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Another X7 - street racer?

Discussion in 'Suzuki 250cc 2 Strokes' started by Fuzzball, May 1, 2012.

  1. Fuzzball

    Fuzzball Active Member

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    Well I've had a pair of Gt250X7's sitting in a shed for a while. Pulled them out with the mind of making a scrambler, but now thinking a street racer/sports - these were basically 70's sports bikes anyway. Making this thread to show off and ask questions and a bit of help...

    Red - the runner
    [​IMG]

    Blue - spares
    [​IMG]

    Now some of the reasons red was stuck in the shed in the first place
    [​IMG]
    If anybody knows how/why the springs did this to the pressure plate or how to stop it...

    [​IMG]
    Idler gear usually sits here. Some of that paint you can see (WTF would you paint the inside of an engine!?!?) between the gear and the shaft and did this. Eventualy the gearbox locked up when ever she was put into 1st. Idler from the spare and some flushing fixed this.

    [​IMG]
    This hole opened up in the frame and water pissed out :o Not sure if it's a drain hole that got filled and painted over or a rust hole... anybody know?

    Other problems - Piston to cylinder gap twice what it should be, horizontal hone marks, buggered shocks front and back, clogged exhaust systems, worn out carbs, airbox had to be replaced with pods, crank drinking gearbox oil, ect ect. Short story, full rebuild is needed.
    So I was a little surprised when this happened without even so much as draining the two year old fuel from the carbs...
    flackbag - MVI_1822.mp4
    :o ;D

    Striped down the bike over the last week or so, this is what I have now
    [​IMG]
    I like the feel and look of these bars on the bike, and if I can get/make some rearsets that sit around where the passenger pegs are now...
    [​IMG]
    Need to get this thing down to a bike shop and borrow a flywheel puller. Then the top end can come of and the cases apart. Will probably end up useing the bottom end from blue anyway, but I want to check out what this one is like on the inside.

    That's it for now. Can't wait to crack her open :D
     
  2. kiffsta

    kiffsta Senior Member

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    awesome stuff  :Thumbs_up: , looking forward to see how you fare with this one, its bringing back memories of Phil's rebuild.
     
  3. mboddy

    mboddy Well-Known Member Premium Member Contributing Member

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    My Bike:
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    I also make my own rearsets.

    BMX foot pegs can be had for under $8 pair.
    http://www.ebay.com.au/itm/Replacement-Child-0-9cm-BMX-Bicycle-Bike-Axle-Foot-Pegs-/150790961418?pt=AU_Sport_Cycling_Parts&hash=item231bd7790a#ht_1755wt_1156
    I like the ones with the 3/8 UNF thread (24T per inch?).
    Because it is a fine thread it will hold if you have a minor spill but the thread will pull out saving the frame if you go down hard.
    The last set of pegs I got from Hong Kong did not have this thread so I had to buy a 3/8 UNF tap and tap it myself.

    Toe pegs here: [​IMG]
    Or here: http://www.ebay.com.au/itm/Race-Rearset-Spare-Toepegs-GSXR-R1-CBR600-ZXR-ZX6-RR-/270672507569?pt=UK_Motorcycle_Parts&hash=item3f0556b2b1#ht_500wt_1211
    (These guys also often have the nylon slider buttons for the end of your foot pegs.)

    To make the longer gear rod I go down to the local VW beatle mechanic and ask him nicely for a VW Beatle push rod.
    They are strong and hollow alloy. Cut the ends off to the length you want and tap a 6mm thread in each end.
    Then cut the threads off two high tensile 6mm screws and screw them into the rod using red stud strength thread locking fluid.
    For the plates I use some 10mm alloy plate offcuts which can be cut with a metal bandsaw.

