Lost 5 mph after adding new exhaust

[supermel74]

First post on this board but I've been reading it for awhile. Tons of great info here. Anyways, I added a Leo Vince TT exhaust plus yellow Leo Vince clutch springs and 4.3 gram weights. Before that, I was getting 47 mph top end. Now I'm getting around 41-42. My rpms went up from 7000 to 8000 and I'm keeping slightly better speed uphill than before but I can't afford to lose any top end. I was actually hoping to gain 3-5 mph but instead lost 5. Do I need heavier weights? If so, does anybody have a good rough estimate of what weight might work best the first time and a good place to buy? The scoot is an Adly with minarelli engine. Thanks.

[90GTVert]

:welcome:

You might wanna try your stock weights again, or are the 4.3s the stock weights? If you haven't already, I would suggest checking your spark plug after a WOT run to make sure you aren't running lean.

[supermel74]

Thanks. The 4.3 weights are what came with the pipe. I was thinking about putting the stock weights in and seeing what that does. I weighed them, probably not very accurately, and they seem to be around 7g. I'll have to break down and buy an impact wrench though. I had someone else put them in along with the springs. It seemed like it wanted to go but was being held back...

Edit: impact wrench has been ordered. www.harborfreight.com/1-2-half-inch-electric-impact-wrench-45252.html

[190mech]

Ya may need to do some carb tuning after a pipe installation also..

[90GTVert]

Don't forget that you can also combine weights to get a different result. If you use 3 4.3g and 3 7g weights staggered you can see what the result would be with 5.65g rollers.

[supermel74]

May 12, 2010 19:28:46 GMT -5 190mech said:

Ya may need to do some carb tuning after a pipe installation also..

I'm hoping not to have to because I'm a complete noob to all of this. I probably should have just stuck with the stock exhaust and left well enough alone.

[supermel74]

May 12, 2010 19:36:17 GMT -5 90GTVert said:

Don't forget that you can also combine weights to get a different result. If you use 3 4.3g and 3 7g weights staggered you can see what the result would be with 5.65g rollers.

Yeah, that gives a few more options in weight to try. Is it ok to leave 2 different sets of weights in or should they eventually be switched to all of the average weight?

[90GTVert]

It's important to check the tune because a lean spot can damage the engine. Start by making a pass at WOT and shutting off the ignition. You can't get a perfect read like a vehicle with a manual clutch, but if you brake the engine will die pretty quickly. Remove the spark plug and see if it indicates rich or lean.

It's OK to leave 2 different weights in.

[supermel74]

OK good to know. I"ll give that a whirl tomorrow. I'll take a pic of the plug too to get a more knowledgeable opinion than mine. :stumped:

[supermel74]

May 12, 2010 20:49:04 GMT -5 90GTVert said:

Start by making a pass at WOT and shutting off the ignition. .

I rev it to wot with the scoot on the center stand right?

[90GTVert]

Take it down the road so it's under load. Of course be safe and don't get a ticket.

[supermel74]

Ok, I need to drive it to where I can mess with it anyways. Not sure if I can bring it in without braking though, lol

[90GTVert]

Actually you need to brake for better results. WOT, hit the kill switch, brake quickly so the engine stops, check the plug.

[supermel74]

Ok thanks. I'll find a road out in the country where I can pull this off properly

[90GTVert]

I know it can be a bit of a pain, depending on your location, but it's worth it to know if your jetting is safe or not.