Specialized Mountain Bike with Shift Kit

Discussion in 'Photos & Bicycle Builds' started by ccpomea, Oct 22, 2010.

  1. ccpomea

    ccpomea Member

    My very first build, I got my shift kit and accessories last Friday and the engine on Monday. Then because I'd ordered a few parts before I had the engine had to make another small order for a new head gasket and head bolts (I ordered 6mm, engine is 8mm)....:rolleyes7:

    2000 Specialized Bike
    Zoom Bicycles Engine
    Sick Bike Part's Shift Kit

    Plus a bunch of other replacement parts - Throttle, Gaskets, Bolt's, rocker switch, air filter and a front engine mount because the down tube is pretty wide.

    Spent a little time each evening putting it together, finished it last night and went for my first break in ride this morning down to the beach. Stopped at the beach to let the engine cool a bit. Only had one issue - engine cut out on the way back, took a little while before it would start again, stopped to check (didn't see any problems) and then it started fine so I'll put it down to one of those thing's for now.


  2. Skyliner70cc

    Skyliner70cc Active Member

    Looks great. The only problem I see with your new build is you are missing a tuned pipe. They are mandatory with a shifter kit ;-)

    Check wiring:
    1. Plug cap often has the small U clip fall out of it causing intermitting connection to plug.

    2. Replace chinese spark plug with NGK one. Have more than several chinese plugs fail internally...first symptom was intermittent spark.

    3. Check connections. Stock connectors are awful with intermittent connecdtions. I solder all of my wiring and double shrink wrap them.

    4. Magneto...ensure bolts haven't vibrated loose. I cut my white wire at the magneto so it doesn't short out and cause issues. Ensure solder joints in magneto are good. Have more than several mags where the wires had poor solder connections and cuased intermittent connection.

    5. Ensure the plug wire is screwed into the black CDI.
  3. ccpomea

    ccpomea Member

    I thought about the tuned pipe, but I'd read here that they are a bit louder. Might still get one down the line because the stock pipe isnt as loud as I expected so a little extra noise wouldnt be too bad.

    I didnt mention it in my first post... changed that many things I lost track :grin5:, but I had replaced the cable and plug with NGK. The brass screw and spring fell out the first day - offcourse the spring went flying and I had to cut one down from a clickie pen until the new cable and plug arrived.

    The original cable was glued in there and just snapped off from the CDI when I tried unscrewing. Used a drill press with a small drill bit to drill the old cable out from around the screw, pulled out the remains pretty easily with hemostats.

    If it happens again I'll follow your advice and solder the wires directly, I cut off the original connectors and soldered on my own spade connectors - but am not 100% happy with how the connection's tinned.

    Didnt check under the magneto cover so that might be worth a try too - Thanks for the tips !
  4. ccpomea

    ccpomea Member

    Just an update to my cutting out problem - Went out for another ride, everything fine for the first 20 minute's then it started cutting out, if I waited a few minute's it would start back up but then cut out shortly after.

    Stopped just like it would if I ran out of gas so after a few minute's checking thing's discovered that the gas tank wasn't venting which was stopping fuel flow.
  5. pbeggs

    pbeggs Member

    nice build!!! for a first attempt,.. you did an excellent job,.. looks like you did your homework,..
  6. RedBaronX

    RedBaronX Member

    I had that very same problem... actually, I am still dealing with it some as the vent seems to get blocked or somewhat clogged-- not bad enough to cause the bike to cut out, but bad enough to make it bog down intermittently.

    For the vent, I drilled straight through the center of the cap with a 1/16" drill bit and then fashioned a "cover" from JB Weld metal epoxy:


    it hangs over and down a little over the back of the cap to keep rain out as my bike has to live outside.

