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Discussion Starter · #1 ·
I just put on my HMF and now my bike revs fine until WOT then it kind of surges and hesitates kind of like a rev limiter. I had the DJ 142 in it with the stock exhaust and it ran just a little rich. I have went from 128 to 140 main jet with the HMF and I still have the same issue. I have a 2" intake snorkle. Any help would be appreciated.
 

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I'm running HMF and a 145main, and having the same problem. I'm going to add a bigger main and a cdi and see if that helps. :chug:
 

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Discussion Starter · #3 ·
The inside of the exhaust was black which makes me think it was running rich but I went down on jet size and still the same problem. I would think one would have to go up in jet size after adding an exhaust. I am thinking about doing away with my stock airbox and just running some flex hose right off the carb and up to a k&n above the pod. Maybe that will give more air. Hopefully someone will chime in that knows what there doing.
 

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:yo_sup: What is the color of your plug? It should be light brown or tan kinda like coffee with a lot of cream? If your lagging on the top end it sounds like your running to rich, the snorkel will obstruct your air flow some even with the k & n you got me confused with what you said you were running a 142 w/the stock exhaust and you then say you went from a 128 to a 140 with the HMF, Do you have an adjustable needle? What clip position are you running?
 

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Last week, my 3 year V2 ATV warranty finally ran out... I installed a VDI CopperHead, DynoJet carb kit, and HMF pipe.

I haven't had the chance to do any WOT runs for plug readings yet, was kind of hoping the lake would be frozen by now but it isn't.

The DynoJet kit replaced the diaphram springs, midrange needles, and main jets. The mains I put in were 122, but keep in mind these are DJ jet numbers not Keihin 122s. I put in the DJ-122 mains because that's what the kit recommended when using a less restrictive free-flowing exhaust... Instructions don't mention an advanced spark map ignition so It's possible I may need to go to richer main jets anyway.

So what I would like to know is.... When you guys post jet numbers, are you talking about Keihin or DynoJet jet numbers?

Also, if you rejetted without using a DJ carb kit, did you only change the main jets or did you change the mid/low range too?

It seems the low & mid rpm calibrations of the carb is way too lean in stock form too... So only changing the mains might not quite be enough for a linear fuel/air ratio from idle to WOT.
 

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ag i have a 05 v2 with hmf and dynatek module with a dynojet kit. 122 (dj) mains, there springs, 3rd spot on the needles (dj's) and 2 or 2.5 turns out a/f skrews. mine runs what i thought was a tad lean wot but after installing new plugs and taking for a run seems a tad rich instead which is ok in my book. this testing i did in the summer mid 70's out.

remember if you are using there needle which is a different tapper vs stock needle.

i have had a moose in before the dynatek and didn't change the jetting at all. the dynatek advances the overall timing 5 degrees to 33 degrees at wot. by next week i will have a copperhead here and i will see if i need to change the jetting any but i am kinda doubting it but will let you know.
 

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Discussion Starter · #9 ·
<div class='quotetop'>QUOTE (dogthehunter @ Jan 2 2007, 09:59 PM) <{POST_SNAPBACK}></div>
:yo_sup: What is the color of your plug? It should be light brown or tan kinda like coffee with a lot of cream? If your lagging on the top end it sounds like your running to rich, the snorkel will obstruct your air flow some even with the k & n you got me confused with what you said you were running a 142 w/the stock exhaust and you then say you went from a 128 to a 140 with the HMF, Do you have an adjustable needle? What clip position are you running?[/b]
The plug looks black but not wet or oily. The numbers are all dynojet numbers. Sorry for the confusion. I was running a 142DJ main before I installed the HMF and the bike seem to run fine. Now after installing the HMF it cuts out at WOT. I tried a 128 main up to a 140 main to see if that would fix the cutting out but no luck. I do have the dynojet adjustable needle, I have it on the 3rd notch. What confuses me is the bike seemed to run fine with the 142 main before I added the HMF. I would think one would have to go to a bigger main after putting on new exhaust but I dont know really. Everything else in the carb is stock with the exception of the main jet and the adjustable needle.
 

