Dolmar/makita 7900 oiler mod

[WoodsliverDan]

I've got an idea to help the 7900 saws get a bit more oil on the chain, or at least make the adjuster screw last a little longer. Most have seen @jar944 oiler screw he turned out of 6160, but I realize that it is out of many people's resources. So, I plan to remove the end nub off of the plastic adjuster screw (this is what controls flow) and drill a small hole in the end to epoxy a small wire or weld rod in its place. This way I can make the end nub a bit longer and more than likely, more durable. Of course, filing the gear shaft end to a steeper angle as well. Tell me your thoughts..

 

[WoodsliverDan]

I will get some pictures up soon..

 

[Poleman]

Dan, that sounds like a good plan, do you think the epoxy will be strong enough? Press fit for no wobble?? Wobble would be the killer I believe.

 

[WoodsliverDan]

I agree with you on that. The hole would need to be snug for sure. I had though about melting it into place as well.. heat wire and stick in undersized hole maybe.

 

[Poleman]

I think your right in your thinking.... it will only take one try and you will have it figured out I’m sure. In my mind it would be good to know the pressure exerted on it. It may be less than one realizes. A deep set would sure help sabalize the nub and if tight there would be no wobble and downward pressure would also hold it in!!

 

[WoodsliverDan]

I mean, the stock on is plastic afterall.. as long as the pin is not loose, it should work ok. Only one way to find out!

 

[WoodsliverDan]

@Poleman , I know you have played with the oiler. How much increase are you getting with the shaft gear end filed steeper? I run a 28 often and it oils very little, it seems.

I would also like to put a hose barb on the output port on the pump. That flange seems iffy for sealing and I think that's the source of a lot of oil leaking from my saws.

 

[Poleman]

Mine easily oil a 32 to where it's visibly wet from oil. The thing I see on these saws are their inconsistency s.......one saw oil great the other is lean.......stock and modded. Modding them sure helps.
On the modded ones I can run the oil out before the fuel.

 

[WoodsliverDan]

Yes, I agree with the inconsistency between them.. my 2006 year 7900 is a weak oiler. This is the candidate for my oiler ideas..

 

[Bbintwn]

I have a question I’ve been dying to ask about oiling a bar. How much oil does it actually need to work properly? Are we over thinking the oiling thing because we think it needs more because older saws seemed to oil more than newer ones. Legitimate question here not trolling

 

[WoodsliverDan]

I'm not sure. Probably not enough if you're getting excessive heat. I just know my chain with a 28 is never wet unless I piss rev it like 5 or 6 times times outside of the cut.

 

[huskihl]

If you cut with a saw with a marginal oiler, the chain will have burned oil and wood residue all over it. On top of the cutter and on the sides of the chain. Usually a chain with enough oil on it keeps it cool and washed off to where the cutters and rivets are still shiny. The 28 on my dolmar before I changed the oil pump control bolt looked like the first scenario. After I changed it, it puts out easily twice the amount of oil and now the chain is shiny after five tanks

 

[Bbintwn]

Now those are answers I can work with

 

[WoodsliverDan]

My 288 for comparison is never dry..

 

[huskihl]

My 288 for comparison is never dry..

372, 385, 390, 394/5 as well. Piss rev a 24" bar on a 394 for a few minutes and the oil will run down the side of the bar

 

[Lightning Performance]

Have a 28" 050 total by sugi with the large angled slot in D009 mount. The bar should be ok. They are all very sad with the small bar hole, remember that first. Both saws are 6401. Do they have different pump housing or drive gear part numbers vs newer xx21 models?

 

[WoodsliverDan]

I have years 2002, 2006 and 2012 models of the 64/79 chassis saws. The oiler is pretty much the same as far as I can see. Same screws and gears..

 

[Lightning Performance]

I have years 2002, 2006 and 2012 models of the 64/79 chassis saws. The oiler is pretty much the same as far as I can see. Same screws and gears..

Do they have part numbers on them?

 

[WoodsliverDan]

Do they have part numbers on them?

I'm sure, but I haven't had any issues swapping with current parts and seen no differences..

 

[066 redeye]

I agree with you on that. The hole would need to be snug for sure. I had though about melting it into place as well.. heat wire and stick in undersized hole maybe.

Could you use a small roll pin,or would it split the plastic when you tap it in?