Engine Breaking Up...and some other things...

echondrite · Post by **echondrite** » Mon Jun 03, 2013 1:29 am

OK, had my RH 50 since 2008 and no real problems at all. But, here are some issues I have been noticing lately

-It breaks up sometimes up hill and in needed time of power and acceleration. Any suggestions for fixes?

-Kickstarter droops down and grinds gears in the gearbox. Not a full kickstart when electric doesn't work.

-Was riding in the rain today and the thing was taking off like a rocket when compared to the dry dry RH!...What would cause this?

-When cruising on a flat fast road, throttling point between the jets seems to be causing issues. There is a bit of a pause or a skip as it switches between the small and large jet. Normally I wouldn't care, but the point of transition seems to occur exactly at the speed I need to cruise at. One time I let it stay between just to experiment and it had a high pitched sound, then just quit. Happened twice and started back up after 5 minutes.

-Also looking to upgrade my clutch, any recommendations for purposes of weaving through high traffic areas and "parking lot" traffic jams.

[b]My setup using all parts ordered from Scooterworks:[/b]

-26mm Kiehn carb that was sold on Scooterworks in 2009
-Larger intake manifold
-Stage 2 70cc kit (spring, rollers, exhaust, cylinder head)
-K&N rond cone filter
-those wedge rollers instead of round ones that came with kit

Can anyone list their setup that works perfectly, thinking of putting in some time to get things right and will plan based on responses.

Is my carb too big? thinking about going down to the 19mm italian one from scooterworks? Can anyone offer insight to jet sizes to use with this smaller carb and if it will work with the larger intake manifold.

Man, this is a long one, any info would be appreciated...

theemptythrone · Post by **theemptythrone** » Fri Jun 07, 2013 5:20 pm

the only help i can suggest is for the kick starter hanging down, put you center stand down and turn the foot peg of your kickstarter out as if you're going to use it, then bring your center stand back up. it should hold your kick start up.
other then that i would recommend taking it to your closest scooter mechanic for all of the other issues.

VinylDoctor · Post by **VinylDoctor** » Fri Jun 07, 2013 7:44 pm

Just sounds like it needs a good going over. stuff wears out. your kick start lever might just need a new spring. sounds like most of the other stuff is just cleaning and tuneup. the speed in the rain might be from your air system drying out, and the rain gives it the mosture it needs. I think these all have wet air filters.

agrogod · Post by **agrogod** » Fri Jun 07, 2013 9:42 pm

https://www.youtube.com/channel/UCUxvvD ... 4OiS2S_B7g

This has a bunch of fix it videos. That is if you plan on doing your own fixing.

OldGuy · Post by **OldGuy** » Sat Jun 08, 2013 6:26 am

I can't comment on your exact setup, but for the issues your scooter has here is where I would look.

"breaking up" on uphill: clean or replace the plug, check over the ignition system including coil and plug wire. Could also be caused by carburetor jetting problems though.

Runs better when it rains: air is probably cooler and more dense when it rains, so check for things that keep it from getting enough air normally, like a plugged air filter or a stuck choke. Better performance when the air is dense is an indication that it is normally running too rich.

Jet issues in the mid-range: clean the jets, especially the needle jet which the main jet screws into. Needle jets often have small orfices on their sides that help atomize the fuel pulled into the carb. These commonly get plugged, and can cause poor running over most of the range except at wide open throttle.

Also, 2 stroke exhausts can plug up with soot over time, which interferes with efficient "breathing". And the cylinder head and piston top can get coated with carbon which throws off compression ratio and can lead to pre-ignition, especially when the engine is hot on those nice non-rainy days. By the way, be sure your cooling fan works and is not damaged or plugged up some how.

So... Check cooling fan, air filter, plug, and plug wire. Clean the carb jets if you are comfortable doing that. Beyond that you may need to take it in and have the service techs check it out.