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Rotary rev limit

Submitted by stephen_udall on Sat, 29/09/2012
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Rotary

Can anyone tell me why the maximum rev limit is set so low on the ip2,at 7500 rpm this seems very low for a rotary with so few moving parts,i heard that a rev limiter was fitted does anyone know why this was done,also i have a ip2 that has been stood for a while i read somewhere it is not wise to just start them up after being laid up can anyone help

many thanks Steve.

Submitted by david_evans on Sat, 29/09/2012

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Hi Stephen, My IP2 gives 80 MPH at 5000RPM that equates to 120 at 7500. How fast do you want to go? I was under the impression that the limiter is set at 9000, that's 144.

There is a lot of good information on the Rotary owners club forum. The general procedure for starting a long dormant rotary is to turn the engine by hand after squirting either rotella 40 or whatever oil you use, into the plug holes.(dont poke your oil can it there while turning the engine or you'll chop the end of your spout off, very painfull) turning the engine backwards as well will get the oil to all the places and not just straight out the exhaust. you could squirt some down the intake past the air filter as well. ultimately you are going to have to bite the bullet and smoke the whole place out. (top tip, wait till the wife's out if you've got one)

They are a rewarding machine and the only Nortons capable of cruising all day at 80 plus without falling apart.

Submitted by richard_negus on Sun, 30/09/2012

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Stephen,

Sparkrite ignition units (as fitted to the IP2) originally had the rev limiter set to 8,750, as did the Classic with a Boyer ignition. All Commanders and F1/F1 Sports have the limit at 9,750 although I have ridden some of these where the limiter has stopped working.

The limiter is there to 'enhance' engine life. Without it, the equivalent of 'bending a valve' is to shorten the life of the rotor bearing or have the rotor flank touch the housing as the eccentric shaft deflects. The latter is not something I've seen on road engines, but occurs with race engines going to 12,000 or so.

Submitted by stephen_udall on Sun, 30/09/2012

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Thank you gentlemen for your wisdom i had always supposed that valve bounce was a factor on 4 stroke engines, and porting on a 2 stroke so i was curious about the rotary,however Richards information that the crank is eccentric would explain the rev limiter to reduce wear. Dave i will be using a silkolene classic premix when i can arrange a mortgage from my bank very expensive,i have heard that there is someway of catching the oil so that it goes farther is this wise and how is it achieved

thank you for your help.regards Steve

Submitted by david_evans on Sun, 30/09/2012

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Richard Negus rigged up a catch bottle to trap excess oil from the frame"plenum" chamber on his Commander. I copied his design and trapped nothing on my IP2. Join the ROC and get the classic premix well discounted, (about £8/litre) You should get 450-475 miles to the litre if your pump is correctly adjusted. Fuel consumption is about 45MPG at the best, driving like a nun.

 


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