...........................has any one had any experience with this system? Good- bad or as gimmick?
Cheers
Cheers
opsled
Active member
Gimmick (or just flawed thinking/understanding of how a Yamaha oil injection system works) in my opinion.
I will change it as soon as someone can prove the perceived flaws in the Yamaha system.
I doubt that is going to happen.
Stock Yamaha oil injection is the best.
opsled
I will change it as soon as someone can prove the perceived flaws in the Yamaha system.
I doubt that is going to happen.
Stock Yamaha oil injection is the best.
opsled
opsled said:
Thanks opsled, i was thinking the same, time to plug em up and put it back to stock
Cheers
the oil gas is mixed in the fuel pump so when you go WOT there is a lag time of the change in condition with bender kit there is no lag in the right amount of oil when you go to WOT hope this explains it. but the bender system work's great
opsled
Active member
DARV said:
I knew this was comin. Old post of mine from Vmax4.com.-----
Personally I don't like the direct oil injection kits. All of them that I have seen have plumbing that I would call rinkydink at best.
I think that the possible "lean oil" condition that many describe is more myth than fact.
I would be more concerned about each cylinder getting the proper lube with a direct injection kit. With all the extra T's, connections and line there is more chance of leaks/line failures and who's to say that two cylinders being fed via a single line with a T in it are being fed the same amount?. Fluid flow will go to the path of least resistance and that T setup does not garauntee and equal split to the two cylinders it's feeding. That bugs me.
I like my oil mixed with the fuel at the pump as I think it has a better chance of doing it's job mixed with the fuel before it enters the carb as opposed to being dumped in after the carb then trying to mix in a milisecond with the air/fuel coming through. Yamaha has used both system for many years but the upper end sleds all have the oil to fuel pump design.
I don't believe in this "lean oil" theory. I believe that the mixture the stock system provides is always right no matter what you do with the throttle.
The oil pump does vary rate but I believe it is to compensate for and match the increased fuel flow at higher engine speeds not to change the actual mixture. This makes sense to me but a change in mixture doesn't. Think about it. If you don't have oil injection and mix your fuel there is never a change in the oil/fuel mixture that is feeding the engine. No one is concerned about that becase there is no need to be. Mix it right, put it in the tank and your good to go. Why would one assume that the factory setup changes this oil/fuel mixture? I don't. It needs to be able to vary to match fuel flow but other than that???? I see no difference.
Now I could be wrong but I have never had anyone prove otherwise and this system has been used by Yamaha on many models without any failures I know of that could be atributed to design.
Yamaha doesn't build junk and when they have had design flaws in the past they have always made them right. This system of injecting oil into the fuel pumps was used right up to the day they quit building two strokes.
That says a lot to me.
Many will disagree but??? None will/can prove me wrong. When they do I will concede.
----------That was the post
Now with that being said here are some pics of the Bender 880 Vmax-4 trail sled my son bought. It ran great. Cylinders comped at 152-155 across the board. The center two cylinders were scored bad. Carbs were clean and plugs read fuel was good (not lean). It had direct injection on it. In the original form two oil lines fed two fuel pumps. Oil/fuel was mixed and sent to two carbs. In this direct system two lines are Tee'd at the carbs and each one feeds two carbs through a (cheap) plastic T. There is no flow control after the T. Which cylinder gets what is anybody's guess. Yamaha never Tee'd oil lines to cabs on their factory direct injection. There was always one line per cylinder coming off the pump.
I think the logic behind direct injection over injection into the fuel pumps/lines is flawed. If you understand how oil injection works and why it needs to be variable the agument in favor of direct injection doesn't stand up.
I have no other answer to the issues on this 880 other than an unequal flow from the direct injection unless it was a tolerance issue between piston/wall when the engine was built. If so it's still odd that it was the center two that showed the most damage.
Check out that sophisticated plumbing in the pics. Notice the inside two pistons are much dryer looking. Tell me why? It's all coming off. Junk.
Again, prove me wrong and I will concede.
opsled
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bufalobob
Member
1.) that's not a bender oil injection kit.
2.) i put over 12,000 miles on my 880 bender vmax4 w/ their oil injection kit & never had a problem. i ran 155-157.5-157.5-155 mains & that was not overly rich & that's many years ago when fuel quality was better.
bob
2.) i put over 12,000 miles on my 880 bender vmax4 w/ their oil injection kit & never had a problem. i ran 155-157.5-157.5-155 mains & that was not overly rich & that's many years ago when fuel quality was better.
bob
opsled
Active member
bufalobob said:
Thanks for the post Bob.
Your mileage claims make me feel better about the longevity of this engine once I put it back together. If you don't mind I may pick your brain on it in the future.
I didn't say that this rinkydink setup was a Bender but only posted the picks to show what I'm talking about. I have seen the same kind of back yard oil injection plumbing on other Yammies that have been converted to direct injection. Fuel is the life blood of a two stroke and oil is the oxygen that sustains it. It really bugs me to see people take the quality of materials and workmanship so lightly when dealing/installing with these systems. Fuel/oil plumbing is the most inexpensive part of what is needed to make a two stroke run and live but some just don't care and do stuff like this. I find no logic in it.
I have great respect for the minds of Kevin Cameron, Tim Bender and others that have discredited Yamaha's system of injecting oil into the fuel pumps/lines. Their reads have been very informative and their thoughts are deep. However I don't believe their claims on this Yamaha system are correct. I would agree with them if they could prove that the Yamaha system is designed to change the oil/fuel ratio that is consumed by the engine (this is the base for their claims). My belief is that the changes in oil flow that the Yamaha system makes is only to keep pace with fuel usage at the time so as to keep the final ratio the same at any speed or throttle position. This has been my contention for years and I have yet to be shown anything to the contrary.
That being said I don't think direct injection is bad. I just think oil injected into the fuel is better. Yamaha must too as that's how they chose to do it and they invented/used both methods.
My 880 will be going back to the stock system when it gets done. Yamaha has had no issues with the design that I am aware of and there are millions of machines out there running on it.
opsled
Vmax540
VIP Member
Question, who and when did they put the direct injection kits on the market ? Curious if the D.I. kits where brought out to cure/hide the Exciter mid range and when backing off of a high speed run burn downs ? I bought a new leftover 88 Exciter in 89 and my dealer insisted we install a D.I. kit, PSI needles, blocked off the pwr jets, rejetted and added Yamaha's updated air box and I ran that over 5000 miles until the day I sold it with out one rebuild or problem.
dsc577
VIP Member
put 9000 on my 90,with a bender kit,psi stuff,never touched the motor,but each carb gets it own hose,i wouldnt use it with tees