stators

onebun · Post by **onebun** » Sat Dec 19, 2009 1:01 pm

talked to a tech. at aaen racing yesterday to try and figure out whats going on with my sled he told me about how the 540 has a weak ignition system and that yamaha came out with a updated stator to fix the problem but did not know in what year it was,has anybody ever heard this before?He also told me that guy's would change the stator and the rest of the ignition system over to 81 srx(i think he said that the srx 440 reved out higher than the 540)and therfore it worked better when you are modifing the 540's and solved the problem with the weak stators.Has anybody ever heard of that as well and is anybody out there running 81 srx stator,cdi,and ignition coil in the 540? thats the way mine was when i bought it,but never ran it like that and messed up my stator trying to pull the flywheel when i was diassembling the motor to change the crank seals and put a stator off of a 540 with a resistance of 207 ohms in it.my problem still seams like electrical to me,it runs strong and crisp down below even wheellies but after the shift out it sputters and won't pull past 7500,i am thinking of changing back to a 81 stator to match the rest ignition system to see what that does really just looking for input to see if anybody has exp.this type of thing before and if anybody is using the 81 ignition system on the 540. thanks john

vmax-540 · Post by **vmax-540** » Sun Dec 20, 2009 7:14 pm

What he is talking about is the 87 Vmax. In 87 Yamaha changed the charging coil in the stator to a higher output coil, by doing this the secondary coil output went up from 18,000 volts to 28,000 volts ,but you also have to use the 87 CDI as well as it is different to accommodate the higher voltage of the charging coil in the stator. The only time you may notice the difference is if you raise the compression or run it at a higher RPM as in porting or aftermarket pipes. All 87's and up (Canadian versions) use this stator and CDI. The #'s on the CDI should start with 83H, and the ohm reading on the R/W-Red wires in the stator should be 50.5 ohm compared to 10.ohm on the 86 & back Vmax's. Hope this will help you out..

onebun · Post by **onebun** » Sun Dec 20, 2009 7:53 pm

Thanks jeff that was great info, I am running aaen pipes so maybe i need an updated stator to pull the higher rpms.I am going to swap over to the 81 srx stator that i have because its free and see how it works like that the tech did say guys put in 81 ignition systems to fix the problem.gotta try something and carburation looks really good considering i'm jetted fat at 370 nice tan brown plugs and no fauling.thanks again john

Bob Vehring · Post by **Bob Vehring** » Mon Dec 21, 2009 8:37 am

John are you running 370 mains with or without the power jets? I am not familiar with PJ carbs. I understand the theory, you can run a leaner main for the midrange and the PJ will cover the top end.. My carbs came with a 290 mains, I went to a 330 and the midrange bog got better but with no real snow here, I can't really test. it I did finally get digital egt on it yesterday but again no place to run it.. I don't know the percentage or over what range the PJ will help. Hope you or Jeff have it figured out.
on my SRV with thin 39.5 carbs I was very lean in the mid regardless of main choice. This is the old Exciter problem. by careful choice of needle jet, and needle I can now keep it at 1250 across mid and top, from around 15 to 30deg. by just moving the needle up or down and am very happy with that set up. I want to get the VM in that range

onebun · Post by **onebun** » Mon Dec 21, 2009 9:57 am

yes bob i am running power jets and i also went up a size on them,no egt(i wish) maybe next year.at first i thought ok your to fat on the jetting but i ran it a while to get a plug reading.and it didnt faul a plug and they look good.might go to the lake today put the stock p.jets back in and drop the mains to 320/330 but gotta be careful it is -21 here right now but will warm up as the day goes on thanks john.

Bob Vehring · Post by **Bob Vehring** » Mon Dec 21, 2009 11:00 am

Its 30 here now, their talking maybe snow late in the week but we have a kart race down south, won't be back till first week in Jan. Doubt I'll get out before then

vmax-540 · Post by **vmax-540** » Mon Dec 21, 2009 7:27 pm

What stator and CDI for the 81 are you running? They had two different ones,the first was the one they came with in 81 ,it was the same as the SS 440 used, and the other was the one Yamaha issued as an update ,it was the same as the 82 SRX used and should start with 8R9 on the CDI. As far as I can tell the stator is the same as the 83 Vmax used,all the coils are the same part #,the only thing that I see that is different is the wire connections on the end of the stator and the CDI. It appears to have the same advance curve as the Vmax,but the 82 did turn up a little higher rpms so maybe it will work a little better for you. I have seen people use Aaen or PSI pipes on the Vmax with the stock stator and CDI with out any problems so I think you may have some other problem going on. Maybe your CDI is going bad there are a lot of circuits in there and you can have one go bad and still run like maybe the high rpm circuit or even something in the fuel system ,how is the fuel filter and things like that?

onebun · Post by **onebun** » Mon Dec 21, 2009 7:52 pm

thanks jeff did not know there are two systems not sure what mine is right now but will check,fuel filter is new, i thought that guys ran aaen pipes with out any problems,didn't get to the lake today my buddy wasn't home.so i don't no what dropping my jetting down will do.370 mains and 147 power jets,needle 2nd clip position from top,running an air box, thats my carb setup and also one dual outlet fuel pump thanks for the info john

vmax-540 · Post by **vmax-540** » Mon Dec 21, 2009 11:07 pm

That sounds allfull rich,what size carbs are you running?

onebun · Post by **onebun** » Mon Dec 21, 2009 11:40 pm

stock 38's i jetted it like that on the advice of a buddy who is the local yammie tech start rich and go down and it does get cold here -20C to -30C for the better part of the winter going to rejet lower and see but i figure if i was to rich it would faul plugs and they would be black but they are on the rich side of a nice tan brown.not to sure about the power jet going to put it back to stock maybe its putting in to much fuel up top want to try it to see what happens but it sure seems like the spark is cutting out up top.going to be very busy the next few days i've got more welding test and x-mas stuff to do and then gone for a few days so won't be till after x-mas now before i can work on it. thanks john

chrisrider63 · Post by **chrisrider63** » Thu Dec 31, 2009 8:35 pm

Can i take the coil off my SRX 440 and put it on the vmax???Im gonna try it right now.

Post by **Vmax540** » Fri Jan 01, 2010 10:36 am

chrisrider63 wrote:Can i take the coil off my SRX 440 and put it on the vmax???Im gonna try it right now.

External Ignition coil.... Yes !

chrisrider63 · Post by **chrisrider63** » Fri Jan 01, 2010 12:18 pm

Hey man my MAX was doing the same thing, (not running well at top end I took the flywheel off and my stator and ignition coils were all loose.

onebun · Post by **onebun** » Mon Jan 04, 2010 11:16 pm

good news dropped the power jets back to stock and put 350 mains and it runs good and crisp pulling over 8 grand on the tach could be 8500.it is a blast to drive had a lot of fun on it today,different riding something without studs or carbides thanks to all for the help and long live the vintage vmax

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