NRG spark plug damage question

Hi folks well , i thought i help my govners son out buy checking his nrg out needed new rollers so easy i thought pulled em out weighed em 5.5 grams so he has to get some,
fresh ones as there sqared off a bit, so cleans em up with wet dry slings it back together,also
needs new belt as its cracked. Put it all back together for him and pulled the plug was badly coked not oily just old (br9es) heres where it went to shit had spare speedfight 100 plug, br8es (new) put that in and sent him on his way. GOOD DEED for the day boss happy and his boy he rings me this am scoots NOW U/S!!! feck i thought what did i forget to do?? Turns out plastic fan had migrated and started to chew up and variator nut was,nt fully home so spline damage? Any hows i pulls it apart cleans the spines up with needle file reasembled it with torque wrench 52nm,s and thread lock all good i thinks he only did 1/2 a mile before the thing came loose so lucky there. On Piagios recommendation new variator nut each time its off? oK fair enough but i rode the scoot and its soooo slow now and does,nt accelerate smooth @ all speeds up an down revs fine upto 5k then engauges drive upto 30 ish but it did 40 odd before my question is have i damaged the piston due to hotter plug for few miles??? Anyone else done this the br8es was only in for 5-6 miles i know it was wrong one but should a been ok for a bit? iM not to confident tha tits ok +8

 

ive used a br8es loads of times (got one in now) in my bike and never had any problems.. it will run hotter though.. and i never keep them in for long. i wouldnt think it would darmage the piston from 5-6 miles cratch:
try some new rollers in it before anything if they were squared

 

Yes seems a little coincidental that now after i cleaned the rollers which were squared that the speed control is erratic,? Just worried about the hot plug but on ly in for few miles,Thanks for the heads up.

 

When you changed the rollers did you take off the clutch side too? You probably didn't pinch the belt to make it slack when putting it back on making the nut come off, I've typed this so many times there should be a button for it.

 

jefro's got it ^^^ :good:

before you tighten the variator next time, push the belt down the rear pulley a bit to create
some slack at the front, what your doing is trapping the drive belt between the 2 variator halves, the nut appears tight, then when the bosses son rides off the belt moves up the variator and the nut is no longer tight

its a common thing, so obvious when you realise whats happening, but most people fall for it...

 

Feck yo boys are a tonic really you are! Thats exactly the thing I did not have, enough slack @ front,1st time and when it was driven up it worked loose and variator front pully came loose.I have refitted it since with slack and the crank threads now show through the nut as per torqued up to book spec. But then i also have riden it since too and the thing picks up crap once upto 30+ it holds off so if you feather the throttle it sort of picks up but poor. New rollers 6grm on order and belt so fingers crossed for next strip and fit. The ramps on the std variator were,nt lipped or badly worn but hey what do i know, its only done 7k rebuilt after 6.5k arrow pipe, ect.

 

Easy mistake, basically:

[youtube]http://www.youtube.com/watch?gl=GB&hl=en-GB&v=hjCzXf2GIaQ&feature=channel_page[/youtube]

 

Re: NRG plug damage question nooo power now?

Right folks just fitted new plug gapped @ .6 new belt and rollers Pm, tuning supplied 6 grams. So all fitted as per book But the little pastic, fan on variator was damaged so fins are quite mullerd now is this really important?? What is the purpose apart from cooling? whats it cool? belts maybe just a question there.
Next thing is since i fitted the slightly hotter plug br8es , only did few miles,breifly rather than nine, its crap from cold first ride it revs nice not jerky rollers not BUT!!! LOOSES POWER no revs no pull it just tails off, the compression test was poor? 50-55 psi cold no better when Hot is this usual? seems low as im used to four stroke 160psi per pot?? Again this s the Gov,s son,s scoot so any help will be greatly apprecited guys.Is it coincidence that now theres a problem had motor build less than 2 k ago?

 

normally if the power falls away as the road speed increases, its normally too heavy rollers...but
the compression seems low, i think its supposed to be around 100 psi...maybe the rings are a little tired, or the barrels scored up, i know the scooter hasnt done mega mileage, but these kids often run them on 99p lawn mower oil or forget to top up the tank at all if its a choice between buying puff or oil :mrgreen:

 

Well before i changed the rollers this am, it was same but just jolty and failed too accellerate smoothly, So not rollers as there now new and its smoother than before but looses power as you warm up inital drive is as per normal accels quite briskly then tails off as heat of motor increases??? Im sure comp is low too going round after work tomorow am and do another comp check and pull the head off. The oil putoline as i recommended it good stuff in my eyes never run low either he,s quite a savvy young lad just pee,d off that its now goosed.

