Can you please give me some direction with any issues with the VAMX engine?
>
> I'm planning to premix the engine. Bump up the compression. Put 44mm carburetors on it. What is the best pipe to use and who is in you mind the best place to have do the port work? I could really use some direction here.
>
> Is the engine capable of producing 130hp?
> Thanks,
>
> Chris
Making My VMAX 540 engine a Kick butt Lake Racer
there are two articles in the article index about porting and pipes... just want to make sure you didnt over look this one.... http://www.vintagevmax.com/86porting.htm
quite honestly im not sure anyone one here has ever really done a lot of testing with different pipes and porting... i think most of that is because they parts and pieces arent incredibly easy to find or very cheap.... also keep in mind that spot on clutching is going to play a HUGE factor in how the motor actually puts the power to the ground
im real curious to see what other people think about this subject....
i remember seeing a set of FIII ported jugs on ebay awhile back and i dont remember what they went for but it was big bucks....
definitly let use know what you route you take....
if you havent already found this site, you might want to check it out....
http://www.delaughterracing.com/
also the another site for you to check out is http://www.totallyamaha.com over there however it is general yamaha stuff, and some of the people are not as familiar with the vmax as they think they are.... dont get me wrong there are plenty of good people over there, but the ones that know about the vmax also frequent this forum also....
quite honestly im not sure anyone one here has ever really done a lot of testing with different pipes and porting... i think most of that is because they parts and pieces arent incredibly easy to find or very cheap.... also keep in mind that spot on clutching is going to play a HUGE factor in how the motor actually puts the power to the ground
im real curious to see what other people think about this subject....
i remember seeing a set of FIII ported jugs on ebay awhile back and i dont remember what they went for but it was big bucks....
definitly let use know what you route you take....
if you havent already found this site, you might want to check it out....
http://www.delaughterracing.com/
also the another site for you to check out is http://www.totallyamaha.com over there however it is general yamaha stuff, and some of the people are not as familiar with the vmax as they think they are.... dont get me wrong there are plenty of good people over there, but the ones that know about the vmax also frequent this forum also....
My airbox is held on by one screw, not because Im lazy but because it is less weight!
Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
I have heard others say the 540 will pull and respond well to a higher gear ratio ?
https://www.youtube.com/watch?v=PFb6NU1giRA
"I prefer dangerous freedom over peaceful slavery." Thomas Jefferson
"I prefer dangerous freedom over peaceful slavery." Thomas Jefferson
From my involvement in other types of racing, there are several aspects of going fast:
Power
Gearing
Drag
Control
Comfort
Traction
GEARING:
The Yamaha clutches are intended to keep the engine at the shift RPM from about 12 MPH up to the time the belt reaches the top of the primary clutch flange. If the belt never reaches the top of the clutch flange, there is no need to gear it higher. All you will be doing is putting more stress and more heat into the belt at slow speeds. If you have trouble with belt life with the stock gearing, it will be noticibly worse with the taller gears. I just dropped four teeth off the upper sprocked on my Intruder and the belts last a lot longer, the belt spends more time in the middle of the flange and there is substantially more starting thrust. Leave the gearing change until you are experiencing the belt reaching the top of the flange.
DRAG:
I have noticed my VMAX does not roll as easy as other sleds. When I have the sled on the garage floor and I pull it forward, the track slides on the concrete even if I remove the belt. The brake never gets hot, so I know it is not dragging. When I had the track off, all the bearings were inspected and half of them replaced, Other sleds roll on the track. Why is this? What can I do to the track, hyfax or skid frame to reduce the rolling friction? I know if the rolliing friction is reduced, the top speed will increase even though all the other aspects are the same. I used an electric motor to spin my secondary clutch to measure the power required to turn the track at about 12 mph. It was about 1.2 horsepower with the back of the sled hanging on a lift and the track off the ground. Track tension was set according to the service manual. By loosening the track tensioners about three turns, the power required was cut in half. At 120 MPH, this power loss would be 12 hp with the track tight and 6 hp with the track looser. Why does the HP requirement go up so rapidly with track tension. What can be done to reduce the friction to match other sleds that roll when pulled on concrete? Running the sled at the lower track tension allows the track sprockets to slip when going over bumps at full throttle. This is unacceptable to me, so I run with the tension set according to the book.
CONTROL:
When you are going fast, you need to be able to steer and stop. You don't want to crash every time you ride.
COMFORT:
It not fun to go fast and be exhausted before all the other riders in your group, You need to be comfortable enough to survive the ride. It is no fun to limp away from the machine every time you ride it even when you do not crash.
