Jonsered 670 champ intake leak

[Ronie]

If you decide you want to put a 272 top end and keep the 670 carb you just have to drill a hole in the 272 intake block and add a nipple.

 

[timg]

David, You got some good tips here from heavy hitters. I'm being the missing clamp camp too. @huskihl makes a good point on brass dressing for a more compress fit on boot to carb. I do what @Czed does also as reassurance to a good deal and let it set up for a day. I prolly have a boot too if needed. Did you pull it out of the manifold to look for tears?? They do crack//tear on the bottom side from crankcase casting//machining.

 

[davidwyby]

Boot looks great. So does inside the cyl…

maybe the plastic is warped, see pics.

 

[Czed]

Boot looks great. So does inside the cyl…

maybe the plastic is warped, see pics. View attachment 314205View attachment 314206View attachment 314207

Sandpaper on a flat surface
Flatten out the mating surfaces.

 

[davidwyby]

The boot is now proud of the plazteck

 

[huskihl]

Here goes the play by play.

Should I do a YouTube Live?! View attachment 314204

I’ve seen those clamps too. Seems like it’s as good or better than the wire

 

[davidwyby]

@huskihl maybe what @Benwa uses - from stihls?

 

[huskihl]

@huskihl maybe what @Benwa uses - from stihls?

Which, the clamp? 670 clamp is way bigger

 

[davidwyby]

fixed the leak. Lots of choke time and yanking to start…runs weird, stalls off rev. Clear Lines bubble and go dry…think it’s carby kitty time.

 

[davidwyby]

Which, the clamp? 670 clamp is way bigger

359…maybe?

 

[Spike60]

Gents, there are two intake systems on these 670's. (same goes for the 625). The wire clamp was replaced around 1989 with the band clamp. Clearly visible in the early pics. Steve; what are you looking at?

But to make things more fun, it wasn't just the clamp that was changed. The boot obviously needed to be changed as well. And in order to accept the new boot, even the cylinder casting was changed, getting a longer intake neck. The new cylinders have a ++ cast into them.

There are some interchangeable option, but I don't think it goes both ways. The new boot can be used on the old cylinder providing you also use the wire clamp. Definitely not room for the hose clamp on the early saws.

I agree that the switch to a 272 top end doesn't accomplish much if anything over a good 670. It's a good option though if the 670 kit is toast, and a great option for a 625.

 

[Stump Shot]

Gents, there are two intake systems on these 670's. (same goes for the 625). The wire clamp was replaced around 1989 with the band clamp. Clearly visible in the early pics. Steve; what are you looking at?

But to make things more fun, it wasn't just the clamp that was changed. The boot obviously needed to be changed as well. And in order to accept the new boot, even the cylinder casting was changed, getting a longer intake neck. The new cylinders have a ++ cast into them.

There are some interchangeable option, but I don't think it goes both ways. The new boot can be used on the old cylinder providing you also use the wire clamp. Definitely not room for the hose clamp on the early saws.

I agree that the switch to a 272 top end doesn't accomplish much if anything over a good 670. It's a good option though if the 670 kit is toast, and a great option for a 625.

I didn't have my glasses on, thought I could squint it through. Lol

 

[davidwyby]

@Spike60 would you school us on the return line on the carb? My spare tank only has one fuel line port and a compressed brass vent.

 

[davidwyby]

So ya know how the forum suggests similar threads at the bottom of the page…?

https://opeforum.com/threads/dukes-...nsered-670-champs-light-projects.22125/page-2



https://opeforum.com/threads/jonsered-670.24936/

I bought it from redtildead and had it shipped to Kevin’s, checked it out and cut with it at the GTG. Funny how they get around, I remember seeing it in duke’s post now. It’s actually a pretty clean saw outside of the cracked top cover, clutch cover, and tank.

 

[timg]

Is that a moly coated piston as well? If so yes she has made some roundy rounds LOL!

 

[davidwyby]

Need to order more kits

 

[legdelimber]

Yeah those pump tabs/flaps (the little tombstone shaped sections) are standing a bit off of that carb body. Makes it a b#### to get one started when those tabs aren't laying flat.

For easiest starting, I prefer the old type "rubber" diaphragms, but they're getting hard to find nowdays.
Just gotta remember ...Ab-so-lute-ly... NO ethanol or the flaps curl up and you're jerking the rope and in the tools again.
The blue plastic ones are a bit too stiff for my taste. Can be a bit hard to get cranked if been sitting a while.
The other ones that you can see the texture of the fabric don't seal so well either. More starting drama again.

Take a look at this image at full size. You can see the curled edges where the die cut pulls it curved.
Between the curved edges and the texture? Personally I'd just throw this one into the trash.
Nothing but aggravation to be had from it (in my free opinion).

Heavier oil to fuel ratio might help a bit with the sealing problems of that texture -IF- the flaps are flat when it's mounted.
But that big curl would make me want to look very closely to see if the flat areas, in the middle of the flaps, are dead nuts over the holes in the carburetor body.

 

[Stackowood]

Gents, there are two intake systems on these 670's. (same goes for the 625). The wire clamp was replaced around 1989 with the band clamp. Clearly visible in the early pics. Steve; what are you looking at?

But to make things more fun, it wasn't just the clamp that was changed. The boot obviously needed to be changed as well. And in order to accept the new boot, even the cylinder casting was changed, getting a longer intake neck. The new cylinders have a ++ cast into them.

There are some interchangeable option, but I don't think it goes both ways. The new boot can be used on the old cylinder providing you also use the wire clamp. Definitely not room for the hose clamp on the early saws.

I agree that the switch to a 272 top end doesn't accomplish much if anything over a good 670. It's a good option though if the 670 kit is toast, and a great option for a 625.

Not sure if you guys ever saw this in the East, but there was also a very early style intake boot with the impulse channel moulded in (no external impulse hose). We received a shipment of these on the West coast and ended up having to modify every one with the "new" boot and external impulse. I think Jonsered was in such a hurry to get a new saw out here to compete with the 266/268/038 that they didn't fully test their design. Also saw a lot of cracked cases before changes were made.

 

[davidwyby]

Finally got kits and got back to this. Cleaned the carb, put a Chinese diaphragm kit in it that I ordered by accident. Pretty much same issue. Low speed tunes, H tunes, but if I rev and let off the throttle it dies. If I nurse it down it stays running. Clear lines seem to stay full of fuel. Not quite motivated enough to swap carbs with the 630…and the 630 doesn’t have a return line.

 

[Woodslasher]

Try turning in the idle screw. My 272 started doing what you’re describing a few days ago when I was bucking up some trees and “speeding up” the idle cured it for me.