Starting 1st build - Grubee Starfire - sprocket kit

Discussion in 'Frame Mounted Engines' started by javelina1, Jul 26, 2009.

  1. javelina1

    javelina1 Member

    Hi group,

    getting ready to launch into my HT build. Picked up a Grubee Starfire, and will be installing onto a Trek 820.

    for now I plan to use the rear sprocket kit. I noticed it mentioned the 9 hole chrome sprocket is compatible with 36 spoke wheels. All I've got lying around my garage are 32 spoke wheels. will the 32 bit work?

    I've also picked up some US grade studs for the head & rear mount, (and will swap those out).

    I'll post picks as I start to progress.


  2. javelina1

    javelina1 Member

    guess not... tried it on one. Can only get 8 holes to line up, the 9th is blocked by the spokes crossing over. bummer.

    Was trying to keep the initial cost low, since I sold Wifey on it being a cheap hobby. :whistling: $150 for the Grubee starfire kit.

    Another $5-10 to replace the head & rear mount studs.

    Now I need a front engine mount, (my Trek 820 downtube is huge compared to what the engine is pre-built with).

    I was planning to replace the 9 hole sprocket/rag setup eventually. It's easier to piecemeal the upgrades over time, that way my budget manager, (Wifey), doesn't get to excited.

    Now I got to deal with a rear wheel, or punt and maybe get an adapter. D*mn, I've got a lot of wheelsets lying around. (I have a few mountain bikes).

    Need blue locktite..... Just ordered a dual pull brake, to make room for the clutch handle.... gotta get a fuel filter.... maybe a different air filter...

    I don't mind though. I love to tinker on bikes and motors. I'm still happy I dove in...

    Last edited: Jul 26, 2009
  3. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    just use 8 bolts
    like leave one off, the sky will not fall & its just [un]common sense

    maybe upgrade the 8 bolts + nuts to US grade
    & make the missing bolt be in the middle of one of the steel rings

    seen it done all the time, even 8 Chinese bolts will get the job done
    Last edited: Jul 26, 2009
  4. javelina1

    javelina1 Member

    or maybe a smaller diameter bolt for the 9th hole? It'll probably be the one that's needed to keep the sprocket alignment true to the drive gear....
  5. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    the original chinese kit sprockets used 5 bolts
    & there were 5 slots, not holes

    so maybe not

    & 5 did not divide very well into 36 so we have the 9 holes today thanks to mikey da bikey if you really want to know the rest of the story
  6. azbill

    azbill Active Member

    javelina, if you run into probs, email me and i will call with assistance
    the 9 holes were so they divide into 36, the first kits had 5 holes which goes into the 40 spoke wheels used in china
  7. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    how are those ez bikes selling for you?
    how is yours running?
    any problems?

    sorry for going off topic here but it seems like it got sorted
  8. azbill

    azbill Active Member

    mine is good
    sales acceptable to me (I didn't get into it to get $$$, I wanted a good kit)
    the mindset of company is my favorite part
    any prob i have had, it has been how can we prevent that from happening again

    sorry Jav...back to you dude :)
  9. javelina1

    javelina1 Member

  10. Sprocket blues

    Hey Jav, for a while, I did a bunch of 68 spoke wheelsets. They were a Blue-eyed sollanovich! BUT along the way I found that if I downsized to 10/32 or 12/24 bolts, then I could have more leeway in aligning the holes.

    BTW yes most were the old 5-holes (which I used to pay 8 bucks each to have the center turned to 1.5 from 1.4) but that last couple I did were 9-hole (still the math is wrong!)

    Consider nice washers, good quality American hardware, and smaller bolts all around so it will still be reasonably balanced (IF that makes any difference.

  11. get a 36 spoke wheel and use all 9 bolts for a proper installation,you dont want your chain coming off.
  12. javelina1

    javelina1 Member

    Thanks Mike. appreciate the input.
  13. javelina1

    javelina1 Member

    I'm hunting on Craigslist! :D
  14. azbill

    azbill Active Member it a cruiser or multi-speed ?
    I have a heavy-duty coaster wheel I could trade or something
    brake arm is already bent for sprocket clearance

    e-mail's are turned off
  15. javelina1

    javelina1 Member

    Bill, multi speed. (MTB - 8 speed setup).

    Kinda on hold with my build for the moment. Just ordered the front mounting kit from sick bike. the down tube dia. on this Trek is very large.

    must be pretty standard fair for MTB's to have 32 spokes. I'll also hit a few garage sales, and goodwill, to see what I can turn up. :rolleyes7:

    I may go with a smaller bolt setup, as Mike suggested. (but use a good American quality hardware).

    thanks for the offer though!
    Last edited: Jul 27, 2009
  16. javelina1

    javelina1 Member

    Got my front mount kit from SB today. Fits up fine on the downtube. Yippee!!!! I'll be building up this weekend. (I'll take pics...)

    still debating what I'll do for the rear wheel. either 9 smaller bolts for the existing 32 spoke, (US grade kit). Or, I go with a new 7sp, 36 spoke wheel. But I'll end up using the rest of 8 speed drive train, with the exception of the cassette. (needing to buy a 7sp).

  17. javelina1

    javelina1 Member

    Man, this totally stinks... I got the SB front mount kit. I took out the front mount studs, but the SB front bracket doesn't line up on the drilled holes. Their site said center to center, from the the studs, should be 1.6". My 2008 Grubee Starfire Gen II looks more like 1 15/16's....

    My bad. I thought the Grubee would be standard for this kit, (not knowing any better).... Now I'm back to square one. No way to get the front bracket mounted to the engine. the rest of the SB mount fits the downtube just fine though...

    bummer... was planning to build it up this weekend.

  18. javelina1

    javelina1 Member

  19. the center bolt to bolt for front mounts are 1.57 inches or 40mm. this is for 48cc engines and simular sizes. maybe the sbp mounts are for 66cc(80) engines which sometimes have mounts for larger bike tubes.
    Last edited: Aug 1, 2009
  20. thats a cool bike,now you dont need special mounts.