Need help with r50 and prima exhaust

Kdrags830 · Post by **Kdrags830** » Mon Mar 14, 2016 2:10 am

Hi. I need some help. I just had a stage 1 prima kit installed on my roughhouse 50. Its has 405 miles and I had the dealer put on a prima exhaust, 5g rollers, 1000 rpm spring and it was supposedly rejetted. I love the top end on it but the bottom end is god awful. Basically it is unrideable in my opinion. From a dead stop when I hit the throttle this thing bogs soooooo bad it cant get out of its own way. The dealer said there wasnt much they could do but i find this hard to believe. I do bo want to bring it back to this dealer because they just didnt seem confident on explaining to me why there is such a low end bog. Basically told me thats how its is but they also said it was the first time they ever did such a kit. Could it be a jetting issue? It seems everyone else with this set up is happy except me. Thanks for any replies!

RoaringTodd · Post by **RoaringTodd** » Mon Mar 14, 2016 10:54 am

Your dealer sucks!

dasscooter · Post by **dasscooter** » Mon Mar 14, 2016 3:31 pm

Yeah, dealers are awful! You know, that whole usually going out of their way to try and help you out thing. Just awful!

But yeah, the Prima pipe basically won't work unless you have a big bore kit or really spend some time tuning/airbox mods/jetting/bigger carb. It might have a chance with 2000rpm clutch springs but I haven't personally tried.

FreeDivr · Post by **FreeDivr** » Mon Mar 14, 2016 9:27 pm

This exhaust was mentioned in another thread by ATony:
(http://www.scooterworks.com/performance ... quf8tIrIdU).

Perhaps getting a refund on the prima and trying this exhaust?

FromHereToThere · Post by **FromHereToThere** » Mon Mar 14, 2016 10:26 pm

Just a guess.........the jet is too big. Too rich?

Go over to ModernVespa and ask. It is an active site and they would love to look really smart. Seriously, someone over there can probably help.

RoaringTodd · Post by **RoaringTodd** » Tue Mar 15, 2016 10:53 am

dasscooter wrote:Yeah, dealers are awful! You know, that whole usually going out of their way to try and help you out thing. Just awful!

A dealer that would install a part and not know what he/she is doing has no business being a dealer. I can understand if this was an individual helping another individual, but if a dealer sells a part, installs it, and then says "sorry.. I don't know what I'm doing, you're on your own" is a jerk in my book.

lovemysan · Post by **lovemysan** » Wed Mar 16, 2016 2:56 pm

It sounds to me like the idle mixture is not adjusted correctly. On my roughhouse I had to remove a welch plug to uncover the screw so I could adjust it. At least thats what I think I remember. First find the screw, you may need to remove the seat bucket. Don't bother bolting it down between adjustments. I hardly ever bolt them in actually. Next locate the mixture screw I'm pointing at with the pencil. The picture is taken standing on the kick stand side. If there is a welch plug( brass plug cover) you'll have to remove it using: try a dental pic and spin it. I was able to work mine out by rocking back and forth. If that doesn't work try a dremel or small drill bit. Drill a whole and using a hook pic or something like it pull it out. Discard it because you don't need it. Now turn the newly exposed screw clockwise until it seats, gentle pressure only. Count the number of turns in and write down the factory setting. Return the screw to factory setting. Now start the bike and warm it up and or ride it around. You cannot adjust the mixture until the bike is at full operating temperature. We want to adjust the mixture screw till you have the fastest idle speed possible. There will be a spot in the middle of the adjustment where its near optimal, you will notice a slight movement in either direction that doesn't have any effect. The rule of thumb is you locate the middle of this "zone" and then set the screw and additional 1/8 to 1/4 richer.

Okay I assume your bike is set lean because mine was as well. Start by turning the screw 1/4 turn counterclockwise at time (this richens the mixture). The idle should increase in speed. Find the maximum idle speed add an additional 1/8 turn richer and go for a test ride.

This is good video on the theory of adjustment allthough he's adjusting an air screw in this video and not a fuel screw which means the settings are inverted. But the process of listening for response is the same.
https://www.youtube.com/watch?v=A1vRMERs4RQ