Power
Gearing
Drag
Control
Comfort
Traction
GEARING:
The Yamaha clutches are intended to keep the engine at the shift RPM from about 12 MPH up to the time the belt reaches the top of the primary clutch flange. If the belt never reaches the top of the clutch flange, there is no need to gear it higher. All you will be doing is putting more stress and more heat into the belt at slow speeds. If you have trouble with belt life with the stock gearing, it will be noticibly worse with the taller gears. I just dropped four teeth off the upper sprocked on my Intruder and the belts last a lot longer, the belt spends more time in the middle of the flange and there is substantially more starting thrust. Leave the gearing change until you are experiencing the belt reaching the top of the flange.
DRAG:
I have noticed my VMAX does not roll as easy as other sleds. When I have the sled on the garage floor and I pull it forward, the track slides on the concrete even if I remove the belt. The brake never gets hot, so I know it is not dragging. When I had the track off, all the bearings were inspected and half of them replaced, Other sleds roll on the track. Why is this? What can I do to the track, hyfax or skid frame to reduce the rolling friction? I know if the rolliing friction is reduced, the top speed will increase even though all the other aspects are the same. I used an electric motor to spin my secondary clutch to measure the power required to turn the track at about 12 mph. It was about 1.2 horsepower with the back of the sled hanging on a lift and the track off the ground. Track tension was set according to the service manual. By loosening the track tensioners about three turns, the power required was cut in half. At 120 MPH, this power loss would be 12 hp with the track tight and 6 hp with the track looser. Why does the HP requirement go up so rapidly with track tension. What can be done to reduce the friction to match other sleds that roll when pulled on concrete? Running the sled at the lower track tension allows the track sprockets to slip when going over bumps at full throttle. This is unacceptable to me, so I run with the tension set according to the book.
CONTROL:
When you are going fast, you need to be able to steer and stop. You don't want to crash every time you ride.
COMFORT:
It not fun to go fast and be exhausted before all the other riders in your group, You need to be comfortable enough to survive the ride. It is no fun to limp away from the machine every time you ride it even when you do not crash.
makes sense but i know my sled spins like crazy if i dont ease into the throttle from a dead stop... higher gears should make this better... then again thats on snow... ive never been on ice, it doesnt exist around here (at least not big ice)Joe wrote: GEARING:
The Yamaha clutches are intended to keep the engine at the shift RPM from about 12 MPH up to the time the belt reaches the top of the primary clutch flange. If the belt never reaches the top of the clutch flange, there is no need to gear it higher. All you will be doing is putting more stress and more heat into the belt at slow speeds. If you have trouble with belt life with the stock gearing, it will be noticibly worse with the taller gears. I just dropped four teeth off the upper sprocked on my Intruder and the belts last a lot longer, the belt spends more time in the middle of the flange and there is substantially more starting thrust. Leave the gearing change until you are experiencing the belt reaching the top of the flange.
when you say your track slides when you pull it... you dont mean it sliding on the studs do you? we park our sleds on 4x8 sheets of thick plastic and i dont believe mine slides... tho it is really hard to pull i will admit
My airbox is held on by one screw, not because Im lazy but because it is less weight!
Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
One of the biggest free HP things you can do is blueprint the chassis, first check the drive and jackshaft for straightness ,then put the drive sprockets back on and check to make sure that they are even, you can put them in a lath and see if they are even across the tops,you can take up to 0.020 off but thats about it without messing up the pitch, they are only plastic so they could be (and are) uneven.Next put the driveshaft back in (with new bearings)and put the chain case and jackshaft in ,use spacers over the jackshaft in the chain case and put the nut on and tighten ,check to see if the jackshaft is centered in the bearing bore on the clutch side,shim the chain case so it is dead center ,next put the gears on in the chain case and lay a straight edge on the gears and make sure they are even with each other use shims to get them even.Now put the rear suspension back in and make sure it is centered in the tunnel,use shims ,or what ever it needs to be centered.Make sure you mark everything so when you take it back apart to put the track in you can get everything straight and even again.Doing this to any sled will get you FREE HP and they should roll freely ,even the Vmax. I have done this to my sleds and they both roll freely.You have to remember these are production sleds and old sleds so nothing is straight or parallel.
JEFFERY M FOURNIER
SLEDS
83 VMAX 540
81 SRX 440
SLEDS
83 VMAX 540
81 SRX 440
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Bob Vehring
- Posts: 659
- Joined: Tue Feb 24, 2009 12:42 am
- Location: Milw. Wi
It might make it easier to understand if you relate your sled to a car. The clutches are the transmission 3,4,5,6, speed. The gears are like the rear end, a completely different thing.
Our clutches don't have gears, but are constantly variable going from a low to a high and some overdrive. Gears will cause you to accelerate quicker or slower depending what ratio you choose.
Back in the 80's we used to race an SRV, we would change the gears dependent on the length of the track. A smaller top, or bigger bottom gear will make you accelerate faster and reach your top speed sooner. The opposite will accelerate slower, but allow you to reach a higher top speed. Today I no longer race that sled, I went back to a 15 on the top because I don't car about top speed on a lake, but want it to be snappier on the trails. And it is.
