So I finally got my NSR250 MC18 running pretty well considering it sat for a very long time (somewhere like 10 years!). The carbs will need some work but I have rebuild kits for those but surprisingly it idles perfectly. It starts so easy, compared to 250cc 2 stroke dirt bikes, I'm really stoked! I got everything to make it go on for a quick lap up and down the driveway and a slight problem occurred.

I know the RC servo isn't working for whatever reason (I knew this early on because it wouldn't reset with the ignition turned to on). I tested it per the manual and no dice. I took the bottom cover off it however, and the motor turns (I'm presuming the smaller thing is a sensor/potentiometer or something to calculate the position). Anyway, I still was keen to see how it went so I tried to take off and it was on the verge of stalling all the time. The engine is actually out of an MC28 or late model SE MC21 I believe so it has a dry clutch. Do you really need to rev these things to get it going? I've ridden plenty of bikes but never a dry clutch so I'm not sure if it is any different to wet. The clutch seems to engage because when you release it with the RPMs up (at say, 4 or 5 thousand), it makes the RPM drop). I'm just wondering if something else sounds wrong or does it sound like purely a RC servo/power valve problem? I have another RC servo on the way also. If it's a jetting problem just let me know and leave it at that (I know the no jetting talk rule in the public forum).

And another thing. Tyga seem to be taking their time with new pipes for the MC18 and I'm getting impatient and really want to try and finish this bike. Are there any places to get MC18 pipes for a similar price? I've seen some pipes on Japanese sites but they're in the $1000 - $1500 range on the low end, plus shipping - I only paid $1000 for the whole bike! The Tyga pipes seem the best value but aren't available til June now.

Last question: What fuel premix should I use? I read somewhere that anywhere from 25:1 to 50:1 can be used. In my experience with my CR125 it was recommended by Honda to use 32:1 so I went with that but it seems a tad smokey. I was thinking going to 40:1. IIRC the jetting settings are stock.

Have you still got an oil pump? If so, why premix? If not, then have a read of the main site where there is info about oil mixture.

Yes you do have to rev these bikes a lot to pull away. First gear is very high, so they do struggle until you're rolling.

Can't help with the Tyga thing, try emailing them direct and asking!

Dave Ett wrote:Have you still got an oil pump? If so, why premix? If not, then have a read of the main site where there is info about oil mixture.

Yes you do have to rev these bikes a lot to pull away. First gear is very high, so they do struggle until you're rolling.

Can't help with the Tyga thing, try emailing them direct and asking!

The engine didn't come with an oil pump. I want to get one for it but for now I'll premix until I have the bike set up good and then get an oil pump for it. The bike was originally setup as a really slapped together race bike. It was pretty rough around the edges so I'm slowly getting it built up.

So I figured out my problem, the gears are reversed! So first is up, and 2-6 are down. That also explains why I could never find neutral. I initially thought I put the shifter on upside down but I'm not sure it would fit. Anyway, A blast to ride. Now I just need to finish my custom tacho/digital dash!