pre build parts list, input please

Discussion in 'General Questions' started by Huntington, Jan 24, 2010.

  1. Huntington

    Huntington Member

    So I am in the planing stage of my build. I have somewhat of a budget, I would like to keep this build around $1,000 and have a well built, good performing, and safe HT MB. I figured I would list my parts, maybe receive some input from you good folks, and suggestions of anything overlooked.

    Frame: The Gurbee GT2 Bicycle frame
    With HD wheels and built in tank, along with a steal frame and duel pull break leaver. I think it's a good base for a quality MB. A lil expensive but with $100 off, its a bearable cost. The tank sticker has to go, should be easy enough with a blow dryer and goo-be-gone. I have plains to paint some decals but till I can find an airbrusher and some more money to wast a few stickers will fit nicely.​

    Engine Kit: Gurbee Skyhawk GT5 66cc Angle Fire Slant Head Motor
    Kings sells the kit for $150. I hear good things about the slant heads. I am considering the billet head from RSE. I guess if I go that rout I dont need the slant head. $100 is hard to justify for a head, but if there is a performance incress over the slant, it might be worth it to me. Any opinions for one vs the other?​

    Expansion Chamber:
    It seems like a no-brainier, sick bike parts makes a great tuned pipe that looks pretty good. I just need to decide between black or chrome. ​

    CNS Carburetor
    Spookytooth has it for $50 and seems like it will be far better then the stock carb. I would like to use a boost bottle but I no longer have use of a machine shop. So drilling and tapping the inlet might be tough, unless the boost bottle supplied inlet would work for the CNS. Can anyone confirm? ​

    HD Airfilter
    I'm looking for the best airfilter I can get, max flow and good looks. I also dont want to spend a lot of time trying to fit K&N. Are there any better air filters out there that are a direct replacement?​

    NGK BP5HS Spark-plug and HP wires/boots
    Im in So Cali, seems like this plug is well suited for our temps.​

    I estimate about $750 for everything listed above, not including shipping. I have another $300 or so to play with. A lighting system is not going to be factored in this build, saving that for another time. I have some high grade 6mm SS all thread and plenty of SS nuts and bolts. A shifter kit, although very cool, is not in the cards for this build. Maybe next time.

    So I need a few things, some better fuel line. What is the ID/OD of the stock cheap fuel line?

    I hear there is a better, slim head gasket.. Does that increase performance?

    I suppose I can upgrade my drive chain. I have a 36T sprocket and 2 46T sprockets.

    Ill need another fuel filter.. dont remember what I used last time, I think a VW filter.

    Also, has anyone used the Brake/clutch lever? is it any good? The bike has three brakes and one duel pull lever, need to clean up the left side controls with the brake/clutch or by removing 1 brake.

    So thats my build list.. please comment or suggest an alternative for anything I have mentioned.

  2. AussieSteve

    AussieSteve Active Member

    Regarding heads, the slant head has significantly higher compression ratio than the stock centre-fire heads, about 8.5:1 vs 6:1. The RSE billet head has a claimed 16:1, although I've read that he used a different measurement system and that the CR is actually 9.5:1.
    I have one fitted and noticed a significant power increase over the stock head right through the rev range, but much harder to turn over for starting. (I kick-start on a stand now.)
    One point with the RSE billet head - I had to fit longer cylinder studs. Stock were 8mm x 1mm x 108mm. I needed 112mm studs.

    Sick Bike Parts have a pretty neat little inline fuel filter. I got a similar one from my local motorcycle shop.

    ... Steve
    Last edited: Jan 24, 2010
  3. Huntington

    Huntington Member

    Thanks for the input Steve, I'm thinking maybe I'll just stick with the slant head and get the MB running smooth and broken in before upgrading to the billet. If true, 8.5-9.5:1 may not be worth the expense at this time. How would that translate to mph diff?). Harder time starting is not attractive but a noticeable increase in the power bad would be nice. Still weighing my options but the RSE head might be on the back burner.
  4. AussieSteve

    AussieSteve Active Member

    Not sure of the power/speed difference between a slant head and the billet head. I've never owned a slant head, only the centre-fire and billet types.
    I'm not sure that the billet head was really worth the $100 cost plus tracking down longer studs. (The thread is 8mm x 1mm, metric fine - not easy to get here.)

    ... Steve
  5. Huntington

    Huntington Member

    And you would think being Australia metric parts would be easy to find. We have a place called McMaster-Carr in the states.

    Not sure if you guys have the same but it sure comes in handy, can find anything with them.
  6. AussieSteve

    AussieSteve Active Member

    Standard metric threads are easy to get and my local bolt specialist? had 8mm x 1mm nuts, but no threaded rod or long bolts.
    In the end, the boys at Sick Bike Parts did me a favour and made a couple of sets of custom studs.
    By now, Tony at RSE might have studs to suit. It would be nice to think so. Others had the same problem. One guy simply left the washers off but that's not a real good idea.

