Rear Brake Problem

rickyd410 · Post by **rickyd410** » Wed Sep 13, 2006 2:04 pm

Has anyone experienced uneven braking from the rear brake?

Like if I hold it down coming to a stop, I get jerked front to back because the brake only seems to catch at certain times. But it's rythmic, like it happens at the same point on the wheel/brake every rotation.

MNBuddy · Post by **MNBuddy** » Wed Sep 13, 2006 4:11 pm

Not I. No braking trouble so far!!

MrNatural · Post by **MrNatural** » Wed Sep 13, 2006 4:14 pm

Absolutely!!! Very rough when breaking w/rear only. Was going to ask about that when I get to the shop.

vitaminC · Post by **vitaminC** » Wed Sep 13, 2006 4:18 pm

How much free-play do you have in your lever? If it's more than when new, try adjusting the cable (there is an adjuster located at the rear brake). The cables are all new and will stretch a bit initially, requiring an adjustment. Then, over time they will continue to stretch a bit, so further adjustments may be needed down the road...

rickyd410 · Post by **rickyd410** » Wed Sep 13, 2006 4:42 pm

Okay, so I talked to someone at the shop, and he said I need twist the adjustment on the rear tire a few times to tighten the brake. He was pretty sure that'd take care of it.

I'll let you know after I make the adjustment tonight.

DO3 · Post by **DO3** » Wed Sep 13, 2006 8:26 pm

Mine is the same way with only 160 miles on it. I'll check out the cable as well.

rickyd410 · Post by **rickyd410** » Thu Sep 14, 2006 12:34 am

Ok. So I tightened that bolt near the rear wheel. It did tighten up the brake, which needed to be happen, however, I'm still getting the jerking motion when I brake using that rear brake.

Did you guys/gals have any luck tightening yours and fixing the problem?

Keys · Post by **Keys** » Thu Sep 14, 2006 6:52 pm

More than likely, you have slightly irregularly shaped brake shoes. It's possible the drum is out of round, but unlikely. There is a way to check, but it's pretty involved. If you are mechanically inclined, I'd be happy to walk you through it...if not, I recommend you have the dealer check.

Also, bear in mind that over 70% of your stopping power is on the front wheel. I know, people think that they will toss themselves over the handlebars, but again...highly unlikely. It's like this; you have maybe 1 to 1 1/2 square inches of rubber on the pavement with these tires. You have 300 to 400 pounds of rider and scooter moving along. More than likely, if you (unwisely) lock up the front, it'll just skid. Recommendation: start your stop with a light rear brake followed by BOTH front and rear application. Front alone or rear alone is NOT recommended. When I was training to roadrace motorcycles, they FORBADE us to use the rear.

--Keys

rickyd410 · Post by **rickyd410** » Thu Sep 14, 2006 6:58 pm

Hey Keys, is a irregular brake drum expensive? Although, I guess it'd be covered under the warranty.

What's involved with checking it myself? I'm going to be at a friends house this weekend who IS mechanically inclined, so maybe I can relay the info you tell me , to him.

Any advice would be helpful.

Thanks Keys.

thepickupbear · Post by **thepickupbear** » Thu Sep 14, 2006 7:00 pm

In regards to brakes, I didn't really feel like this warranted its own thread...but at idle at a stoplight or what not, does anyone else notice that squeezing the front brake changes the idle?

i know a little bit about engines, but not a lot...I'm guess it has to do with wiring and the automatic transmission? gearing down as brakes are applied? just curious....trying to learn as much about these scoot engines as I can

vitaminC · Post by **vitaminC** » Thu Sep 14, 2006 7:28 pm

thepickupbear wrote:In regards to brakes, I didn't really feel like this warranted its own thread...but at idle at a stoplight or what not, does anyone else notice that squeezing the front brake changes the idle?

I don't think it's changing the idle, it's just reduces the vibration, as with the brakes applied the bike as whole can't move as much. If you squeeze front and back while stopped, it makes it even smoother!

i know a little bit about engines, but not a lot...I'm guess it has to do with wiring and the automatic transmission? gearing down as brakes are applied? just curious....trying to learn as much about these scoot engines as I can

If you're stopped, then the engine is not actualy connected to the driveline. I believe these have a centrifugal clutch, so as the engine spins up is starts spinning the belts that make it go. And there are no stepped gears (1st, 2nd, etc) in the tranny, as it's a CVT (continuously variable transmission), which is why the rev's stay pretty constant as you accelerate.

thepickupbear · Post by **thepickupbear** » Thu Sep 14, 2006 7:31 pm

Neat! Thank you for the info, I will start reading up on CVTs. I'm curious about the vibration thing.

Keys · Post by **Keys** » Fri Sep 15, 2006 9:59 pm

Okay, Ricky, you asked for it.... Start by removing the exhaust (just because it's in the way). With the scooter on the center stand, remove the rear wheel. Using chalk (your basic color-on-the-sidewalk-because-mom's-not-watching type of chalk), coat the wide part of the brake shoes...the part that presses against the drum. Put the wheel back on. Turning the wheel, lightly apply the rear brake so it drags. Remove the wheel. Inspect the shoes. The chalk should be uniformly scraped from the shoes by the drum. If it ISN'T uniformly scraped away, this indicated an irregularity in one of the surfaces. More than likely, it is the shoes. If the irregularity isn't real profound, don't worry about it, it will wear to uniformity with use.

To check the drum, you will probably need a large set of calipers to read the inside diameter. Readings should be taken at numerous spots around the inside of the drum. Always work it back and forth to obtain the largest reading at any given spot. Your mechanically inclined friend should be familiar with caliper use. If he/she is not, let me know, and I'll try to guide you through the procedure.

Make sure the nut that secures the wheel to the shaft is torqued correctly. If it is loose, it could also cause the pulsing you described.

Good luck, my friend. I'll be here if you need me. I'm doing a piano bar during the day Saturday, but should be here in the evening.

--Keys