2008 Atomik Blitz 250 review

[synergy17]

Oh and Synergy, if you happen to be taking the tank on and off yours, keep an eye on the fuel lines... found out the hard way on the weekend, if you dont have the fuel line making a gradual downhill loop from the tank to the carby, it runs lean, backfires heaps, and makes the motor run REALLY hot... also gives off symptoms of running very lean jetting specs... different fuel line routing made the difference between a motor that wouldnt idle, and would boil coolant in under a minute, to a motor that will idle forever.... Fuel starvation being the direct cause...

sorry to hear u had to learn the hard way but thanks for sharing, checked mine today and i got a few loops, as the new fuel line that came with the carby was to long and i hadn't got around to shortening/neatening up the engine bay area yet until i put the bike back together, hope this will sort my slight problem of a lil hesitation/lag wen i crack the throttle oh and found a press at mile end that is a bit more user friendly ( not as big as the other but big enough to do the job) PM/sms me wen u want it done

 

[retrac]

hi chaps.i now ime going over old ground here,but i am supprised no one can get a 28mm oko to work well,i have looked at engine size,valve size and exhaust and seems no reason why it wont work.please tell me any different.

 

[thump*140]

sorry to hear u had to learn the hard way but thanks for sharing, checked mine today and i got a few loops, as the new fuel line that came with the carby was to long and i hadn't got around to shortening/neatening up the engine bay area yet until i put the bike back together, hope this will sort my slight problem of a lil hesitation/lag wen i crack the throttle oh and found a press at mile end that is a bit more user friendly ( not as big as the other but big enough to do the job) PM/sms me wen u want it done

hmm... reckon your hesitation *may* be a result of needing to dial in either the air/fuel screw, or raising/lowering the needle clip.. even with the 1/8 turn throttle on mine, it revs clean from idle to redline no matter how quick you crack the throttle...
If memory serves you have a #K100 main jet?? if so, this may be the cause as well. Mines running a #k97, and is VERY crisp... and for some unknown reason, Main jets on the OKO's directly effect the jetting off idle if they are a tad too big..
I'll have a handful of jets available on the ride day, so we can tinker then if you want, see if we cant clean it up a little.

hi chaps.i now ime going over old ground here,but i am supprised no one can get a 28mm oko to work well,i have looked at engine size,valve size and exhaust and seems no reason why it wont work.please tell me any different.

Retrac mate there's no reason a 28mm OKO cant be made to work, I just couldnt be stuffed spending the time rejetting mine. The 26mm was literally a bolt in winner, and i've not touched it, even the idle screw from pulling it out of the box, the riding the thing. The 28mm however, with a little bit of tinkering, still couldnt be made to run cleanly, so i chose not to pursue it. The 28mm does offer even more top end performance on the Blitz than the 26mm does, but it means you will have to spend a lot of time tuning it... Sadly, the 28mm is a prick to tune, regardless of what bike it's on. It's relatively easy to tune one section of the rev range with them, but usually at the expense of another... ie: you can tune the pilot jet and mid range easily, but it wont run clean up top, and vice versa... They have an inherit flat spot/bog off idle as well that is difficult to tune out. If it was easier to tune, then yes, the 28 would be better to run. who knows, once i've sorted the rear suspension, i might go round 2 with the 28mm on mine, see if we can find a baseline jetting that will work much as I have with the 26mm's..

 

[Atomik drew]

Synergy17---
yea mate the kit I bought shows the angled filter.

The OKO 26mm Flatslide from DHZ comes standard with #36 pilot jet and #100 main. I had to order the #38 pilot seperate for $4. Just putting it out the for anyone who plans to buy one for the blitz.

Anxiously awaiting the arrival!!!

 

[thump*140]

^^^^just on the jetting side of things, i might have a bit of a tinker with mine on the ride day, cause i reckon there is two Jetting baselines starting to come up for the Blitz, if the same mods are done.. (Muffler, OKO26 and CDI)...
#K36 + #K97 for crisp and very responsive jetting, with Tan plug chop... (still runs clean in deep sand, which is a jetting test for ANY motor)

#k38 + #K100 for jetting on the safer (richer) side for general trailling about...
Might try them back to back on the ride day, see which one offers the better performance...

