NICHE Cylinder Piston Gasket Head Kit for Yamaha Big Bear Kodiak 400 4GB-11631-00-Y0 4GB-11610-00-00 4KB-11351-00-00

Everything fit perfect minus the exhaust. Easy fix you only need to drill oem exhaust flange to accommodate larger bolts and buy two m8-1.25 nuts to fasten. Any local parts store should have them. I installed everything and adjusted valves and bike ran great.

This is a well built head, and it worked VERY nicely on my ’96 Yamaha Kodiak which was smoking, sputtering, and stalling. After this head/cylinder/piston was installed, it cranked up and ran immediately very smoothly, with zero smoke. When I test cranked after the install, I actually had my electric starter disconnected (for other reasons) so I had to use the pull start, and before the cord was halfway pulled out, the engine started and ran perfectly!!For the price, I’d definitely recommend this entire setup…. soooo much cheaper than having a shop do it, and it replaced virtually everything that could be causing rough running issues (obviously the carburetor is another major part to consider).There are several online videos that show how to replace these, and it’s not terribly hard if you have some mechanical abilities (you definitely don’t need to be an experienced engine builder to do this). You will have to adjust valve clearances after install (not nearly as intimidating as it sounds… again, YTube videos walked me through it).There are some covers and parts that you’ll need to transfer from your old head, but nothing major.The only issue I ran into was the exhaust outlet on the Niche cylinder had much bigger stud bolts than the OEM exhaust output. (see photo of my old OEM cylinder next to the new larger bolts). The larger bolts were nice to have, BUT did not fit through the collar that holds the exhaust pipe on to the cylinder (this collar is the thick oval shaped ring that slides freely over the exhaust pipe with 2 bolt holes so it can mount the pipe to the cylinder). The solution for me was to drill the two bolt holes in this collar so the new Niche bolts would fit through. Also, there were no nuts for these larger stud bolts in the kit, so I had to buy them separately. Not a big deal, just an unexpected hassle. If you don’t have the resources to drill out the exhaust pipe collar, they do make stud bolts that have a larger diameter on one end and a smaller diameter on the other, which could solve the issue (not sure of the exact size, but I do remember finding a pair of the appropriate bolts called “double end threaded stud” on Amazon for around 10 bucks).All in all, I’d still recommend this over spending MUCH more having it done at the dealership. I feel as if my old 1996 ATV has a LOT more life in it now!!I’ll update this if I run into any long-term issues or problems, but so far, it’s fantastic.