VintageVmax.com

Just picked up a 1983 with an extended track and 2200 miles. I know nothing about this sled. It appears that the track extension is similar to those I've seen on a few Phazers. Do they share the rear suspension and tunnel? At some point the previous owner installed an egt sensor in each pipe (stock exhaust). What range should the exhaust temp be in? The Power jets have been removed as well as the airbox and oil injection system. It now has K&N filters. I pulled and cleaned the carbs today, and I think the main jets are 240s? They are very hard to read. I think that there has been some minor porting done to at least the intake side of the cylinders. Having never seen stock cylinders, however, I can't be sure. I was just wondering what everyone thought of the way the sled is set up (power jet removal, premix fuel, K&Ns) and what jets would be appropriate at 7000 feet an about 32 degrees F. Thanks in advance for your help. Regards, Dave Henneman

I would DEFINATELY put a stock airbox back on it. I've heard ALLOT of bad stories about these sleds with pod filters installed...

Hi Dave, welcome to the VM world. EGT is basically the same for everything, a few things to understand. Number 1 learn whats right for your sled simply meaning watch plugs and piston at first to your comfortable. For your set up, where the probes are relating to distance from face of piston will vary your number some. Further away gets cooler. Timing also shows up in EGT if anything was changed there. On my VM the probed are about 2 in down from the joint were the pipe goes on to the manifold.
The style of probes can also be a bit different, there are both fast response ( open tip) and the standard probes. The open tips simple read faster. I look for numbers between 1000 and 1250. Most people only play with the main jet and thus really only jet it for WFO. At anything other then fully open, metering is done by the needle and tube for the most part. Since other then racing only, most use is in part throttle range, that is where getting the jetting right is important if you want performance.
Jetting from the factory has the main goal of being safe in any conditions, which is what most riders need. More performance can be had by changing the jetting but understand "right" changes by temp and alt. the closer you get to that 1250 deg number, the more you better watch it if conditions you ride change
I also do not use the power jet, no air box or oil injection, which I know others also have changed. Hopefully someone will post their jetting. I will tell you what I use but you have to understand my engine is changed a great deal from most VM engines you can see the thread in my Projects
Main 360 or 370 depending on temp if trail riding
Pilot 40
needle 6f4
tube Q0
Slide 3.0
My engine is 627 cc, has more compression and very different porting so do testing to see what works for you

Killer Klown, what stories have you heard? If K&Ns producing a lean condition, I would think you could just alter the jetting to compensate. I plan to put a few fairly easy miles on the sled and watch the egts. I am glad that they are installed (about a foot down from the exhaust port). Thanks for everyone's input, like I mentioned I'm in the learning process.

Dave

A foot is a long way down. On my kids race sled we monitor pipe center, that would read in the 900 range whlie EGT was 1200. Jetting can compensate for air box, filters or whatever all can be made safe, I really can't remember seeing a full out race sled with an air box anywhere in my life. Just be careful 240 sounds lean to me.

"Do they share the rear suspension" The Phazer had a Modified Pro-Action and the Vmax has the original Pro-Action. In reality they are two different suspensions.
viewtopic.php?f=2&t=1529
Search all the following sleds that had the original Pro-Action Rear Suspension.
1983 to 1991 SRV 540
1983 to 1991 Vmax 540
1991 to 1993 Exciter
1992 to 1997 Vmax 750/800 with the exception of the 97 XT models
1994-1996 Vmax 5/600 with the exception of the 96 XT models

I really don't know how they extended the track, but looks like they used oem components. I doubt they would have changed the original pro link system, but don't know for sure. I really haven't had much time to look at it because right after I got it my Dad fell on the ice and had to have surgery in Denver,which is about 400 miles away. In any event, I am a long way from my new 83 Vmax for a while.

Carguy, good luck with your dad, family is the more important.

Well, I have finally had a few hours to mess with my VMAX. After I had restrung the recoil, I did get it running for a short time. I seem to have a couple of problems. The first is that I seem to be running on one cylinder. I just put a set of new NGK BR9EYA plugs in prior to trying to start it. I chose those plugs based on their resistance to fouling (from what I have read). I thought they would give me a chance to fine tune the carbs without running through a set of plugs. The other problem i have, I fear may be more serious. After running for a short time the engine dies. Actually, it doesn't just die, it freezes. It's almost as if it hydro-locks, or a piston seizes. But after it does that, I am usually able to slowly pull the recoil and the engine turns over and the process starts all over again. Do you think I have a bad crank or rod bearing? I was really hoping not to have to pull the engine apart. The sled had been sitting for a couple of years and has about 2200 miles on it. Let me know what you all think. Thanks again, Dave

Or maybe something in the chain case let go.

Forget the chain case idea, I forgot it was separate.

First, you need to find out if the moment it freezes or stopped is the engine physically locked up, or did it die from something like elec failure. A compression test may or may not show problems, but do one if you can. Does it have fresh gas?. Try it with the belt off to be sure the clutch for some reason is not locking up on the belt. The last thought, which is rare but happened to one I bought is, pistons are to tight to cyl walls, when it starts to get warm it grows and sticks to the wall. Possible at idle not really a hard enough "stick" to really stay stuck, thus it will start again when cooled down

Well messed around with the sled some today. I forgot to mention that the belt has been off the whole time I've been working on it. I turned the engine over by hand today and found the "sticky" spot. It occurs every 360 degrees clockwise or counterclockwise. It almost feels like something broke off and gets wedged, then if I relax the pressure or turn it just a little ways the opposite direction it frees right up. I pulled the carbs and the plugs and the Pistons look OK and seem to have no slack that would indicate a bad rod bearing or piston pin bearing. It has led me to think it may be something behind the stator in the pump case. I've never been into one of these engines before, so everything is new. What do you guys think?

You feeling the hard spot even with the plugs out?

carguydave425 wrote: The sled had been sitting for a couple of years and has about 2200 miles on it. Let me know what you all think. Thanks again, Dave

Sitting a couple years, 2200mi (on a Vmax540 that is rebuild time) and 33 years old, all three of these tell me it needs pulled, inspected, gaskets and at least rings.

http://www.vintagevmax.com/reliablitity.htm