 

[synergy17]

hmm... reckon your hesitation *may* be a result of needing to dial in either the air/fuel screw, or raising/lowering the needle clip.. even with the 1/8 turn throttle on mine, it revs clean from idle to redline no matter how quick you crack the throttle...
If memory serves you have a #K100 main jet?? if so, this may be the cause as well. Mines running a #k97, and is VERY crisp... and for some unknown reason, Main jets on the OKO's directly effect the jetting off idle if they are a tad too big..
I'll have a handful of jets available on the ride day, so we can tinker then if you want, see if we cant clean it up a little.

yea mate i got the #100 main, taking it away next week for its maiden voyge ( hopfully with the yzf front on it if my axle ever shows up) and knowing me i cant help myself but hav a tinker with it but im no expert on carbies, all my knowledge has come from the tech section on here which has given me a basic understanding how they work, but would be great to get it sorted at ride day. still has stock throttle control on it atm, waiting for bars and bar mounts to turn up before i fit my 1/8 throttle that came with the carby, although wen i turn it, it still turns 1/4?? diconected.

oh also did the muffler mod today, only took a 100mm off just to see wat its like ( i can always take more off later) after chopping through with the drop saw i notice have cut off the lil restrictor with tin plate inside it inside the the inner perphirated tube, was i supose to refit that or leave it out,making it a staight through muffler??

 

[retrac]

just wondering thump what jetting was in you 28mm oko and what was it doing when fitted,just so i have a bench mark to start with .

 

[Atomik drew]

Wow dhz are fast with their shipping!! I ordered my oko26 on Tuesday around 1030am and it was on my door step the next day! Woohoo time to tinker and get this bad boy hooting!

 

[thump*140]

my 1/8 throttle that came with the carby, although wen i turn it, it still turns 1/4?? diconected.

oh also did the muffler mod today, only took a 100mm off just to see wat its like ( i can always take more off later) after chopping through with the drop saw i notice have cut off the lil restrictor with tin plate inside it inside the the inner perphirated tube, was i supose to refit that or leave it out,making it a staight through muffler??

Not sure about the throttle... mine is a definite 1/8 turn from closed to wide open.. it may differ once the carby is connected, as the throttle i would imagine, is designed to work with a range of carbys, having different slide travel heights... see how it goes once fitted, and even still, a 1/4 turn will work fine.
As for the muffler, i'm not sure about the restrictor plate... Mine was literally a straight through job... No restrictors in there at all, just the perforated core all the way through, with no other baffles... May explain why mine has around the same decibel level as the 450 at WOT... is your's pretty quiet stock? mine's always been loud, without being overloud, if that makes sense... but no, leave the restrictor plate out. It's an off-road bike only, so you have 98 decibels to play with til it's considered "illegal"..

just wondering thump what jetting was in you 28mm oko and what was it doing when fitted,just so i have a bench mark to start with .

Retrac when i fitted the 28mm to my Blitz, it was running the same jetting that i run in the 140 Lifan i pulled it off. Oddly, the 140 runs clean from idle to redline with a #k39 pilot jet, #k102 main jet, and the needle set on the middle clip. Yes, this jetting would be considered massive for a little motor, but is a set up that works. This is what got me thinking that despite the fact they are BIGGER jets than the jetting baseline i run in the 26mm on the Blitz, it still had symptoms of running LEAN. Crackly and backfiring off idle, but clearing out once on the needle and main... So theoretically, a #K42 might be a better pilot jet to run, with a #k104 main jet....
HOWEVER, OKO's, particularly the 28mm, have a weird tendency to exhibit symptoms that are actually OPPOSITE to the problem.. ie: when i was tuning my 140, it seemed like it was running lean jetting, when it was actually very, very rich.. It had a #K44 pilot, and a #K135 main jet when i first got it, and bottom end response was HUGE, but it wouldnt pull into the top end/WOT.... So i dropped the main jet down to #K102, which sorted out the WOT problem, but i lost all bottom end response... I then tried a heap of pilot jets, finally settling on the #K39. Still not great, as the bottom end response is a little doughy/hesitant, but it's the best working setup for the 140... Even though the 140 is highly modded in the breathing department, the 250 *should* still breathe better, so when i did try the 28mm on my Blitz, i'm still going with the jetting being a bit lean...
It seems however, that everyone who has tried the 28mm, hasnt been able to tune the bottom end properly... the hesitant doughiness down low seems to be a trait restricted purely to the 28mm... i'm still yet to find, or hear of a solution to tuning it perfectly, other than to use a 26mm in the first place.
Not to rain on anyone's parade, being someone to do things the hard way myself, but i think you will have more luck with a 26. having said that, if you persist with it, and find a way to get the 28mm running perfectly, i'd loce to hear it.

