Purchased one of these kits after the previous owner hot siezed the piston to the cylinder. Install was cake, nothing different then a standard cylinder and piston, bottom end picked up a little bit for sure, I really recommend adding a few drops of oil to the piston rings and adding a little bit to the top of the piston after it’s in the cylinder to keep it from binding really hard during the install, getting the piston initially in the cylinder is difficult but afterwords it’s a clean install, I run engine Ice with a super cooler kit and I have zero issues with over heating. You will likely require a re-jet kit, a 269 with stage one cams a loudmouth intake and a fmf exhaust caused a very lean run in my bike to the point where starting and idling the bike was almost impossible. I recommend sigma six they’re very helpful. This is on a kx250f 2010
I just installed this Big Bore Kit with a set of Hot cams stage 2 on my RMZ250. Everything went on perfect with no issues. Starts and runs great only problem is I haven’t got to take it to the track yet.
Thanks you Motorsport for your great customer service.
Am vary happy with this product simple to install and definitely can tell the increase in torc on the bottom end! Do recommend sending in your computer to be reprogramd for full power gain!
I have never liked the gaskets that come with big bore kits but these actually come with oem style and fit gaskets. Theres no replacement for displacement!
Power difference is great and perfect. Excellent buy
At first I was skeptical buying this. But after reason all the positive reviews. I decided to buy this kit and a crank kit due to a engine seize I had with oem parts. I put the bike back together and it roared. Sounded meaner. After the break in period,it was hammer down with no issues at all at 15 hours in so far. Bike is running strong and great. I recommend this kit to every one who is looking for a big bore. Installation was a ease with no issue. Also have had zero over heating issues even when running in a Sugar sand feild with the Florida sun bearing down at 89 degrees out
Improves power where you need it without sacrificing anything. It;s no 450 but it does help narrow the playing field.