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dynatech engine miss

8K views 22 replies 10 participants last post by  jcummins 
#1 ·
well went out riding this weekend and noticed after I installed cdi I have a miss at mid throttle or so put stock cdi back in and surprise ,surprise no miss what do I do will they take it back my brother bought one also and that works fine help me:mad:
 
#3 ·
hey todd do you think dynatech will take this cdi back how are they to deal with? cant wait to get the rest of the jet kit from you tpi valves and springs and drill bit not running to bad right know but I have stock springs with dynojet mains and needles and 2 turns out on fuel screws. just dont want to have to buy a new cdi box the one I have is only a week old!!!!
 
#4 ·
This has been quite common it seems, I have talked to others who say that miss is there, even stock, just really comes out with an aftermarket CDI. I know everyone has different ideas in regards to the Dynatek hot coils, however, it appeared to work on my machine...so much so that when they were tuning it they brought up the fact that I did not have that miss.

Wonder what is going on though?
 
#7 ·
i sent my dynatek back to dyna when i had the miss..it was returned stating unit tested and was performing properly. This was before any of my friends got dynateks for there 08 teryx's. well after trying 3 different dyna's they all have the same miss on all of our bikes. My dyna came from hunterworks, one came from ebay for 174$ with free shipping, one came directly from dynatek website, and the last one came from a dealer in the area..we are all at sea level and our stock jetting was setup the same..all bikes came from the same dealer..i dont know if we all got a bad batch of cdi's or what but my final option is to try the dynatek hot coils. If i still have the miss after the coils its going back to the stock cdi. Jetting is not my issue. Ive gone from one extreme to the other using different pilot jets, stock needles, hunterworks needles, shim on all different grooves 1-5, air mixture screw at anything from 1/2 to 3 turns out. Nothing i do makes the miss any better or worse is why i still think the cdi isnt getting enough spark or too much timing. I have my hands up in the air at this point. As soon as the dyna coils come in ill report back with the results.

I did run into a guy on the trails last week that was running the procomm. I even drove his bike around, the miss was not present on his teryx. his teryx came from the same dealer and the procom was his only mod. I should have got his phone number to see if the procom would cure my miss but like a fool i didnt.
 
#9 ·
Todd....I want that cure to. I 'improved' the problem when I went to the 2nd grove in the needle....and I'll admit most of the time I don't notice it....but at times I do...and it's been agravating. My night riding in case you don't recall is iffy...the brown out voltage problem. I still have stock battery. Kind of holding off to see if someone comes up with something. And like db...thinking of the coils.
 
#12 ·
This is great news, please report back if you can!
 
#13 ·
Personally I think the miss with Dyna CDI is a jetting issue. I have at times been able to eliminate the miss, now it is back again with my STD Bore kit but I have not had time to fine tune the jetting like it needs to be done, but if it went away once, it will go away again if I can figure it out.
 
#14 ·
hey guys just got todds kit for the dyno jet, kit tpi valves ECT... took it out and running pretty good but not sure where to run valve position seems to run pretty good a half open. my dj kit didnt come with a 144 for the front so Im running a 142/146 hope that is ok any thoughts? im gonna try to run my dyna cdi again and see if my engine miss comes back looking forward to see what todd comes up with.
 
#16 ·
i also have the mid range miss with the dynatek cdi
 
#18 ·
I think Megallen has the answer....but we will see what db comes back with. This is why I say this, I went from bone stock to adding Dyna's CDI,HW Jet Kit,UTV O/D Cap,EPI Clutching and a New Uni Filter in one weekend of wrenching.Changed Oil,filter and adjusted out 1/2 in of belt deflection w/16 hrs on it. I was in a hurry to take for a spin and soaked my new uni with ATF and sqeezed out the remainder,then paper dryed it. On the first 2-3 mile run late that night I had the poping low and mid. The next day I fired it up and no more poping at all and ran much stronger. Keep in mind I didn't buy the tpi valves but cut two 1 3/4 in squares out of the box. These boxes were supposed to be 1 1/2. Then placed tape over 1/2 in of ea. square cut out, inspected filter and noticed bottom of air box was wet with ATF. Too much oil in the filter and maybe? the cut outs were to big? But I'm thinking it maybe some of your guys problem with the type and Qty. of oil in your filters. I will not be running atf, that was a temp fix and there was only snow on the ground on my rides. The temp from the first ride to the second warmed about 20 degrees also.Have a total of about 70 miles on since and not a single pop or hick up. Knock on wood;)
 