 

[Atomik drew]

synergy17

my muffler had the baffle inside too but I turfed it out and put new wading in and replaced endcap. Works a treat!!

thump*140

with the oko26, did u adjust the needle at all?

 

[thump*140]

^^^Not a sausage mate, left the clip on the middle groove... however we are in very different parts of the country, so your jetting may not be the same as mine...
Where i ride is close to sea level, and is dry...
Not sure about your altitude, but the humidity is higher, so your jetting might be slightly different to mine...

Oh, and when you go to fit the OKO, do yourself a massive favour, and remove the seats, sidecovers, airbox, and undo the top shock bolt, and swing it back out of the way. make it a heaaaaap easier to get the oko in there, particularly the pod filter... once you have slipped the pod filter on, twist it around a bit so that with the angled rubber boot, the actual foam filter section is pointing STRAIGHT BACK towards the rear of the bike... simple little thing i know, but i discovered on the weekend it lets it fit a lot easier between the frame and shock body..

 

[Atomik drew]

Cheers.. Yea I'm not too sure about altitude but with a small amount of power, I don't think it's gona make too much of a dif. I had to re-jet my kx250f wen I took it to NZ for a trek but that's alot different to sunny muggy qld!
I've removed the seat, tank and side covers and got old pumper off. Just gota pick up the new bolts this arvo and trim up the new manifold adaptor. Did u use only that adaptor or did u attatch that adaptor to the exhisting manifold?

 

[thump*140]

yeah i bolted the rubber OKO manifold, to the existing stock manifold... Bolt partterns are different, so you have to use both.

 

[dirbatua]

good read thump*, got plenty of good ideas for my blitz.

Got mine bout 2 months ago to learn to ride on since my parents just brought 17 acres to ride on and i was the only one without a bike out my parents and 3 younger brothers,its one of the new ones and i've noticed a few difference's while going through this thread, main one is the engine looks different, at least the covers do, the new ones have atomik written on them etc etc, pics will show.

Going to order at least the Hi Rev CDI, 1/4 turn throttle and 26mm carby and ill try 97#-36# unless you find a better one before i order it and do the muffler mod for the moment.

Been riding a few times and had no issues with the bike other then it being a ******* to start the first time (which i'm guessing is from the fuel sitting in the carby as you posted way back so i'll be drying the carby out from now on when im done riding) & the kick lever rattling like a bitch which i have since fixed by removing it putting tape around the inside and forcing it back on and doing it up

Had to replace the fuel tank since it got punctured, had to replace the handle bars cause the cheap **** bent and got the same ones as you thump* i think, cept the pitbike cover doesn't fit over the standard atomik front.

Replaced the clutch lever with a 2003 Honda CRF lever since i cracked mine, replaced the gear shifter since i bent mine and buggered off those ****** hand grips that it comes with and stickers to cover the crappy white panels.

The suspension seems to be quite good on mine, handles bumps really well and haven't had any really issues with the bike over all minus general wear and tear like ripping the rear tube off the valve and having to get it replaced and catching cooling lines on branches.

Even the original oil that came in the engine was good, rode on it a few times and came out fine, dumped the coolant and put proper stuff in when i changed the oil and its been running perfectly fine, take it out for 2 day rides every 3 weeks and run it for 6-10 hours straight each day and its been great.

Glad i know alot more about my bike now and what i can do to make it better while i'm still learning to ride it properly

 

[sebsktm]

nice green machine in the background
i used to love them xD!

