Third build, first post, Genesis GX7 (Astra) with SBP Shift Kit

Discussion in 'Motorized Cruiser Bicycles' started by mbearden, Feb 7, 2017.

  1. mbearden

    mbearden Member

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    Hey All! This is my first post, though I have been following the forum for quite a while. I put my first build together a year ago next month! My first build was on a 700c Roadmaster Adventures $99 Wal-Mart special. I learned quite a lot from that first build, including but not limited to; 700c tires are WAY too narrow to motorize, and leaning over to reach the handle bars was not comfortable! My next build was a Huffy Bantam 29" mountain bike. I actually purchased 2 of these bikes, as I couldn't find a replacement rim at my local bike shop. Needless to say, my next build will be on the extra frame I have still lying around. I have retained parts from each build onto the next one, but the bike I have running now as my primary is the Genesis GX7 (blue version of the Genesis Astra) and I love it. I bought this bike with the intention to put a SBP shift kit on it after seeing KC's chrome Genesis build (Thanks for the inspiration KC!) I will say this, I am glad I never attempted a direct drive option on this bike, as I've read that people have trouble with the added spokes. I took the front fork off of my Huffy Bantam 29" mountain bike, as it was a suspension fork, and the same size as this one, so I had to use the front tire from the Huffy on account of I wanted a disc brake on the front. I love how it looks! I can say from experience that the shift kit wont give you a whole lot more speed *unless* you are in super ideal situations. My top speed on my DD 48 tooth bike was 40mph, and that was only for a second downhill, and so far my top speed on the GX7 with the shift kit is 41mph. I use an old phone w/o service as my speedometer, as the GPS still works. I got the Shimano MegaRange freewheel for the back of the bike, and that first gear is freaking AWESOME with the motor! I also have ape hangers on it, upgraded throttle and carb (RT) I have a GT80 ported cylinder jug with an RSE reed valve, X-Port exhaust and expansion chamber. I haven't modified my piston at all, and I'm honestly wondering if I would even see a lot of difference if I did? Anywho, I just wanted to share my experience for anyone else thinking about getting this bike. I highly recommend motorizing the GX7, but I would for sure combine it with the SBP shift kit. It makes riding a whole lot more versatile. My ride to work is less than three miles, but I can usually make it there through traffic in about 6 to 8 minutes. I'm very thankful for all of the people on this forum and all the trouble and trouble shooting you have done to help the noobs like me without ever having to post! I'm getting to the point where I think I might start building for other people (a lot of people who see me riding it ask me if I can build one for them) and would love any input, questions, or suggestions. Let me know what you think of the bike and what I can do to improve! Thanks!
     

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  2. mbearden

    mbearden Member

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    Here are a couple pictures of my first two builds. I'm gonna put a motor back on the orange one with a 56 tooth direct drive for trail riding.dnut
     

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  3. mike carter 2

    mike carter 2 Member

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    the gt 80 jug has a third transferr port added to it.that port is desinged to work with ported piston.check out appolo motors for more info. i did and he has a lot of knowledge about high peformance bike engines.i have the gt80 kit from gasbike .well over 1000 miles,alot of small mods,a couple big ones including a ported piston and a x chamber from a 1979 suziki rm 60. will do 40 with 44 tooth rear cog. i run it hard every day rain or shine as its my daily driver.not one problem from this engine.dnut
     
  4. mbearden

    mbearden Member

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    Thanks for the reply Mike! My only real point on all of it was I'm not convinced I'm going to see an actual difference in performance by cutting on my piston. I've read conflicting things about the third transfer port with and without the cut-on piston. Some people claim it makes all the difference in the world, others say that the third transfer port is enough. I've never heard of anyone doing a side-by-side comparison of with and without a cut piston. I do have a high compression head on the way, and I bought a pull starter for it too, though the rope broke on the third day I had it on. I just need to go buy some quality rope to use for it.
     
  5. Potato_In_Exhaust

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    I dig your rear fuel tank setup. Nice. :)
     
  6. mike carter 2

    mike carter 2 Member

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    go to high proformance engine tips and mods..... hit search look for rse reed valve info .that should help. theres a discussion on there about thus very thing
     
  7. mbearden

    mbearden Member

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    Thanks Potato! It's a new item from gasbike. I built my own out of pvc, but didn't trust the glue I used, so I opted for that one. I will say to check the threads on them first if you get one, my fuel cap doesn't screw all the way down...
    Thanks for the info Mike. I'm sure I checked them out a while back when I was researching it, but I will freshen up. I have a few extra pistons I can play around with.
     
  8. mbearden

    mbearden Member

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    mike,
    I read the thread you were talking about. Do you know of any sources that have actual numbers that can see what the differences are? Honestly its not a huge deal, when I have some spare time, I will play around with it and figure it out.

