Author Topic: Parts suggestion, want to change powerband (Read 6211 times)

paulkx5 · « **on:** January 17, 2004, 11:33:10 AM »

I have a completely stock 90 which is in excellent mechanical condition, but i am not too thrilled with the power characteristics, especially down low.
The suspension etc., are all set for my weight/ riding style, the sprockets are 15/50, stock size tire, the bike is jetted properly. This bike has plenty of power everywhere, pulls front up in all five gears at will. All the maintenance [sp?] stuff, bearings etc., has been done, so I don't have need to worry about all that.
The bike is very hard to manage down low/ off idle, very little throttle movement makes for big wheelies, this bike is almost violent off the bottom. I would like to soften, or prefferably just smooth out the bottom end without loosing any mid/ top. I have been running 92pump at 40/1 with belray mc-1, i will be switching to race gas in the spring.
The parts i have been considering so far have been; desert pipe fmf/pc,
fmf/boy reed valve, and or thicker head gasket. My problem is that being a law student, i have very little money to spend on important things like my kx, and need to get it right the 1st time. I can afford $450 or less.
My question is which of the above, or any other suggestions, or combination, are most likely to change the power curve the way i want.
Thanks for your advice.

YUNGGUNNAZ · « **Reply #1 on:** January 18, 2004, 05:22:07 AM »

PAUL,WHAT TYPE OF RIDING ARE YOU DOING?TRAIL,MOTO,DRAG ETC.AND YOUR WGHT.DON'T WANT TO SUGGEST SOMETHING IN WRONG DIR. FOR YOUR THE USE OF THE BIKE.TIS WILL HELP EVERYONE.

doordie · « **Reply #2 on:** January 18, 2004, 06:09:43 AM »

paulkx5!
A very simple mods is to raise the cylinder with thicker gasket,that reduce the compression and move the powerband up.You can also retard the advance of ignition.Change the rearsprocket to 44-46.
Put on a flywheel weight.

paulkx5 · « **Reply #3 on:** January 18, 2004, 06:36:19 AM »

YUNGGUNNZ,
I weigh 240 geared up, and I ride both trails and a little moto (recreationally), basically I ride everywhere from tight woods to fast open fire roads and do a little mx track riding. I ride pretty agressively, and have been riding since I was seven (21yrs). Hope this helps, if you need more info let me know.
Doordie,
Thanks for the suggestions, which would you suggest I try first?

kawdude · « **Reply #4 on:** January 18, 2004, 11:53:39 AM »

I vote for the flywheel weight and change the rear sprocket to 48-49. Mine had a 47 and I went to the 49. Big improvement.

YUNGGUNNAZ · « **Reply #5 on:** January 19, 2004, 02:40:32 AM »

the flywheel weight change is good to smooth out hp hit in the power curve but it will give more torgue.with low # rear sprocket look for clutch use to mangage wheelie at the start.use a lower front sprocket(even the stock one)with what you have on back to allow bike to spin away some before wanting to come up.thicker base would also give more mid range by raising tranfer and exhaust ports.retard the timing a little helps on the top.whats left is to lay that 240 over the front, take a deep breath,twist the throttle let her rip cause these guys just put you a rocket.

kawdude · « **Reply #6 on:** January 19, 2004, 04:53:29 AM »

John · « **Reply #7 on:** January 19, 2004, 08:50:27 AM »

You could also try the Moose spacer kit. It's another "cheap" solution which more or less addresses the same problem.

//John

teamgreen500 · « **Reply #8 on:** January 20, 2004, 10:29:47 AM »

The gearing change is the cheapest fix. ESPECIALLY if you an go up 1 tooth on the front (About the same as going DOWN 3 teeth in the back; BUT, A LOT CHEAPER!)

Another UNKOWN secret...so...don't tell anyone...Shhhhhhhh!

