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TPS setting

19K views 136 replies 4 participants last post by  Blayzin212 
#1 ·
Will start and idle, runs fine when on throttle, dies when I come off of throttle. Starts back up and idles? I got the bike from someone, so dont know what settings he had dialed in...............thanks a million- I want to go ride!
 
#3 ·
I am having the same exact problem. I just bought a power commander 5 to try and take control of the situation. Can anyone tell me if the power commander can fix an ecu problem if the problem actually lies in the ecu? My bike is getting drowned in fuel so I cut back the fuel ratio for the stock map on a stock bike. It didnt really help but have added a jeep coil that works great. I have checked and cleaned the wiring all over it. I've replaced the coolant temp sensor, I've calibrated the tps and cleaned the 30amp fuse connector. I was hoping that if it is the ecu not working correctly that since both the fuel and ignition now comes from the commander that the problem may disappear. I am going to get an auto tuner as well. Can an injector be dumping way too much fuel?

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#4 ·
The power commander is only a piggy back unit.

It won’t fix an ecu issue.

Verify the battery is 12v+

The auto tune still requires a close base map to adjust from
 
#5 ·
Ya the battery is at 12.8 and since I've been working with it I periodically put a trickle charger on it just because I'm spending more time starting it instead of having it running because of this issue. It's to the point now that I foul a spark plug after 5 min of it idleing due to far too much gas. I can tell that the gas is raising my oil level after maybe 15min idleing.
I am guessing that for as bad as it is I should start by replacing the ecu? I wont be able to test the injector or fuel pressure until sat. But I'm looking for ideas.

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#6 ·
(Your quote: I can tell that the gas is raising my oil level after maybe 15min idleing...)

It might NOT be an ECU problem...low compression can cause your symptoms too...!!!

Check if fuel is getting into your oil by smelling it for gas....If so...you might have bad piston rings...also do a compression test...!!!

•Hold the throttle wide open and crank the engine with the
electric starter several times. When the gauge stops ranging,
stop cranking and read the gauge.

Cylinder Compression
Service Range 49.0∼ 81.8 psi) @900 r/min (rpm)
 
#7 ·
Damn I was hoping it wasnt going to be low compression. I just got this kfx and I dont have any history with it.
I'm going to attempt to explain exactly what's going on in hopes that maybe you think its something else...I have a compression gauge but I need an adapter for it that's smaller than the one I have for the spark plug hole. I'll order one today.
Anyway yes I have smelled the oil and yes its diluted with gas. From tuning car engines I know that even with half way decent rings, if way too much gas is being added it makes it's way to the oil.
It only idles and I cant ride it more that 30 sec without it stalling and fouling the spark plug. I can start it pretty easily and it will run for 30 sec to a min before stalling. It wont stay running at 22 clicks ...I have to put it at about 15 clicks to get it at about 1800rpm. I can rev it fast but fully, and when the rpms come down it goes strait to stall. My spark plugs are saturated in fuel and I have to leave a plug out for maybe 10min so the flooding in the cylinder dries a lil and makes it easy to start again. With the pc5 I was able to turn the fuel percentage down a full 100% and it would run better but randomly miss about every 10 revolutions. I advanced the timing about 3deg and it helped but not too much so I put it back to zero. I am thinking about just ordering parts one by one until I figure it out. But I think a smart person would check the compression before that happens so I'll start by ordering that today.

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#8 ·
One more question...is the jug sleeves? Like I can take it and have it bored out? Or I have to buy the whole cylinder. I dont want to run race fuel so can I use a high compression piston and hotter cams?
Thanks for the help

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#10 ·
(only) If the cylinder is bad/scorn or worn out...such as dirt getting in through the intake....!!!

No it's not sleeved or can be bored out like a typical steel cylinder...the kFX cylinder is aluminum with a nikasil coating...So you'll have to have it re-plated if bored out...!!!

bore & re plate I recommend https://www.millennium-tech.net/serviceInfo.php?id=1

or you can have it sleeved locally or send it out to be sleeved.... https://www.lasleeve.com/cylinder-sleeves/l.a.sleeve-sleeve-ka5675
 
#12 ·
The more I think about it the more I think ur right. I ordered the compression fitting for the tester. So I will know on sat or sun. I really appreciate the info.
I will likely stay with the stock compression ratio. Do I understand this correctly that I can just buy a pair of 06' kx450f cams and slap them in there with no extra work?

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#15 ·
I went ahead and ordered a wiseco stock top end rebuild kit. Hopefully I can just replace it and get a few months out of it. I'll rebuild the entire engine top and bottom probably next winter. I need time to read and plan a path to get the most amount of power possible with out using anything over 93 pump gas....what would you recommend?
I already have a fci intake and a full dasa exhaust but I haven't installed them yet. I wanted to leave it alone until I could find the problem. I will also get the auto tune for the pc5.



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#17 ·
Well I just did the compression test and cold engine throttle closed was about 63 and cold wot was 75psi. So I dumped the fuel out into a clear jug and it was obviously mixed. I've had 2 strokes my entire life. I already have the kx cams... how much work would it be for me to put them in without a top end rebuild?

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#19 ·
So the guy I got the bike from says that he thinks that there are stage 2 hot cans in the engine right now. I have these kx cams and I have the head apart. How do I identify hot cams or stock kfx cams... or do I have to use a caliper?

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#20 ·
Well the kx cam lobes are clearly about a quarter in. taller than the cams in the engine so I started to remove them and the front right bolt on the exhaust cam is stripped and just sitting there. I'm very versed in mechanical engineering but I find it much more useful to ask someone who is experienced on a particular platform about that platform. I now have the idea that I may need to do a complete engine rebuild.

