Changing the intake

[cousinit]

Ive got the 08 kfx450r and i'm wondering if a new intake will help with stalling... I'm getting used to clutching it, but i ride really tight, technical trails and any help would be good... Also, does the fci work with the stock inbox??? I ride through a lot of mud, water, in the rain and snow, so i don't think i should run without a lid... Would i have to do anything else to the bike with a new intake??? (PCIII or other controller) I don't want to change the exhaust yet and i would rather not get anything else now, if i don't need to... I really like this quad and i'll eventually do the big 3, but paying it off is the first priority... Thanks

[k4f5x0r]

FCI makes a intake box that is basically running no lid. you should be fine as long as you dont drive into water or mud above the seat. which you shouldnt do anway. and yes with teh intake you will need a pc3. preferably a pc3 because its the best tuning device.

[MtnEX]

Ahhh... someone else who rides stuff like I do and thinks this bike is a little "stall happy".....



To be honest with you, I myself think something is "off" in the electronics/injection. I don't think it's normal for it to stall like this. But I have not been able to find the time, weather, instruction or my digital tach to run down the "source" of the issue.

I figure it is the throttle position sensor, or something to do with the injector.

Does yours have a slight flutter at idle?
Mine does.



Anyways, if I can't find anything electronically wrong, you and I will probably have to resort to a Rekluse clutch kit to remedy this.

I thought about trying a 13 tooth front sprocket too. I probably would rarely miss the loss in top speed. But I fear having to shift too much then.

[cousinit]

Thanks for the replies.. Mtnex, My bike runs fine, i just think it's not set up for the slow tight trails... It helps that it has the electric start and it really hasn't given me starting trouble... I did get a 13 tooth front sprocket and will be trying it soon... Before this, i rode a trx250x with a 13 tooth front and it lugs through everything... The KFX is a different animal, so i will need to adjust it and my riding.... I'm open to any other suggestions and will post the results of the 13 tooth at some point.....

[bo142s]

I tried a 13 up front and all it did was make me spin the crap out of tires It was fine until I put on a new intake and exhaust then it spun the tires so bad I went to 15 up front and its perfect I ride a lot of technical trails where I never get out of first you just have to ride the clutch or you will be stalling it all over I still stall it more then I like but I think its me and not the machine

[BLU82]

Maybe try turning the idle up? Or, no offense to anyone here, but maybe your just not used to the clutch feel of the 450 and need more practice with it.

[spanky101]

Also id look into a rekluse clutch if your really stalling out that much. Its an expensive upgrade but well worth it if you ride alot of tight technical trails

[MtnEX]

Originally posted by BLU82
Maybe try turning the idle up? Or, no offense to anyone here, but maybe your just not used to the clutch feel of the 450 and need more practice with it.

I've been riding ATV's since before they added the 4th wheel... and never have I seen one so weird about stalling out.

I'll admit it's been a while since the 2 strokers, but even they didn't stall with these sorts of manners.


Mine stalls so quick without warning so often.
That's what bugs me so much...
It gets me when I'm not expecting it.

[MtnEX]

Originally posted by spanky101
Also id look into a rekluse clutch if your really stalling out that much. Its an expensive upgrade but well worth it if you ride alot of tight technical trails

I've been planning that upgrade anyways, but for other reasons.
(scooting the kiddies around the yard in 1st)

[MtnEX]

Originally posted by bo142s
I tried a 13 up front and all it did was make me spin the crap out of tires It was fine until I put on a new intake and exhaust then it spun the tires so bad I went to 15 up front and its perfect I ride a lot of technical trails where I never get out of first you just have to ride the clutch or you will be stalling it all over I still stall it more then I like but I think its me and not the machine

Stock intake and exhaust... was it worthwhile or did it make the gears real short?

I thought about trying it and then moving up to a 22/21 tire set if it's too much. But I haven't done the gearing calculator math yet...

[bo142s]

I have 22's so thats why try I first tried a 13 to compensate for size it kinda helped but after I did the big 3 it was a whole different machine so I went to a 15 and I like where it's at

[cousinit]

All right, i changed to the 13 tooth front sprocket and it made a big difference... For what i ride, this was what the bike needed... I'm clutching and stalling a lot less and i get into second more, instead of reving out in first... It does want to shift quicker in the open areas, but 90% of what i do is trails... Also tried it on a woods track with 50 foot hills, berms, and whoops, and it was great there to... You don't have a lot of speed going into the hills and the tops are tight turns, so it was great gearing there also...
To me the bike wants to pull more in the lower rpm's and the throttle is snappier... The technical **** is more enjoyable, so i would recommend it, if that's what you ride...

[MtnEX]

Originally posted by cousinit
All right, i changed to the 13 tooth front sprocket and it made a big difference... For what i ride, this was what the bike needed... I'm clutching and stalling a lot less and i get into second more, instead of reving out in first... It does want to shift quicker in the open areas, but 90% of what i do is trails... Also tried it on a woods track with 50 foot hills, berms, and whoops, and it was great there to... You don't have a lot of speed going into the hills and the tops are tight turns, so it was great gearing there also...
To me the bike wants to pull more in the lower rpm's and the throttle is snappier... The technical **** is more enjoyable, so i would recommend it, if that's what you ride...

That is good news because I have already ordered some sprockets in with my big order, just to mess around with.

I picked up a 13t front and also a 39t rear in case I felt the 13t was too much... and because those were the two sizes they had that were lower than stock.

Just waiting for the brown truck now...

