aaen pipes

rustman

rustman

Active member
I just toook my aaen quads off my '93 750 for cleaning and painting so I figured Id pass along a few things that I noticed. First off if you're ever confused which pipe goes to which cylinder, they have little raised spots of weld about 4-5 inches, 10-12cm, back from start of the pipe. Just after the spring tabs, if you dont see any spots at all thats #1, stator side. I found installing number 2 first helped me get them back in alot easier. This followed by #1, #3, and #4. I found that getting them close at first was preferable to snugging them right up. I also found that w/out a little spring ingenuity, the #1 pipe, the only one to exit stock hole rubbed against the chaincase. Easy fix however, just need to make sure springs are installed to "pull" pipe away from chaincase. The last thing that should be done as far as I can tell is to reroute the drain hose that comes from the bottom of the rad tray. In its stock poistion it will be burned up by the aaen's. As far as jetting is concerned I'm still working on it. I have 140 mains installed right now, up from 135's, but they are a touch lean for my liking, they work fine up to about -5 celcius, and better the warmer it is. I have 145's on the way that I will be trying as the temperature here is -20 celcius quite often. I didnt change any other jets. She idles and starts fine and the mid range is great. I just have high rpm concerns. As far as clutching goes I'm way off still, but working on it. Hopefully some of this will be useful to someone.

-Rustman
 

Great info and if your 145's are too rich Yamaha offers 143.8's 142.5's and 141.3's mains as well.
 
Sputter Trouble with 92 w/Aaen

Questions?? Just picked this 92 sled up in Dec, came with Aaen pipes. It tends to backfire out exhaust when starting. Also compared to my stock 93, this sled is a dog. It tends to sputter & pop when cracking open the throttle. I checked compression, all @ 120. I cleaned the carbs (140 jets) and adjust the floats, I checked the reeds. Aftr a good night of road running with new plugs, I pulled em out to check. #1  lightly toasted marshmellow, but 3 &4 are almost black. 1-2 coil (left side) had been replaced but 3-4 seems to have good spark. Any Ideas, can timing be altered? Is it possible the cranks are not indexed properly?
 
If the crank wasnt welded and they ran aaen's for any amount of time it is a good possibility that the crank is out of phase. There are some pretty good threads here on how to check this. Someone will chime in or just try a search.

-Rustman
 
Happened to mine with PSI quads back in the day on my 92', almost right from the start after I put the pipes on, she started to backfire and sputter. I had to send the crank out to be phased and welded. Once I got her back together what a difference.
 
if ur running aftermarket pipes on a 750 the cranks will need to be welded so right now u are out of fase so thats why its back firing
 
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