Welcome to NESR! Most features of this site require registration, including replying to threads, sending private messages, starting new threads, and uploading files. Click here to register.

Results 1 to 19 of 19

new toy - Thumpstar TSX 125-C BW - seeking hop up parts

  1. #1
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    nabbed another pitbike to rip around with the childrens, 2020 Thumpstar TSX 125-C BW (17/14) ... fun bike, runs decent but dialing in (or is it out?) the China is always kind of a drag, will start applying Japan to it over time.

    anyone have any pitbike parts laying around they don't need? looking for an authentic Mikuni VM22 26mm carb, 140cc cyl (Lifan compatible) or Piranha 140cc complete. willing to hear about any other pitbike parts as well.

    fuckin' thing BARKS, need a dB Dawg.. .


    5 Not allowed! Not allowed!
    Beta 200RR

  2. #2
    Don't run with the pack. whynot's Avatar
    Join Date
    May 2009
    Location
    Arlington MA 02474
    Posts
    1,625

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Looks fun.

    You prolly know about https://www.chinariders.net/

    1 Not allowed! Not allowed!
    And don't believe everything you think.

  3. #3
    Expert Agitator GearHd6's Avatar
    Join Date
    Jun 2008
    Location
    Ashford, CT
    Posts
    1,010

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    I ordered a carb for one from here.
    https://tboltusa.com/store/mikuni-22mm-carb-p-375.html

    1 Not allowed! Not allowed!
    Jeff

  4. #4
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Let me dig through my carb box...

    1 Not allowed! Not allowed!

  5. #5
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Quote Originally Posted by whynot View Post
    Looks fun.

    You prolly know about https://www.chinariders.net/
    Quote Originally Posted by GearHd6 View Post
    I ordered a carb for one from here.
    https://tboltusa.com/store/mikuni-22mm-carb-p-375.html
    yes, thanks, guys ... and TBolt is awesome, but they're out of stock at the moment on the 26mm Mikuni, late Nov estimate ... took it apart yesterday and was pretty impressed with the build quality of the knockoff carb but the jets aren't marked and i know i need a fatter pilot, fuel screw is way out at 3 turns or so, wants more fuel for sure ... ran decent last night WFO around the hood so the main seems OK but was boggy off idle under load with the open pod filter ... we got it dialed enough that i could run it off choke consistently and it actually ran pretty awesome at Crow Hill today on the 50 track although the transmission is a different story, wow, so shitty same with boingers. hahaaa. super fun bike though! really dig the 17/14 setup, first time i've ridden that size on a mini.

    Quote Originally Posted by Kurlon View Post
    Let me dig through my carb box...
    thanks man, appreciate it

    0 Not allowed! Not allowed!
    Beta 200RR

  6. #6
    Don't run with the pack. whynot's Avatar
    Join Date
    May 2009
    Location
    Arlington MA 02474
    Posts
    1,625

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Came across this Mikuni on FB, IDK if this is what you're looking for or if it's legit, etc.

    https://www.facebook.com/marketplace...4461377260485/

    1 Not allowed! Not allowed!
    And don't believe everything you think.

  7. #7
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    thanks for looking, whynot ! but that's the Chinese knockoff i currently have installed ... frustrating to track down an authentic Mikuni, they've not only gotten good at replicating the Mikuni logo (although they're usually bare with maybe a PZ26 stamped in) but the Sudco labeling as well. nuts.

    0 Not allowed! Not allowed!
    Beta 200RR

  8. #8
    Don't run with the pack. whynot's Avatar
    Join Date
    May 2009
    Location
    Arlington MA 02474
    Posts
    1,625

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Quote Originally Posted by typeone View Post
    thanks for looking, whynot ! but that's the Chinese knockoff i currently have installed ... frustrating to track down an authentic Mikuni, they've not only gotten good at replicating the Mikuni logo (although they're usually bare with maybe a PZ26 stamped in) but the Sudco labeling as well. nuts.
    Crazy! Funny thing is, I didn't look for it, it popped up for whatever reason in my browsing. Closer reading, I see now that it says "fully compatible with Mikuni" not that it "is" Mikuni.

    1 Not allowed! Not allowed!
    And don't believe everything you think.

  9. #9
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Dug out my carb box, I've got a Mikuni VM26, 'Oko' 26, and a Keihin PE28. I actually had good luck with the Oko on my 160 build, it uses a mismash of Keihin and Mikuni brass. I *think* I was monkeying with all three trying to coax one to behave on my TT-R 125 but just didn't have enough motor to make good use of them. You're welcome to play with any of them.
    Attached Thumbnails Attached Thumbnails new toy - Thumpstar TSX 125-C BW - seeking hop up parts-img_3796-jpg   new toy - Thumpstar TSX 125-C BW - seeking hop up parts-img_3797-jpg   new toy - Thumpstar TSX 125-C BW - seeking hop up parts-img_3798-jpg   new toy - Thumpstar TSX 125-C BW - seeking hop up parts-img_3799-jpg  

    new toy - Thumpstar TSX 125-C BW - seeking hop up parts-img_3800-jpg  

    2 Not allowed! Not allowed!

  10. #10
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Quote Originally Posted by Kurlon View Post
    Dug out my carb box
    sweet ! thanks for digging this stuff up ! let me do a little research and i'll get back to you. the Oko was on my radar as well ... i'd really like to ditch this Lifan 125 and go bigger but it's brand new and in the bike so i'm on the fence. i hate the trans for my use, unsure i want to build off of that base.

