Alpha intake question

[Turboflash]

Pics from '22 had one funny looking plug & did a compression test. All three cylinders were 160psi using an AutoZone gauge. No oil on plugs.
Yes, cheap gauges can cause faulty readings. But the point would be, all equal. You think all cylinders would be down, evenly??
View attachment 174064View attachment 174065

Not necessarily. Center cylinder is hottest. Most engines I've rebuilt for guys have 1, maybe 2 bad holes but 3rd is good. Leakdown test is best to ascertain health of each.

 

[Doc Harley]

Not necessarily. Center cylinder is hottest. Most engines I've rebuilt for guys have 1, maybe 2 bad holes but 3rd is good. Leakdown test is best to ascertain health of each.

Oh, good....now I know who to bring my sled to when she pops. Lol. Understand.... But its like I told nyturbo, The results are only as good as the tools used. Using autozone leak down tester doesn't bring me a lot of confidence.
I hate buying things I don't normally use.
Btw.....shell probably go not too far from your place. Hahaha....

 

[KnappAttack]

Well..... A lot of guys get blow by through this tube. That doesn't make it right. Someone explained that if your oils too high that you'll get a little bit more than normal. And I run my oil high. Who knows. But as of now I'm not too worried.
Same applies to my Harley. If I don't run it a half quart low, s*** spraying everywhere.

I have a lot of machines thru the shop and have not seen any with blowby thru the valve cover hose. Certainly no oil being pumped out of the hose at all.

I’ve never checked, but being a dry sump system there should be vacuum there when running, not pressure. Now the vent off the oil tank is a different deal, there is air and perhaps oil mist coming out of that one.

 

[Doc Harley]

I have a lot of machines thru the shop and have not seen any with blowby thru the valve cover hose. Certainly no oil being pumped out of the hose at all.

I’ve never checked, but being a dry sump system there should be vacuum there when running, not pressure. Now the vent off the oil tank is a different deal, there is air and perhaps oil mist coming out of that one.

I understand all that you're saying & as always 100% respect. But it's very difficult to argue with the masses. so, it puts me in a place as to not worry so much. To be completely honest, it was very little, but definitely coming from the valve cover line as I've blocked off the Bov.
And I promise no mercy to this motor this season.

 

[1nc 2000]

I run a Hurricane under hood intake with no provision for the valve cover vent hose. Instead of having it dangling on by belt gaurd I ran a hose to rh footwell. I dont have any oil coming out of it but I moved it anyway.

 

[Turboflash]

I have a lot of machines thru the shop and have not seen any with blowby thru the valve cover hose. Certainly no oil being pumped out of the hose at all.

I’ve never checked, but being a dry sump system there should be vacuum there when running, not pressure. Now the vent off the oil tank is a different deal, there is air and perhaps oil mist coming out of that one.

Agree for most part. That said, ring seal is never 100% perfect so any internal combustion engine has some minor blow-by due to this which is the reason for PCV systems. The only way there would be more than minimal (indescernable) pressure would be if rings are not sealed very well (ring and/or cylinder) damage. I've repaired 998s where rings got so hot it took the temper out of them making them ineffective.
Again, cylinder leak-down and compression tests are best ways to learn ring/piston health. I also have a nice HD fiber-optic camera to insert in plug hole to see clearly what piston, cylinder, rings, and valves look like. My camera has a mirror to be able to see valves too. I can even save and print images.

 

[1nc 2000]

Cross hatch on cylinder walls here with a snap on bore scope.
How much boost and miles before the cylinders begin to go out of round?
The tan line is oil film being pushed up with the rings. It's not very much but the picture makes it look misleading. Sled doesn't use any oil.
I was doing compression tests before I used the bore scope.

 

[Turboflash]

From my experience w Yamaha engines, they last a long long time IF deto doesn't ruin them. My '17 manual says to check valve shim at 25,000 miles. From the 998s I've rebuilt, even w substantial ring or piston deto damage, the rest of the engine was like new (bearings, seals, rods, crank, etc). So, I'd say Yamaha engines are VERY durable, even whole being abused. Just keep up pn oil changes, keep cooling system working right, and prevent deto and they'll run a long time. I've not measured cylinder roundness butcI bet it's almost same as new. NiCaSil bore. I've rebuilt 998s with 5000 miles and still see cross-hatch.

