750 oil pump removal

chrisk

chrisk

Hero member
Location
Brisbane, Australia
In an attempt to strip my 750 cases, for soda blasting. But.................................... the oil pump and drive gear have remained fitted to the case, which has been sitting for years. My dilemma is this. How the fuck do I remove the key in the shaft?? I need to know if it is a half moon type or square type. Half moon would be easier to remove.

Also, as I think I may be Phils long lost brother, in that my theory is, the lighter the better: Swiss cheesing the oil gear to the max should be OK, wouldn't it???

I've never played 750 motors before, so I need some assistance with a couple of other things:
1. There are two galleries I don't know what they are for. One is from the primary case side, running diagonal and exits in the valley behind the dipstick. And there is another on the other side too, it exits through a rough hole. Are these just breathers or am I missing something?

2. The clutch basket has two rubber lobes broken, one is opposite to the other, what is the best fix?

3. On the clutch, is there someting missing? there's the backing plate, the friction and clutch plates, the pressure plate and springs, the basket, the sprocket................. but then what. Bear in mind, I bought this motor in pieces many years ago.

4. Lastly, I have found a shaft, that I've seen before on triples, but can't remember what it is for. I haven't measured it, but it's about 12mm dia, stepped and has a half moon cut into one end. I'm not sure where it goes, any clues?

Chris









 
Hi Chris,

I will set the ball rolling before the 750 experts give you more info.

The 'half moon' is a woodruff key, much favoured for some reason but sometimes tricky to fit as the key can roll on the circular cut shaft and spit out when inserting the coupling/gear, so you have to be vigilant.
Have a look at the front or rear edge and see if there is a slight angle on the key, if so then it is circular and thus a woodruff.
To remove it you need  either to knock one end down and thus the other end up, and/or use a device that looks like a flat screwdriver to get under the front edge and lever it up. The disadvantage with using the 'knock down' method is that if the key is a tight fit you may make it a tighter fit in the groove.

Swiss cheesing the oil gear? Is it really worth the effort?
You need a nice smooth and flat surface to provide a seal on the side of the gear to stop oil escaping down the side. If too much gets down there your oil output will be lower.
 
Not sure what you are saying  your problem with the oil pump is -if it is still fitted to cases then the Oil pump drive gear and spindle will only pull off in one position - there is a slot in the pump body to allow the spindle key to pull through - unfortunately you can only see this with the spindle out! there are 2 possible correct positions which are explained in the green book I think.The spindle key is just a short length of round bar which fits through a hole cross drilled into the drive spindle with a bit sticking out to engage the Pump internal gear. It can stick out either side - hence the 2 options for where the shaft will pull out of the cases.

1. Galleries sound like cable routes cast into cases primary side for points -coil leads and starter side for dynamo lead.

2,3,4, Photos would help us to help you or look at a parts book or Andy Wagners catalogue online (Laverda Paradies) for exploded diagrams of parts.  
 
just "tug" very lightly on the drive sprocket, and rotate it about 3 degrees with each "tug", when the drive pin is in line with the slot in the body, the gear and shaft will come out,it is "retained" by bolting on the primary cover, which gives the outer bearing bore for the shaft, and prevents sideways movement. then you can get at the screws (use an impact driver).There is an arrow on the gear wheel to direct you, but it is not very clearly etched and after all these years it might be hard to see.Be sure to look out for shims and retain them in the corect order, but still check the slop when you refit.
CLEM
 
There's a pin through the oil pumpn drive shaft on the large gear. There's a cutaway in the pump body to allow the pin through. The cutaway is horizontal, either 9 or 3 o'clock, should be 3. Turn the gear whilst pulling gently, at some point, it'll come a bit and you won't be able to turn it any more because the pin has engaged in the slot. Take it easy, pin is steel, pump body is alloy.

As Norman says, lh gallery is points cable, rh is dynamo.

Change all clutch rubbers.

You should have a square bar to lift the clutch and of course the two rods and a ball through the primary shaft.

No idea what your stepped shaft is.

Ciao
Paul
 
Paul Marx said:
There's a pin through the oil pumpn drive shaft on the large gear. There's a cutaway in the pump body to allow the pin through. The cutaway is horizontal, either 9 or 3 o'clock, should be 3. Turn the gear whilst pulling gently, at some point, it'll come a bit and you won't be able to turn it any more because the pin has engaged in the slot. Take it easy, pin is steel, pump body is alloy.

