Author Topic: Altitude compensator  (Read 729 times)

injuhneer

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  • Mike O.
Altitude compensator
« on: August 07, 2019, 09:40:41 AM »
I am wondering if any of you fine ROV have installed an altitude compensator on your carb?

I live in an area at about 4600ft elevation. If I go any to nearby cities/towns there are dramatic changes in elevation. I am thinking it would be nice to jet for about 3000 ft and add a compensator to run ~1000-8000 ft with no changes to the carbs.

- Mike O
1982 Yamaha XZ550RJ

fret not

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  • Mike Lewis - Grass Valley CA
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Re: Altitude compensator
« Reply #1 on: August 07, 2019, 05:37:19 PM »
Maybe a conversion to EFI.  Some years ago when I had a Suzuki SV650 I got thinking about changing the XZ550 to EFI, much the same as the second generation SVs.  I found a set of throttle bodies with injectors for pretty cheap, about $50-60. if I recall correctly, so I got them and began scheming.  The problem with my scheme is that it got a bit heavy in technical details and the modifications I would have to make on the XZ for cam position sensor, crank sensor, O2 sensor, mass air flow/temp etc.  Then there is the higher fuel pressure ( a mimimum of 46psi) and all that entails, plus the different angles of the V motors meant the brackets holding the throttle bodies would have to be significantly modified so the throttle bodies could be positioned correctly.  It was easier for my old brain to grasp the concepts related to carburetors rather than all the necessary aspects of an EFI system.  I know it isn't rocket science, but it turns out to be a bit more complicated than I was ready to tackle.  Maybe it isn't as difficult as I made it out to be, but maybe it is more difficult.  So I went the route with FZ/YZF carbs, though I am still a long way from making this project run.  Anyway, the point I was going for is that the EFI system does the air/fuel control automatically.  Just a thought.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

injuhneer

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Re: Altitude compensator
« Reply #2 on: August 16, 2019, 09:02:49 AM »
I too am thinking about EFI but in the near term a compensator may do the job. I know they are used successfully on ATV and snowmobiles.

http://holtzmaneng.com/carburetion-products#ATACC

I am thinking this would work nicely in my case. It lean the mixture by allowing air to bleed into the air side of the emulsion circuit. This lowers the internal pressure differential and leans the mixture. The lean bleed is control by barometric cell.

- Mike O
1982 Yamaha XZ550RJ