KLX250S (EFI) Big Bore Kit

Discussion in 'Technical & Motorcycle Services' started by johnnysneds, Jan 12, 2011.

  1. TonyBKK

    TonyBKK Ol'Timer

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    Cheers Jim,

    I'd be happy to help, but I'll be back in the US for the summer, touring again with my son. Should be back to Thailand at the end of August / early September.

    If you still need help then, give me a shout!

    Tony :happy1:
     
  2. jimmyklx

    jimmyklx Ol'Timer

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    Have done varying mods to my KLX including PCV and am planning on big bore in next few months but maybe a little beyond my ability.
    Anyone think a semi competent home mechanic should attempt it.
     
  3. Joelthailand

    Joelthailand Ol'Timer

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    I have "watched over" or should I say made tea/coffee & held tools, while 2 different farang mechanics we're doing D-Tracker big bore kits & nothing looked to frightening but pros do make things look easy.

    There are a couple of detailed big bore tutorials on other forums. Print them out & make sure you have every conceivable tool to complete the job (including a torque wrench). A good mechanic can do the whole job in less than 4 hours but as a home mechanic you can take as long as you want!
     
  4. yankee99

    yankee99 Ol'Timer

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    Jim.
    Like joel says this is not a very complicated job. I just installed a 300kit and it basicaly took 2 days. You need some proper tool (torque wrench and allen sockets) made from good quality. This will simplify the job. I stayed away from the 351 as i dont know any running propropely witg efi. I would have went with the 331 but a NOS 300 came for sale cheap. I did a.smalll.write up on teakdoor so you can see whats involved. It is in no way a complete guide but if you have questions you can ask me.
     
  5. TonyBKK

    TonyBKK Ol'Timer

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    As mentioned earlier-

    There are tons of detailed write ups and guides on various forums that take you step-by-step through the installation and set up of the Bill Blue big bore kits. I've never searched but assume that there are plenty of guides for the Kawasaki OEM 300cc big bore kit as well.

    Armed with the KLX service manual, proper tools and a good installation guide I reckon just about anyone could install a big bore on their KLX 250.

    Here are some of the best instructions / installation guides I've found:

    http://www.kawasakiforums.com/forum/...351-mod-31703/

    http://www.kawasakiforums.com/forum/...s-links-32538/

    http://www.advrider.com/forums/showthread.php?t=405545

    :happy1:
     
  6. jimbobs

    jimbobs Ol'Timer

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    Ok ile let you into a little secret, in the UK i was the proud owner of a hobby 750 twin axle motorhome i lavished nearly $50,000 on, i was away camping an thought it would be a good idea to change the spark plugs drop the oil etc, i done $3000 worth of damage and had to get the 37ft motorhome and trailer and X girlfriend home.
    So after that day i swore i would never touch an engine again ha ha.
    Maybe a little off topic but i think it is alot cheaper and safer to let Tony do mine haha
     
  7. jimmyklx

    jimmyklx Ol'Timer

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    Think I'll be ordering BB kit soon, can't be too hard.
    Did I mention I bought the bike a few months ago and a week later at work started internet shopping.
    Filter, exhaust etc.
    Month later came home to pile of goodies and realised a Dynojet kit from States doesn't really fit in a bike with fuel injection.
    Still got the jet kit if anyone wants it.
    Thanks for all replies.
     
