pm tuning/bgm crank

Discussion in 'Maxiscooter Tuning' started by DYS VTR, Feb 14, 2009.

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  1. red180172

    red180172 New Member

    Messages:
    124
    Rides:
    172 + custom mk2 vr6
    hi to all ive just joined

    minor i feel the same as u with the pm tuning stuff there selling its all cheaply made :(

    also i was thinkin of trying 1 of those top racing cranks but noticed there same price as a 55 bgm so i might just go for that and do the work thats needed to make it worth doing (porting,matching)

    ive been around scooters for a few years down here in southend (essex) this year me and a friend and doin sum porting/polishing/rebuilding + gold and chrome plating service for scooters mainly runners

    ive been reading alot of posts on this forum so thought it was time to join
     
    red180172, Apr 5, 2009
    #21
  2. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    no i havent had chance to try one as nobody had them in stock to actually order one. dont like waiting for parts (id rather bounce off all the euro sites and eventually settle on a british stockist) the bgm quality is starting to go down a little altho there still using the same big end bearing (for now) malossi have REALLY gone downhill.. what is it wiht people, credit crunch dont mean over use blunt tools, it means put a better product out and generate more buissness... :wallbash:

    but ye, not yet try'd and not sure i will.. got 2 cranks at mine waiting for rebilds for my own personal use so unless a customer chosses to run one i doubt ill go out my way to grab a top racing now. will just be a copy of the bgm again. wondering if bi di zem actually make the bgm stuff or if its now a subsidary company run entirely seperate rather than just a brand name for scoot bits :confused:
     
    MiNoR cOnFuSiOn, Apr 6, 2009
    #22
  3. jayzee19

    jayzee19 Member

    Messages:
    204
    so would you recommend the long storke 55mm bgm crank from scooter-center for quality build?? cause i already have a racing bgm crank on my 70cc and it feels and sounds really nice and since i'm doing a complete engine rebuild on my typh id thought i'd opt for the torquey option/long stoke! and btw bzm have theor owm machines in germany and make products to spec i've been there!!!they own a airfield and a massive tuning center with 5 dynos!
     
    jayzee19, Apr 6, 2009
    #23
  4. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    its the same company that own blata if i remember rightly... in wich case they will havce more than a workshop and a few dyno's in germany... thought the head was in the check republic (spelling?)

    but yes, used plenty, not had a failed bgm crank in 4 years of using them? speaks for itself really.

    long strokes are real good if you can do the corrective work yourself.. otherwise stick with a 52, a 52 will be faster than a non corrected 55 by ALOT (hence the supposed know all tunnersa inn the countrey wouldent touch them till a couple years ago..)
     
    MiNoR cOnFuSiOn, Apr 6, 2009
    #24
  5. jj180

    jj180 Active Member

    Messages:
    2,250
    Rides:
    Mrt 183/Vespa 300
    i had a bgm crank fail within a month and put a pm crank in after and its still working to this day
     
    jj180, Apr 8, 2009
    #25
  6. italjohn

    italjohn Member

    Messages:
    531
    Rides:
    Runner 172
    I'm sorry to interupt this tread, but what you say is that you can't use a 55 crank, unless you are fiddeling with the port times?
    And what is the difference between these two cranks?

    Product Nr.: BGM038025
    Crankshaft BGM Evolution 2 55mm stroke, 110mm con rod - Piaggio Maxi 2stroke.
    The bgm EVOLUTION 2 crankshaft is completeley forged. THe crank webs as well as the con rod. The crank comes with an increased stroke of 55mm and a 110mm con rod:
    * the forged Kawasaki con rod with its length of 110mm gives a better angle of the forces to the big end bearing. This gives a smoother running and more reliable engine.
    * The design of the big end bearing is identical to the ones used in the Moto GP. The open design of the needle cage reduced the friction and hence the build up of heat in the bearing
    * With horizontal engines a balancing of 30-40 is recommended for the smoothest running and the highest power. With heavily testing at our rolling road as well as on the street we found the best balancing for a 172cc Malossi kit is 37.
    * The crankshaft cone of the drive side has been altered and is now a one-piece solution.
    The delivery does contain a 5mm spacer to equal the longer con rod. Anyway you should measure your squish clearance.