    You cannot go past this brake pedal for the price:
    http://www.ebay.com.au/itm/Folding-Brake-Pedal-1999-2002-Yamaha-YZF-600-R6-Chrome-/300607736189?pt=Motorcycles_Parts_Accessories&hash=item45fd9e097d#ht_5053wt_1099


     
     
  4. Fuzzball

    Fuzzball Active Member

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    Thanks for the info, very helpful. Have to admit I have no idea what a toe peg is though. Thinking about using scrap wood to make mock ups for the rearsets.

    First screw up has been made - If you use a harmonic balancer to pull the flywheel on these things, make sure you don't screw the puller bolts in to far... Those holes go right through the flywheel and your coils are back there.
    :BangHead: I was thinking about replacing them anyway. And the case is ready to split  ;D
     
  5. mboddy

    mboddy Well-Known Member Premium Member Contributing Member

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    The toe peg is the thing that you move to change up and down gears.
    In this picture of the Tarozzi based rear sets on my TDR it is the small rubber covered part of the gear lever.
    [​IMG]
     
  6. Fuzzball

    Fuzzball Active Member

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    Oh. Yeah. That makes sense *palmface*
    Got both engines split, decent amount of wear on reds gears and one of the selector forks is "burnt". Oh and the sump is full of shiny and dull magnetic stuff...

    Blues gearbox looks much, much better, but has drips of liquid gasket all over it. Will give everything a closer look tomorrow. Photos later tonight. Maybe.
     
  7. Fuzzball

    Fuzzball Active Member

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    Hmm... no edit button? Or am I missing something.
    Anyway.
    I had fun the other night  ;D
    [​IMG]

    Burnt fork... *shrug*
    [​IMG]

    The good shaft from the spare box
    [​IMG]
    :D :D :D
     
  8. Fuzzball

    Fuzzball Active Member

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    Small update. Good frame is stripped, just need to knock the steering head bearings out. Looking for a shop that can inspect the frame for damage and to make sure it is straight - no point in rebuilding an engine if there's nothing to put it back into.
    Also looking at suspension and brake options. These up front - http://www.racetech.com/page/title/Emulators
    In the back I'm not sure yet. Front brake I want to replace the entire system with something modern... though If I can make a new calliper and master cylinder work on a drilled disc with good pads can live with that. Might be able to make the system from a KLE250 work, but the disc was damn thin, I don't think it will be able to stand up to hard road riding.
     
  9. mboddy

    mboddy Well-Known Member Premium Member Contributing Member

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  10. Fuzzball

    Fuzzball Active Member

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    Sweet, thanks again. Now to find a floating disk.
     
  11. Ian B.

    Ian B. Active Member

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    Hi,

    Looking good. I am thinking about an X7 engine for a possible engine swap into a Harley SS single frame. Can you tell me dimensions for the front and rear engine mounts, i.e. how wide is the 250 engine at these points? I want to see of it will fit in the Harley frame, or if I am better off modding an X7 frame.

    Thanks very much for any info you have.

    Ian B.   
     
  12. Fuzzball

    Fuzzball Active Member

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    One of the old HD dirt bikes or a "modern" one? Will try to remember to grab the tape measure next time I pull the mock up out.
    Recently spotted a 550 Katana, wondering If I can make the front wheel from one fit the X7, finding a disc with four mounting bolts is proving to be painful. Might nick some of the styling as well...
    [​IMG]
     
  13. Ian B.

    Ian B. Active Member

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    Thanks Fuzzball. It's one of the old 2-stroke road / dirt bikes. The road / trail versions had the same frame after 1976. I have 2 ea. roadsters - a US and a Euro model. I like the big single, but they vibrate horrendously and should really have been released as a twin (which AMF-HD did have for racing, but never carried over into production). I want to bolt in a hi-po period 2-stroke 250/350 air-cooled twin. If you get a chance to get those measurements. I can measure my HD frame - much appreciated.

    Cheers,

    Ian B.




     
     
  14. Fuzzball

    Fuzzball Active Member

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    Took some measurements with a tape measure and a block of wood, so not perfect. Measured from the centre of the bolts, and the inside face of the mounting plates.

