davidgboy
New member
yup i am at it again. hear me out. these oil pumps are variable rate. i believe that they vary the actual oil /fuel ratio.(not just supply more oil for increase in fuel consumption). that is great. 1 problem: when a new ratio is created at fuel pump there is a delay before it gets to carbs. fuel in the lines and what has been mixed in fuel pump must be displaced before "new fuel" enters carbs. there is ~ twice the delay for the carb. feeding mag cyl. this cannot be desireable. is it acceptable? obviously yes but this does not mean it is optimum. so to satisfy my morbid curiosity i have spliced in 3 tees into the fuel lines just before the carb inlets. ran 2 tees after oil check valve to supply fuel tees. now all 3 carbs. will receive the "new fuel" much sooner and at the same time. 1 problem: not sure if it will create desireable ratios or even work at all. only 1 way to find out. i think it will mix o.k. i will first run line from cont. of premix until lines are primed. not even sure how that will go. i will monitor the situation real close like. could i toast my topend? maybe. i still have to try it. wait til u see my rear exit exhaust. came out as well as could possibly be expected. got tired of people bashing old school 2 smokers because they stink after a ride. will get my nephew(laporte 429-poor kid) to help me with video, probaly will go youtube. i used ~5ft. of 2.25 o.d. .049" alum. tubing. wt.= 2 lbs. reduced weight of muffler ~ 1.5 lbs. with redesign(only 4th[last] chamber is mod.) all quiet. seems to run fine. not sure on w.o.t. runs. i can put it back to stock exit if need be. only spent about $90. i luv it! even if it dont work out. tried posting a couple of pictures but they are too "large for this site". not sure how to downsize them.
staggs65
Moderator
well....youre never short of ideas, thats for sure
Right click on photo and open with Office Picture Manager.
Hit the "Edit Pictures..." at the top tool bar. Hit Resize button on the left and choose Predefined Width x Height. Choose Web Large 640 * 480 and save file. Then try and reupload to site.
Hit the "Edit Pictures..." at the top tool bar. Hit Resize button on the left and choose Predefined Width x Height. Choose Web Large 640 * 480 and save file. Then try and reupload to site.
davidgboy
New member
staggs65 said:
yup not surprising that they are not all that good. u were correct about my premix idea. i thought these pumps kept a rather constant ratio. was lazy about the investigation. i think for premixing for racing keeping line to crank and running line from check valve(2 fuel pump) into oil res. is good way 2 go though. maybe some snow coming? we wil see.
opsled
Active member
Stay tuned for the next episode of,,,,,,
Death for a Viper
lol,
opsled
PS, Seriously man, put it back to stock. It will be just fine. Oil injection systems are designed to match fuel flow to keep the mix ratio consistant. Idle, midrange, wot, no different. The same oil/fuel ratio is being fed to your carbs at all times. A variable rate pump is needed to do so on an engine that sustains variable loads at variable throttle positions.
No other way to do it.
Death for a Viper
lol,
opsled
PS, Seriously man, put it back to stock. It will be just fine. Oil injection systems are designed to match fuel flow to keep the mix ratio consistant. Idle, midrange, wot, no different. The same oil/fuel ratio is being fed to your carbs at all times. A variable rate pump is needed to do so on an engine that sustains variable loads at variable throttle positions.
No other way to do it.
davidgboy
New member
opsled said:
well that is what i thought originally. but i read here on ty that it will vary depending on throttle opening. at small openings it may be as low as 80:1 and as high as maybe 35 or 40:1 once u are past a certain amount of opening.
bluemonster1
LIFE MEMBER ONLY ONCE!!!
I would leave it as is also.My 2001 SXR600 now has 8000 miles on the motor.I put a new top end in last year just because,otherwise that motor ran like a top.Now I also run my sleds full bore a lot of the times.I even tried to blow up my motor on purpose one Spring..just giving her..couldn't do it.So I am thinking that the oil injection system that Yamaha designed works well enough..must be getting good oil delivery or else motor would of been in pieces by now...
opsled
Active member
davidgboy said:
Yea it does vary with throttle position but so does the fuel consumption rate.
At low throttle the fuel flow is low so the oil pump pumps less oil. As throttle opens and fuel is used at a faster rate the flow of fuel to the carbs increases to keep them full. The oil pump is tied to the throttle position via the oil pump cable. That cable varies the rate to increase the oil flow that must now match an increased rate of fuel headed to the carbs.