    I think the "clogging" is happening because gas is getting into the cap through the vent and not able to drain back out, so I'm going to drill a couple more small holes in the plastic part of the bottom that do not go all the way through the metal of the cap
  7. ccpomea

    ccpomea Member

    I'll be drilling a small hole in the center of my gas cap too. I've also ordered a "gas fuel tank breather" from eBay and will enlarge the hole and put that in when it shows up. Hopefully that will fix it.

    I emailed the vender I bought the engine from and they suggested to drill a small hole around the underside of the bevel (and also said they would be sending me a new gas cap anyway).

    Didnt get a chance to try it out today, but have my finger's crossed that it fixes both the cutting out and another issue I found out after strapping my GPS to the bike. Have a shift kit and bike slows down on the smallest two cog's on my cassette. Gets up to 30mph no problem on cog 6, but slows down to 26mph when I shift to cog's 7 and 8.
  8. Ghost0

    Ghost0 Guest

    Your slowing down in 7th and 8th is pretty normal especially with a new engine. So basically in 6th you have reached terminal velocity with the amount of horse power you have. As your engine breaks in you will gain quite a bit more horse power and should be able to probably pull 7th at around 35mph but if you want more than that you will need to get more horse power. First thing to do is port match your intake and exhaust ports to increase flow and then work on fine tuning your carb by adjusting the needle and maybe rejetting. Then if you still want more a tuned pipe would be the next step. BTW very nice build for #1.
  9. ccpomea

    ccpomea Member

    Thanks for that info ghost. I was worried it was something wrong with the engine. Was surprised because it preforms so well in the lower gear's.
  10. Looks really good. If you do mild porting, and piston notch that would help alot. I'd let the engine break in first though. Also SBP pipe is a good upgrade, and its not all that loud.

    I went in a different direction with my bike. Instead of getting a shift kit I went and made as much power as possible out of the 68cc engine.

    My first build.

    Attached Files:

  11. ccpomea

    ccpomea Member


    Same advice SBP gave me about waiting for it to break in/Port matching, However I did order the expansion chamber exhaust (arrived today) because of the sale. Will wait for break in and carb tuning before I put it on though.
  12. solfanole

    solfanole New Member

    Nice looking bike! I've got an 05 specialized that is a blast to run. 40 mph with no gears. Am considering the shift kit, but not sure I want that speed.
  13. A-TownTX

    A-TownTX Member

    how do you like your shift kit has it put a longer life on your back rim or even noticed a difference I want one but not sure if its worth it.
  14. Hawaii_Ed

    Hawaii_Ed Member

    Shift kit is the best mod ever for these kits. Nice build my friend!
  15. ccpomea

    ccpomea Member

    A-Town -

    I'm very happy with the shift kit. It's easier to get up hills and my cruising speed is much quieter because engine is operating at a lower rpm.

    No idea about longevity of rim - This is my first motorized bike and I installed the shift kit at the same time as the engine so have never had a sprocket mounted to spokes. It hasn't seen much use - Bought a motoped shortly after I finished building this so I tend to take that out.

    Going to repaint the frame black I think.
  16. maxsent

    maxsent New Member

    fantastic build! I am currently building just about the same bike. I am using a RAW 66cc and Jack shaft kit on a Specialized bike. having one problem and would like to get your take on it.

    the chain from the jack shaft to the chain rings is loose by 1/2 link. did you encounter this problem? and if so how did you solve it?

    thanks for any help
  17. adrian101

    adrian101 Member

    Very nice build. I likey alot! :D
  18. ccpomea

    ccpomea Member

    I couldnt get that chain right until I added a 1/2 link.
  19. maxsent

    maxsent New Member

    Well I am sorry to hear about having to add the half link. I just turned the bike upside down and got it tight then used a wood dowell to shim it into place.

    I will be bringing a turnbuckle from the top bar and providing tension from the top. I noticed that the SBP kit uses a frame brace and nut to tighten the chain from under the jack shaft pushing it up. mine is looking good as I tried to start it tonight (huph huph). it is staying tight. I will post pics when I get my tensioner installed.