HONDA MELODY 50CC 1982 ATTEMPT TO TUNE!!

Discussion in 'General Tuning' started by GRUSSY, Apr 5, 2009.

  1. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Hi this is my first post, i'm currently restoring my 1982 honda melody. basically i'm wanting to try and make the thing go faster. I've heard myths about taking the washer out of the cvt etc. I want to know if i could possibly fit any heavier rollers etc.....any help would be great.
     
  2. Dec

    Dec Active Member

    Messages:
    3,183
    Rides:
    nothing ugm
    cue swifty boy with the 172 comments....
     
  3. Sw1fT

    Sw1fT Active Member

    Messages:
    2,940
    Rides:
    200SX S13
    ive played with these for a while actually, fact is, the engines were never fast, they just dont have the right parts as standard, the carb is tiny, the transmission is old and just about everything really is smaller/worse than the standard parts on a piaggio engine.

    if you really are intent on doing it, you need to properly understand everything, as the setups are quite weird on them. Best bet is whip the engine out and work on it, and as far as i know, the biggest restrictors are the exhaust, but even so, they dont go fast haha.

    have a poke about behind the variator (left side pulley under the case) and it might have a washer under there, it might not, it seems like honda didn't restrict them a lot of the time because they were just slow engines.
     
  4. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    engine transplant.... only way (that or spend thousands adapting parts to fit the engine casing... for it to be slower thanm a stock piaggio engine)

    whip the lump out, take a pic.. post it up and we can advise what engine has a similar mount position.. will probably mean some welding but it should be fun if you pull it off right.. maybe some zip forks for good messure
     
  5. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Ok the engine is out, took 15 mins lol. Got talking to a bloke at work and he mentioned raising the exhaust port by 1mm and chopping the front pipe and welding another exhaust system on... how do i post pics, i'm going to have a look been the variater but tbh in the haynes manual it doesnt show a washer
    CHeers
     
  6. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    everybody who thinks they have a clue will say "raise the exhaust 1mm" as it will prittymuch put gains on any stock barrel, also the expantion chamber will work, kind of, but again, its a big fat waste of time and will end up more expensive than just putting a better engine in there.

    plus WHEN the weak ass crank gives way you wont be finding a replacment this side of a chineese flee market
     
  7. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Right, the engine is fully in bits, quite a bit of carbon on the piston and on the head and combustion chamber etc. Stripped the variator down where the 6 rollers live. theres deffo no washer in there.. how do i post pics?
     
  8. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    well, it seems your completly ignoring advice and wish to further bodge this engine. good luck, you will need it, it will be lots of money adfapting parts for it and you will feel like an idiot once its built.

    have fun
     
  9. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Not at all but putting another engine in would also be more money. i only want the thing to commute to work on 3 mile down the road,was just after that extra few mph thats all. :tup:
     
  10. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    ok, but any tunning will mean a new crank VERRY son, a crank you wont find be it stock or aftermarket... but ye, find an expantion chamber and messure the stud distances for the barrel aswell as the skirt diameter and stroke. you may be able to fit somthing else to it ;)
     
  11. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Ok the engine is back in and running again after the decoke and polishing of the combustion chamber and ports etc. Can i fit any 50cc newish scooter expqnsion chamber to it? also thought about sticking a vision 80cc carb on. Would this make any difference? lol
     
  12. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    IF the engine can actually make use of it a bigger carb will make it faster... its wether there is a bottleneck through the inlet tract (small reedblock manifold or sheer engine design)

    like we said, there is NO pipe for this, you wont find somthing that just bolts on... EVERY tunning part you fit to this will need adapting. there are NO PARTS for these engines.. not even stock
     
  13. GRUSSY

    GRUSSY New Member

    Messages:
    42
    I would cut my front pipe off and then weld a suitable expansion chamber to my original fron pipe thus making a new exhaust, my question would be which pipe/expansion chamber would be suitable? A honda vision 80 carb will fit so i can try that as well.
    cheers
     
  14. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    well, you want a nice simple construction chamber (cheap) as the more expensive utalize bends so they fit a cartian bike, the cheaper ones use bent tube from identical expantion chambers similar to how you plan on doing it.. somthing off a gilera/piaggio/minereli will do aslong as its pritty straight.. you have the bike infront of you, look at it while crusing ebay.. somthing will seem right,

    the carb is a good option as is some sort of enlarged inlet (be it a BIG spacer and adapted reedblock) minerelli's have the largest of any 50 altho a piggy will work. wont be too hard to nock somthing up ether way, you seem plenty capable with your responces.

    sighn up to photobucket.com and upload some pics, can link them here an we can all see the butchery :D helps when sudgesting replacment parts too... id seriously look at ether a new lump or adapting a crank/cylinder from another.. its bearing holes and stud positions with the crank's overall length. any other factor can be eliminated with clever machining but again, its more work than its worth.
     