    Upper front mount to upper rear mount - 350mm
    Lower front mount to lower rear mount - 205mm
    These next two were measured by "drawing a line" through the top two mounts and measuring straight down, vertically, to the lower mounts
    Lower front mount - 100mm below line
    Lower rear mount - 80mm below line

    Upper front mount length - 53mm
    Lower front mount length - 120mm
    Upper rear mount length - 190mm - with a 50mm spacer to allow for chain clearance
    Lower rear mount length - 122mm - off set to one side to allow for chain clearance

    Both my engines are in bits and spread between several box's atm, but the stock frame gives about 400mm for the hight of the engine. Not sure how wide she is either.
    That good enough?
     
  15. Ian B.

    Ian B. Active Member

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    Hi Fuzzball,

    That's really great - thanks for getting all that information so quickly. I am going to measure up the AMF frame and see if I can locate an engine out here (Japan) and see if I can match it up. The main problem is the cradle clearance as the AMF has 2 ea downtubes vs. the X7 single tube. As modding frames is tough here, I need to keep the cuts to a minimum. 

    The GT250 X7s are known as the RG250E over here and Yahoo Auction Japan has a bunch of stuff for them as they are not really very popular. I am looking for some mild tuning up to about 30 BHP by keeping the weight down to try to make it a 'fun' bike.

    Cheers,

    Ian B.
     
  16. Fuzzball

    Fuzzball Active Member

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    Unfortunately most of the tuning info was lost when a UK based forum for the bikes went belly up a while ago.
    http://www.suzuki-gt.co.uk/
    Part of the website is still alive.

    The header pipes exit fairly near the "outside corner" of the cylinders and point about 45* down, not sure how that will go with your frame
    Pod filters and a 105 pilot jet are a good first step, makes it easier to sync the carbs as well. Other mods included enlarging the exhaust ports, but that's all I can remember.

    Edit: Just found this while going through old links
    http://www.suzukix7.com/Suzuki%20x7%20club.html
    scroll down to the photo of the red framed bike with white body work.
     
  17. Ian B.

    Ian B. Active Member

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    Hi Fuzzball,

    Thanks for all the great info and links - plenty of stuff to be getting on with. X7 stuff still appears here in Japan, but it is more the RG250 Gamma stuff now (early 80s). The frame needs cutting / widening, so I need to get to work and figure out how to do that...

    Cheers,

    Ian B.
     
  18. Fuzzball

    Fuzzball Active Member

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    I sent an email to the owner of the website - turns out everything is live and well over there, but I can't access their forums for some reason. Some more info on engine mods from their forum.

    I'm rather happy about this myself, I might try to take my "bad" cylinders to "race spec".
    What needs to be changed with the frame?
     
  19. Ian B.

    Ian B. Active Member

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    Sounds good.

    The frame problem is that it is a single cylinder roadster / dirt bike frame w/ twin down tubes. I need to widen the frame and fab new engine mounts to shoehorn in a twin, but keep as many stock AMF-HD parts as possible, like tank / fenders / seat etc. I

    also have access to a lot of RG250 Gamma engines / parts for low $$, so the option of bolting in a Gamma engine over the air-cooled unit is also possible. This 'duplicates' the racing twins AMF-HD Aermacchi had in the 70s. However, the AMF-HD frame is not up to it as is and would require a lot of strengthening. But it would make a good ride - I want to make the bike the way AMF-HD should have made them.

    (Sorry to hijack the thread - back to the X7 discussion...).

    Cheers,

    ian B.   
     
  20. Fuzzball

    Fuzzball Active Member

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    No probs mate.
    What about cutting the two frame down pipes from the head stem to under where the engine would sit, then rebuild it  with a large diameter  single down tube, and the lower frame rails coming to meet  the down tube in a "Y" shape. It would basicaly be an X7 frame then...
    You would need to find a good engineer/welder though.
     

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