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Discussion Starter · #1 ·
KTM 525 XC Stock Engine - HMF Exhaust Full System - Two 1-1/2" Circles cut out behind air scoops on breather - K&N Filter System

JD Jetting Kit:
Red Top Needle - Clip 4th from top
185 Main
45 Slow Jet
2-3/4 out on fuel screw

Runs great pops on decel - if you don't chop the throttle and just keep it on it doesn't pop - something to do with cutting all the air off - this can be adjusted out - i've got to think about it and do some research - Called HMF and Hans (Owner) is racing 525XC same problem with his they are working on it also - Note the Full System header from HMF is more of a top end header it sweeps straight back from the head...
 

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below is where i am going to start my jetting...

#45 pilot jet
1 1/2 turns out on the fuel screw
Red marked needle in the #5 from top clip position
#185 main jet
Float bowl screw for accelerator pump set at 1 1/4 turns out from lightly seated

i am going to have to come up there and ride that hmf exhaust... the last hmf i had was way too loud for me! along with my paddle crisis, i am also having an exhaust crisis! not good. hopefully i will get the dasa slipon soon and that will hold me over until another full system that like hits the market
 

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Discussion Starter · #3 ·
below is where i am going to start my jetting...

#45 pilot jet
1 1/2 turns out on the fuel screw
Red marked needle in the #5 from top clip position
#185 main jet
Float bowl screw for accelerator pump set at 1 1/4 turns out from lightly seated

i am going to have to come up there and ride that hmf exhaust... the last hmf i had was way too loud for me! along with my paddle crisis, i am also having an exhaust crisis! not good. hopefully i will get the dasa slipon soon and that will hold me over until another full system that like hits the market
Come on up...she is ready to go...HMF much quieter than the one on my wife's Z400...that popping on decel is annoying however
going to seal exhaust leaks then start on carb fix...
 

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45 slow jet
188 main jet
OBDTP needle jet, clip in the 4th position
R&D Keihin power pump turned out 1 and 1/8 turns from lightly seeted
 

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45 slow jet
188 main jet
OBDTP needle jet, clip in the 4th position
R&D Keihin power pump turned out 1 and 1/8 turns from lightly seeted
I tried the power pump for a bit then went back to stock, just wondering if you mash the throttle does it stall? I had to go to a 52 on the pilot while using the power pump.

Now that the power pump is off ....
JD-Blue 2nd from top
45 pilot
185 main
I run at the Oregon dunes - sea level
To me it feels like there is no weak spots in the throttle with this set up. Only other changes I made so far was just remove the snorkel and the air drain plug. Was thinking of cutting more holes in the air box but so far I don't see a reason for that unless I go to a higher elevation.
 

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I tried the power pump for a bit then went back to stock, just wondering if you mash the throttle does it stall? I had to go to a 52 on the pilot while using the power pump.

Now that the power pump is off ....
JD-Blue 2nd from top
45 pilot
185 main
I run at the Oregon dunes - sea level
To me it feels like there is no weak spots in the throttle with this set up. Only other changes I made so far was just remove the snorkel and the air drain plug. Was thinking of cutting more holes in the air box but so far I don't see a reason for that unless I go to a higher elevation.
I was thinking about getting an R&D product, either their power pump or power bowl. It sounds like you didn't have much luck with the former. Would you advise against buying one?
 

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The FMF Speed slipon where put in the two bikes this weekend and jett kit, only had one jett kit and james at jd gave me those instructions on how to jett them both with one kit.


Did that and it works very good.

 

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I was thinking about getting an R&D product, either their power pump or power bowl. It sounds like you didn't have much luck with the former. Would you advise against buying one?
I don't want to dis anyone's product, but for me it was more of a pain than it was worth. I must have taken my carb off about 8 times jetting it over and over and it seemed to me when I mashed the gas it stalled and I could never completely get rid of that but I got very close. So for me it seemed like this product was suppose to eliminate stalling not create it. Maybe I didn't give it enough of a chance and maybe someone else has better advice. I will say there customer service was spot on. Another thing that made me take it off and say the heck with it was I was reading somewhere from a link posted on this site that talked about jetting and it said something to the affect of don't believe in pump accelerators that promise to solve all your carb problems. Anyway I think there are a few people using it here and maybe they can give a better opinion.
-Voodoo
 

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I don't want to dis anyone's product, but for me it was more of a pain than it was worth. I must have taken my carb off about 8 times jetting it over and over and it seemed to me when I mashed the gas it stalled and I could never completely get rid of that but I got very close. So for me it seemed like this product was suppose to eliminate stalling not create it. Maybe I didn't give it enough of a chance and maybe someone else has better advice. I will say there customer service was spot on. Another thing that made me take it off and say the heck with it was I was reading somewhere from a link posted on this site that talked about jetting and it said something to the affect of don't believe in pump accelerators that promise to solve all your carb problems. Anyway I think there are a few people using it here and maybe they can give a better opinion.
-Voodoo
My jetting is as follows
188 main
45 slow
OBDTP Needle In the 4th position
R&D power pump turned out 1 1/8th turn from slightly seated
I can be loping at idle and go WFO with no hesitation what so ever very crisp through out the throttle range. I would still like to get it dyno tuned though to see how close I am with the F/A ratio
.
 

