Jred 670 questions

[Chris J.]

Thanks for reading this. I'll start with the simple question.

How do you remove the gas vent screw? I'm trying to remove it so that I can send it to an AS member. Idiot me thought it was something simple like unscrewing it--all that does is turn the entire tube inside the tank. Next I tried holding the tube & unscrewing it--the screw turns, but doesn't unscrew. Next I tried using needlenose pliers on the tube to push it out--that didn't work.

I have a parts saw. I did the quick compression check of letting the weight of the saw pull the recoil, & it pulled the cord out quite a ways. When I got the covers off I could easily turn the saw using the flywheel; the carb & muffler were still on the saw. I removed the jug, & it seems to be OK (no obvious problems to this novice). The piston has a few VERY light scratches, & the ring seems to be fine. I know that you can't really judge them without seeing them; if some photos would help I'll try to post some when I get home tonight. I also have a seriously shot Stihl 009 piston that I like to hear some opinions on what happed to it.

Thanks in advance for your help. Chris J.

 

[Mange]

Compression:
If there is no scratches or were that you can see, my guess would be the ring. If the ring has been araund a while the tension can be almost none, also check how thick the ring is seposed to be.

 

[Swannie]

If the gas tank vent is set up the same as a 272 Husky it looks like a screw in assy but in reality it is just pressed in. I use a 1/4" socket extension and a socket that will fit over the end of the vent tube inside the tank (flex tube down to get on it) and gently tap it out. Once out you can take the assy apart if desired, I was told by a local parts dept the porous nylon button that goes in it was no longer available so I just cut a small piece of blue paper shop towel and roll it up like a cigarette butt filter to put in vent assy in its place.

 

[Chris J.]

Good info, guys.

Swannie: I'll try your method a little later tonight. Who knows, maybe some other folks here will share their method. If nothing else I'll use my 4# hammer !!

Mange: Good point about the ring. It moves around the groove freely, & to me it looks "looser" than it should. Taking measurements would be difficult; I haven't used my micrometers in over 20 years & they show the neglect. Anyone know how to clean, lube, & calibrate a Starrett 6" dial caliper? I might try calling Jeff Sikema tomorrow to check on ring availability, pricing, etc.

One thing that I've noticed is the Champ & my West Coast use different parts with different parts #s (such as the plastic bracket that holds the carb onto the case, & the plastic bracket [venturi?]that the air filter attaches to).

Thanks for your help. It's time for me to go work on a saw.

Chris J.

 

[Grande Dog]

To check piston ring wear, push the ring into the cylinder about a 1/2". Measure the end gap and if it's over 1.0mm, replace the ring. The piston ring grove shouldn't be over 1.6mm. The piston ring play (space between the piston ring and the and the groove vertically) is .15mm. For those vents I thread a sheetock screw into the hole and pull it out with a pliers. Of course this ruins it, and it must be replaced. Part # 501 62 96 01.

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

 

[Chris J.]

Thanks, GD

I don't have any metric measuring devices; looks like I'm going to be investing in some new tools, or find my conversion table. All I know is the ring is really loose when compared to the used 011 piston/rings/cylinder that I just received. At least the problem is on the parts saw, not the main saw. Would be nice to have a good spare P&C.

I got the vent screw 'pushed' out using Swannie's method. Now next time I'll have some idea of what I'm doing.

Now a real DA question--I feel like an idiot here: On the carb, which is the fuel intake nozzle, the upper or lower? I checked 3 other saws & not one of them has the same carb set-up (a Tillotson HL).

A sincere thanks to all for your help. Chris J.

 

[Grande Dog]

All of those measurements I gave you can be done with feeler guages. Most of the ones you buy have standard and metric sizing on them.

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

 

[Chris J.]

It's ALIVE!!

Got her fired up this afternoon. I didn't get to do any cutting / testing under load; I figured that my neighbors might want to keeps their trees just the way they are. Other than adjusting the idle everything seems to function ok.

I do have another ?. The chain brake works fine, but when it's back in the off position it drags on the clutch a little (just enough to make the chain adjustment a pita). I pulled the brake handle back towards me, further than the point where it snaps in to the notch. After doing this a couple of times the brake no longer drags. Is this the correct way to adjust it, or is there some other adjustment that I'm missing? I removed the cover & blew out the mechanism with my air compressor, but I didn' t see any way to adjust it.

Thanks to: Grande Dog, Swannie, & Mange for your help & interest.

