There you go then!

anyone know if the speed rod would work with the jx21? If not, what rod would work besides the ninja rod.

It works.

k i figured. Just wanted to make sure. thanks!

12.03 minutes runtime outta my JX21...Matched with a 2060.

I have a question I have been using byrons 25% in my jx.21 I want to change to 30% will I have to add a shim thanks for any info

Nope.. Stock shimming for 30%

thanks for the info

I'm starting gallon number 4 and I can turn the flywheel pretty easily when the motor is cold.

I woudnt worry about it. I would check the bearings, I have heard of a few of them tear motors apart right at the 5 gallon mark.

Remember these motors are OS based and like to run a little "looser" than other brands. It sounds like your JX is in its prime-enjoy it, I would say you should get another 2 or 3 gallons easy before you need to worry about. Although it is a good idea to take apart and check bearings, they should be good but its a good idea to check them regularly. Most I have seen get 7+ gallons before there are any worries, then repinch and its good for another 4 gallons or so.

i have one of these jx.21 love it in my truggy but as of late i have been getting mystery flameouts now i took it out too have a look and the flywheel nut was loose then i pulled the hole motor apart and i have noticed the front bearing is leaking are these none for this they are the standard bearings front and rear its done a gallon or so
would it be advised to change them now so id say the flywheel loose nut would of caused the flameouts but the bearing issue makes me think any suggestion

IN my experience the O.S. stock bearings have a reputation for not being the greatest on the market. Most engines will have a small amount of bearing leakage while breaking them in (Engine running on the richer side). Then generally the leaking will slow as your able to start leaning things out.

Mine leaked through the first gallon and a half but has since slowed or stopped all together. I have right a 4 gallons on my latest JX21 and will be replacing bearings shortly. It will have new bearings before our next nitro season starts anyway

If your not sure, it's never a bad idea to just replace them. Mainly for your piece of mind, and it can't hurt anything.

thanks champ was thinking that may be the way to go

Hello all. I finally have had the opportunity to run in my jx.21. I am using it in a mbx6 buggy with the 2042 pipe, L header, OS p3 plugs, and OD 30% fuel. I am very pleased with the power and fuel economy is getting better. I purchased an EB mods head button to try out, which is the original version 1 and have a few questions. I read on here somewhere to install the new button only using the supplied shims, is this correct? Should I change to a colder plug? I really like p3's but I will do what is necessary. Also has anyone found if any of the other ninja headers net any better mileage? I have all 3 and have been wanting to try the 2 C shaped headers . So far very happy with the L header but I think the bottom would be stronger with either of the C headers. Any input? Thanks.