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I am at 900ft and mine is as follows

45 pilot
1.5 turns out on fuel screw
4th clip on needle
power pump 1.25 turns out
170 main.

What are the a/f you guys are getting with those huge main jets. I put in a jd kit and with the 180 main it was so fat it wouldn't hardly rev compared to the 170. It runs so hard now I couldn't imagine wanting a 185 or 188 main

Lvr
 

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Discussion Starter · #11 ·
I am at 900ft and mine is as follows

45 pilot
1.5 turns out on fuel screw
4th clip on needle
power pump 1.25 turns out
170 main.

What are the a/f you guys are getting with those huge main jets. I put in a jd kit and with the 180 main it was so fat it wouldn't hardly rev compared to the 170. It runs so hard now I couldn't imagine wanting a 185 or 188 main

Lvr
You have a full aftermarket exhaust with a K&N Air Filter? Any holes cut in your air box and snorkel removed? Thats the way I am running now and it runs near perfect, I'm sure there are gains to be had, but for breaking in this new motor I thought running fat was a plus...
 

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Stock twin air filter and just a slip on. When I talked to hmf they said their head pipe flowed less than the stock and the only reason to go with it was weight. I was just wondering what everyone was getting for a/f on the dyno when they are testing. Hmf told me not to go above a 172 with either full or slip on

lvr
 

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Discussion Starter · #13 ·
Stock twin air filter and just a slip on. When I talked to hmf they said their head pipe flowed less than the stock and the only reason to go with it was weight. I was just wondering what everyone was getting for a/f on the dyno when they are testing. Hmf told me not to go above a 172 with either full or slip on

lvr
Went by James Dean recommendation's a 185 MJ (Same as Eyvi's post)...HMF header is totally made for top end, look how it sweeps directly back off the head...HMF wasn't running a K&N with 3X's surface area for air either and they didn't install a JD Jetting Kit (They did pull the Spark Arrestor/Back Fire Screen out of the Twin Air though)...another note on the HMF Header is it can be removed without disassembling the rear shock for easy engine removable or access...
One thing to note after jetting JD recommended..."Bumped" the starter and it fired...same everytime hot or cold...starts, runs, rips with plenty of over rev what little I have over revved it...no hesitation anywhere...pure power that is a blast to ride...
I only jetted once turned the fuel/air screw out one round and haven't changed anything...I saw where guy's were rejetting over and over so I am very pleased with the jetting on this quad...
 

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My quad ate alot of dirt (internally) this weekend so Im putting a 525 jug and piston in my 450. I had it running awsome. but now i need to rejet for the 525 im sure. any help? here are my specs

525
JD jet kit
Full FMF 4.1 mega bomb exhaust
stock air filter, and air box with snorkel.
R&D power bowl.
around 1100ft
 

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Discussion Starter · #15 ·
My quad ate alot of dirt (internally) this weekend so Im putting a 525 jug and piston in my 450. I had it running awsome. but now i need to rejet for the 525 im sure. any help? here are my specs

525
JD jet kit
Full FMF 4.1 mega bomb exhaust
stock air filter, and air box with snorkel.
R&D power bowl.
around 1100ft
This where I would start...
180 MJ
Red Top needle 4th slot down
1-3/4 out on fuel screw
Thicker O-ring on the pump linkage
#45 Pilot Jet
 

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Just getting ready to install the FMF 4.1 slip on only, on my 450.
Got the JD kit and would like some help on good starting point, jetting, air box mods, etc.
Any help would be appretiated!
 

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You guys must have way better air then I do here in Boise, 2800 ft

45 pilot
160 main
stock needle 2nd from bottom
1.5 turns out

Mod'd stock can, removed sparky from can and mod'd end cap, brown wire disconnected, snorkle removed, big hole in side of air box, stock filter

top end I'm still rich (7.5K to 9.8K) on the dyno like 12 to 1 A/R
 

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Just getting ready to install the FMF 4.1 slip on only, on my 450.
Got the JD kit and would like some help on good starting point, jetting, air box mods, etc.
Any help would be appretiated!
Went with a CT racing full system instead of FMF. Jd kit with a 175, 42, red needle 4th position, screw turned out 1 1/4 turns out. Dynoed at 54.9 peak HP. Runs great except after running hard for 20 mins or so or doing 10-15 laps it wont start after being shut down for a few mins. smells like its getting flooded, but not sure. Gonna try turning out the fuel screw another half turn tomorrow at Glen Helen. Any other thoughts?
 

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well as of today my jetting has changed...

195 main
45 pilot
custom jd needle clipped 5th from top
fuel screw 1 turn
leak jet 1-1/4 turn

i must say it runs pretty damn good!
 

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well as of today my jetting has changed...

195 main
45 pilot
custom jd needle clipped 5th from top
fuel screw 1 turn
leak jet 1-1/4 turn

i must say it runs pretty damn good!
I see most of you have 525's. On our 450 should I start with a leaner main jet 180 vs 185 or should i just move the clip up one slot?
 
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