A sled reaches its top mph when it can no longer overcome its frictional drag, the point when it just cant go any faster. From the factory gearing, taking away bottom or adding top teeth will give you a higher MPH if you engine makes enough power to pull that gear but it will take away from acceleration.
Drag, as Joe explained is you worst enemy. It will slow you down, and limit your top speed. On any of our drag sleds or the 120's we build, the chassis are blueprinted. This goes beyond checking bearings and aligning wheels. All shafts are measured to besure they are square with each other and everything is in alignment. Wheels are trued on a lathe. I set track tension just a hair tighter then where it will ratchet on a hard launch but be careful that your track doesn't balloon and the picks hit anywhere if its that loose.
Today its no longer cool to use slide rail lubers with anti freeze, but you can get slides with graphite in them and I take a 1/2 in. drill bit and drill small pockets all along the slide surface. This both cuts down on the surface area which creates drag, and the little holes fill with snow to help lube things.
The page that Tyler directed you to on pipes shows a graph that I believe comes from Dyno tech show that the stock pies are about as strong as it gets. Pipe technology has come a ways since those tests were down, but unless you have serious porting and are willing to twist it harder, I doubt you'll have much luck with custom pipes.
For carbs, I have cut and bored (39 1/2) on my SRV, but theres alot of work done to that engine. I doubt the V Max will need much more then the 38's unless alot of work is done also
One last word of advice, to get my SRV to live on crappy trail gas, I have taken all the compression back out of it and still have to continue stay on top of jetting and watch the EGT all the time. And last trust me on this, no one ever thinks of this. My SRV gets exactly 41 miles to a full 7 gal tank of gas. Man I hate it when that happens. Bob
Our clutches don't have gears, but are constantly variable going from a low to a high and some overdrive. Gears will cause you to accelerate quicker or slower depending what ratio you choose.
Back in the 80's we used to race an SRV, we would change the gears dependent on the length of the track. A smaller top, or bigger bottom gear will make you accelerate faster and reach your top speed sooner. The opposite will accelerate slower, but allow you to reach a higher top speed. Today I no longer race that sled, I went back to a 15 on the top because I don't car about top speed on a lake, but want it to be snappier on the trails. And it is.
A sled reaches its top mph when it can no longer overcome its frictional drag, the point when it just cant go any faster. From the factory gearing, taking away bottom or adding top teeth will give you a higher MPH if you engine makes enough power to pull that gear but it will take away from acceleration.
Drag, as Joe explained is you worst enemy. It will slow you down, and limit your top speed. On any of our drag sleds or the 120's we build, the chassis are blueprinted. This goes beyond checking bearings and aligning wheels. All shafts are measured to besure they are square with each other and everything is in alignment. Wheels are trued on a lathe. I set track tension just a hair tighter then where it will ratchet on a hard launch but be careful that your track doesn't balloon and the picks hit anywhere if its that loose.
Today its no longer cool to use slide rail lubers with anti freeze, but you can get slides with graphite in them and I take a 1/2 in. drill bit and drill small pockets all along the slide surface. This both cuts down on the surface area which creates drag, and the little holes fill with snow to help lube things.
The page that Tyler directed you to on pipes shows a graph that I believe comes from Dyno tech show that the stock pies are about as strong as it gets. Pipe technology has come a ways since those tests were down, but unless you have serious porting and are willing to twist it harder, I doubt you'll have much luck with custom pipes.
For carbs, I have cut and bored (39 1/2) on my SRV, but theres alot of work done to that engine. I doubt the V Max will need much more then the 38's unless alot of work is done also
One last word of advice, to get my SRV to live on crappy trail gas, I have taken all the compression back out of it and still have to continue stay on top of jetting and watch the EGT all the time. And last trust me on this, no one ever thinks of this. My SRV gets exactly 41 miles to a full 7 gal tank of gas. Man I hate it when that happens. Bob
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Bob Vehring
- Posts: 659
- Joined: Tue Feb 24, 2009 12:42 am
- Location: Milw. Wi
-
Sno jetter
- Posts: 4
- Joined: Tue Oct 27, 2009 6:40 pm
- Location: Durham,ny
Bob Vehring wrote: Today its no longer cool to use slide rail lubers with anti freeze, but you can get slides with graphite in them and I take a 1/2 in. drill bit and drill small pockets all along the slide surface. This both cuts down on the surface area which creates drag, and the little holes fill with snow to help lube things.
Bob another one ive been told is take the divits that you drill in the slides and pack them with grease..... i know it's an old timer trick some guys used to use, when your rails get warm the grase slowly comes out and keep is nice and slippy!!
sorry bout bein late to the party...lol
Joe
I got to many projects....