Sr50 2015 derestricted standard equipment advice required

Discussion in 'Newbie Scooter Tuning' started by GJ7RWT, Feb 10, 2017.

  1. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Thanks MC

    All makes good sense to me. I will put that plate back in over the weekend. By sounds of it there are many scoots out there with this plate removed for no good reason.

    I wonder if they could be re-sold as a performance enhancing mod to those without them . Could dress it up as something like "powerwave vortex inlet adapter" could make millions!

    Cheers
    Andy
     
  2. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    just get all the old plates of those younguns then charge them to re-fit them and tweek idle screw lol ;)

    yeah clocks dont say exactly whats true via gps , then again you cannot trust gps perfectly ( a decent gps will be down to a few meters , any others to a 10m radius ), only true way is by gatso - radar gunning them lol and by that time you know your in some poop lol. i will gps the sym tomorrow it reads 42mph flat out on the clocks , but then again its a tiawan scoot that 42 mph could mean anything lol
     
  3. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Ok so had a chance to look at the rollers this weekend. The scoot seemed to be hitting the fixed gearing early where the revs drop appreciably at a certain speed and then start rising again as the scoot gains speed. I mixed in 3 old 6.4 g with the 5.5g which seems to have helped level out the gearing so that the revs no longer drop too much before accelerating again.

    Now when warm the scoot runs very nicely. When riding off from cold though it misses (i can only liken it to a car with a high lift cam at low revs) for about 3 seconds before clearing itself and accelerating away properly. I tried disconnecting the automatic choke but the problem remained.

    Does anyone have anything to suggest. It's bugging the hell out of my son as many of his trips are short ones (living on an island all trips are short!)and to him it seems his scooter isn't running right. I must admit, when I've seen his mates scoots start off from cold, they do seem to run clean right from the start.

    Thanks in advance for any info. This thread has already been of great help to me

    Cheers
    Andy
     
  4. gilburton

    gilburton Active Member

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    558
    I was going to suggest the automatic choke until I saw you had already tried disconnecting it lol
    All the scooters I've had with an automatic choke have always done that. They "8 stroke" and it only lasts a few hundred yards before the scooter picks up and is away.
    Might I suggest either a manual choke conversion or start the scooter before getting your gear on which would allow a few extra seconds for it to warm up??
     
  5. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Thanks for your reply.

    I am glad it's not just my son's scoot that does this. I am not sure if going to a manual choke will do much as it suffers from this problem without the automatic choke connected.

    I am just wondering if it's more to do with the needle adjustment in the carb. Maybe someone has managed to cure this issue and will let me know or maybe i will just have to tell my son to be more patient and let the thing warm up before setting off

    Thanks for your help
     
  6. gilburton

    gilburton Active Member

    Messages:
    558
    When you say connected/disconnected do you mean just unplugged??
    If so you need to understand the choke is always on and extends after a few minutes running to cover off an extra drilling that allows the choke to enrichen the fuel mix.When the engine is off for any length of time the plunger retracts back i.e. opens ready for a cold start.
    If just disconnecting the electrics to the choke it will still be on.
    This might be why you are getting "similar" symptoms when disconnected but for different reasons.
    Take the choke off and put 12v across it from a battery and see if it's actually working although being a newish scooter it should be.
    A manual choke would enable you to turn it off a bit quicker than the electric choke.

    http://www.pedparts.co.uk/blog/automatic-choke-unit-50cc-mopeds
     
    Last edited: Mar 13, 2017
  7. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Ah ok that makes perfect sense. Yes i only disconnected the power so the choke was still in operation then. I am quite certain the choke is working as it should as the idle speed drops after about 3 minutes from cold start.

    I think my son is just going to have to put up with it! His ride to school every morning only takes about 2 minutes!

    Cheers
    Andy
     
  8. gilburton

    gilburton Active Member

    Messages:
    558
    Tell him to go the long way round lol
    I suppose it's to do with street cred but does he really need it for school? lol
    There are 2 types of choke conversion. One is just an on/off lever that sits on top of the choke and the other has a cable/knob which can be sited somewhere convenient eg under the nose of the seat or if the cable is long enough on the front apron.
    The cable one will have more control but the lever is just a flick on/off and can be awkward to get at.
     
