M.H. Posted October 30, 2020 Share Posted October 30, 2020 How fast was that going? Quote Link to comment Share on other sites More sharing options...
tortron Posted October 30, 2020 Author Share Posted October 30, 2020 The last number on the speedo is 120 Quote Link to comment Share on other sites More sharing options...
M.H. Posted October 30, 2020 Share Posted October 30, 2020 Does it go off the clock g Quote Link to comment Share on other sites More sharing options...
tortron Posted October 30, 2020 Author Share Posted October 30, 2020 The gearing limits it, but it might now with the few extra RPM the cam offers Quote Link to comment Share on other sites More sharing options...
tortron Posted October 31, 2020 Author Share Posted October 31, 2020 Sinnis Apache 125 has a china clone of the gn125 engine available in fuel injected for the last few years. Might try import some parts for that They also seem to do 0-100 in 17 seconds standard? must be a gearing thing i dont think my gn is any slower than normal 1 Quote Link to comment Share on other sites More sharing options...
keltik Posted November 1, 2020 Share Posted November 1, 2020 10 hours ago, tortron said: They also seem to do 0-100 in 17 seconds standard? must be a gearing thing i dont think my gn is any slower than normal I think you'll find it's a lying thing. My last Chinese clone Honda motor was supposed to be 50cc but was a sneaky 70 3 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 1, 2020 Author Share Posted November 1, 2020 perhaps, tho the one guy i have questioned said he swapped his to 150, so his engine at least wasnt  dunno tho if you look for gn 0-100 times it says like 14 seconds. maybe the bike with no rider could do that Quote Link to comment Share on other sites More sharing options...
keltik Posted November 1, 2020 Share Posted November 1, 2020 A ski slope was probably involved Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 oh boy it soft seized  I dunno what happened there, But it lasted the same number of km as that last set of rings that shat them selves. Theres no printed minimum ring gap for a gn125 or dr125, so i used the DR200 specs. and went 0.12mm. (0.1 to 0.2mm min, 0.5mm max) Maybe i need to use 0.2? fuel mix looked happy to me. around 12.5 at wot, as lean as 14 on cruise. i dunno, any ideas what im doing wrong here, or is it just shit bike syndrome 1 Quote Link to comment Share on other sites More sharing options...
M.H. Posted November 3, 2020 Share Posted November 3, 2020 Just looking at the specs for ring gap on other air cooled engines and they all seem about the same as what you have. Have you pulled it apart yet? Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 nah im sulking 5 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 Bugger it  Might just gone the cylinder again and send it tbh  1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 Piston pin looks as new so i dont think it had an issue with oiling or not being oiled when i put it in plenty of oil up around the cam, so i dont think theres a problem with oiling   or am i way off and its just running hot due to timing (tho it is running on 95 and has 2 base gaskets)     piston expanding funny or too big?  i didnt check it, other than the piston fitting and moving.  I guess thats my fault for assuming enough tolerances on new piston and a bore i have honed a couple of times      i dunno what to do next tbh Quote Link to comment Share on other sites More sharing options...
cletus Posted November 3, 2020 Share Posted November 3, 2020 Is it a Chinese piston? Last big bore scoot engine I did with china parts , the piston was too tight in places and I had to creatively "machine" some extra clearance It then survived a trip around the east Cape at wot for 3 days so it must have been good  Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 yea of course its china piston (even the stock one is) i dont think you can even get a not china piston (even weisco ones are nla)Â Might have to just bore it out and run those cbf pistons, wonder if i can get a japanese one of those Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 whad did you do to machine the piston @cletus? did you measure the bore clearances to find the tight spots or just eyeball it? Â il probably take one of my cylinders and a 160cc piston to a machine shop and tell them to make it fit and not bother with another 150Â Quote Link to comment Share on other sites More sharing options...
cletus Posted November 3, 2020 Share Posted November 3, 2020 Something rough as guts, like rubbed it in the bore to see where it had high spots, then sanded the high spots with a DA sander  3 Quote Link to comment Share on other sites More sharing options...
cletus Posted November 3, 2020 Share Posted November 3, 2020 Might have filed it by hand then finished with the sander  Whatever it was it was only a step better than rubbing it on the concrete floor 5 1 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 3, 2020 Author Share Posted November 3, 2020 hmm i might just run a flat stone over the rough spots and pop it back in then, ran pretty happily after it nipped up Quote Link to comment Share on other sites More sharing options...
M.H. Posted November 3, 2020 Share Posted November 3, 2020 Did you buy piston and barrel together? I've always had the machinists bore it to suit the piston, it's only $90 odd to get it bored Quote Link to comment Share on other sites More sharing options...
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