My Rotax wont reach max RPM's??

[Darren Campbell]

Your only starting your apprenticeship jeremy, you have to learn to get to know your motor

[Scott Falcone]

I just tested there a couple of weekends ago. Great track!!!! I have some great test data and could share with you. I can at least get you a base line set up. I can already tell you your too lean based on my testing. I also have very good idea why it's not reving down the straight. Call me at 3035004060. I will try yo help you out.

[Jean Stafford]

Jeremy,

We routenely get 14,500 from the FR 125. Secret is in the power valve. and spring combination. Most are told to run the DD2 spring as it is stronger and keeps the power valve fron opening too soon. Our experience is it just ain't so. On short tight tracks you might get by with this, but generally the stock spring is adequate.

Ours works best with 25-26 clicks of the rave valve from closed. Additionally, use the ROTAX oil recommended at the recommended ratio of 2.5 oz/gal. A richer mixture clogs the valve, an d makes it sluggish. Clean the valve often, even between heats. it MUST move freely, without any drag.

Follow the recommended jstting for the carb considering what slide and floats you have.

The exhaust pipe is prone to burning out the scilencer packing. Place a ROTAX sticker at the entry end of the scilencer. When it burns off, or melts, it''s time to change the packing. Drill out the rivets and pull the center of the scilencer out, along with the packing. Replace the packing and secure the center in place with 4mm screws and nuts. (Legal)

The ROTAX FR125 pulls strongly at 8500 RPM all the way up to 12,500. Ours puls 31 Hp at this span. One trick is to not "Mat" the gas when exiting the corner. The carb is made to operate =through a very wide band of RPM, but flooring the gas pedal will cause the engine to run rich. Slowly raising the needle out of the emulsion tube regulates the gas flow as the engine demand rises.

You have got a good engine package from what I can tell. ROTAX has warranted several items that have failed, and have replaced hem at no charge. See if you can get that from Yamaha.

Good luck,
_________________
Jean Stafford
Stafford's Racing
Dayton, Ohio
ROTAX Repair station,
jean@sgandt.com
Started Karting in 1959
"Some people are like 'Slinkies', worthless, but they bring a smile to your faqce when you push them downstairs."