Sr50 2015 derestricted standard equipment advice required

Hello,

I am posting this on behalf of my son who bought a 2015 SR50 in the belief it was still restricted. He is no mechanic but I have some experience with car tuning. I found a bag of parts under the seat with the carb restrictor plate, rollers and vari washer !!!!!!!
So clearly the previous owner had the scooter derestricted but didn't tell his parents .

Now we live on an island with a max speed limit of 40mph with the majority of roads being a 30mph limit. He is having difficulty keeping up with his mates on acceleration. I am assuming the rollers that have been fitted are still too heavy to give the best acceleration. What weight should go down to bearing in mind we do not need a high top end speed?

Also is it ok to run the scooter on the original jetting. I haven't looked at the spark plug yet as I only just found all the restriction bits under his seat.

Any advice would be most welcome. Please be gentle, I am a total newbie to this scooter thing.

Cheers
Andy

 

The thing you need to do is find out what weight you already have in there first and work down from there.
It sounds like the engine is not getting into the powerband enough before it takes off.
This can be adjusted by either:
Lighter rollers
Stiffer clutch slipper springs
Stiffer Torque Spring
Shim washer between the variator fixed plate and centre boss

What you dont want is the engine revving it's nuts off just to keep it moving, so it's a fine balance between everything.

Does the bike have the standard exhaust or sports exhaust?

A sports exhaust will mean that the carb will need re-jetting to suit the pipe. Might be that it hasn't been done.

More info on the bike and what it has on please

 

Hi Stevep

Thanks for your reply.
The exhaust is standard and so is the rest of the scooter from what I can tell. I have ordered the locking tool to get to the rollers so can't offer any more info till that comes down. I don't have accurate scales but it looks like they were 6.4 grms that were removed. My guess is the new rollers still weren't light enough. From what I've seen the clutch engagement comes in with a bit of a kick, I am not sure if this offers a clue as to what's going on?

Like I say, I am total newbie to scooters so am still trying to get to grips with everything that's going on under that engine/drivetrain cover. Being the youngest in my year at school, by the time I could get a scooter my mates were getting cars so I never took the plunge myself.

Hope this limited info helps.

Cheers
Andy

 

OK.
Still need to know what rollers are in there before guessing what to try next. It may not be the rollers at all.
With the standard exhaust on, it should have the standard jetting in the carb. However, saying that, if the brass plate has been removed from the back of the carb, then it will be getting more air anyway now, so could well need an upjet of two sizes maybe.
You've come into the realm of tuning now by the way, it's a nightmare on 2 wheel street.

 

Indeed Steve.

That said, it all seems a little bit more manageable than car stuff. Still, it's a steep learning curve. As soon as I have the current roller details I will post back on this thread. It may be a week or so depending on how long it takes to get that locking tool down.


Cheers for now
Andy

 

Where abouts in the world are you Andy?

 

Jersey

 

I'll be in Guernsey beginning of July, sunday 2nd, I believe the ferry is stopping at jersey on its way to St malo.

 

It's a small world! Are you holidaying in Guernsey or business? I think the highest speed limit in Guernsey is 30mph. Leave the rollers out all together !

 

For what its worth,
The restricted models have a slightly smaller main jet than the full power models (i think sveits have no restriction laws?).
Its fairly normal the factory tune down the carbs on restricted models.
Welcome to the never ending world of scooter maintenance..

 

Thanks Scubabiker,

I am hoping it will be a simple change in rollers that are required but things do point to an upping in jet size from what I've gathered so far. Will have to watch a few videos on YouTube to find out what's involved!

Cheers
Andy

 

its quite easy, plop the carb off, remove the float bowl, and the main jet is in the middle. normally the full power models have around 2-5 sizes bigger (ei 72 or 75 instead of 70)
and you will also learn why i hate piaggios....

 

have a look at the exhaust , dont need to take it off just get down on the knees.

about 1/4 to around 1/2 the way from the engine manifold to the rear muffler , they tend to add a restrictor , its a short tube thats usually sealed at one end, it robs the exhuast of a healthy back pressure wave on two strokes and acts as a third/fourth restriction, its robbing power the exhaust creates.
to get the power back ( done this on a peugeot) you cut off the short restriction pipe and either weld it up so its sealed, or flatten the stub and fold and crimp it sealed.

with the stock exhaust the motor makes its powerband at the low end of the rpm range , but as the rpm builds the powerbands spread ( where the exhaust produces its max hp) is exceeded and the horsepower drops away .

the attachment shows how a SR 50 R exhaust used to be restricted before they started using internal restriction baffles and washering.

 

Thanks Tamiyacowboy for the advice. I will take a look when he gets back to see if we have this extra pipe on his.

Cheers
Andy

 

your welcome Andy , i think you may find your exhaust is going to be the newer type with restrictions inside it.

if your son is going to keep the scooter (ie not grab a 125cc when he hits 17yr old) you may just want to swap out the stock exhaust for a sports type exhaust, there are pipes on the market that look just like a stock factory fitted exhaust but give the scooter that extra kick your sons looking for.

and if he gets bored, scooters are awesome machines for us older folks to mess around on nipping to the shops etc etc and cheap to on the fuel side and parking lol , no need to pay and display just pull up get off and do your thing

 

The std main jet will probably be a 53 or 56, up it to a 58 or 60, start big and work down on jetting.

 

Start of the holiday.
We have a friend who lives on the island so we are having a couple of days there before he joins us, going on to St Malo and through france, netherlands, luxembourg, back through france and back home.
12 night, 13 day trip this year for 7 bikes.

I'll wave as we get into the port

 

Sounds like a nice trip Steve. Hope the boat doesn't suffer any delays. There's been a fair bit of controversy over wether the ship is suitable for the route it's on. It keeps breaking down !

 

Just took a look at the exhaust and it's the type with 2 crimped branches. Can't be good! Had a look just now at the tecnigas pro sport which says its quiet but provides a good increase in mid/upper range. Sounds like a good candidate? Any experience with these?

Cheers
Andy