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    Product Nr.: BGM038026
    The bgm EVOLUTION 2 crankshafts are racing ones which are made to the highest standards.
    The crank webs as well as the con rod are forged. This gives a ultra reliable and hard wearing crankshaft.
    To achive the maximum weight possible with limitations of the crank web diameter, the crank webs were designed as full circle ones. So there is not the necessity for using plasic paddings to get it full circle. Does not look as bright and colourful but it is the technical more advanced solution.
    The full circle cranks do give a better filling of the cylinder thanks to the reduced space in the crankshaft casing.
    The bearing of the Evolution crank is top stuff as well. The SSC racing bearings do sustain the hardest revving engine setup. The twice slotted con rod with silver cage bearings at the big end and two holes for lubricating the small end bearing gives the best grade of reliability.
    The holes for balancing are filled with copper and alloy weights to get a ultra smooth running engine.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
    italjohn, Apr 9, 2009
    #26
  7. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    wiht the squish set wiht the spacer the bottom edge of the ports doesent go as low as the piston position at bdc.. meaning you have to grind the port's downwards to meet the piston, also as the stroke is increased the port timing and area is retarded (less % of the stroke than the original) for a 55 its 3mm drop and 1.5 raise on the exhaust, 3mm drop and 1mm raise on the transfers (altho the raise isnt necisasary and you CAN play wiht the primary/secondary timings to gain torque)

    the 105mm conrod is the stock lkength conrod meaning you only use the stock gasget and a 1.5 spacer... the 110 means you need a 5mm spacer aswell as a gasget and 1.5. the reason for this is conrod angle.. the throwdown angle on the 55 105mm is a litle wastefull on low rpm, the throwdown angle on the 110 (the angle the conrod sits across the big and small end bearing is 37 degtree's.. meaning you get more push on the crank as the conrod starts pushing more vertically on the crank for the same degree in rotation..... ive used one of these, not had chance to set it up.. rollers go WAY off the scale (still need to fiddle) and the primnary compression is decreased by the spacer area.

    hope that helps a little?
     
    MiNoR cOnFuSiOn, Apr 10, 2009
    #27
  8. nibbles

    nibbles Active Member

    Messages:
    2,169
    a little? A LOT
     
    nibbles, Apr 10, 2009
    #28
  9. nrgandy

    nrgandy New Member

    Messages:
    2,180
    i didnt realise that there was that much difference in the 110mm sounds quite interesting may have to get one of these built (would it be ok to run this one on the barrel i have abz's old one).
     
    nrgandy, Apr 10, 2009
    #29
  10. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    so in theory the 110 rod has the potential to make quite abit more power than the 105.

    mean piston speed will be higher though at the same rpm so less life for the piston and rings.

    yea?
     
    seanwhite06, Apr 10, 2009
    #30
  11. nibbles

    nibbles Active Member

    Messages:
    2,169
    its made for the job init coz his was a 183
     
    nibbles, Apr 11, 2009
    #31
  12. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    no the conrod's length wont affect piston speed... it will however change a few other factors....

    for one the big end has an easier time at the expense of more force on the small end bearing.. the piston speed is determend by the stroke alone not the conrod length.. also as its further from the big end the small end will be more likely to "wander" meaning slifghtly more piston side load..

    its swings and roundabouts. theres as many for's as there are against. means you CAN actually run diff b arrels with alot less fuckintg about port wise (the euro's have been using go cart/aprilia/powervalve barrels for a while now)

    the main advantage is the throwdown angle and the angle at wich the port opens. the bad point is the length means the piston is not held as well in the cylinder. also you loose compression.

    these are direct replacment for ANY 55 stroke crank. just make sure you run the 5mm ASWELL as the respective 1.5mm spacer and a gassget to set squish.
     
    MiNoR cOnFuSiOn, Apr 12, 2009
    #32
  13. italjohn

    italjohn Member

    Messages:
    531
    Rides:
    Runner 172
    Minor you are a walking lexical, very well explained.
    Thanks.
     
    italjohn, Apr 12, 2009
    #33
  14. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
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    et2 monster

    that is a complicated word to describe my responces.... flatterd all the same LOL
     
    MiNoR cOnFuSiOn, Apr 13, 2009
    #34
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