    ... Steve
  7. ezdzd

    ezdzd Member

    Sounds like you've got a pretty solid start. As far as the boost bottle is concerned you can put it on with a drill and I believe a 1/8 npt tap. Kind of a nerve racking undertaking, drilling into your intake but it is worth it. I'm not sure how the bottle will work with the upgraded carb, but with stock it's pretty hard to dial in the idle. That being said, it runs soooooooo much smoother. I strongly urge you to upgrade your chain to a 415. The stock one will most likely break at some point. If your lucky you wont have to use a tensioner with the larger chain. Also look up large filipino's clutch pulley idea. It makes things alot easier. Also reconsider headlights, it'll only take one close encounter with a cager for you to wish you had them. Take a look at maniac mechanics sprocket mount. I think they're about $65 but it's a huge upgrade. Anyway to each his own. Happy building.
  8. Huntington

    Huntington Member

    Im saving lights for another time, I have some safety lights for now.

    I dont need the sprocket adapter, the bicycle comes with a drum break mount for the sprocket. I have done the boost bottle before, I used the mill to get a stright hole, I just dont have the use of a mil or any drill for that matter now. Im just a college student, no longer an employed craftsmen.
  9. ezdzd

    ezdzd Member

    you can pick up a drill for 20 bucks if you watch the ads. Granted you won't be able to build a house with it but you will be able to work on and fabricate parts for your bike. Or look into your schools automotive dept. They might let you use their equip if you can talk them into it. Personally I'm a "retired" finish carpenter who has gone back to school as well. I've traded in my milwaukee for a cheap HF version that economically does the trick. I used a 7/32" i.d. for my fuel line, it provided a good tight fit. Also picked up a fuel filter with a colored metal casing off of ebay for about 5 dollars shipped. They had a bunch of different colors to choose from. And never forget the slime for the tires! One more cool mod for the ht is the mounted choke pull. I think the cns carb may already have a cable attached. If it does, performance benefits aside it would be worth the cost for the upgrade. Last thing sorry for rambling, design/use high quality engine mounts.
  10. AussieSteve

    AussieSteve Active Member

    The HT kits already come with a 415H chain. (At least, mine did.)
    Do you mean a better 415 chain? Any recommendations?

    ... Steve
  11. Huntington

    Huntington Member

    Kings advertises the kit with 410 chain. I remember my BGF kit didn't come with 415. in any case, a better chain is one of the first upgrades I do to these MB.

    My goal is to do as little fab work as possible with this build, having said that, anyone selling a spring loaded chain tensioner?
  12. ezdzd

    ezdzd Member

    steve, My kit came with a "415" chain however, you can print the word circle on a box, call it a circle, tell people its a circle, but in the end it's still a box. In my own experience a true 415HD chain wouldn't even fit on the drive sprocket due to housing clearance issues. I got a 415 chain from a farm supply store for half the cost of the 415HD(from a bike shop)and I have enough chain left over for a future build. The kit's supplied "415" was identical in pitch and size to the 525 already on my bike for the pedal side, and it broke after roughly 150 miles. If you could get a 410 chain to fit in the housing for the drive sprocket go with that. There are a plethora of 410 sprockets readily available at most well stocked hardware/farm supply stores that are much cheaper than industry specific sprockets. You'd have to be comfortable drilling into them to get them properly mounted though. Best o' luck.

    chain tensioner ideas
    consider using a shim on the rear motor mount instead of a tensioner
    Last edited: Jan 28, 2010
  13. AussieSteve

    AussieSteve Active Member

    The chain supplied with my kit, from ZBox Australia, would never fit on the pedal side. It's a much larger pitch and about double the overall width of the standard, (525?), chain on the RHS and is stamped '415H'. I can't see it breaking in a hurry. It's hardly even worn/stretched in 400km.
    From the sound of it, different kits have different chains and sprockets.

    ... Steve
  14. Huntington

    Huntington Member

    Im going to upgrade to #41 chain.. I did this on my last build and it worked well.
  15. retromike3

    retromike3 Member


    one of the best things I did was replace my 415 chain with a better BMX version of the 415. Its chromed and I haven't found any stretch or problems with this new chain. I got a KMC K415H freestyle extreme chain but I don't remember if I had to buy one or two to get all the links I needed.

    Its been working flawlessly for about four months now.(looks cool too, matches my silver chain on the other side.) Its one less thing I have to worry about.

    Mike Frye-the bike guy
  16. jon scott

    jon scott New Member

    The dual brake system works well on my double drum bike just need to dial in settings for the cables
  17. Huntington

    Huntington Member

    Just wanted to update this thread real quick. Im ready to order parts but now I question going the 2 stroke route, with all the upgrades I mentioned or a 4 stroke with EZM trans.

  18. Huntington

    Huntington Member

    Ordered the GT2 Bicycle today, stupid paypal using echecks, it should be here in a week. I'll have to do a product review on the thing when it comes.