 

Well did a wet comp tests this am with throttle wide open managed 60 psi so rings are worn for sure!!!! Pulle the head of this a/c cooled nrg? No head gasket weird never seen that before metal to metal,cylinder not scored or damaged either so orderd new piston kit today and will Hone and rebuild it asap. And re comp test for comparison will update for just for info,s sake.

 

get a gasket set 2 it should have gaskets this could be the problem who rebuilt the engine and dont hone the barrel either theres thin nikasil lining which honing will remove

 

you can hone iron barrels out, only ally barrels are nikasil lined

but i agree about the gasket issue

 

Well agree with dave all the Iron blocks ive ever bored/honed are all still good it is defo just the ally nikasel lined ones that don,t hone well. The head gasket issue is a weird one as theres no rebate for an o-ring and no evidence of a thin metal one either just machine finished head and barrel(blocK) So will contact Piaggio direct on that. I have orderd polini std gasket set so will see what it brings. As im sure the squish will be way to high comp without a gasket. hock:

 

its not an o ring its like a bit of paper or thin card and im pretty sure this is where your loosing compression

 

Sorry fella NOT talking about cylinder base, gasket here yes there NORMALLY! paper or fibre type granted there. But im talking head gasket these are allways usually ,on a/c metal alloy type (soft)7074 alloy or water cooled O-ringed type. The Nrg im working on had neither fitted??? Just odd to see this called the gent who rebuilt the motor last 5k ago and he said if it came in like that it went out like that well im not happy with that answer @ all. Very odd not to have any head gasket @ all? Well how do you get any compression and or correct squish with no gasket,even if its torqued down with correct figures and the faces of head-too cylinder are sqaure and flat i fear it may still leak proof in the pudding i will be rebuilding the top end one the parts are here and we will see how it compares with new rings, :eh:

 

oh im with you well a way i accidentaly found to check this when i had my kit put on and i had forgotten to put the rubber o ring on when i moved the crank round using the kickstart i could hear air leaking so stick a plug in to block of the hole and move the kickstart down slowly and im pretty sure youd hear air escaping as metal on metal doesnt make for an airtight seal suprising that theres no groove for it to fit in...r u sure?
my knowledge is only in the 125 head...which has 1 and 172 which also has 1 and im pretty sure in evry 70 kit you see on internet shops you can see the groove for it so id assume one should be there...odd that it isnt any way have a go at the what i said just move the kickstart lever down very slowly

 

Well there is no rebate for an o ring as its aircooled only water cooled have o-rings, so im going to take pics and post them to show what i mean am sure the zip models same motor ish!! the gasket set supplied has metal base gasket- exhaust gasket and couple of small o-rings thats it for top end kit? Suprised yes non the wiser yet won,t get to spanner it until wed am so will update then.Just spoke to piaggio dealer No head gasket fitted to aircooled nrg.s well 2007 model anyways. So will make sure that the heads flat and cast cyclinder with engineers blue to show high spots if any and some fine wet dry/+ (flat plate) or glass . watch this space. :amen:

 

Well just spent last day off top end rebuild on the Nrg heap (2007)aircooled fault was i took variator off to weigh the rollers to help out govnors son well the front vairiator outer pully had come loose so had to refit that with correct torques 52nm and tread locked. ANY way this things been running shit since? no power now runs ok for first pull off new rollers fitted 6grms new belt carb clear all lines ok,top end new,s i can only get 50psi compression? even after rebuild all new gaskets before you ask all torqued as per book, its weird am i missing something. HOW MUCH COMP DO THEY HAVE? As im only getting 50 ish maybe crank seals i don,t know really stumped now its only done 5k since full crankup rebuild 9k total.iTS std bore too with std piston maybe its due oversize on the cylinder guess i will have to strip check again.
HELP cratch:

 

Well cylinder off to BDK race enginnering for .5mm oversize and piston kit then we will try for more comp than 50 psi on the refit of cylinder.With regards the variator the outer pulley with starter gear is slightly out of round WOULD!!!! this cause speed control problem and or also the inner pulley alloy one with the variator rollers ect, this has wear marks on it too when the belts been sitting i guess at certain speeds,only few thou lip doe this also cause agro with speed control. Just asking really.