Warning Yj Bbk Kit Hkmotos

just wanted to let you guys know that this kit comes with wrong piston. it works but the way the windows are cut in the piston dose not really line up with the boost ports good. i am runing it like this now but i would recomend getting a oval port piston. and the bore work looks kinda crappy. but all and all its ok for me (dont race) it dose make alot more power but if youre picky might want to get something diffrent

oh yeah you have to grind on the head a little to make room for pipe if you have the dule tip pipe and you have to do some grinding behing the coil so they dont touch.any one know why is thare a grove above the exhaust port it runs from the middle of the exhaust port up the bore like 3mm maybe and is verry shallow it looks like some one did this on purpose?

that slot is a compression release so you dont break pull cords even though its not needed cuz the hkmotos kits have terrible squish unless you mill the top of the head. the bottom can also be milled a tiny bit.

and yah pistons windows dont come close to the boost ports one port is almost blocked off entirely. also the boost ports can be raised as high as the transfers which will help correct the 90 degree angle which blows the mix back out the exhaust.

i would buy a different piston and window it yourself by drilling 3 holes cuz even the oval windowed piston wont line up.

It typical china crap . I own the 4 port that HK sells and I like it however it does need some work to make it better . and all of the kits the squish is terribly bad . boost ports are too short also . All in all you cant expect italian quality for $70 lol . Maybe you should buy the 4 port cylinder kit and have a more functioning kit . Im gonna buy antoher HK kit just to have an extra cuz for the $$$ you really cannot go wrong just wish they had some 40mm kits

well im short on $$ now cuz i bought this crap kit bit it dose run good out of the box. i will run it as long as i can. i do like the head setup its huge dont think you could over heat this setup if you tride! mine is hard to start it dose feel like i got alot more compression than stock. dose any one know why this kit comes with two copper head gaskets was i supose to use them both seems like you would lose compression doing that.

i dont think i can set the squish on my bbk cause the head is taperd. i dont think i would get a good reading. hay screw it it runs fine the way it is cant complane. i have heard of guys running boost ports without a window piston the fule/air still gose up the boost ports any way

yah the windows are supposed to release the pressure from under the piston on the downstroke. they're also supposed to help lube the piston pin needle bearing. without a good computer simulation its hard to tell if it really works or not all i know is it doesnt decrease power and theres tons of 2 stroke motors with windowed pistons not only cag motors so its gotta do something.

i also forgot to mention the hkmotos kits dont come nickasil plated! they're bare aluminum with what looks like a quick ball hone job.

and to measure the squish you'll need to lay a piece of solder cut the exact same length of the bore on top of the piston bolt the head back on and squish it! the L shaped piece inside the spark plug hole method wont work with these domes. this is another reason i went for the ada style kit im hoping real ada domes fit this rep kit.

yeah, my YJ bbk sucks. the bike runs well, but takes years to top out. i will be replacing it with a ADA kit. at least i got a FSC with the one i purchased.

want to sell me your YJ head kit??
dont need the crank, let me know

well i just installed my ADA kit from HK motos. i havnt gotten to use it yet though. im waiting for a flywheel and starter. what do you have to do to the dome to fix it?

did your fcc come with a 10mm or 12mm pin

it might take longer to top out but the lowend is great and i am running a stock carb thinking of re jetting to .70 and i just orderd a 3rd bearing 6 tooth gear box to get higher revs faster

mine came with a 10mm pin i think. it was the same as stock so i just left it in the bag. figure if i need a new one i have it

is it hard to find 40mm pistons in a 10mm pin if i fry this one? all i can realy find is 44mm pistons with 12mm pins

wow some of these guys go crazy with squish and port timeing i like bolt on power!! lol i just cant spend hours on end screwing with this thing it starts to make the wife testy and everyone knows happy wife happy life lol. is thare anyone here i could send my motor to to have all the squish,port timeing,porting and all those other pain in the a$$ things done?

send a pm to sr20hardbody

or boosted 306 and possibly hmb_boy

not really an hours on end job if you have the right tools (dremmel and bits)...maybe and hour and a half tops....

yea, i ported my old cylinder in about 1hour and i only had sanding bits...lol

i tried to on my old stock jug but the dremmle jumped and scored the walls. so i wont dare to try on my new bbk. just dont have the hands for it.

Drop me a PM! I'll hook you up with bolt on power.....
Any of you guys running one of my ported heads, please, let this guy know about your results.
Thanks in advance and as always if any of you guys need help or head kits just drop me a line....

Thx!