  8. jimbobs

    jimbobs Ol'Timer

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    If you dont mind Jimmy give me a list of what youve ordered and ile do the same as i will probably buy a load of stuff i can not use, ime only interested in giving it more umphhh, not giong to go down the cosmetics route because i will probably drop it alot, ime not too far from you aswell in Roi et.
    Thanks in advance
     
  9. jimmyklx

    jimmyklx Ol'Timer

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    I can tell you what I've done so far but can't tell you what difference each mod made as I did it all at once.
    Bypassed clutch switch (permenently closed), Snorkel removed, UNI air filter, FMF Powerbomb header, FMF Powercore exhaust, Dynojet Power Commander 5 and Autotune, Blocked Pair valve, Renthal 50 tooth sprocket (remember you'll need a longer chain, I didn't).
    Maybe I should have researched the exhaust more as many people seem to go for Mega bomb header and Q4 end can.
    I bought a quiet insert for mine but is still a little load for Thais (not been near any major towns yet but think I'll get grief from police.)
    Bike definately feels more responsive but it's barely done 600kms.
    I can tell you with around 50 km on the clock with standard 42 tooth sprocket it would only do 126km/h now with 50tooth I can get 130km/h.
    Emailed Bill Blue today for info on his kits so will probably go for 331. And if I can get a Thai registered Paypal account up and running will be ordering cams, injector and maybe oil cooler from Webike in Japan.
    Do what I did and copy Joelthailand as his bike seems to be pretty much sorted and he's not shy about sharing information.
    Remember import tax tends to be directly related to nothing in particular so expect to pay.
    Got new pair of Alpinestars last month $250 + $50 postage, 10000baht tax. Kicker was that they were made in Thailand.
     
  10. yankee99

    yankee99 Ol'Timer

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    @jimmy B & Jimmy K..........I have a 250 cylinder for sale it has <2500 kilos on it. If interested send me a pm.
     
  11. TonyBKK

    TonyBKK Ol'Timer

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    I might be interested in your cylinder- how much do you want for it? :)
     
  12. yankee99

    yankee99 Ol'Timer

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    how about 5500 baht shipped and i will throw in the piston, rings & pin. c-clips are gone
     
  13. Joelthailand

    Joelthailand Ol'Timer

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    Hi Jimmy,

    1. The Beet injector is not necessary. My friends bike has a Bill Blue 331 & has the standard injector that comes with the bike & has no problems or power loss!! I only bought the Beet injector because I was the first guinea pig with 331 EFi big bore, (that i knew of - with a 100% running big bore) & didn't want to be without my bike running while waiting for a 3 week delivery from Japan....so i had it delivered beforehand, just in case etc. BUT having the Beet injector does mean i can buy a 351 big bore in the future & be sure the injector would work! Just for the record the 331 is a better revvier choice for road riding & 351 from what i have read & been told is better for torque & lower/mid revving off road riding. And did a lot of research before modding my bike!!

    2. Aftermarket cams are a bit of a luxury item IMO. There is very little performance difference with a set of Webcams or Beet cams. It is however the icing on the cake & does give the bike a small torque boost in the low/mid range & lets the bike rev higher while still gaining power. Power will start falling off quite dramatically after 8000rpm with stock cams.....the aftermarket cams will raise this to about 9000rpm (+/-).
    BTW i had a set of spare stock cams available to post before receiving my Webcams & this meant i didn't have to pay a core-charge, which made the deal a little cheaper for me.

    KLX331 Crazy has got an identical list of mods on his klx (S) model & does some serious offloading in Indonesia...we have swapped power commander MAPS for example. He has never complained of over heating riding in the jungle & i have never overheated doing traffic or hard Motard riding! Maybe the oil cooler is not necessary. The Kustom kraft 331 big bore kit is a bored out klx300 jug & nicasil plated....the cheaper Bill Blue option is a bored & steel sleeved klx250 jug. Some people say the water jacket is a little compromised on Bill Blue kit as a result & may cause the bike to run a tad hotter but would be difficult to prove in reality.

    BTW you will always pay full post office tax with anything from Webike (Japan) as they stick the full cash amount on the outside of the parcel. Most American companies are much more discrete & you get a 50/50 chance of not paying tax.
     
