KX Riders
Maintenance & Technical => KX500 Original => Topic started by: bandit88 on May 20, 2016, 08:15:35 AM
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Hey guys, been tuning up my 500 and it now seems to run like a champ but down on power. The bike isnt as violent or scary as I thought it would be. Has no issues lifting the tire in first and second, but wont do it under throttle in any other gear. I have no issues holding it wide open on dirt roads and yeah its fast but I feel it should be faster. It sounds good, starts easy, and runs like a champ. I am just curious what you guys think since I have never ridden a known good 500. Things I have done so far are:
-New ProX piston and rings
-New crank seals and bearings
-New Barnett clutch discs and springs
-New OEM headgasket
-Reeds are OEM and look brand new, no gaps
-Has FMF Gold pipe and spark arrestor
-Powervalves cleaned, seals and guide replaced, when tested opens and closes as it should
-Carb jetted for 5500 ft per the chart that is floating around here.
-Running 91 octane fuel with 40:1 Motul 800
-Stock gearing with new JT chain and sprockets
Thanks
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I would re-check the KIPS, even though you said they were opening ...confirm they're actually working when you rev it up, and re-check the "KIPS timing"...if the KIPS timing is off, it'll run like you describe as well.
have you actually done any wide open throttle plug chops to verify that it's not jetted too lean or rich?....some of those charts floating around here aren't that accurate, at all...you need to verify by doing plug chops.
I'd start there, if all checks out...then off to other possibilities.
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I would re-check the KIPS, even though you said they were opening ...confirm they're actually working when you rev it up, and re-check the "KIPS timing"...if the KIPS timing is off, it'll run like you describe as well.
have you actually done any wide open throttle plug chops to verify that it's not jetted too lean or rich?....some of those charts floating around here aren't that accurate, at all...you need to verify by doing plug chops.
I'd start there, if all checks out...then off to other possibilities.
Thanks,
A plug chop was my next plan. I have checked the KIPS valve in Neutral and it does open when revving. How would I check the timing? Hook a tach up and make sure it opens at the correct RPM? Thanks
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no, you need to take the pipe off, and look up inside the exhaust port, and see if the side valves are opening and closing precisely the same.
when you were assembling the KIPS in the cylinder, there's "timing" marks that need to be lined up...grooves on the govener rod, and "marks" on the side valves....
but if you can see that they're opening and closing correctly and precisely the same, through the exhaust port, you should be good.
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If it's anything like my bike on dirt roads... traction is the problem...
:lol:...there's definitely some truth there.
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no, you need to take the pipe off, and look up inside the exhaust port, and see if the side valves are opening and closing precisely the same.
when you were assembling the KIPS in the cylinder, there's "timing" marks that need to be lined up...grooves on the govener rod, and "marks" on the side valves....
but if you can see that they're opening and closing correctly and precisely the same, through the exhaust port, you should be good.
Yep, used the timing marks when assembling the cylinder and checked that last night when i pulled the pipe to take the kips cover off to check the governor functionality. Im hoping to ride tomorrow to do a plug chop and do a road test.
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keep us posted. :mrgreen:
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Even with 15/42 gearing I don't get any traction on dirt until 5th gear...when it does finally stop spitting out gravel like a snow blower it's like warp speed
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Plug chop looked near perfect. Not sure what speed I had it up to since my gps was broken but I would guess 70ish, was still accelerating. Got it to wheelie in third but took a little work with the throttle. Starting to think that it is just the way it is, and to ride it as is until I get the cylinder replated in the winter. Was just expecting it to be more unmanageable.
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something doesn't sound right....I can get mine to wheelie in any gear, even at 60+mph, with ease...granted my motor is far from stock, thanks to Pinnsonault, Pro Circuit, CrankWorks....but when I bought it in 2011, it was stock, and sacked out, and would still wheelie with ease in any gear.
as Motorrad mentioned...maybe you're losing traction...easy enough to determine, just look back over your shoulder whilst you're on the gas.
your clutch isn't slipping is it?
how bad is your cylinder?...you mention getting it re-plated in the winter...have you done a compression test to find out where it's at?
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mine's like that too, on certain surfaces...a little gentle clutch grabbing takes care of that.
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I've thought about the clutch slipping, and have got that sensation every now and then.. It's all new but maybe something's not right. I'm running redline 80 wt oil, maybe I'll try something else.
Cylinder plating looked a little worn but wasn't cracking or flaking so I was hoping to get a summer out of it. Haven't done a compression test but my foot says there's plenty. I know I shouldnt go by that though haha. Will check it one of these days
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you never mentioned where you set your ignition timing.
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Timing has been set with the stock marks on the stator plate.
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Did a compression test tonight. 155PSI so that looks good and maybe I dont need a replate. Good news haha. I guess im going to pull the clutch cover next take a look at things again. I am not sure what I am going to find but I feel like I have checked everything else.
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Think I found the issue. Was looking at the power valves again and found that the center valve does not open flush with the top of the exhaust port, it hangs down a millimeter or two. Any words of advise on getting it to open all the way? Going to pull the top end tonight.
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found that the valve guides were dropping a couple mm since the gasket is cut out for them. Made some shims to prevent that and all seems good now. Hoping for a test ride tomorrow.
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found that the valve guides were dropping a couple mm since the gasket is cut out for them. Made some shims to prevent that and all seems good now. Hoping for a test ride tomorrow.
Worn Pins on the centre valve wont help things either
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Think I found the issue. Was looking at the power valves again and found that the center valve does not open flush with the top of the exhaust port, it hangs down a millimeter or two. Any words of advise on getting it to open all the way? Going to pull the top end tonight.
here's a good thread on KIPS tuning and the center valve...thanks to KXcam22 and Doordie...
http://www.kxriders.com/forums/index.php/topic,1367.0.html
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Got to shim em... and don't run the base gasket with the big holes
What gasket do you run? 86-88 or some custom cometic one?
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cometic P/N: B0036SP1018AFM
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awesome! thanks guys!
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after yu torque it all up make sure the KIPS actuates smoothly
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after yu torque it all up make sure the KIPS actuates smoothly
Then check it once in a while to make sure it continues to operate freely...
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Took it for the first test ride since shimming the valves and it was better but still not 100%. Is the custom gasket the ultimate fix? Is this an issue if everything is new? I dont see how the oem base gasket would not have this issue unless the orings on the valve guides are supposed to hold it in place without it dropping?
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Since none of us are able to see for ourselves....take into consideration, that just maybe your expectations on just how powerful it should be, could be higher than what it actually is.
This doesn't sound like the case, but again...we can only speculate without actually being able to take it for a ride ourselves.
You do have a few "bolt-on" mods, but for the most part, sounds like a stock motor.
You know anyone that has a K5 you could take for a spin, to compare?
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I thought about that and it very well could be the case. I was going to run a hill climb this weekend with my 72 TM250 but due to a transmission problem, and not getting parts in time, im going to run the K5. Im sure there will be a number of K5s there that I could probably get a ride on, or find someone else to ride mine.