I’m in Canada I’ve raced karts for 46 years I used to build a lot of Yamaha and iame engines with iron liners iam a chainsaw performance builder my UA-cam channel is Donny walkers chainsaws I’ve been asked to do some newer kart motors so im just checking things out mr clean haha good stuff
I have a diamond hone "stones" specifically for nikasil cylinders. Instead of the usual abrasive stones used on cast iron liners. At a push you could use a flex hone but the diamond hone gives a much better cross-hatch
Great video. I have a Rotax 125 as well but when the kart is used it leaks oil gas mixture through the exhaust pipe. Do you know what could the reason for it ? Thanks mate
Hey mate bit of a odd question but if squish gap is good and fresh top end , what sort of PSI compression should I expect to see on me 125 Evo Any help would be amazing and your video was great 👍🏽
Long story short most engine builders don't use compression figures to check engine health after building. But if you wanted to use psi you would never check it after assembly. Only after running in to bed the ring into the cylinder. So many variables will change psi reading. Piston to bore clearance, how the cylinder was honed (or not honed), how much residual fuel and oil are in the motor, also the power valve kicks open during cranking speeds to reduce combustion pressure to aid with cranking speeds.. The simple answer is with a fresh engine you need to be seeing about 120 at the minimum Last point I will bring up is that I have seen massive variations in readings on gauges so 110 on your gauge might be the same as 120 on mine
This video is the most helpfull video on Rotax Top end rebuild on UA-cam! Thanks for sharing!
I would love to see a bottom end rebuild
Great video 👍up for karting
I’m in Canada I’ve raced karts for 46 years I used to build a lot of Yamaha and iame engines with iron liners iam a chainsaw performance builder my UA-cam channel is Donny walkers chainsaws I’ve been asked to do some newer kart motors so im just checking things out mr clean haha good stuff
So you wouldn reccomend doing this yourself? I have a cracked cylinder and wondering if i need to hand it in or if i can do it myself
Hello, what is the specification of the tool to install the piston circlip?
I've just had mine done after 30 hours😂
surprisingly the cylinder looked pretty good
Damn. I’ve gone 23 hours and was starting to get worried. I guess i should be good for a few more hours.
Does the rotax have nikasal and if so do you use a flex hone when fitting new piston do give it a bit of cross hatch
I have a diamond hone "stones" specifically for nikasil cylinders. Instead of the usual abrasive stones used on cast iron liners.
At a push you could use a flex hone but the diamond hone gives a much better cross-hatch
Do your rebuild also Mini max engines?
Awesome! When time permits could we have a BTM end rebuild stating the tolerances and torque settings..? Thanks for your efforts..
What brand of torque wrench do you use on cylinder nuts
its a norbar brand fixed head torque wrench with a 2" snapon extender (that needs to be machined or ground down for clearance)
Great video. I have a Rotax 125 as well but when the kart is used it leaks oil gas mixture through the exhaust pipe. Do you know what could the reason for it ? Thanks mate
Your exhaust could have a hole causing the leak
Hey mate bit of a odd question but if squish gap is good and fresh top end , what sort of PSI compression should I expect to see on me 125 Evo
Any help would be amazing and your video was great 👍🏽
Long story short most engine builders don't use compression figures to check engine health after building. But if you wanted to use psi you would never check it after assembly. Only after running in to bed the ring into the cylinder.
So many variables will change psi reading. Piston to bore clearance, how the cylinder was honed (or not honed), how much residual fuel and oil are in the motor, also the power valve kicks open during cranking speeds to reduce combustion pressure to aid with cranking speeds..
The simple answer is with a fresh engine you need to be seeing about 120 at the minimum
Last point I will bring up is that I have seen massive variations in readings on gauges so 110 on your gauge might be the same as 120 on mine
Thank you really appreciate your response just checked mine got 122 psi with a squish of 1.03mm after 2 race sessions 😊
What kind of oil do you use when putting in the piston pin and putting in the cylinder?
Just whatever 2 stroke oil you use in your engine
What was the tool called you used the place the sirclip in with and where would I obtain one 🤔 please
Buxtools c-clipper
what are you doing when you are not happy with the squish?
You alter the gasket thickness to suit