 

[NYTurbo]

I understand all that you're saying & as always 100% respect. But it's very difficult to argue with the masses. so, it puts me in a place as to not worry so much. To be completely honest, it was very little, but definitely coming from the valve cover line as I've blocked off the Bov.
And I promise no mercy to this motor this season.

Blocked off the BOV ?

 

[Doc Harley]

Blocked off the BOV ?

Yes, did that and pulled the intercooler to drain, last year. I'm getting very little bit out of that valve cover vent. I'll keep an eye on it and see what's going on. I think some blow by is acceptable. And I run my oil clear to the top of the sight line. And that is probably causing things to exacerbate.

 

[Turboflash]

You must mean ROV? Can't block off BOV.

 

[KnappAttack]

From my experience w Yamaha engines, they last a long long time IF deto doesn't ruin them. My '17 manual says to check valve shim at 25,000 miles. From the 998s I've rebuilt, even w substantial ring or piston deto damage, the rest of the engine was like new (bearings, seals, rods, crank, etc). So, I'd say Yamaha engines are VERY durable, even whole being abused. Just keep up pn oil changes, keep cooling system working right, and prevent deto and they'll run a long time. I've not measured cylinder roundness butcI bet it's almost same as new. NiCaSil bore. I've rebuilt 998s with 5000 miles and still see cross-hatch.

I'd agree with that one and the reason I'd only use the Hurricane tunes and not the others. Too many reports of the others having problems over time as you know. Dave at Hurricane refuses to turn down the sensitivity. Some of the others do turn down the sensitivity ,and some just have a non working or less than stellar working det protection. You and I know who the others are. But if they deto at all, over time the damage can be done and catch up to them. Its why having the logging is so important. You can see timing being pulled well before the dash was to flash. I prefer to see zero timing being pulled.

Yes, did that and pulled the intercooler to drain, last year. I'm getting very little bit out of that valve cover vent. I'll keep an eye on it and see what's going on. I think some blow by is acceptable. And I run my oil clear to the top of the sight line. And that is probably causing things to exacerbate.

I run my oil right at the top of the line on the oil tanks, sometimes even a bit over and have never had any "blowby" coming out of the valve cover hose ever. I could leave the hose hanging and never ever get any vapor or oil out of it, part of the reason I believe there to be vacuum on it. Maybe you babied it too much on break-in where the rings didn't seat good, or you already have internal damage? All the machines I've had thru here I've never seen oil in that valve cover hose or signs of blowby from it.

Does your machine consume some oil?

 

[Doc Harley]

I'd agree with that one and the reason I'd only use the Hurricane tunes and not the others. Too many reports of the others having problems over time as you know. Dave at Hurricane refuses to turn down the sensitivity. Some of the others do turn down the sensitivity ,and some just have a non working or less than stellar working det protection. You and I know who the others are. But if they deto at all, over time the damage can be done and catch up to them. Its why having the logging is so important. You can see timing being pulled well before the dash was to flash. I prefer to see zero timing being pulled.





I run my oil right at the top of the line on the oil tanks, sometimes even a bit over and have never had any "blowby" coming out of the valve cover hose ever. I could leave the hose hanging and never ever get any vapor or oil out of it, part of the reason I believe there to be vacuum on it. Maybe you babied it too much on break-in where the rings didn't seat good, or you already have internal damage? All the machines I've had thru here I've never seen oil in that valve cover hose or signs of blowby from it.

Does your machine consume some oil?

I agree, and would put sled towards the babied side.
Oils always full. When I pulled the cover off the air filter housing the smallest puddle of oil you can imagine was laying in the left hand corner of the interior box. Almost unmeasurable. Nevertheless was in there.

 

[Doc Harley]

You must mean ROV? Can't block off BOV.

Correct....sorry about that.
I'm so amazed that there's so many people on Facebook claiming the same (let's call it an insignificant issue.) It's like you say turboflash this thing could puke out on me this year or could go another 20,000 miles.
Last year was definitely the hardest year I've been on the sled. With testing & longer runs up top. Idk ..

 

[Turboflash]

I agree, and would put sled towards the babied side.
Oils always full. When I pulled the cover off the air filter housing the smallest puddle of oil you can imagine was laying in the left hand corner of the interior box. Almost unmeasurable. Nevertheless was in there.

Are you sure oil wasn't from foam air cleaner element? Many of those were saturated w oil from factory and actually dripped into air box.