Dolmar 7900

[ahlkey]

Just bought a used Dolmar 7900 that has sat for 3 years but appears in excellent shape.    However, when running at full speed a small amount of exhaust/oil appears from the exhaust exit on the muffler?  The fact the muffler has a small cut in it, no spark arrestor,  the dogs removed & replaced with a one smooth one, and a small 18 inch bar on it makes me feel the saw was used a racing saw in the past? Anyone familar with this small Partner Bar?  Thoughts on next steps I should take on this saw?  I have another 7900 and it is my favorite saw so thought it was worth a chance even though not a lot of history is available. As anyone tried a Big Bore kit on the 7900 with success?  I guess if I need to buy a new muffler might as well consider a full ungrade.  Thoughts/concerns?

  

  

 

[JohnG28]

Could have been raced I suppose, or just maybe how someone set it up for firewood. If you only need 18" bar why waste the power on more. Some guys also like the flat bar instead of the dogs. I like dogs on a saw personally, but to each his own. The muffler sounds like it was opened up and probably tuned rich, making for oil on the muffler outlet. Pull the muffler and look at the cylinder, see if there's any damage. If the factory screen is in place make sure it's clean. Otherwise if all is well I'd let it run, maybe tweak the tuning if needed. Check the fuel lines to make sure they're in good shape too. Nice clean looking saw. ;D

[SawTroll]

What drive sprocket size is on the saw, and is that bar a sprocket nose or a roller nose one?

[Andyshine77]

The oil is likely from the previous owner running 32:1 with race oil, maybe even castor oil. The slit is likely just an extra port, which is a good thing. Honestly sounds like you have a nice saw that was ran by somebody that knew what they were doing. Yes a 7900 with an 18" bar should have an 8 pin sprocket for sure.

[ahlkey]

Thanks for the responses.  It has a roller nose with an 8 pin sprocket (see below).   I doubt I will ever use it on this size saw but it does appear as a quality bar.  I also feel the little oil on the exhaust may be due to a rich setting but it is a little concerning nonetheless.

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[Andyshine77]

Where did you get this saw? Pretty much all roller nose bars are, well awesome, especially when racing. The oil in the exhaust is normal. Again it's from running more oil, sometimes even 16:1 if using happy fuel of some type. Don't give it a second thought.

[ahlkey]

Saw came from an estate sale with little history. Stopped at the local dealer and found out it is an 05 saw rather than an 09 as I mixed up the first four numbers.  Given how it ran and the fact it appeared in excellent condition I really thought it was a much newer saw.  The first two digits are the year of manufacture rather than the month.

I likely would of not purchased it if I had known it was 9 years old at the price of $450.  From the same dealer today I could of bought a new Dolmar 7910 "powerhead only" in stock for $750 (with warranty).  I guess time will tell if the saw holds up. 

[Andyshine77]

Age doesn't matter much, condition does, you did good and you have a very nice saw. The older 7900 also has better power and is lighter than the 7910.