Anti frothing race oils

[chuckhahn]

I have a kinda unique problem. I own a 1973 Yamaha TX750 motorcycle. Back in the day it was known to burn up cams due to oil starvation. Engineers found that the counter balancer system whipped the oil and made it frothy...thus the pump would loose prime and therefore the top end wouldnt get any oil. I was advised to check with you folks for your opinion on what would be the very very best non foaming race oil to use in this bike since it is prone to frothing using "regular" oils.

Here is a link to an article that was written by one of the guys that was directly related to the recall program back in 73, The article details the problem to great extent. Thanks for taking the time to read the article and brainstorm how I can best protect the bikes engine. I have fully rebuilt it and just am at the point of needing the oil puzzle solved before firing the bike up again.

http://www.classicyams.com/4-stroke/4-stroke/yamaha-tx750-story.html

 

[quarterliter]

I would run the oil level low. Not low low, but lower than the full mark, maybe slightly lower than halfway but still in the safe area. So the balancer wouldn't hit it. I like redline oil, and if you aren't concerned with clutch slip, the 40wt race oil is good stuff. It also needs to be changed often. Dave at RedLine told me half a season of street riding. I mix it 50/50 with a 10w30 car oil to get some detergents so I can run it longer. Both of these oils contain no viscosity improves from my understanding so they will not shear much. There is lots of moly in that combo, but it makes an audible difference in how quiet the engine runs.

 

[chuckhahn]

I should also note that this is a dry sump engine. Oil runs straight to the sump..which the balancers just clear the bottom of the pan..and a scavenger pump is supposed to suck it up and return it to the oil tank under the seat so the oil can be recirculated. But if its frothed up, the pump cant recycle it back to the oil tank..follow the problem here???

I was also looking at some anti foam additives such as that Navistar Fleetrite stuff. where can i get that at ??

 

[Cardenio327]

Originally Posted By: chuckhahn
I was also looking at some anti foam additives such as that Navistar Fleetrite stuff. where can i get that at ??


Ryder (the heavy truck leasing corporation) has a website where they sell truck parts over the internet, they might have something wacky like that, I think I've seen genuine Navistar parts on there. An International truck dealer could order it for you.

 

[quarterliter]

Originally Posted By: chuckhahn
I should also note that this is a dry sump engine. Oil runs straight to the sump..which the balancers just clear the bottom of the pan..and a scavenger pump is supposed to suck it up and return it to the oil tank under the seat so the oil can be recirculated. But if its frothed up, the pump cant recycle it back to the oil tank..follow the problem here???

I was also looking at some anti foam additives such as that Navistar Fleetrite stuff. where can i get that at ??


I would have never guessed that it was a dry sump. Sounds like some sketchy engineering went on in the early 70s at Yamaha.

 

[Smoky14]

I had a 1974 TX750 with the interstate tank and of course it had the adjustable balancer chain. I was working in a Yamaha shop at the time and must have replaced the original 1973 cases and balancers on at least 5 machines.
That being said we never had foaming problems with the bikes because of the dry dump system. The oil did have a habit of draining down over night and could do quite a bit of splashing for a few minutes while the bike warmed up. Many people would over service the oil because they would check it cold in the morning and add oil before the sump cleared.
I'll check my old books, I may still have a parts and service manual for the TX.
I rode my 74 for over 80K miles without trouble between CO and AZ.
Ride the old girl

Smoky

 

[chuckhahn]

Smoky14...Thanks for the insight. I am basing my info on the foaming oil situation from the article I posted in the link in a previous post. Seeing that this one is the 73 and was before the sump extention modification, this is probably why your 74 wasnt problematic. By 1974 they had came up with the fix, but the damage had been done and noone seemed into these bikes after the 73 model problems.

However, I would like to ask that should you have the 1974 updated oil sump extention collar thing ( and maybe the bolts ) I would like to purchase it from you. As I understand things, it will directly bolt to the bottom of the 73 engines as well.

Ideally, the extended sump and anti foiming oil ( or an anti foaming additive ) combined should be the best of all worlds for the bike. Least this is my thinking. What do you think??

If you have the parts and wish to sell them leave a message here and I will be sure to contact you immediately. Thanks, Chuck.