#19 ·
I have tried a stock air filter right out the bag without adding any filter oil at all to it and have the miss..also tried a uni without oil and still have the miss..sprayed both filters with the blue bell-ray foma filter oil throughly, then dabbed with paper towels to get rid of excess..still have the miss...Before you all say thats not a good idea to ride without oil on the filter, i ride the highway and there is not enough dust to ingest dirt through the filter. When i ride dirt roads or trails, the filters are oiled properly.

my theory is that the stock coils possibly are weaker on some bikes than others. The weaker coils cause the dynatek to have a brown out effect thus causing a weak spark throughout the low and midrange. Ive had several people send me messages that they tested the spark and before they installed the dyna coils the spark was yellowish/white and after the coils the spark was a bright blue...

Hopefully by this comming weeks end Todd and I will have a cure.


Another bit of trivia why is it that some people see speeds of 61 mph with just a dyna cdi and some see about 55 mph with just a dyna cdi? are the speedos that far off?

IM seeing 65-67 on my speedo with the dyna, hunterworks carb kit, and clutch cover.
 
#20 ·
The ones seeing the slower speeds are probably using GPS. My speedo on my 08 shows over 65+ when my GPS shows 57. I can hit 70 on the Speedo no problem, but the GPS says I am really going 65 or less. I don't have a good place to really test top end however and I know I am rich on the mains.

I think the miss is a tuning issue myself, I do have the coils though, so no reality check from me with the stock coils. I am curious to see what Todd finds in his testing with a gentleman on TeryxHQ.
 
#21 ·
That's a tough one db, my speedo hits 63 and cant get to the rev limiter yet. It's the speedo's as megallen describes,will be watching for the fix. Off subject I had idle today going up and down after a hard run of about 6 miles.Thoughts...
 
#22 ·
not sure about your up and down idle SRX??

Saturday i fooled with the jetting one last time before the test product gets here from Todd at Hunterworks to see if i could get the rex running better..Initially(last month) when i first installed the hunterworks carb kit, as recommended in the instructions i put the clips on groove 2 on the needles. After a quick spin around the block i had just a slight flat spot just off idle. ABout the only way to duplicate the flat spot or bog is to cruise around at a steady 30mph and just barely press the pedal to increase speed. The moment the pedal is pressed you could here and feel the flat spot. Same scenario cruising at 30 then hammer down on the pedal, the flat spot isnt present. I remember in the original instructions with the hunterworks kit that it called for putting the clips on groove 1 on the needles. Then after a few weeks Todd updated the instructions to groove 2. The update was due to a slight lean condition off idle. Thus going from groove 1 to groove 2 would richen the mixture. Last weekend thinking i may be a little lean i tried groove 3 on the needles. The flat spot seemed to have become worse. So figuring i was going in the wrong direction on the needles, like stated earlier i tried groove 1 on the needles. Bingo it cured my flat spot just off idle. But the miss and sputter is still the same as it has always been.

My final jetting setup is as follows. This is with the dyna cdi, hunterworks carb kit, and the exhaust tip removed.

Main Jets 146 front and 148 rear ...dynojet jets
Needles with clips on groove 1 with 2 shims on top of the clip
Mixture screws are 2 turns out on both..

I realize that everyones teryx is different and especially at different altitudes and temps..Im at sea level in lower alabama and the above jetting so far seems to have the best seat of the pants feel..
 
#23 ·
That flat spot you cured by going from groove 2 to groove 1.....

I had the opposite results. My problem got better going from groove 1 to groove 2. Everything else, sea level etc is the same except the main jets. I'm at 144 front, 146 rear.

I'm running the tpi slides completely open.
 
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