rev limitter on racing commando

question:
I'm using a boyer ignition with a double ended honda coil on my 850. how can I fit a rev limitter which will cut at 7,500?

Boyer makes a rev limiter but i don't know what models it works with. Contact Boyer or many this place to see what they offer.

http://www.gremlinracetech.com/category/383605

Had a look at the Boyer page, and saw them mentioned. Do you know of anyone who has ever used a rev limitter on a Commando engine? I think if I set it for 7,500 it might never get to function unless the revs got really dangerous. I hate the idea of causing the engine to miss, but I suppose it wouldn't do damage except it might cause plug fouling ? I don't know what model Boyer I have on my bike it's about 30 years old and still sometimes causes sparks to come out of the end of the wire. I looked at the programmable units on the web site, and I think my old bike would have a fit, if I put a computer near it. I wonder what sort of ignition curve you'd use with methanol fuel in such a strange motor ?
There is some interesting reading on this subject:
http://www.rscycles.com/tech_articles/p ... ystems.htm

I'm a bit confused, you mention methanol as fuel and Boyer in same note, huh? Boyer curves are universal and limited adv rate so Triumphs can use em. Boyer made a rev limiter that cost as much as one of their ignitions and have heard of one or two installing them [not on this short term forum though] One thing I like about Norton and so do some others is when configured well they scream to redline and beyond before ya can react to it in lower gears. Methanol engine usually up their CR which make it harder to ignite so hope the Boyer is up to it.
I got a Powerarc with 4 curves and adj limiter as lost 2 engines by stuck throttles out of gear on start ups so caught my surprise. Past750 Peel and a V8 that powered a van Ole Blue that friends nicked name Millennium Falcon. Never again thank you verymuch.

Here's some methanol spark discussion that might apply to you. i am interested in methanol for Ms Peel to try sometime down the road.

http://www.eng-tips.com/viewthread.cfm?qid=174777

I ran Boyer rev limiters on my race Nortons for a while. They were analog units, with a screwdriver adjustment, and you had to set the rev limit by trial and error. I usually set them as close to 7200 as I could get them for the 89 mm stroke engines. Never used them for the short strokes. Mostly I used them when I had other riders on the bikes, and didn't trust them to mind the revs. They did work reliably, but as newer and better parts (crankcases, crankshafts, rods, etc.) became available, I quit using them. As I recall, they worked with other ignitions as well, not just with Boyers. I've still got a couple somewhere in boxes, and could probably find the original instructions if you need them.

Ken

One of our club members sells rev limiters, made in Queensland, no less.

I have no idea how they work but there's an advert for them at the bottom of this page

http://qemsc.com.au/forsale.html

Pazon has a rev limiter

I just pulled the Boyer off my BMW racer and fitted a Ignitech ignition , you can adjust the curves to suit any application, one feature is a 'soft' rev limiter, and you can set it up on the laptop with the motor running...way cool.
Cost me around $400 all up including 2 dual output coils.

I used a boyer rev limiter (as lcrken describes) on the 750 ultra short stroke. Once set it performed fine. I no longer use it.

The 500 ultra short stroke (59.6mm stroke) uses two Dyna coils and two triggers and a Dyna rev limiter which is a must have. It is currently set at 9,500 rpm. With a six speed the rpm can get away from you in one half of a blink of an eye.

From a practical stand point, if the rider is not tethered to a kill switch, a rev limiter might be cheap insurance when he or she gets off. On the other hand, a rev limiter is just one more component to fail and cost yo a race although I never had that happen to me nor have I heard of it happening.

From a practical stand point, if the rider is not tethered to a kill switch, a rev limiter might be cheap insurance when he or she gets off.

Click to expand...

That is wise advice to me so a kill cord is one of Peel features besides rev limiter.
We used kill cords on racing hydroplanes to kill engine so it didn't circle around to mow us over or run into something or smack into shore. In those daze had to make our own by out rigger fishing line clips with thumb tack contacts the shorted with the plastic card got jerked out between.

Running methanol fuel doesn't create problems with ignition. The problems come when you dramatically raise the compression ratio in the way methanol allows. I run standard comp of about 9 to one. I use methanol because it saves the motor by running cooler, and gives a power increase because of its high latent heat of vaporisation. It also gives a bit of flexibility in getting the mixture to the optimum. I use Amal MK2 carburetters which I bought with the methanol kit. I threw away the needles and used 6FP mikuni needles, and made my own needle jets which I drilled to 0.117 inch. On a tight circuit, if you drop the needle one notch, the motor coughs as you wind the throttle in corners. With the needle in the right position, the bike accelerates extremely rapidly, and even with the 4 speed CR box, you have to be careful not to over rev. I always try to change at 7000, it invariably goes to 7,500.
I am about to start using the TTI 6 speed CR box, so the danger of a blow-up could be worse.

Very good sale pitch for methanol acotrel. I must try it some time on blown heater Peel, after a drivetrain that could stand it. You are living dangerous if no rev limiter -in the heat of the moment. Don't know If I could source a needle to reconfigure Lake injector for meth instead of petrol. Will have to study up on it.