    i have it running pretty damn well but experimented with adding a washer with smaller hole into the silencer tonight. quieted it down a bit, no real change in power, will tear it apart and see if i can add more packing as well. stock it's too free-flowing and noisy, i want more power and lower tone.

    jesus i hate 4-strokes. (i now have 3 to deal with, FML)

    0 Not allowed! Not allowed!
    Beta 200RR

  11. #11
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Josh, thanks again for the pics + offer but i've secured a Mik VM26-606, jet kit, UNI filter and CDI ... now to figure out what shock i can swap in

    0 Not allowed! Not allowed!
    Beta 200RR

  12. #12
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    CDI likely isn't any different from what you've got now. Anyone claiming any of these Honda style machines (Or actual CRF50/CRF70s) have rev limiters is lying through their teeth. As far as different advance curves, when they've actually been checked out, they all seem to have roughly the same one. I've yet to see a CDI swap actually show up on a dyno on these machines.

    Do you know if you've got a small valve or big valve head? Most of the gains in that block size are in the head, if looking to really wake it up I'd see if the TB Parts 'V2' race head is still available, if so get it ported and match it with a 57mm bore kit from TB Parts. You'll still have the effectively a three speed noodle delivery girl gearbox but it'll rip. When I was playing there wasn't a transmission upgrade available to improve the gear spacing on those motors, I've no idea if that's changed. The Daytona motors are supposed to have a better setup, but they are NOT cheap. I think they have a 5 speed that isn't made out of glass as well? Back in the day, if you were going 'big' you'd get a mongrel Honda Wave motor out of Thailand for a BIG block with a solid transmission. Check to see if Zongshen/etc have cloned it maybe?

    0 Not allowed! Not allowed!

  13. #13
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Also - You ARE racing Masters of Mini on that beast, right?

    0 Not allowed! Not allowed!

  14. #14
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Quote Originally Posted by Kurlon View Post
    CDI likely isn't any different from what you've got now. Anyone claiming any of these Honda style machines (Or actual CRF50/CRF70s) have rev limiters is lying through their teeth. As far as different advance curves, when they've actually been checked out, they all seem to have roughly the same one. I've yet to see a CDI swap actually show up on a dyno on these machines.
    hear you, but only trying another CDI (TRC EZ-Start) in an attempt to lessen the kick-back. i forgot how brutal that can be on these little motors if you don't have your start routine down. my last GPX was a 150cc but this little 125 (actually 120, i think?) can kick back pretty hard as well. i'm also teaching my 8 y/o clutch on this bike and the kick-back had him crying the other night. he wasn't expecting it when starting and got jacked pretty hard. hahaa.

    Do you know if you've got a small valve or big valve head? Most of the gains in that block size are in the head, if looking to really wake it up I'd see if the TB Parts 'V2' race head is still available, if so get it ported and match it with a 57mm bore kit from TB Parts. You'll still have the effectively a three speed noodle delivery girl gearbox but it'll rip. When I was playing there wasn't a transmission upgrade available to improve the gear spacing on those motors, I've no idea if that's changed. The Daytona motors are supposed to have a better setup, but they are NOT cheap. I think they have a 5 speed that isn't made out of glass as well? Back in the day, if you were going 'big' you'd get a mongrel Honda Wave motor out of Thailand for a BIG block with a solid transmission. Check to see if Zongshen/etc have cloned it maybe?
    brand new, totally stock Lifan 125 was installed before i bought the bike, no clue what head they supply but assume small. the GPX 150 had all the treats and was built right, which spoiled me 'cause now i wish i kept it but that was ages ago.

    even though the gear box shifts like shit down low, at least it's a 4 speed ... 1-N-2-3-4 ... but yeah, light searched for trans upgrades although as mentioned, not sure how far i really want to mod this Lifan. it's a front clutch and the cable stay has already cracked off the case. hahaa. QUA-LE-TEE

    Quote Originally Posted by Kurlon View Post
    Also - You ARE racing Masters of Mini on that beast, right?
    ripping around the CH mini track, smiling like an idiot, had me wondering that very same thing but is this even a 'mini' with 17/14 setup? it's pretty tall!