Chris J.

 

[sedanman]

There could be sawdust caught between the brake band and the clutch cover not allowing the band to retract fully.

 

[Chris J.]

I gave everything a good lookover,

blew it out with the air compressor, & I haven't done any cutting since I got it running. I'll double check tomorrow night. When I was working on it I thoroughly cleaned every part that I removed, & everywhere on the saw that I could reach, spray with cleaner, & blow out with the compressor.

When I had the cover off I did check the band with the brake in both the on & off position. There was very little difference, but I know that there shouldn't be a large difference. I'm not too concerned as long as pulling the handle back a little extra releases the band enough to get the cover on more easily & allows easier tension adjustment.

Paul--When I think of a brake band going bad or having problems, I think of it becoming loose or 'sprung.' Is my thinking off base?

Chris J.

 

[glens]

Another one of the real benefits of letting a clutch cover be just a clutch cover by having the brake and tensioner mounted in the chassis.

 

[Lawn Masters]

In other words buying a Stihl.

 

[Chris J.]

Hmm..OSA--My Stihl 011s & 009 have

the CB mechanism is built into the cover. If I were at home I'd check the 025. I haven't spent much time on it yet, but I'm pretty sure the same holds true. I have no experience with other Stihls, except for my trusty Stihl repair CD (which also is at home).

Chris J.

 

[glens]

By and large, he's right.  Most of the current Stihl models have inboard clutches, brakes, and chain tensioners.  The 025/MS250 does.

But I don't care who makes the saw.  A clamp that only clamps is always a better clamp, and the things that might be stationed in either the clamp or the fixed side will perform better when in the fixed side.

Glen

 

[Chris J.]

Another question.

Who was it who said a little bit of knowledge can be dangerous? Better make that two questions.

The saw came with an oregon bar, & I have to guess that everything (s, b, & c) are compatible. At least nothing weird happens when then the saw is revved up. The Oregon bar fits really tight on the bar studs. When tensioning the chain & tightening the cover I don't need to lift the nose of the bar because there's no play. None. Is this normal for some bars on certain saws? On my Stihls with Stihl bars there's play, & I do lift the nose.

Thanks in advance for your input. .......Chris J.

 

[glens]

I suspect mushrooming of the clutch cover into the bar groove.  Probably a result of overtightening through the years to combat perceived movement while cutting with dull chain that stretches like the Eveready Bunny.

If you find such displacement of the cover, I'd say remove it with a flat file.  It surely doesn't allow the bar tip to be raised to the proper position and it won't allow smooth tensioning adjustment.

Glen

 

[Chris J.]

Glen:

The bar is SNUG--no play at all--on the studs with the chain loose & with the cover completely removed. I don't gently quide the bar on the studs; I have to PUSH the bar onto them. I would test the bar on my parts saw, but it's missing the bar studs.

I also don't follow the idea of the clutch cover getting into the bar groove. I suspect that you're having some fun?? If you're being serious, I apologize. As for dull chain, stretching, overtightening, etc., I have no idea of the history of this saw, other than it was definately a work saw, & someone put a K&N AF on it. The chain could use a good sharpening, but it's not Holy Crap dull. I've never cut with this saw.

Chris J.

Edit: Meant to say work saw, as in this saw didn't sit around on a shelf.

 

[Grande Dog]

If it's the correct Oregon bar it should have 009 as the last three digits of the part number stamped in the bar.

Grande Dog
Master Mechanic
Discount Arborist Equipment and Tree Care Supplies

 

[glens]

I'm not playing this time.  I've seen clutch covers get mushroomed into the bar groove and prevent both smooth and proper adjustment.  I suspect that on covers which also house the brake, it could cause misalignment problems on that as well.

Glen

 

[Chris J.]

Might have found bar answer.

I did a quick go over on the Jred 90 that I received today. Lo & behold I found a shim between the bar & saw housing, & it doesn't look homemade. So I checked the box that I used for storing the 670 parts, and yes I have a couple of thin metal pieces that I couldn't figure out. I'll check the 670 tomorrow to see if I can make sense of how to use them. I don't want to block the oiler, as it is working very well.

Grande Dog--The following are the markings that I could see with the bar on the saw.

8730 GTN (the G might be a 6)
200---D176
Oregon
Made In Canada

Stumper & Dennis provided some info under the 670 parts thread; maybe they know something about 670s using bar shims.

As always, all input is appreciated. .....Chris J.