Stuck and dont know what to do next!

I have a runner 50sp 2012 which i have put new open filter, 24mm pwk flat slide carb with 110 main & 40 pilot), malossi reed block & petals, PM tuning Full circle crank, 70 MHR Rep kit, Yasuni C16 exhaust, Malossi variator, malossi belt, PM tuning clutch bell, hard Contra spring, Primary gear up kit.

It runs ok but when you pull away it doesnt accelerate properly until 20mph then pulls up to 66MPH onwards, revs round to 11,000 but if you back off then accelerate again it wont rev over 9,000 whatever you do.

I've talked to at least 4 different shops of which all have different opinions. One says its electrical and you need de restricted CDI to allow it to rev freely, another said it won't make a difference, another said you just blow the restricted CDI and you should get a £180 racing rotor kit and the other said it sounds like transmission problem. I have tried all variations of rollers from 2g to 8g, i have 5 different contra springs hard to soft which i have tried, clutch springs soft to hard still no difference.

I have even put all the original variator, belt and clutch bell back and still the same. Tried diffent carb and still the same symptoms. i even sent it to be dyno'd and looked at and they seemed to think it was electrical. Im at a loss now as i dont want to keep chucking money at it to find its still the same.

Anyone help?

 

the cdi usually has a pink wire, that would be a restrictor.
did you check the rollers for flat spots? other things to check would be the belt, for any signs of wear or loose threads. the variator, for any wear on the plates. it sounds to me like a transmission problem.

if a garage has checked over it they would have probably found these problems but alot of garages miss easy things due to pure lazyness. check the inlet manifold for a split/crack, replace plug, check air filter. it's not likely to be a carb based problem if it isn't bogging.

 

just come to think of it, if you reckon its electrical for definite, then trace it from the plug-ht lead-coil-stator using a multimeter, all should read 12v. unfortunately that's as far as my electrical knowledge goes, sorry bud

 

Everything i have put on is new! The roller, the belt, variator etc. Everything ive listed is new including the manifold. The only thing does makes me think it isnt transmission is it won't rev over 9,000 on the stand. If it was transmission i would of thought it would of revved over 9,000 on the stand as nothing is holding it back if there was something a miss with the transmission

 

The transmission will still work at the same rpms even if it's on the stand. Piaggio ignitions deffo aren't limited in any way though mate whoever told you they are just wanted to sell you stuff

 

I know the transmission would still do its job and roll up through the "gears" but with no load behind it, i though it would rev out to 10/11,000 revs.
Why do PM Tuning & Ped Parts sell de restricted CDI units if originals arent restricted and actually in the decription say that the original CDI units only rev to 9,000. I even spoke to Shiny Red Tuning and he said that the Original CDI is restricted

 

I've seem stock ones go up to and above 10k with my own eyes and stay there and pedparts say they're apparently restricted to 10k so even if they were yours still wouldn't stop at 9k lol? It's a waste of money honest

Surely all the roller and spring sizes can't be doing the same thing? Have you seen how the belt moves upwith the side cover off?

 

yep I've seen stock go 11.000 and beyond

 

This is a facebook message i got from Shiny Red Tuning today:

hi fella its defo the cdi ,i have seen it time and time again ,you need the doppler inner rotor ..i have a zip in the shop now with one fitted and the revs go up to 16 k lol if you need pics let me know and i willtag you
but thats 100 per cent your problem the cdi
shiny

Im getting more and more confused lol

 

i reckon, just to eliminate the possibilty, you should take off the gearup kit and put the standard gear back on.
what %increase is your gear up?

 

We did, we took the belt and malossi variator off and machined a spacer to hold the water pump belt pulley in place and ran just the flywheel basically and it still topped out at 9/10,000 revs

 

nearly all of the 50cc 2 stroke piaggio moped cdi's are restricted to 10,000rpm- normally this is not noticed even if you have say a sports 70 kit and a sports pipe because these setups run optimally at 9500rpm and only top out and limit at high speed when the variator is changed all the way out and can't hold at 9,500rpm any longer...
some cdi's are not restricted but this seems to be more that the restriction isn't working for some reason, the majority will not rev past 10,000-


you say that the bike will rev to 11,000 and run perfectly normally once you get past 20mph, is this definitely correct? if so your cdi is not restricted- if you're not sure buy a derestricted one anyway, they are only around £14 and your bike will need to be running at around 11k+ with your setup
there is no difference between the restricted and derestricted cdi's other than one will not rev past 10,000

it is perfectly normal for your bike not to rev properly on the stand with your setup, this is because there is no load on it- the engine (especially tuned ones) will only work properly when loaded (be careful, it can cause damage to high rev the engine without load!)
2-stroke motocross bikes for example do this on the stand- they just pop and bang and don't rev properly if you full throttle them with no load-

if your cdi is not restricting the revs, *and* the bike is running perfectly normally and well once you get past the 'dead spot' up to 20mph then it will almost certainly be a variator issue, your bike with a C16 makes very little power at low revs and if the variator is in any way worn or mis-spaced this is a common problem as the engine struggles to make enough power at low revs to 'pull' the variator through to the powerband
the symptoms where this is the case are the bike will not pull away (can often hold it back with your feet) until you reach approx 20mph- sometimes it is ok when the engine is cold for the first few minutes but gets much worse once the engine is warmed up- after this engine runs normally until the next time you drop below 20mph- sometimes it can be impossible to pull away once you stop on a hill
aerox standard variators are especially bad for this (particularly the newer ones) where a revvy pipe has been fitted and the subject is touched on here (click me)...
read from the paragraph starting ... "This graph is also interesting in that it shows insight into a problem...."

I would recommend to firstly be sure that the cdi is derestricted and that the bike really is able to revving to 11,000+...
next make sure that there is a variator spacer washer *behind* the front variator pulley (in the bit where the belt runs)- if this is missing it makes the belt ride up too high in the variator initially which affects the pull-away gearing- and can do exactly what you describe
once you are sure of the above two I would try a decent new aftermarket variator (or borrow one)... the Stage6 one is designed specifically for high revving bikes and is probably the safest bet for this circumstance (don't forget the spacer washer must be in the correct place!)- avoid polini hi-speed and standard variator with this setup, *usually* malossi is fine unless worn is mis-fitted
to prove if it's likely to be the variator you can try fitting a milder pipe temporarily which makes more power at lower revs to see if this makes a difference to the pull away

i can't say 100% this will fix things but these are by far the most common causes for what you describe- other than this no-one can really advise you without seeing the bike-

 

"hard Contra spring"
just noticed that- I would put a weaker spring on for now, e.g. the one which came with the malossi kit - you only really need a heavy spring for fine tuning or where the bike is so powerful the belt is starting to slip (massive screech) otherwise the higher pressure on the belt causes power loss through friction

who dynoed it ? can you post up or email the dyno graphs ? it should be possible to see easily from the graphs

 

Andy, thanks for all your helpful advice. We did virtually all what you have said Yesterday and it is now running well. I have put a De restricted CDI on it and we went down to the softest contra spring in the Moto Force set of 3 i bought. It is now running well. I may have to adjust rollers etc slightly as the revs are just slightly to high to early for me. Just need to bring them down a touch.

Thanks again