951DI Air Pump Crank Pin

[68ragtop]

According to the Manual, The crank pin should have a beveled edge that installs towards the CB. What I found was both ends of the pin are the same. very outer edge is beveled. However, it does have a groove on one end that is not mention in the manual. Anyone know what way this is suppose to go in? If I installed it based on the wear marks from the bearing, the groove would go "away" from the CB shaft. But, there has been nothing about this engine during teardown that would make me believe it was installed correctly. Is this a superseded part?

 

[Sportster-2001-951C-Stock]

Yep, clear as mud to me too........ The word "concave" really throws me off. This sounds like a swaged fit, which makes no sense to me whatsoever.

Edit: Thinking about this more, I guess you have either an aftermarket bushing or a later improved revision. I'd be tempted to install the bushing with the grooved end at the fastener head, out of concern the groove would otherwise weaken the end of the bushing at the mounting surface, then flex or wobble under load and could allow the bushing fastener to work loose?

 

[68ragtop]

My thoughts too.

When I put a straight edge on all sides. I don't see any difference between them. I was expecting a sharp edge on the
outside, with the CB side tapered, or something. Not sure what they are after. maybe its supposed to dip inward? I'll look again...........

con·cave (kn-kv, knkv)
adj.
Curved like the inner surface of a sphere.
n.
A concave surface, structure, or line.
tr.v. con·caved, con·cav·ing, con·caves
To make concave.



they should also decide if its a pin, or if its a bushing.....

 

[Sportster-2001-951C-Stock]

I'd install the groove at the fastener head, for the reason in the edit above. I think the bevel is just to get the pin centered into the recess and there must ultimately be a flat mating surface there a swaged mating surface would seem unreliable in that location.

 

[Sportster-2001-951C-Stock]

Swaged, meaning like ball and socket joint, which is just what you don't want........

Oh jeeze, and how does lubricant get into the big end of the compressor rod? No needle bearing there, or even babbit insert............???????

Ha, ha, ha, don't apply thread locker, that sounds like good advice, but the new fastener has a pre-applied coating...... Would be ugly if the fastener let go.

Wonder how much time the English translator working on the service manual spent struggling to select the best terminology? Gotta say, they did a pretty good job, I'm sure it wasn't easy.

 

[Sportster-2001-951C-Stock]

Also, the groove is probably the marking (referenced in the service manual) that identifies the end that should go under the fastener head

 

[68ragtop]

Good point on the mating surfaces needing to be flat. I ordered a new bolt last week, I missed the "torque + rotation" spec on that bolt.
Of coarse that equates to. Don't re-use the bolt!

I have to admit, the seadoo manuals are pretty darn good in general. The Arctic cat engine manuals are terrible by comparison. Those engines being made by Suzuki doesn't help much at all.......

I chuckled a few times when reading the BRP manuals where they would say "use tool number XX-XXXX, or a a solid chunk of wood will work" Not plagiarizing here, but it was something to that effect.

On the oiling, its an interesting system. It has a check valve/oil injector placed in line with the air pump rod. This lubricates the rod bearings, the CB end bearing & the cylinder. Then there is a return drain in the bottom of the cavity the goes back to the fill neck of the oil tank. Then, there is a vacuum line hooked up the the throttle body that puts the oil tank into a vacuum, this vacuum appears to be what pulls the oil out of the Air pump cavity. Not 100% positive on this yet, but it does appear to be plumbed that way.

If the oil tank has a leak, or isn't sealed well, I believe the pump cavity would become drown in injection oil.

 

[68ragtop]

Also, the groove is probably the marking (referenced in the service manual) that identifies the end that should go under the fastener head

What year book did you see that? This 2002 manual doesn't talk about anything except the "con caved" end. I am going to install it like you mentioned, I was just curious.

Thanks for you efforts!

 

[Sportster-2001-951C-Stock]

I'm reviewing the 2001 manual, it advises to mark the bushing end before disassembly. I guess the inference is, one end should be marked, the outer end. Apparently early(or factory?) bushings weren't marked. and the manual instructs during disassembly, to mark it.

From bottom of p 06-03-10 of 2001 manual, disassembly:
"IMPORTANT: Trace a mark on crankpin (bushing) outer end. This is needed for reinstallation."

 

[68ragtop]

When i removed the pin, I could see the marks left from the being, So I could tell what end what what. But, this thing was such
a mess, I didn't trust it was put in the right way when the PO took it apart last time.

Thanks again for your input!

 

[Sportster-2001-951C-Stock]

It has a check valve/oil injector placed in line with the air pump rod.

This makes sense, this oil supply could be the one coming from the crankshaft driven injection pump, the third injection line that carb engines don't have.

Yep, I'm definitely in an oily fog(attempted pun) concerning the minor plumbing details, I was under the impression that air pressure in the compressor crankcase along with pressure released from the RAVE valve system is used to push the return oil back to the oil tank.

A few months back, another poster had changed out his 951DI for a reman engine and was experiencing issues with his RAVE valve solenoid air supply hose, it kept bursting. I don't think he resolved the issue, unfortunately.

 

[68ragtop]

yep, its the third port on the oil pump. Same check valve as the crank case has. The Air pump cavity is pretty much sealed up with exception to the oil inlet & return. The piston or air pump might very well drive the oil back to the tank, until I looked at the plumbing I was thinking that way too. The return line is uphill the whole way back to the tank, But seeing this air pump creates over 90psi, I am guessing any blow by of its rings would also create a positive pressure in this cavity as well. So maybe that it too? maybe its both? I'm still not sure myself.

 

[68ragtop]

I installed the Pin with the new bolt. 58inch-lbs + the 80 degree turn. Let me tell you that was a bit hairy. at 45 degree's it already felt tight, at 80 when I stopped It felt like an effort level where I was going to snap it right off. Definitely not a bolt to reuse as these really get a stretch. If I didn't have the service manual specs in front of me, there's no way I would have turned that little bolt that far.

 

[Sportster-2001-951C-Stock]

Is there a grade stamped on the fastener?

 

[68ragtop]

Is there a grade stamped on the fastener?

Yep, 12.9 stamped on the allen cap head. I believe thats a grade 8 equivalent.

tough little 6M bolt for sure

 

[Sportster-2001-951C-Stock]

Best grade, that puppy's good for 31/42ftlb wet/dry on the chart.