 

[synergy17]

Not sure about the throttle... mine is a definite 1/8 turn from closed to wide open.. it may differ once the carby is connected, as the throttle i would imagine, is designed to work with a range of carbys, having different slide travel heights... see how it goes once fitted, and even still, a 1/4 turn will work fine.
As for the muffler, i'm not sure about the restrictor plate... Mine was literally a straight through job... No restrictors in there at all, just the perforated core all the way through, with no other baffles... May explain why mine has around the same decibel level as the 450 at WOT... is your's pretty quiet stock? mine's always been loud, without being overloud, if that makes sense... but no, leave the restrictor plate out. It's an off-road bike only, so you have 98 decibels to play with til it's considered "illegal"..

fitted throttle, definatly a 1/8 dam touchy thing. only to find out i hav either pulled the cable through the little white plastic collor in carby ( which shouldnt hav coz i done the lil trick with the screw) of the white collor in the carby itself has poped out of the slide. will check 2moro, ran out of patients today as for the exhaust it was quiet but now hahaha... its bloody loud, scared the **** out of my boss 2day wen i started it but for some reason my throttle response didnt hav the hesitation anymore, well until the cable came loose anyway.

synergy17

my muffler had the baffle inside too but I turfed it out and put new wading in and replaced endcap. Works a treat!!
?

new wadding?? is the stock stuff crap? coz i just put the old wadding back in..

 

[dirbatua]

yea i just cut down my exhaust by 125-130mm and left the standard wadding in, well what was left after i cut the exhaust down, starts first kick now for some reason.

 

[synergy17]

Even the original oil that came in the engine was good, rode on it a few times and came out fine, dumped the coolant and put proper stuff in when i changed the oil and its been running perfectly fine, take it out for 2 day rides every 3 weeks and run it for 6-10 hours straight each day and its been great.

good oil in a china?? drained mine staright away before even starting it, came out with the consistancy of water and had a marble streak floating on top of the oil in the drain container, even dumping the oil in the waste oil container at work it came out quick, i.e. didnt gave to stand around waiting for the last little bit of oil to drain.

yea i just cut down my exhaust by 125-130mm and left the standard wadding in, well what was left after i cut the exhaust down, starts first kick now for some reason.

i found mine was a ****** to start wen i first got it aswell even ended up flattening the battery once or twice, however after fitting the 26mm oko carby( before i did the exhaust mod), its fuel tap on, pull the choke up and tap the button and BAM.. bikes started. well woth the mod if u havnt already done.

 

[dirbatua]

good oil in a china?? drained mine staright away before even starting it, came out with the consistancy of water and had a marble streak floating on top of the oil in the drain container, even dumping the oil in the waste oil container at work it came out quick, i.e. didnt gave to stand around waiting for the last little bit of oil to drain.

i found mine was a ****** to start wen i first got it aswell even ended up flattening the battery once or twice, however after fitting the 26mm oko carby( before i did the exhaust mod), its fuel tap on, pull the choke up and tap the button and BAM.. bikes started. well woth the mod if u havnt already done.

Yea it was strange that the oil was decent, wasn't watery and was the correct consistency and checked ok in the tester.

going to order the carby, 1/4 throttle and high rev CDI's this weekend, watching em all on ebay atm, just waiting for pay to go in.

But yea the bike has always been a bitch to start but i cut the exhaust down, whacked it back on and started it and first kick it started, i was like WTF.

Only just finished the exhaust bout 25 min ago

 

[synergy17]

going to order the carby, 1/4 throttle and high rev CDI's this weekend, watching em all on ebay atm, just waiting for pay to go in.

which CDI u getting?? if it't the cerolli (sp?) that thump* mentioned earlier in here, it's a good choice.. however the plugs dont match the blitz and couldnt find a plug to suit the cerolli cdi ( asked 2 electrical reps.. no luck) had to cut the plug of the cdi and put new plugs on or ya could use bullet conectors (cheaper), aslo the wiring is a different colour to the blitz loom, but isnt to hard to wire up. e.g cdi has blue wire and blitz loom has blue wire with white trace e.t.c.