As Norman says, lh gallery is points cable, rh is dynamo.

Change all clutch rubbers.

You should have a square bar to lift the clutch and of course the two rods and a ball through the primary shaft.

No idea what your stepped shaft is.

Ciao
Paul
Click to expand...

On my very early American Eagle #1303 the cutaway is vertical at 12 o'clock.

Could the stepped bar be a part of the cam chain adjusting mechanism?

J
 
      Swiss cheesing the oil gear? Is it really worth the effort? 
Click to expand...

Why - yes of course - if only that it means you would be able to reach the oil pump screws without removing the driven cog!! - I lighten everything i can get my drills/mills/turning/boring/grinding/ tools into!  Is it worth it?? - well maybe an engine or transmission will last a tad longer/wear out less quickly - use less fuel - not so important on the road - but maybe would make a tyres width or so difference in a race.

Go for it chris - but I'm not sure if you mean you need to remove cog and shaft from pump - or the cog from the shaft? BTW - i think the SFC750 has this cog lightened as standard - Regards - Phil
 
Ok, got all of that, a great help. Problem was I had all my books at work and had no reference, at work now and it all makes sense. Except the stepped shaft with the crescent cut into one the side of the shaft.
Hang on..... it's not a rocker shaft is it? It's got a slot on one end and a hole though the length of it.

Phil, harking back to my speedway days: I converted one motor to a dead loss battery system, deeming the magneto useless, apart from the drive for the points. I turned up a new shaft and replaced the heavy magnet with the new shaft. Man, that weight/drag reduction created the most amazing difference!

The first time I gated, I thought my arms were going to be ripped off my body, and the power increase had me wheelying out of turns, that motor was a slug before, in comparison. I was a covert in an instant. And, I do see your point about being able to remove the oilpump screws, without removing the gear, once drilled. I think I'll replace the screws with countersunk socket heads too.

One other thing too. I have two sets of cams. One is C6, the other set is not stamped, the profile is way differant, the lobes drop off really sharp in comparison to the C6's, any clues to what these are, perhaps they are just standard ones.
 
 
Hi Chris - sounds like a rocker shaft. I was an avid speedway fan in the sixties seventies and eighties - used to go to Wimbledon every Thursday - the likes of Ronnie Moore, barry Briggs, Ivan Mauger, Ole Olsen etc were all riding at that time - some still on JAP's but Jawas were taking over. Peter Johns was riding as a novice - he's the top engine tuner in the speedway world these days. I did learn to corner on the throttle only on a dirt track that appeared on a local common years ago - great fun!
          I use the 6C's in my (now) road 750 - but have a smaller radius on the rockers to decrease overlap and make a smoother start to the lift. The other cams could be anything as there were a lot to choose from. Don't forget - if you use the 6C's you will need to use the SFC valve springs as well or it may well not rev out - Regards - Phil
 
I can't remember but you got to Clock the Oil Pump Gear at either 9 or 3 O'Clock and simply pull the gear off - It's an enigma for the 1st time - What ever you do DO NOT force it.

Another thing - I recommend you change out them stupid Oil Pump Casing Slot Bolts for Allen Head Bolts.
 
Yeah, had a win at 9.00! Soaking the screws as I type, cause they are stuck hard. Once off there could be a nasty surprise, because there is something awfully gritty in there as I turned the gear..... :o

Thanks for your help fellas!

Phil, I did a two day "school" with Ivan Mauger, he taught me more in one day that I learnt in a year! Spent time with Ole Olsen, Simon Wigg, and Hans Neilson while they were out here on a "Champions Tour" organised by Ivan Mauger. Wig and Olsen were the funniest blokes I met in my time of riding.

I rode Jawa two valves with Streets 4 valve conversions, but ended up running Weslakes. Weslakes were great at the time, but I had one do a big end while bike was warming up in the pits at low revs, twice! :o :o Ah, the memories.

Sliding on dirt is fun, but sets you up well when you are on the riding on the tarmac, and there is no greater thrill than smoking 'em up out of a corner on the gas hard, in front of your opponents! I've only done track days on tarmac, but the spine frame and 750 motor, should see me on the track for part of 2013 season,  fun funds allowing.
 
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