  14. KLX331 Crazy

    KLX331 Crazy Active Member

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    Jim Bob, where in Thailand are you, I am in the Surin area if that is any help?? I will be back in country around mid August and as Joel has already stated I have the same mods done to my bike as he has. Make sure you have all the gaskets for the cylinder, larger head gasket etc (these normally come with the Kustom Kraft 331 kit). Would also recommend the FMF mega bomb and muffler but you will need a plug welded into it for the AFR sensor to be fitted for the Autotune unit. Could probably finish the installation in a day, taking it steady.
     
  15. jimbobs

    jimbobs Ol'Timer

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    Hi Crazy

    Sorry if thats not your real name ha ha, i think Tony BKK is going to sort it when he comes back from the states, if not i would really appreciate your help doing the mod as the bike really is underpowered.

    I am back in Mexico at the moment and will not be back in LOS untill August so thanks for the offer and i may be in touch.

    Regards

    Jim
     
  16. KLX331 Crazy

    KLX331 Crazy Active Member

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    Hi Jim,

    Did you ever get the kit installed??
     
  17. TonyBKK

    TonyBKK Ol'Timer

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    I was unable to get the Bill Blue 351 Big Bore while I was back in the US last summer. Bill was on holiday for a good chunk of the summer and when I did finally track him down he was out of cylinders for the 351, so I ended up ordering a 331 big bore from Kustom Kraft:
    KustomKraft331BigBoreKitKLX.

    I haven't chased up Jim to see if he wants it. (My bad).

    I believe Bill has the 351 kits back in stock now, but with shipping, duty and VAT it would be a pretty expensive proposition to have one mailed to Thailand, but it's certainly an option.

    :happy1:
     
  18. TonyBKK

    TonyBKK Ol'Timer

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    Dunno what happened to Jim, never heard back from him, so if anyone else is interested in this Kustom Kraft 331 kit I'm going to list it in the classifieds now. :happy1:
     
  19. jimbobs

    jimbobs Ol'Timer

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    Hay Toni

    I didnt know you had it ime over in the Shetland Isles working

    My Skype name is jim.mannion2 i asked you to get it and fit it for me if you can and i never heard back from you

    I am back in Thailand around the 16th i can get my wife to post the bike to you, can you fit it and how much for fitting etc

    Can you PM me or call me my email address is [email protected]

    Sorry about the mix up, ive been off GTR for a while

    Nice one we will speek soon mate
     
  20. TonyBKK

    TonyBKK Ol'Timer

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    Hi Jim!

    Happy New Year!!

    PM and email sent! :mrgreen:
     
  21. jimmyklx

    jimmyklx Ol'Timer

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    Also interested, drop me a line [email protected]

    Cheers
     
  22. Bozza

    Bozza New Member

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    I am about to undertake the 331 Big Bore on my brand new 2014 D-Tracker 250 here in Bali. I have asked around the local motor bike supply shops here and no one has heard of anyone doing it in Bali yet.
    I know of a good mechanic here that has been putting the BB300 on the 250 Ninjas with lots of success.
    Planning on using KK 331, Beet Injector, PCV + Autoune, Web Cam Grind 101, FMF Powercore + Megabomb.

    Would any of the seasoned BB331 crew here be willing to share their PCV maps? I would really appreciate it.

    Cheers,

    Beau
     
  23. Bozza

    Bozza New Member

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    I have started purchasing all the parts needed to make my KLX250s(D-Tracker 250) into a 331 monster here in Bali.

    Are any of the BB331 veterans here inclined to share their PCV map for the EFI. I would really appreciate it.

    I am planning on running KK331, Beet injector, web cams 101, PCV + autotune, FMF Powercore 4 with megabomb.

    Cheers,

    Beau
     
  24. heilong

    heilong Ol'Timer

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    Hey Tony have you sold your 331 Kustom Kraft kit?
     
  25. TonyBKK

    TonyBKK Ol'Timer

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    Hi Gene,

    Yes, sold already, will install it upon receipt of Jim's bike and the powercommader i've ordered for him from the States and will post a detailed installation guide and fuel map once it's done :thumbup:
     
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