The FMF "Fatty" and (More so) the DG "Fat-Pipe" will increase your upper mid to top end power while "Mellowing" the bottom. Playing with the jetting when using these pipes is also helpful. The combination of gearing and Pipe will give you a very "LINEAR" feel! You'll pull harder and longer than those fashionable "Thumpers". If you want a D.G., I've got one that I've never used...p.m. me.

The flywheel weight isn't one of my favorites(I don't run one), it can cost me too much acceleration out of turns/berms...especially when it's really nice out and I'm Hookin' it up like the Bigs!

Good Luck,

Manny

Rick · « **Reply #9 on:** January 20, 2004, 11:35:55 AM »

Smaller rear sprocket (48 tooth) and flywheel weight get my vote. There are disadvantages to the flywheel weight, but for the recreation rider, I believe the tradeoffs are worth it. I have been running one for awhile now, and don't bother to take it off for races.

Good luck.

Rick

paulkx5 · « **Reply #10 on:** January 21, 2004, 01:37:09 AM »

Thank you all for your suggestions. I am kind of leery about trying the flywheel weight, I don't want to lose throttle response in the mid and top. How much difference will the weight make, also what brand/ size would you recommend [thread on only]? I was kind of hoping to aviod changing the chain/ sprocket, they were new when I bought the bike [still excellent] and Iwas hoping to wear them out, also the bike seems to be pretty high geared already. I may try it anyway though.

I am having a hard time finessing clutch as YUNGUNNAZ alluded to, as I am still recovering from a bad wrist, and an elbow fracture a year and a half ago [kid ran onto the track]. First and second gear wheelies are hard to maintain without clutching with the touchy throttle. I have read all the posts on easing clutch pull and already have T2 cable etc. Thinking maybe a hydro would help.

Rick, [or anyone] would you mind describing some of the disadvantages/ tradeoffs of running a flywheel weight?
Thanks,
I really appreciate all the input.

John · « **Reply #11 on:** January 21, 2004, 02:03:25 AM »

May I suggest that someone writes a review on the flywheel weight instead... I would but I am kind of busy right now...

//John

toddwunsch · « **Reply #12 on:** February 17, 2004, 02:07:58 PM »

Moose spacer at www.denniskirk.com (Fuel and intake section) Flywheel weight at www.steahlyoffroad.com and definately go with a 45 in the rear. That was the first mod I made to my bike was going to a 15/45 and it made a huge difference. Depending on where you are riding you may also want to look at the Team Green jetting settings at http://www.kawasakisportscenter.com/2000_Jetting.htm I changed to those settings and felt a little difference in the mid / low range.

gowen · « **Reply #13 on:** February 17, 2004, 05:24:23 PM »

If I'm correct, you are looking for mid-top end not torque as in low-mid.

I'd suggest sending it off to have it ported and have the head worked. It has been the most effictive so far. I just got a FMF Desert pipe, but have not tested it yet. Also, Boyesen Power Reeds did alot of top-end magic. I needed a total engine overhaul last year and had a company do it, top/bottem end for $1150 (total new crankshaft, hot rod, 88mm piston, mid-top port, head work, powervalve work, nickle plating, ect. ect.) If it is just a top-end job it is $400. So, very happy with results. Just now need to try out this FMF pipe, also have a Powercore silencer.

I do have a stealthy flywheel if you want it, took it off when I purchased it. don't need it. if you want it, I can dig it out.

My KX runs more like a 125 now. But, with alot more power.

and the low-end of a 4stroke still is almost there. But, the top-end is absolutely insane. But, since I do more wfo farm lands, it is been a godsent.

toddwunsch · « **Reply #14 on:** February 18, 2004, 02:39:05 AM »

Gabe. If you're willing to sell the flywheel, please contact me via private message.

Author Topic: Parts suggestion, want to change powerband (Read 6211 times)

paulkx5

paulkx5

kawdude

kawdude

teamgreen500

Rick

paulkx5

toddwunsch

toddwunsch