Sr50 2015 derestricted standard equipment advice required

Sorry it's the tecnigas silent Pro exhaust I've seen on a website

 

Thanks Marsh for the advice. I think my son might start getting a bit worried when he sees his scooter in bits on the drive

 

Ah if its like the one i posted it can be derestricted .

but the silent pro is ok to its a more stock looking pipe so mr policemen wont be so interested in the scooter if he is pulled over. a little less noise and a little extra power.

i run the technigas trek with a full derestricion to it , its a little louder but boy its got a nice powerband spread 30mph upwards the scooter flys , 0-30 the scooter is nice and sensible , hill climbs 25-30mph

 

Better not bleedin' break down!
We're late enough getting to france, not particularly fond of late dinners.
Technigas are decent pipes, just don't get the chrome ones. Rusty in 3 months. Better to have self colour and use VHT black rattle can paint.

 

Here is an interesting graph showing a standard pipe versus various other pipes. The silent Pro looks like a good bet. I know the rollers have been changed (surely for lighter ones) which I think I am right in thinking moves the revs higher for a given speed. So that would fit with what my son says, acceleration is a bit lacking as with a standard pipe the power starts declining after 6000rpm. If with the rollers fitted his motor is running closer to 7000 he will have a power disadvantage. If my theory is incorrect here then please let me know.

My thoughts are that the silent Pro will be more forgiving if everything isn't matched perfectly. I am about 95 percent committed to purchasing one as it's an easy bolt on job.

Hope the file uploads ok

 

Found that on ped parts?
Useful innit

 

if you willing pop on a technigas trek , this will give you a really forgiving powerband spread, so even if he went with heavyer rollers it would still do ok.
the trek pipe powerband spread is from around 8000 rpm to 9000rpm , so as the motor builds its rpm the pipes soon going to kick in and deliver that kapow punch .

at the mo your stock pipe holds you back due to its tuned for low rpm so at around 6000rpm its at its optimal and above its falling away , so if he is producing lets say 3.4hp now @ 6500 rpm when the bike starts to rev higher the HP will drop down to around 3hp. with a propper sport pipe like a technigas triops / trek that base 3.4hp its gonna shoot up to around 5.8hp.

throw on a malossi multivar hi speed variator his little scoots going to top out somewhere between 45-50mph flat out on the rpm ( he going to be hitting around 9000+rpm or just shy )

heres a couple attachments showing whats possible and another putting the sleint pro up against sport pipes the slient pro makes just over 5hp at around 8600rpm ...... but if we look at the trek pipe its producing a max hp of around 9hp but this is with a 70cc barrel, so a standard 50cc barrel your looking close to 6hp maybe 6.05 hp and its operating around the same rpm and a little higher than where the silent pro hits its max

 

Yup! Very handy comparison. Lots of very useful info on their site. I've learnt a lot from it in a short space of time.

 

Hi Marsh,

I am just about to buy a set of main jets for the 17.5 phva. Are they the 5 or 6 mm ones I need? I think the sizes run from 50-70 so that should be well within the range I need as I am going with the tecnigas silent Pro.

Cheers
Andy

 

6mm, start with the biggest jet and work down in size until it work's !

 

Thanks Marsh. Sounds drastic going from a mid 50 (apparently) to a 70 but hey I am brand new to this so I will do as you say

Looks a right pain in the ass to get these jets changed. Carb off probably, lots of clips, hoses etc. Access not great heh

 

Also found in the bag with the rollers and inlet baffle was this rubber pipe. Anyone know what it's for?

Cheers
Andy

 

I've been trying to find a definitive answer on the interweb as to whether that inlet baffle between the air box and carb should be left in it not. Never before has one little piece of brass caused such differing opinion!

Some say it's not a restrictor at all and it's there to create a better mix of air/fuel at low revs whilst others say it should only be taken out on 70cc engines. Looks like the majority say it's a restrictor and needs to come out no matter what.

Whats the opinion of my learned friends on this forum?

Cheers
Andy

 

Yeah, that brass plate has caused a lot of opinions to be voiced.
It acts as a restrictor to the airflow into the carb.
Technically, if you remove the plate, you would probably have to up-jet at least one size anyway to compensate for the increased air flow.
If you're tuning the bike, fitting 70 kit's, exhausts and stuff, then remove it; you are going to re-jet the carb to suit everything else anyway, and the better the airflow, the better the bike will run.
I personally have not had a problem with removing these brass plates

 

Cheers Steve,

I've got some bits arriving any day so hopefully I will be able to take a look over the weekend to see what's in there at the moment with regards rollers and jets. All good fun !

Cheers Andy

 

OK so the latest is the Tecnigas silent Pro exhaust has been fitted which has improved acceleration considerabley. The lighter rollers that were fitted by the previous owner couldn't have suited the stock restricted exhaust.
The main jet fitted was a 64. With the tecnigas exhaust it was running just on the leaner side of perfect so I upped it to a 65 to be on the safe side. I have yet to pull the plug to see how the 65 is doing but the scooter certainly runs well according to my son who is now able to keep up with the rest of his mates!

I haven't looked at the rollers. As the scooter is doing what it should do now there seemed little point. The silent Pro has a wide power band so the weights aren't too critical. Also, I don't have an accurate enough set of scales to measure tenths of grams.

So I think we are there now. Thanks for all the advice from everyone. My initial guess that it was a problem with the rollers was wrong (it was more a case of wrong exhaust for the rollers fitted)

Cheers
Andy

 

Thanks MC for th detailed reply.

That brass baffle plate on the inlet certainly devides opinion! So if if put it back in, theoretically the jetting shouldn't need to be changed as the amount of air entering is still limited by the carb throat and not the total size of holes in the baffle plate? I checked the plug yesterday and it's a nice dark coffee colour without the baffle so hopefully putting the plate back in won't upset that?

I think we could still go lower on roller weight as the revs do drop a but on the hills according to my son. I got him to carry a small GPS unit on Saturday to check the accuracy of his speedometer. The speedometer was showing 50mph whilst the GPS showed 44mph. I am not sure if the scooter was still accelerating at this point or if it had run out of chuff? As you can most probably tell, I don't actually ride this scooter!

Thanks for your help.

Cheers
Andy

 

Why do the put that plate in? I am pretty sure full power models (switzerland) have it, maybe its an emmissions thing?