My Son's JR 50 just died, can anyone help?

[yy4u]

My son has a 2004 JR 50 we went riding yesterday and decided do some more riding today and the thing just died. I’ve tried all I can to get it running but to no avail…
Basic Check List
1.) Fuel switch ‘ON’
2.) Full tank of gas
3.) Full tank of oil
4.) New spark plug
5.) Checked for spark
6.) Fuel getting to carb
7.) Cleaned carb w/ carb cleaner
8.) Cleaned air filter

Has this happened to anyone? Did I miss something on my checklist? I am baffled and frustrated. The thing has at the most 50 hours on it. Can anyone offer any input?

Thanks in advance!

[digipoi]

Have you checked for compression?

I feel for you, i hate working on my son's JR. In fact, mine came with a bad carb right out the box. These bikes are so simple yet caused me the biggest pains.

[yy4u]

Hey digipoi,

Ironically it started this afternoon? I read on another thread (thumpertalk.com) and it seems these machines are notorious for carbon build up. So I spayed some WD40 in the cylinder head and to my surprise it started right up? This technique worked on my nephew’s RM 85 when he ended up in a drainage ditch at the local track. Although my son never dropped it in a drainage ditch I figured I have nothing to loose. So I decided to give it a shot and see if it would work on carbon, it must have because the pipe blew black spew after that and ran ‘GREAT’ all day.

Thanks for the response, --YY4U

[Dave2122]

Glad you got it running.

I have had my sons bike for 3 years and it has run great. No problems what so ever.

[digipoi]

I know the exhaust pipe gets major carbon built up right where it exits the cylinder. I need to take it off every now and then to scrape it clean.

Im glad you got the little bike going again. Im going to overhaul mine and put the training wheels back on for my 2 year old. My five year old just stepped up to a TTR90, no problem with hillclimbs now.