  9. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    whats it like on throttle twang ?

    do you have this slight hesitation on the throttle when you twang it on stand once its warmed up ? if so i could be a slighlty outta tune idle/airscrew (idle/airscrew is the 0 throttle to 1/4 throttle area ). if its between 1/4 and 3/4 throttle its down to needle , depending on carb you maybe able to swap to a slightly differnet shaped needle ie going from an a24 to an a28 needle

    keep bike chained, start it up , take a wazz , gear up fully, go back out unlock scoot , stride it, now dont pull away just wait a couple mins while feathering throttle so idle rpms pick up a little and hold it there ( helps put heat into motor but not under load ) , once a min or so is up roll onto throttle slowly . have son leave 5-10 mins early than he does so he becomes used to warm ups.

    His mates bikes should be doing the same, not warming up is not ideal for the motor and is a quicker way to ring wear etc etc.
     
  10. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Hi Tamiya,

    Throttle twang is good when warm now that I've put the brass plate back in the inlet side of the carb and adjusted the idle air mix screw. It wasn't that great before i did that.

    Does seem a bit silly riding only 2 mins to school but all his mates have their scoots at school and go off for lunch break (dodgy pies and sausage rolls) every day so he needs it for that otherwise they run out of time to eat it!

    I will tell him to warm the scoot up first before screaming out the driveway full chat! I don't think they teach them about expansion and contraction and its effect on parts tolerance anymore. Maybe when the top end goes bang he will understand!

    Cheers
    Andy
     
  11. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Thanks Gil.

    I think the best way forward here is to get him to warm the scoot up first before screaming it down the road. I think there's something hardwired in to a 16 year olds brain that says lots of reving and noise is good and to hell with mechanical wear and tear!
     
  12. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    Yeah andy cannot be comming between dodge pies and sausage rolls lol .

    its like all young ones buddy, its the freedom to just jump on scoot and go , no hanging round for the taxi of mum and dad or waiting in the rain for a bus lol. come summer time when the heat stays in scoot most of the night he will notice its not to ragged , then when winter comes round again he will notice its raggy again , thats the point you step in and tell him warm bikes work , cold bikes play up ;)
     
  13. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    i would say 90% of top end rebuilds i do are from people who dont warm up their bikes.....
    the boggyness you describe will be slightly off mixture, you could try and correct it, or just leave it like that and get used to it, nothing to worry about either way
     
  14. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Thanks Scubabiker,

    Warmed it up this morning for 5 mins before he rode off. It was much better for doing that.

    Cheers
    Andy
     
  15. GJ7RWT

    GJ7RWT Member

    Messages:
    32
    Just an update on what's been done to my son's scoot.

    This morning i took the restrictor out of Tecnigas silent Pro and fitted a 62 main jet. The needle clip is still in the top position. The carb inlet plate has been refitted. Ricky at Pedparts was of great help suggesting what the best main jet was for the setup.

    The total weight of the rollers is just a smidgeon under 36 grams being made up of 5.5 and 6.4 gram rollers. The variator keeps the revs around 7.5k which is just about optimum for this exhaust (it could be a little higher for about a 0.2 bhp increase) but am happy with the compromise.

    The result of all this is a scoot that's runs flawlessly from cold start right through to top speed. I haven't got a GPS top speed yet but my son says the needle is off the clock on the flat. Going up a steepish hill has seen a rise of 10mph from how it was setup with the restrictor still in the exhaust.

    So my son is a happy bunny. Yes he won't be able to keep up with those of his mates with expansion exhausts but then again our neighbours will still be our friends in a years time.

    Oh and one last thing. I tried taking the rubber Venturi out of the air box where it connects to the air inlet hose that runs to the front of the bike. The scoot ran fine up to 30mph then just cut out. Presumably this was from the fuel/air mix being far too lean. This could however be the next stage of performance increase when incorporated with a much larger main jet size. Anyone tried doing this ?

    Cheers
    Andy
     
  16. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

    Messages:
    1,850
    Rides:
    Piaggio Skipper
    upto around 30mph then cut out, with rubber venturi removed .

    yes thats a to lean mix on the main jet , a couple more jumps up in main jet size and remove that venturi pipe should see gains. removing it on its own is showing that the main jet just cannot cope with that extra air flow.
    your silent pro is an expansion pipe its just hidden in the rear large can and is smaller than those on his mates bikes.

    good to hear he is hitting the max on clock and the hill climbs gained a 10mph extra ontop , wait till he is 17yr old then throw on a 70cc sport kit but dont tell his mates lol they will cry when is little scoot flys past them like a fighter jet lol, and make 125's look like pedal bikes from the lights upto his top end speed.
     

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