Is it possible to heli coil this or is there another alternative?

I removed the hole covers to check the timing marks on the left engine cover. Should there be small amounts of oil in there or is a lower end seal gone bad?

I really appreciate you helping me out.
Thank you

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#26 ·
Absolutely I did what u said. It took me a sec to figure it out. The previous owner had it one notch out of time...I took a pic before I took it apart because I've put many dohc cars in time and the Mark's never exactly match up. I cant believe the difference in it in neutral and revving. It accelerates so much faster. I've not gotten to ride it whatsoever in the month I've had it.
It's all stock as it sits but I have a dasa full exhaust and fci intake. I have the power commander v and the autotune. I will weld the bung in and install it hopefully tomorrow. I'm going to ask for a shelf map from the business I bought it from. I cant wait.!

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#28 ·
When I initially hooked up the power commander on the complete stock setup (which didnt run right to begin with) I had to cut the fuel by 50% just to get it to run and it gave me a 14.7 afr. I spent all day and installed the dasa exhaust, the fci intake, the PVC and autotune, and kx cams, I welded a second bung for a wideband i already have for tuning cars and its falling on its face at idle. It's running a 10.2 afr over all. I just fouled a plug after 2 min of idling with a map set all the way to 0 fuel across the field, and ignition 0 as well. It was in the process of trimming but didnt work fast enough because it takes a few min or hours sometimes. It was warm enough because I gave it 5 min or more with a 12v source before I started the bike. I then loaded a map with - 50 for every column up until 4000 rpm and it wont start because the plug is fouled. The radiator cap is pushing coolant out of it and the engine cant be but 120 degrees. Looks like a head gasket to me. I have a complete top end rebuild kit here but I didnt go past the cams. By the way I am using an a accell jeep coil brand new. Fires great but I had to use a 1 step hotter plug to get it to run right initially,(this attempt was a stock plug).
Do I have a bad injector?
Blown head gasket?
Bad ecu?
It a brand new coolant temp sensor.


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#29 ·
It fired up with the hotter plug and I gave it a negative 50 on the fuel. It actually went to a 14.0 afr at 1800rpm after a min or two. But I gave it a 50% control because I have a second wideband that's proven right so I know for sure it is, and I wanted to see what it was going to do to get it right so I could figure out what's wrong. Still spitting antifreeze out of the cap and I would imagine it's not past 130 degrees farenheit.
I have one more day until I start working 6 10's and I want something to ride this summer....what do I do from here?

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#31 ·
I also set a piece of cardboard under the bike because the small plug was stripped so I put an o ring on it to hold the oil so I could just get it running right before I tapped it. It leaked like 15 drops a day ....it could draw oil to my plug and foul it right?

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#32 ·
I apologize for typing so much on here but your posts are on the money and I see you've been doing this for quite a while.
Correct me if I'm wrong....I have to cut the fuel by 50% to make it run because its mixing with antifreeze in the combustion chamber. And that's how I am managing to foul plug after plug in a four stroke with a hotter than normal spark and the plug appears to be wet when I pull it out. And it accounts for the pressure in my coolant system at such low heat level.

Do I need to have a forged piston at 12.4 compression ratio ?

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#33 · (Edited)
Coolant in the combustion chamber is a blown head gasket...Needs to be inspected/replaced, ASAP...!!!

Tap the small oil plug/bolt m6 to the next size (is what most here do) being a common problem with aluminum engines...

An Air/fuel mixture of 14 is way too lean & should not be allowed...!!! A proper A/F ratio should be 12.4 ~ 12.8 range for best performance....!!

Not sure of the condition of the piston until the head is off if needing to be replaced...stock 12.0 or 12.4 ratio piston would be your preference to stay on pump gas...max is 12.8:1 needing 93 (min) octane
 
#34 ·
I have the head off now and everything looks good. I need some shims for the cams so I think I will order a kit. The head appears to be true with a flat edge. I will replace the gasket and I am considering arp studs. If the head gasket isn't blown then the next most likely place for pressure in my coolant would be the water pump seal? Or a bad radiator cap?

The 14 afr is at an idle. I still cant ride it yet. I havent even had it up to operating temp yet.

The stock coil would foul a plug in about 45 sec...the dynoteck coil made the plug last about 90 sec. And the jeep coil lasts for 3 min or so before fouling the plug. The plug always comes out soaked in what smells like gas. That's y I kept leaning it out to stop fouling but it still hast really worked. How am I able to foul plug after plug?




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#37 · (Edited)
I'm suspecting that the wet fouling may not be gas but coolant...due to the head gasket....??

Is it a necessity for arp studs or can I get by with changing them next time?
Someone stuck normal steel washers in place of the copper washers. The head may not have been tight as it should have been.

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Arp stud is highly recommended ( I'm using them)...using steel washer in place of the copper will cause the head bolt to stretch, motor case aluminum threads to pull out or both destroying the head gasket seal....!! either way you'll need to purchase new head bolts & washers or the arp studs...!

Is there a way to tell what compression ratio piston I am using now?
I didnt see anything wrong with the piston so I didnt remove the jug. I will post some pics tonight.

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rotate the piston to the lowest position & check the cylinder wall for scuffing/scarring due to the coolant...water/coolant in the combustion chamber causes extreme lean condition both the a/f mixture & piston ring lubrication...!!!

It would be easier to pull the piston out to look for a part#'s to determine the compression...the other way is to pull the piston and measure the piston compression height...

Note:.... compression height is the distance between the centerline of the pin bore and the top of the piston. To determine the compression, three things about the engine must first be known: block height, connecting rod length and crankshaft stroke length.
 
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