    As for other stuff on the bike I forgot to mention, I have an upgraded CDI in the mail with the high compression head. Does anyone know of a good source for rope to use on the pull-starters that wont break? I think I mentioned I had mine on for about three days before it broke the first time. I fixed it and used the remainder of what was left, and it broke again the next day. Also, is there a wide crank set that will work with the SBP crank set-up so I can pedal and have my pull-starter on?

    I also have to mention BIKEBERRY... What a sad excuse for customer service! I won't go too far into it on this thread as it doesn't really pertain to much on here, but I did buy a motor from them that I wanted to use on this bike and wasn't able to. You can read about it if you check out BIKEBERRY's google reviews, as well as pictures.
     
  9. mike carter 2

    mike carter 2 Member

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    go to your local lawnmower repair . i just bought about 5 feet for under 2 dollars
     
  10. mbearden

    mbearden Member

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    Sweet, thanks! I was thinking that or like home depot or something. I wanted somewhere I could get the product in-hand. Ordering on-line was going to be a last resort. Do you have any pictures of your bike mike?
     
  11. mike carter 2

    mike carter 2 Member

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    theres one on high proformance thread under kings motors gt 80
     
  12. mbearden

    mbearden Member

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    UGH!!! Serious frustration! I keep having head bolts come lose, then I over tighten them and the threads on the crank case pull out!
    :-||
     
  13. mike carter 2

    mike carter 2 Member

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    thread savers might help
     
  14. QuietRiot522

    QuietRiot522 Member

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    Love the build! I always wanted one of the geared Genisis bikes but, I have alot sunk into my Onyx now that I haven't made the switch. As far as the piston modifications for the RSE reed valve I'm in the "should be done" camp, I cant offer any tangible facts. Only perceived performance. worst case scenario is you need a new 5 to 10 dollar part haha.

    I spray one coat of silver grill paint on the threads for the crank case side of the studs to keep them from backing out on me, only on the ones that give me trouble. Ive had pretty good success with Helicoils for stripped out parts if it gets to that point and you dont want to replace your crankcase it might be your best bet.

    hope you dont mind if I share some Genisis love in your thread here:

    [​IMG]
     
  15. mbearden

    mbearden Member

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    Hey thanks for the reply! Your bike looks AWESOME! Thanks for sharing, I really like seeing other people's as it gives me ideas for mine! So my crank case came in the mail but my Jack shaft was seized in the bearings and I had to cut through the bracket to get the motor out. Waiting on a new one from sbp now. I have 4 extra pistons, so I think I can afford to drill into one of them, haha. (I like having extra parts, I probably have enough parts lying around to build two complete bikes with another one almost all the way built) As far as getting your onix shift worthy, couldn't you install a free wheel, or is there not enough room in the frame? You would have to rig up some kind of connection for the derailer and wire, but it seems like it would be doable? Or even the three speed internal hubs they have? I've read people like those a lot more actually.
     
  16. mbearden

    mbearden Member

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    Oh, also, does anyone know a good source for bicycle fairings? I've been looking around but can't really seem to find what I'm looking for. I'd like to build a bike that looks like a motorcycle, like it could fool people who didn't look close. Not the genesis of course!
     
  17. QuietRiot522

    QuietRiot522 Member

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    I think Wald makes decent steel 26 inch cruiser bicycle fenders. If thats what you were referring to. Otherwise if you dont mind spending the money fenders from Worksman bicycles would probably be the strongest bicycle fenders I can think of.

    I thought about putting a 3 speed hub on my onyx with the shift kit but I'd have to get new wheels. If I went that far then I wanted disc brakes too, when I priced the upgrades out as a whole it came out to about 4 to 500 bucks I think. Which I couldn't justify because I could get a Fito MODENA GT-2 with disc brakes and 7speed rear hub included for 300. Maybe this spring ill weigh the pros n cons again.
     
  18. mbearden

    mbearden Member

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    Yeah, I guess when you weigh in everything else you'd have to add to it, makes it a little harder. I got the Genesis at Wal-Mart for $180, but I had to put a different fork on the front (suspension) so that I could have shocks and a disc brake. Now that I have the shift kit set-up, I've been thinking about a rear disc brake! But I have a couple other builds I want to do first. I really really REALLY want to build a Fat Tire MB next! I just got my bracket in the mail from SBP, so I will be in the garage working this weekend on the Genesis rebuild.
     
  19. XxxHookedxxX

    XxxHookedxxX New Member

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  20. mbearden

    mbearden Member

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    Wow, that blue one looks awesome! It's nice to see I'm not the only one who motorized the GX7! It just looked like it was perfect for a motor! I've been thinking about going 4 stroke because of how much more reliable it is (I've been in the process of rebuilding for about a month now!) but the sticker shock on the initial investment is what's keeping me from it. I might as well build an electric build! I like your light on the silver one too, it looks very sleek!
     

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