    0 Not allowed! Not allowed!
    Beta 200RR

  15. #15
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Point, I forgot Tbolt or someone else did come up with a CDI that way retards timing at low RPM for less kickback. That could have saved my interest in pitbikes 10+ years ago... I've had kickbacks put holes in my boots, drive my knee into the bars hard enough to bend'em, throw ME over the bars like a rag doll... but what really sucked was trashing multiple bottom ends from the cases breaking on kickback.

    Forward clutch Lifan will be the 'small' head, primary clutch will be big valve. Not really worth the effort of building unfortunately.

    As far as MoM, there are absolutely classes for that machine. Sadly, my 150SX can't masquerade as a mini or I'd try sneaking that in as well.

    1 Not allowed! Not allowed!

  16. #16
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    yeah, the TBolt TRC CDI seems to get great reviews, even on big motors, so figured i'd give it a try ... i can't imagine how violent kick-back can be on powerhouse builds ... my son was teary asking over and over, 'WHY would it do that?! WHY?'

    yup, $277 cheapo replacement motor off eBay ... unfortunately the PO blew up the stock YX and gave away the Mikuni. lamesauce ... if i can find a Piranha 140 for decent cash i'll grab it and swap over the carb, etc.

    great to know on MoM. i can also swap on a 14/12 setup if the chassis proves to be reliable, which i think it will be, but shock is next on the list.

    0 Not allowed! Not allowed!
    Beta 200RR

  17. #17
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    @Kurlon ... so i'm still trying to jet this fucking Lifan 125 with Mikuni VM26-606 and it's frustrating the hell out of me. Rob at TBolt said i should be close with 22.5p/155m but that setup seemed WAY rich for this small motor. i'm currently at 20p/95m AS 1.5 or so, starts and idles well but won't take throttle snaps and sputters mid-top. pretty sure i'm headed in the right direction going leaner but was curious if this sounds right to you with the 125?

    i've tried about 7 different configurations from way out on the main down to where i am now, all different needle clips as well. 90 main seems crazy far off from what Rob recommended but i've read on the pitbike forums that it should in fact be around 20p/95m. 17 pilot was too lean, high idle.

    my next move is to bump the needle clip up again from 4th to 3rd, 20p, 95m.

    if it helps for comparison, Thumpstar recommends 15p/95m, 1.75as for the VM22 ... how would that translate to a VM26 carb?

    0 Not allowed! Not allowed!
    Beta 200RR

  18. #18
    Lifer Kurlon's Avatar
    Join Date
    Jun 2007
    Location
    Waterboro ME
    Age
    46
    Posts
    13,518

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    So, no, whatever the VM22 wants you'll be fatter to make the VM26 behave the same, larger carb so the vacuum signal will be lower. AKA larger jets.

    That said, I wonder if you've got the idle turned in too far, so your 'idle' is pulling off the main too? Worry about getting WOT first, don't pay any attention to anything else. Once it's happy at full throttle, then chase the needle, THEN chase idle and idle mix. If that motor is a stock low compression low overlap cam, that 26 may be a PITA in general to get dialed in, lotta carb for 7hp.

    2 Not allowed! Not allowed!

  19. #19
    Lifer typeone's Avatar
    Join Date
    Aug 2006
    Location
    central MA
    Age
    51
    Posts
    7,736

    Re: new toy - Thumpstar TSX 125-C BW - seeking hop up parts

    Quote Originally Posted by Kurlon View Post
    So, no, whatever the VM22 wants you'll be fatter to make the VM26 behave the same, larger carb so the vacuum signal will be lower. AKA larger jets.

    That said, I wonder if you've got the idle turned in too far, so your 'idle' is pulling off the main too? Worry about getting WOT first, don't pay any attention to anything else. Once it's happy at full throttle, then chase the needle, THEN chase idle and idle mix. If that motor is a stock low compression low overlap cam, that 26 may be a PITA in general to get dialed in, lotta carb for 7hp.
    thanks, yup, that last bit is what i'm wondering as well. think i'm going to take the VM26 off and save it for the 140+ swap, just run the PZ26 clone for now ... idle isn't too far in, it's barely seated on the slide ... i kept trying for WFO runs with the super fat mains but never found a happy place.

    0 Not allowed! Not allowed!
    Beta 200RR

Similar Threads

  1. For Sale - Motorcycles | Thumpstar pit bike
    By Trouble in forum For Sale
    Replies: 0
    Last Post: 04-18-15, 07:02 PM
  2. FS: 120CC Thumpstar $500
    By KB in forum For Sale
    Replies: 69
    Last Post: 03-21-11, 08:08 AM
  3. Thumpstar mini motard
    By SVRACER01 in forum For Sale
    Replies: 2
    Last Post: 08-11-10, 02:16 PM
  4. (2) minibikes- Thumpstar 125
    By seth399 in forum For Sale
    Replies: 11
    Last Post: 02-05-10, 09:21 AM
  5. Thumpstar 125 mini/pitbike
    By seth399 in forum For Sale
    Replies: 16
    Last Post: 12-31-09, 05:46 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •