4T external oil line

I'm rebuilding a '89 510TE. I am wondering if the external oil line introduced by Cagiva on later models is a modification worth doing? Was there a specific problem they were addressing?



I bought some parts from a 410 and comparing to the 510 there are some added holes in the left hand case, apart from the hole where the hose attaches. See pics.
Are there any more differences concerning that oil line that would need to be modified if I would add it to the 510 engine? Grateful for any input!

Firstly great question and one I’ve asked myself as I’m rebuilding ‘89 510’s too. I may need some confirmation here but pretty sure the oil mod your discussing is to give a more positive oil feed to the big end. They (Cagiva) obviously did it for a reason so there must have been an issue with big end seizures or high wear. They may also been thinking of the next move to the 610’s ? In 1990 the sort of transitional first Italian modded four stroke came out and that was a 510 but with the water pump on the head. 1991 was the first 610 actually 577, I’ve got a 91 610 and it has the external oil feed for the big end. But I don’t know if it was first introduced on the ‘90 510.

So I think my answer will be based on intended use. If your going to put a lot of hours on the bike and do extended road sections I’d seriously think about adding the oil feed. If your going to compete and ride like Jacky Martens I’d add the feed. But I happily raced an 89 with standard oil set up for three seasons and just changed the oil pretty much every meeting and had zero problems with the major motor parts. So if your an average joe, leave it as is.

So, if you must .... how to do it ? By the way I haven’t done it yet but am thinking of it....Two basic choices either mod existing cases or swop the cases.

I spent a little while figuring out the basic differences between 410/510/610. All dims are my rough measurements or gathered from reasonable sources. Forum gurus pls feel free to correct.

410 is 399 cc with 91,5 mm bore x 60.8 mm stroke, cylinder height 92mm (base gasket face to head face)
510 is 503 cc with 91,5 mm bore x 76,5 mm stroke, cylinder height 102 mm
610 is 577 cc with 98 mm bore x 76.5 mm stroke, cylinder height 103 mm (prob same as 510....)

So, if I do an oil pump mod of one of my ‘89’s I thought the easiest way to do it looks to be using a later 410 set of cases. This will also save drilling holes my existing 89 cases. Just got check that the crank fits but looks like it will and the crankcase mouth should be the same size as the bore is the same.

I also took some photos of my bikes and cases, hope these help too. Bikes are 99 410 (gold flywheel cover) 91 610, couple of cases one 610 one 510. Thanks again for posting the question. Lastly think this thread m6 be in the wrong category? Cafe Husky elders will put us right !

Pics found on facebook ! Have a night reflexion...

Merde, I’ll never get to sleep now.

Thanks, I figured I couldn’t be the only one pondering this modification. I’ll use the bike for gravel roads and single track but nowhere near hard use.
So maybe it is not needed really, but I’ve spent a good bundle restoring the engine so if I can make it last even longer that would be nice!

But I guess it could easily screw the RAL-system up by boring holes in the cases here and there without knowing the whole plot..

Re. bore size etc: The 410 parts I have has a bore of 83,5mm. Not sure what year it is. Engine no is "2001 0XXX"
The crankcase mouth is 100 mm so same as the 510 engine.

But the crank case halves I have are not from the same engine and I'm not sure if it's ok to use a set of non-matching halves for the same engine?

Indeed, they are not cheap to restore properly. By the way we like pictures of engine rebuilds....You say the bore size you have is 83,5 mm ? That sounds very close to the size of the TE 350 rather than the 410. 350 has 84mm bore and the 410 has 91,5 mm.

As you may already know crankcases are matched pairs as they are final machined as a pair. That way everything lines up exactly on the hollow dowels fitted to make sure the halves bolt together the same every time. UsIng non matched pairs runs big risk that the main diameters such as crankshaft, gearbox main shaft and lay shaft won’t line up properly. Keep your eyes on eBay as 410’s seem to get broken for spares quite frequently. Should be able to pick up a pair of matched crankcase halves for reasonable price.

Some more pics for you, black barrel and case is 510 other case is later 410.

Ok thanks, that makes it 350 parts then! I said bore was 83,5, I should have said piston skirt diameter.
I'll probably sell those parts on anyway and leave the mix & match of engine parts to the more knowledgable mechanics.
Getting one 510 back together is good enough, and hopefully with more pictures of it being done.

If the oil line mod is confirmed as a good idea and only consist of making the extra holes, as in my pics above,
it would be easy enough to get the parts machined properly with the 350/410 case as template.

You can also consider the late model 410 motors had an oil pump.

True, I might have to get one of those too...

This 510 will be built as close to stock as possible though. I have most of the parts already. I think..

Are they the 410 e with a proper oil pump but with the clutch on the opposite side. Attached is a picture of a current 2001 610 e lump I am in the middle of with the separate. So I guess I asking if any left kicker engines have a proper oil pump.

The 99 on left kicker models have an additional Mikuni oil pump, surely a set of cases from one of these models would be easy enough to source wouldn't it?
Tony.

Yes the 1999 and later left kick models have an oil pump added.

quoting myself here.. I mailed an experienced Husqvarna engine builder the question and he replied he has done the mod himself on some engines.
The external oil line directs oil to the rod big end and extends life of that bearing. So it seems the modification is a good idea at least.

But I'm not all clear of exactly what machining and parts that are needed, so I'll give him a call so he can talk me through it.
I'll get back and post here when I know.

Sounds good, thanks for the discussion and good luck with the build. I’m not too far behind you, see attached 89 510 pic

I'd say you're way ahead of me!.. I have a lot of work to do before I'm close to that pic.

Disclaimer: Please note, I have not tried this mod myself yet. I will probably try it on my 1989 510TE. But I can't say for sure if it works!

Ok, I had a chat on the phone with this guy who has a lot of experience building race engines with the old HVA four strokes.
According to him you need to plug the hole marked by red arrow.



That is done using Husqvarna part no. 800066405 (pic below). That is a stock part and is used on the engines with the external oil line.



You can remove the filter screen too and use the magnet without the screen.
EDIT: But on second thought I'd leave it there to help hold the plug in place!


Doing this should make the suction draw the oil through the external oil line up to the other end of the hose and spray oil directed at the rod's big end.
If you don't plug the hole with above plug you won't get enough suction.

Then of course you'll need to machine the hole on the top of left hand crank case + all parts for the oil line banjos etc.

Making the other holes marked on my photos in the first post shouldn't be done according to him.

This is from the parts book for a 1994 350 showing oil line etc. and p/n's.