It's all about oil flow matching fuel flow at the oil delivery port to keep a consistent mixture supplying the carbs.
opsled
davidgboy
New member
not the way i read it. this system varies the actual ratio. my idea very well may not work. i still like trying out ideas. i am willing to take chances. its fun
motorhead327
VIP Member
davidgboy said:
So your looking for a constant ratio at all rpm's vs lets say 50.1 at 8000 and 100.1 at idle?
davidgboy
New member
looking to cut down time it takes for gas with "new ratio" to get into engine. especially the mag. cyl. which gets the "new ratio" at twice the delay of the other 2. it is a risky venture to test. certainly foolish also. there is a small section of fuel line(clear) between tee and fuel inlet so ican see if fuel is mixing with oil. gonna run it on premix in seperate cont. while i try and prime it. may not work. cant help myself. just got to prove it 1 way or other.motorhead327 said:
Rustman
New member
davidgboy said:
You're using flawed logic, the same ratio is always flowing if everything is working right, which seems to be the norm rather than the exception. Opsled already laid it out for you. The gas in your bowls have been premixed at idle with no throttle applied, you then apply the throttle which also extends the oil cable. More gas flows but so does more oil keeping the ratio the same as whats in the bowls already. In my mind it seems that the ratio is constant. Yamaha has been doing this for many years, with proven results, it wouldn't make sense to keep using a flawed system.
Bender for years had a direct injection kit avail for Yamaha models that injected the oil directly into the intake tract behind the carbs. The concept was to elliminate oil lag to the engine when full throttle was applied. People used the Bender kits with few problems but stock sleds also operated just fine without the Bender kits.
The biggest advantage of the stock system is that the oil has a much better chance to blend completely with the fuel as it is pumped into the fuel pump , travels thru the lines, rushes into the float bowls to be distributed thru the jets...lots of turbulence, lots of blending.
Some points of interest:
-When Yamaha first started injecting two strokes they had a more direct injection system, they evolved to the system used on the SRXs + Vipers.
-some other manufacturers used a more direct injection system...notice Yamaha sleds tend to out last all others
-many years ago when I was modifying my 1991 4 cylinder Mercury 125 outboard I found it interesting, that on this model, Merc injects the oil into an enlarged fuel line just prior to the fuel pump...not unlike what Yamaha does.
Yamaha engineers have proven many times they know what they're doing....
IMO....
If it aint broke...DON"T FIX IT
[LOL!...if I could only listen to my own advice...]
Bob
The biggest advantage of the stock system is that the oil has a much better chance to blend completely with the fuel as it is pumped into the fuel pump , travels thru the lines, rushes into the float bowls to be distributed thru the jets...lots of turbulence, lots of blending.
Some points of interest:
-When Yamaha first started injecting two strokes they had a more direct injection system, they evolved to the system used on the SRXs + Vipers.
-some other manufacturers used a more direct injection system...notice Yamaha sleds tend to out last all others
-many years ago when I was modifying my 1991 4 cylinder Mercury 125 outboard I found it interesting, that on this model, Merc injects the oil into an enlarged fuel line just prior to the fuel pump...not unlike what Yamaha does.
Yamaha engineers have proven many times they know what they're doing....
IMO....
If it aint broke...DON"T FIX IT
[LOL!...if I could only listen to my own advice...]
Bob
Now, I am one for inovation and self taught ingenuity. So, go ahead and try all of your ideas. Some will work, some won't. Note, it will cost you, it sure did me. I still even at my age, try differant ideas. Some work, some don't. But, that is how you learn. I have stopped messing with modifying engines, as I have now found OEM stock works the best for me. I like being able to run several hundred's of miles or even thousands without any issues. But as for suspension, that is where I have turned my thoughts. So, keep up the good work, let us know you results. Al
09nytro
New member
Bender makes a oil injection kit. Got it on my viper works great ( been on for 5500 miles) so I guess I'm saying you are not doing nothing new well maybe were you are injecting it in at I wouldn't do it there but two each its own
davidgboy
New member
sideshowBob said:
this will still have chance to mix as it is pushed into fuel goes into carbs and is forced into jets. will it be enuf? will it work at all hard telling. my concern is what will the ratios be relative to before? i really hate the idea of the extra delay to the mag cyl. good chance it will end up back as stock though. might be after it gets some new pistons lol - hopefully nothing more than that
davidgboy
New member
did not want to change the original concept much just try and fine tune it. good chance i will fail but it is still fun. well til i ruin engine. oh well things blow up everyday whats a snowmobile engine matter?09nytro said:
opsled
Active member
I would like to say that today I cut down a tree and had a real nice conversation with it's stump.
opsled
opsled
davidgboy
New member
opsled said:
at least maybe it listened to ya
bluemonster1
LIFE MEMBER ONLY ONCE!!!
are you gonna record your sled blowing up when you are testing??Just wandering,it is just a snowmobile engine.They are cheap to find now anyways..loldavidgboy said: