trx90 update

[double d 1]

well my son has the 07 model and ive slowly been getting it going. when it was stock i put a washer from powroll to raise the needle and a bigger jet a 92. it starts so much easier this way. i had to start it before because i had to keep messing with the choke for 15 minutes. now it starts without the choke. i also cut the pink wire but i dont know if it helped or not since it only works for the top end of fouth gear. he said it was faster. but with the washer and bigger main jet it seems to stumble at 1/4 to 1/2 throttle, and from a idle if you wack it wide open it will die. i just put on a Hetrickracing pipe and this thing sounds so good. it sounds like a piped mini 400 ex. you can deffinatly hear it. way louder than stock. i have some pilot or slow jets coming from jetsrus in a day or two. i'll let you guys know how that goes. i rode it after i put the pipe on and the other mods and it runs pretty good. i weigh 275 and i was really surprised!!! it runs so good. i'd like some better suspension but that stuff is really exspensive. we mostly dune or trail ride. if he gets into racing then we might go that route. he is only 7, be 8 in sept. i think ama rules you have to be 8 on a 90. all in all for the money i think i spent 320 total for pipe and jets it runs a whole lot better. thanks for letting me ramble on.

[double d 1]

well the pilot jets were the wrong size. so im still stuck with not being able to find a pilot jet for it. was talking to a guy at the honda shop and he said it sounds like its running to rich . i put the origanal main back in and it runs the same. the plug did look really black before i changed it. so now im back to a stock 90 except for the hetrick pipe. it still has a stumble when you wack the throttle from idle, it will die. dont know how to correct this. any suggestions?

[koh0001]

I just put a Big gun pipe on my sons and was wanting to know what size jet I needed to go up to also?? And what do you do about the air filter?? do you remove the box and run a aftermarket stright to the carb like our bikes?? or does it fit in the airbox correctly??

[ALEXANDERJASON]

I NEVER EVEN STARTED MINE WHILE IT WAS STOCK. I ADDED THE BIG GUN EXHAUST, WHEELS TIRES AND SOME OTHER COSMETIC THINGS RIGHT AT THE DEALERSHIP IN THE WAREHOUSE BEFORE I BROUGHT IT HOME. AFTER I WAS DONE, AND WENT TO CRANK IT FOR IT'S MAIDEN VOYAGE, IT STARTED AND IDLED, BUT IF YOU GAVE IT ANY GAS AT ALL IT JUST DIED. THE SALES GUYS AND ONE OF THE TECHS WERE THERE, AND WE WERE ALL BAFFLED. ONE OF THE OTHER GUYS WALKED BY AND ASKED IF WE HAD PULLED OFF THE AIR INTAKE RESTRICTOR. WE DID, AND IT STARTED RIGHT UP AND REVVED TO THE RED LINE.

THE ONLY CHANGE TO THE ENGINE WAS THE NEW BIG GUN EXHAUST, YET IT WOULD NOT EVEN GO ABOVE IDLE WITH THAT CAP ON. IT MAKES ME WONDER HOW IT WOULD HAVE RUN HAD I CHECKED IT BEFORE I EVEN STARTED WITH ANY MODS.

I HAVE FOUND IT DIFFICULT TO FIND JETS AS WELL. IF YOU TYPE IN KEIHIN JETS ON EBAY, THERE ARE A HANDFUL OF AUCTIONS THAT WILL LET YOU PICK THE STYLE AND NUMBER YOU NEED.

FOR NOW, WITH THE AIRBOX LID REMOVED, AND THE FULL EXHAUST, IT SEEMS TO RUN PRETTY GOOD. MINE STUMBLES SOME AT 1/4 TO 1/2 THROTTLE AS WELL, BUT NOTHING MAJOR.

I AM IN HOUSTON, SO SEA LEVEL, HOT AND HUMID!!

I WANT TO DO SOME OTHER MODS, BUT I THINK I'VE KINDA HIT THE POINT WHERE I HAVE DONE ALL THE LEAST EXPENSIVE THINGS. FROM HERE, IT'S REAL BUCKS TO MAKE ANY DIFFERENCE.

NO LID, FULL EXHAUST, CUT THE PINK WIRE, AND 18" REAR TIRES. I THOUGHT I MIGHT DROP A TOOTH ON THE FRONT SPROCKET, BUT I HAVE NOT BEEN ABLE TO FIND ONE. ANYONE HAVE ANY OTHER CHEAP IDEAS?

[double d 1]

well i put the original main back in, it is an 82. it runs just as good as the 92 that i put in it. so now it is a stock bike except for the hetrick pipe and a small shim under the needle to raise it a hair. starts with no choke now. the pilot jets i ordered from jetsrus didnt fit, so i sent them back. oh, im also running it without the air box lid. i think i saw some sprockets at rockymountainatv.com not sure though. it still will die if whacked open at an idle. pink wire cut also. i think the after market air filter just goes inside the box, not sure about the k@n, but pretty sure the uni filter does.