83 Vmax 540 Jetting Help

[Packman]

I've got an 83 VMax 540 that I've recently purchased that had stock powerjet carbs on in that were in pretty bad shape. I've got a good set of standard bowl 38's that I would to run instead.

I know the stock power jets ran a 290 main jets with 135 and 130 power jets.

Anybody got any experience with making this carb change to standard bowls and jetting experience?

Thanks,

Ross

[Bob Vehring]

Ross,I'm alittle hesitant to make these recomendations based mostly on my engine has had, since I've owned it problems do to the previeous owners port work, so Ive never had this sled work to my satisfaction. I'm currently working on a new engine
To the point, I do not like PJ carbs because of the way the mains draw fuel off the bottom of the float bowl. That doesn't mean it won't work well for others.
Heres where I was at last time out
Main 350
tubes Q2
pilot 50
Needle 6F4 which is a hard needle to find but I am happy with it in my SRV which makes about the same HP as the VM
sorry didn't write down which slides are in it

I did use the stock carb bodies from the VM because of the smaller fuel line Yami used on these

[chrisrider63]

Here we go again, so Bob your telling me your srv makes at least 85 horsepower?? What has been done to it? I find that highly unbelieveable....

[Vmax540]

Here we go again, so Bob your telling me your srv makes at least 85 horsepower?? What has been done to it? I find that highly unbelieveable....

Not, if you know Bob, his shop and resources......

[Packman]

Bob,

Thanks for the help and insight.

I'm just looking for a good base line since I know I'll have to fine tune once it's all put back together.

I too am running the VM bodies so they fit to the airbox better then the other set of 38 that I've got.

I bought the sled as a mostly complete project that need the finish details to to get it reliable.

I made the conversion away from PJ's on my 79 SRX as well, went with a conservetive set up since it's a trail sled. I'm looking to do the same with this sled.

Good luck on your project.

Ross

[Bob Vehring]

Here we go again, so Bob your telling me your srv makes at least 85 horsepower?? What has been done to it? I find that highly unbelieveable....

Good mourning Chris Yes I do think we have talked about this before Actuly, I'm surprized because you doubt this. Really both 535 engines other then cooling share many of the basic dementions. The Fan engine has the advantage of reed induction. The VM came OEM with more carb, porting and pipes so of course it is factory rated at more HP. Now given the same bore/stroke/ rod lenght, nothing says you can't bring the induction, port timing and ex. up to or beyond what came OEM on the VM, on the fan engine, which I did, and then some. I do have alot of work on the reed cages and intake, and I did add some extra transfer ports. It has taper bored 39.5 carbs and currently has a Aaen single pipe altho I do have the twins from years ago. There is no Black magic, engine building is a basic well doumeneted process backed up by years of testing. Their are books everywhere on it.
Some people think, and certianly there comes a point where its true, that liqued cooling is needed to control heat. 80-100 HP is no where near that limit. Many air engines in that range. In Oval racing the Sprint class dictates a fan cool engine up to 600cc, all of them make 100 hp
Honestly, I'm more suprized that my SRV is now beating our '81 Eltigre 6000, which also has work done to it, that sled was always faster. The SRV is now 550 cc's the Cat is 500. My wife is not happy, the Cat is here favorite

In the VooDoo Max thread of My Projects there are some pictules of both the new VM engine and some on the SRV from my kids race sled which has a SRV based engine. On any given engine, doing the basics with ports, int and ex. will bring you to XX HP. Going beyond that point takes considerable custom work. Looking at the pictures you can see cases milled down and a billet plate made to increase the transistion area in to the ports from the crankcase. The jugs had the fins milled off, and welded completely to allow for much wider transfers with a much better angle.. Even on my trail VM engine, we milled out the head to acept custom chambers so we could get rid of that offset chamber Yami insisted on using in the 80's. Thats something that given enough time, I would like to try on my trail SRV engine to help with todays crap they sell us for gas

[agfirecat]

if i remember correctly the srv was produced to run in the popular cross country racing in the day and they had a 56 hp limit.

[Bob Vehring]

80-82 Srv were rated at 56 hp which was a std class in many forms of racing, most brands had an entry for that class. That was taken over in Yamaha with the then new Phazer. Manufactoers used this class to promote new sleds.
The SRV got slightly larger reed cages and HP was moved to 64.

[chrisrider63]

Hahahah Bob i was just ribbin ya but you can bring your srv over anytime against the 88 vmax with the updated cdi i think its comparable with my exciter sx and has a stock motor. Hey ive been meaing to ask you a guy wants to give me a 82? srv 540 for 50 bucks the blue ones, i dont know which year i thought it would be a fun cruiser sled when theres not alot of snow.

[Bob Vehring]

My red one is a '81. I like those early years because of the plastic "trunk" in the back rather then the storage in the seat the newer ones have. 80-82 have a shorter 116 track, adifferent skid, and slightly smaller reed cages. 83 and up went to the Pro Action skid, 121 track and the bigger reeds. Really theres not much differance ride and handling wise between my SRV and the V Max, they feel about the same, both of mine now have the xtra 10 in them.
My SRV even with 81 skid and track has always been my favorite sled, I don't really have a reason why, just seams to fit me I guess Even with all the different variations of the engine, it has always and still is my most relieable sled. Always starts. always runs, gas milage does suck.
I laugh my ass off reading some of the new sled forums, when I need 14 in of travel, 180 HP and power steering, prop me up in a chair and turn the lights off