  15. GRUSSY

    GRUSSY New Member

    Messages:
    42
    OK thanks for your replys, had a play around with tuning the std carb today and the airfilter really restricts it. I took the airfilter off and raised the needle so that the clip was in the middle postion. the clip was originally second notch from the top. Then i screwed the pilot air screw all the way in then back out 1 full turn. In the manual the std setting is all the way in then 1 and a quater turns out. The engine now revs nicely but am i doing this correctly, i'm waiting on a new plug i'm ordered from ebay so i cant really check the colour just yet. Just dont want to seize the thing up! lol
     
  16. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Another thing i wanted to ask is will the transmission limit the top speed any way? I've left one of the rollers out which i need to weigh. so.... for example if i fitted a 80cc carb open air filter and bodge a expansion chamber will the thing go any faster?! surely its got to do more than 30mph, depending on the transmission etc
     
  17. kyle1b1

    kyle1b1 New Member

    Messages:
    5,191
    mate my advise wouls be put a new engine in.

    its an old engine !! things will be worn and tuning reduces component life so things will start to go and with no replacements going to run into problems fast !

    will be cheaper, simpler to fit a new engine.

    such as a piaggio 50/70 or even 125/172 ac engine

    will have unlimited spares, will be quciker, more reliable is just WIN !
     
  18. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    top speed is dependant on 2 things, power and gearing....

    the top speed is basicly the engine rpm times by the increase in ratio of rotation between the variator and rear pulley minus the reduction throughout the gear's.... the rollers just time when the engine progresses through the range of ratio's the p[ulley can produce. to gain more top speed you first have to max the variator ramp (mark wiht pen, take it for a ride, see if both pulleys are rubbed CLEAN, if not go lighter or heavier on the rollers bearing in mind rpm, if you still cant you need to respace the variator or alter the belt length) if you are hiting the top of the clutch pulley and the revs/acceleration are constat you need to increase the gearing/fit a bigger rear wheel

    putting heavier rollers in for more top end is a MYTH people just dont understand what there talking about and misconstrue what there told

    too heavy and it will affect acceleration, too light and it will kill off top speed. NOT the other way round. no rollers means no weight meaning no drive.. useless.. also too heavy and it will hold the revs back not leting the scoot hit its powerband (rpm the cylinder/pipe produce peak power) id be sorting an expantion chamber, you want the scoot making its power high up, trim the rollers so it sits on the happy rpm spot and pulls well... then see about increased gearing.. your already geting carried away tho as the engine wont take a bigger wheel, mabey a tyre, you cant buy gears, you wont find belts that easily and you DEFFO wont find variators/clutches when you mangle/burn them out...


    so, expantion chamber, THEN nset roller weight as per the roler guide in the guide section THEN start dreaming about gear ups you wont be able to buy for your obcolete engine...



    HONESTLY. get a pic of the fuckin engine, somone will probably have somthing similar you can HAVE
     
  19. capri dave

    capri dave Active Member

    Messages:
    5,076
    if youve removed a very restrictive air box/filter, then the air fuel mixture will be much weaker,

    raising the needle and richening the idle mix is a good move, but i would bet 50 pence on the
    main jet being too small now ;)

    As minor has suggested, go through the whole inlet tract, carb to engine, if there is any part of it that isnt as big as the venturi in the carb, then that could be a potential bottle neck/restriction...some scooters have very restrictive inlet manifolds, like the speedfight for example, and a lot of people try to bolt bigger carbs to these, not realising its the manifold that needs changing as well :D
     
  20. GRUSSY

    GRUSSY New Member

    Messages:
    42
    Dave, i did think about changing the main jet but its pressed into the carb body and other replacements aren't really available, the reed block looks quite large, i havent checked the inlet manifold yet... if i lift the needle to the highest postion do you think that will be ok, or will i still have problems with a weak mixture. I'lve got my eye on a few expansion chambers on ebay at the mo.. Whats the best way of tuning it so that i get the mixture spot on, keep checking the plug? i'll have to take the screw driver out with me and play around i guess. its all good fun!
     

Share This Page