 61mm have the right piston height (pin to top).