View Full Version : Rebuild rm125
A&R
20th February 2013, 22:14
Anybody got any opinions on the cranks that motocross parts .co.nz sell?
here :- http://www.motocrossparts.co.nz/images/cache/images%7Cimages_image_filename_9719.jpg~scale~600~ 600~1339979997.jpg
They are called "race ready". It includes balanced crank with Conrad fitted and small end brg.
Just wondering if I go down this route or get a bike garage to split and fit new big end and Conrad. Crank just seems cheap for $265.00. I can fit the whole crank myself . But can't split crank myself and fit big end. Suzuki crank conrod etc is about $600.
Also getting wossner piston kit. Anybody used these before?
Thanks
scott411
21st February 2013, 05:51
we fitted 3 of these chinese cranks ( we fitted Hot rods cranks, which i am pretty sure would come out of the same place)
the 1st one was to a CR125 that went well, and last time i sore the guy 3 years later it was still running fine)
the second was to a KX85 that lasted 3 minutes till it seized,
the 3rd one went into a YZ125 and lasted about 15 minutes,
we did not fit any more,
we used genuine or Pro X rod kits, some bikes the whole genuine crank was about the same price as a rod kit and the fitting,
as for Wossener pistions, i am not a fan of forged pistons in 2 strokes, but the people that are say they are as good as a wiesco, when we used aftermarket pistons we used Vertex or Pro X,
had some customers with issues with the cheaper pistons (matika) but others had good runs with them, 2 higher failure rate for us to sell and fit them,
A&R
21st February 2013, 12:05
we fitted 3 of these chinese cranks ( we fitted Hot rods cranks, which i am pretty sure would come out of the same place)
the 1st one was to a CR125 that went well, and last time i sore the guy 3 years later it was still running fine)
the second was to a KX85 that lasted 3 minutes till it seized,
the 3rd one went into a YZ125 and lasted about 15 minutes,
we did not fit any more,
we used genuine or Pro X rod kits, some bikes the whole genuine crank was about the same price as a rod kit and the fitting,
as for Wossener pistions, i am not a fan of forged pistons in 2 strokes, but the people that are say they are as good as a wiesco, when we used aftermarket pistons we used Vertex or Pro X,
had some customers with issues with the cheaper pistons (matika) but others had good runs with them, 2 higher failure rate for us to sell and fit them,
Ok Thanks Scott. Yes they are cheap . I'll tell you how we get on. If it sizes I'l be ringing you up for a OEM or aftermarket crank.
BTW how often do you do whole engine rebuilds. This RM is on 128hrs and has had two piston changes to date. One by me one by previous owner. So thought it was about time to do the botom end as well. I used a pro x piston last time changed it at at about 75hrs. So done 50 odd hours on it now. Still looks ok.
scott411
21st February 2013, 12:32
Ok Thanks Scott. Yes they are cheap . I'll tell you how we get on. If it sizes I'l be ringing you up for a OEM or aftermarket crank.
BTW how often do you do whole engine rebuilds. This RM is on 128hrs and has had two piston changes to date. One by me one by previous owner. So thought it was about time to do the botom end as well. I used a pro x piston last time changed it at at about 75hrs. So done 50 odd hours on it now. Still looks ok.
we never did bottom ends at a certain hours, occasionally we would do one for a top rider who was going to nationals or some other big race and wanted to be 100% on it, I would take it apart and see if you have any movement in crank, i have seen 125's with over 250 hours on them, same with 85's,
(and i dont have anything to do with MR MC anymore, but the boys will help you out there for sure)
barty5
21st February 2013, 17:08
ive used a couple of them in the past with out problems.
there is a guy out west who will split crank and balance it for $60 but buy the time you drive there twice etc the 265 is bout the same cost and can be fitted straight away
cambocambo
21st February 2013, 18:46
we have used them in a rm125 with no issues.
A&R
24th February 2013, 22:14
Ok thanks for the feedback. Stripped it and found fork gear selector badly worn. Look like lads been resting on the gear lever. Crank actually looks fine. But now I have it will,be putting new one in anyway. But selector fork is $130.00 ! Just as well we stripped else gear box would have probably gone before the crank !
Well "race ready" crank and wossner piston seems all ok. Lad raced flat out over the weekend ringing the poor Rm125 to death and it survived six 8 lap races so guessing it is unlikely to fall apart now.
So can recommned the "race ready" cranks and wossner pistons on that basis.
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