[KFX450Rrider490]

Mtnex good luck with the sprockets and please post what you thought of the change because my old kfx did that all the time when it got hot is yours like that or just me??

ill see when i get the new one (dealers a pain ive been basicly quadless for a good 5 weeks now) if it still happens cause i know what ur talking about its the only quad that ive reciently ridden that i stall constantly

[MtnEX]

Originally posted by 300exrider490
Mtnex good luck with the sprockets and please post what you thought of the change because my old kfx did that all the time when it got hot is yours like that or just me??

ill see when i get the new one (dealers a pain ive been basicly quadless for a good 5 weeks now) if it still happens cause i know what ur talking about its the only quad that ive reciently ridden that i stall constantly

I will most certainly keep you posted.


At this point though, I decided to play with the gearing to see if I could get into 2nd and 3rd more in the tighter sections.

I personally think the stalling issue is ELECTRONIC and not mechanical though.

I think the problem is that this EFI is new to the MFG's and dealer shops, so they have a hard time getting it right, and a hard time figuring out what if anything is wrong in the first place.

Other sectors like outdoor power equipment have gone through the same thing with the addition of fuel injection.

So in the end, as much as it sucks, right now it's a good time to learn how to work with this system yourself. That way you can check things yourself and know what is wrong already before you bring it in for warranty coverage.... and after the warranty coverage, you can handle it yourself.

I have the service manual and plan to go get the test plug leads in the next few days. I'm going to go over it myself and see if it is something that can be adjusted out.

I think it's an adjustment, a sensor, a wire, a ground, or an injector... weak spark... some crap like that.

[bustedknuckle]

most dealers should b able to put your kawi on there computer.it will help find any elec. problems.the cpu stores any problems and elect. failures.thats if they know how to do it.

[bustedknuckle]

my son raced a kawi. we never changed the sprockets the kawi is built for the woods.we ran hetricks box and air tube,in the gncc and awrcs. never had any water.you still had to prep the bike for the woods.

[MtnEX]

Originally posted by bustedknuckle
most dealers should b able to put your kawi on there computer.it will help find any elec. problems.the cpu stores any problems and elect. failures.thats if they know how to do it.

I know the dealer shop "could" check it out for me.
Should not cost much if anything either...

I just don't happen to trust a shop to be that detailed.
I'd likely to be lucky if it was even checked...
Much less checked for accuracy to 0.00 V


I just bought the test leads so hopefully I can do it easily myself.
Cost me $32.33 for both.
Just waiting for them to ship in to the dealer from Cali.

[bustedknuckle]

one thing i found out .is clean out all elect.connections.and fill with elect.grease.ck the grounds.rember alum. fram.vs metal bolts.also ran a ground directly to batt.

[MtnEX]

I finally got through all of this TPS stuff today on my own...

The test lead makes it VERY easy to do the test and see a reading while you are adjusting.

My TPS was off, so I had to adjust it. To do this you have to loosen the star screw in it and rotate the assembly a little.

The screw part is MUCH easier said than done though, unless everyone knows of a tool I don't. I have a Craftsman "bit ratchet"... a tiny little ratchet that accepts the little screwdriver bits. The screw is behind the frame a little. You can't go at it from an angle, and even as short as what I have was... it was still too long. That's nuts!

Ended up doing it with the star bit and an adjustable wrench to turn it with.
GETTO!

I've ridden it very little so far. So it's hard to say, but it has not seemed to stall on me as easy YET. I'll have to ride it more.

It starts faster now, but I'll have to get in a few more cold starts to judge that.
I still have to use the choke/idle RPM knob though... errr...

[MtnEX]

OH, and on the down side, the flutter I knew was there in the idle....

Well it is a more pronounced MISS now.

So I have to get some more time on it, and if it doesn't settle out I'll start on chasing that down.

[MtnEX]

Guys... I never did get the gearing changed... because I've been doing a lot of head scratching over the electrical... convinced there was a problem.

I think I finally found it....

My crank position sensor fails inspection.
It does not pass it's resistance test.

It's not dead... just not in spec.


If you are having problems with stalling or missing, it's worth a check. Very easy to do... unplug it's connector and put a meter on the contacts inside....

If anyone needs help with the details of where the connector is or what the specs are, just let me know.

[KFX450Rrider490]

i think i may have told you this before but if the miss gets worse
or the bike stalls while riding (dont go far fom home unitl its fixed)
and doesnt start back up truly just take it to the dealer and let them deal with it like i said the got so fed up with my bike they gave me a new
one good luck i hope you get it fugured out

[MtnEX]

Oh... it's been sitting at the house...

I haven't trusted it to take it out for a ride.
I didn't want to get stranded.

Also, the fact it's fuel injected made me extra leary of it. I'd be afraid to ride it much, thinking it may lean out and burn itself down when not running right.

[KFX450Rrider490]

DO YOU still have your warenty on it?
because if you do, let the dealer play with it if your not riding it i didnt put a penny down on the on the hours i guess kawie covered it ( thats what i was told) and if your finding me a pain in the but tell me and ill shut up
i just wouldnt want to see someone stuck with another problem bike

[MtnEX]

Yeah, it's still under warranty... I just bought it in March. It's going in to the dealer.

I had just figured to start with this was old gas the dealer put in... burnt that out... then figured it might need the TPS tweaks, so I ordered the Kawi test leads for that and tweaked... still not it...

So I checked over the machine myself to see if if was something easier and chaper to fix myself than make two 160 mile trips to the dealer.

Since it turns out the whole stator probably has to be replaced over the crank sensor being bad (far as I can tell) I'm not sinking over $200 for that.

A closer dealer sold out recently, so I'm going to check with the new folks there tomorrow and see if they will take it in for warranty repairs so I don't have to haul it so far.