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<div class='quotetop'>QUOTE (kevinbender0311 @ Jan 2 2007, 10:03 PM) <{POST_SNAPBACK}></div>
ag i have a 05 v2 with hmf and dynatek module with a dynojet kit. 122 (dj) mains, there springs, 3rd spot on the needles (dj's) and 2 or 2.5 turns out a/f skrews. mine runs what i thought was a tad lean wot but after installing new plugs and taking for a run seems a tad rich instead which is ok in my book. this testing i did in the summer mid 70's out.

remember if you are using there needle which is a different tapper vs stock needle.

i have had a moose in before the dynatek and didn't change the jetting at all. the dynatek advances the overall timing 5 degrees to 33 degrees at wot. by next week i will have a copperhead here and i will see if i need to change the jetting any but i am kinda doubting it but will let you know.[/b]
Coool! Thanks! :thumbsup: :chug:
 

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basically if it seems to run fine, i would leave alone. dynojet does there research i would think. mine runs like a top with these settings.

how do you like the copperhead? have you played around with making any maps or just running preset ones?
 

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<div class='quotetop'>QUOTE (kevinbender0311 @ Jan 3 2007, 10:31 AM) <{POST_SNAPBACK}></div>
basically if it seems to run fine, i would leave alone. dynojet does there research i would think. mine runs like a top with these settings.

how do you like the copperhead? have you played around with making any maps or just running preset ones?[/b]
Yes, it does seem to run flawlessly... Had to fine-tune the idle air screws though, 3 turns as suggested by their instructions was a very close starting point.

I just want to verify WOT jetting because of winter temps. If the jetting is safe for that, a bit on the rich side for the summer won't be a biggie because WOT runs will be few and short-lived. Summer WOT 'moments' aren't quite the same as keeping it pinned WOT for a while on frozen lakes.

I like the CopperHead and would buy another one if faced with the same decision again. The 2nd generation CopperHead is programmable for almost any ATV make/model, all it takes is a new spark advance curve program and an adapter plug to fit the new ATV's wiring harness connector.

I haven't programmed any advance curves of my own design yet... I still need to get their proprietary flash software to do it. I'm running the pre-programmed one at switch position 2. It is considerably better than the lame stock advance.
 

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<div class='quotetop'>QUOTE (oleblue @ Jan 3 2007, 08:54 AM) <{POST_SNAPBACK}></div>
<div class='quotetop'>QUOTE (dogthehunter @ Jan 2 2007, 09:59 PM) <{POST_SNAPBACK}>
:yo_sup: What is the color of your plug? It should be light brown or tan kinda like coffee with a lot of cream? If your lagging on the top end it sounds like your running to rich, the snorkel will obstruct your air flow some even with the k & n you got me confused with what you said you were running a 142 w/the stock exhaust and you then say you went from a 128 to a 140 with the HMF, Do you have an adjustable needle? What clip position are you running?[/b]
The plug looks black but not wet or oily. The numbers are all dynojet numbers. Sorry for the confusion. I was running a 142DJ main before I installed the HMF and the bike seem to run fine. Now after installing the HMF it cuts out at WOT. I tried a 128 main up to a 140 main to see if that would fix the cutting out but no luck. I do have the dynojet adjustable needle, I have it on the 3rd notch. What confuses me is the bike seemed to run fine with the 142 main before I added the HMF. I would think one would have to go to a bigger main after putting on new exhaust but I dont know really. Everything else in the carb is stock with the exception of the main jet and the adjustable needle.
[/b][/quote]
that sounds like its running rich, did you try a new plug? You run WOT then just nail the kill switch and let it coast down and pull the plug and look at it, this is the best way to see what's happening, I would actually try taking the jet size up because you should be moving more air now so it should be running lean, try the throttle chop and see what you got but I would think that your lean
 

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thats why i left my 122 (dj's) in, don't mind a tad rich in the summer just as long as not too lean in the winter. good to hear you like your copperhead, getting mine off modn gen one but it's for my v2. i have had the moose and dynatek so i guess i get to be the guieny pig and compair. it is coming with the cables, and software to design my own timing curves, auta be interesting to say the least!
 
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