Next project. 371xp

[PB]

I don't think silicone is designed to seal fuel. I'd recommend getting the proper sealant. You mentioned several. I have used Yamabond in the past. I now have ThreeBond 1194, which replaced 1104.

Permatex has both, you just have to make sure you get the right one.

This one won't work with gasoline.

This one does.

Hey Timberwolf, how hot does an engine get running all day? Is 350F warm enough for a sealant?

 

[timberwolf]

The base is always cooled by incomming charge, so I doubt it ever gets much past 200F worst case.

I have used the Permatex red and copper too with good results, even on head gaskets for race type saws with two piece heads.

 

[PB]

The base is always cooled by incomming charge, so I doubt it ever gets much past 200F worst case.

I have used the Permatex red and copper too with good results, even on head gaskets for race type saws with two piece heads.

Thanks. I just seen the Motobond had a range to 350F, wasn't sure if that was high enough. I too have used the red permatex with good results, just switched to the maximum oil resistant type when the red ran out.

Sorry if I hijacked your thread parrisw, back to the 371xp.

 

[blsnelling]

Good the hear that there are more dependable options.

 

[parrisw]

Not sure if it will work for your project or not, but I use the black Permatex sealant. The one that is high temp and solvent resistant. I have had no trouble with it. A lot of people recommend Yamabond or Durco (I think that is what it is), but Permatex is a lot easier for me to find. Jacob or Brad would know what works best for modding purposes.

Nice work by the way.

Thanks. Ultra grey is actually better I think then the black. I use it all the time at work on car engines where there is no gasket, just a machined fit, mostly on timing covers. So I figured it would work well here. Don't think fuel harms it either.

Thanks. I just seen the Motobond had a range to 350F, wasn't sure if that was high enough. I too have used the red permatex with good results, just switched to the maximum oil resistant type when the red ran out.

Sorry if I hijacked your thread parrisw, back to the 371xp.

No problem, all useful info.

 

[Jacob J.]

Cutting windows in a 372 piston is counterproductive unless substantial modifications are made to the transfer ducts. I would not go that route on a work saw.

I'm putting together a 372 that will indeed have substantial transfer port modifications. To the point where the inside of the cylinder won't be easily recognizable as a 372.

 

[parrisw]

I'm putting together a 372 that will indeed have substantial transfer port modifications. To the point where the inside of the cylinder won't be easily recognizable as a 372.

:greenchainsaw:

 

[parrisw]

Slowly coming together. Did some more work yesterday.

 

[super3]

Yamabond is/was fine think it's discontinued, Hondabond is much the same thing

Yamabond 4 was much better in IMO,Hondabond is much more runny
But just my opinion

 

[blsnelling]

Threebond 1194 recently replace 1104. The 1194 is much runnier as well. I do not like it as well.

 

[parrisw]

Ok, ran into a problem today. I got it all together minus handle and bar. I got it running, was running really nice, I had a grin from ear to ear, unbelievable throttle response, I don't have a tach so I don't know what I was turning, sounded pretty high though, seemed to have it all tuned in, went for another WOT run to check for 4stroking, then it just all of a sudden started bogging down and quit, well, that grin went to a frown. I immediatly thought I blew it up, so I went and pulled the muffler and carb, piston still looks really good, I think a crank bearing is siezed up???? Now when I turn it over it makes a slight screaching sound, and tight to turn, I felt the bearings when I was doing the build and it felt ok. Looks like I got to do a complete teardown now. How hard is it to split the case on these??

 

[blsnelling]

Sorry to hear it. Did you lube the bearings during assembly?

 

[parrisw]

Sorry to hear it. Did you lube the bearings during assembly?

I never had them out, I never took the case apart, but after I cleaned the crankcase I sprayed it out with wd40, and soaked the bearings with it.

 

[blsnelling]

Check your clutch. Maybe the coil is rubbing.

 

[parrisw]

Check your clutch. Maybe the coil is rubbing.

Ya, I checked all that, seemed ok, maybe I'll pull the coil just to be sure. I'm pretty sure its the bearings, it feels pretty horrid when I turn the flywheel by hand.

 

[Jacob J.]

What about the rod bearing on the crank? Did the mains have good, tight bearing retainers?

 

[super3]

I never had them out, I never took the case apart, but after I cleaned the crankcase I sprayed it out with wd40, and soaked the bearings with it.

Should have been enough but,

Tip it a little sideways and dump some oil directly into the bearings next time

 

[blsnelling]

Well this just plain sucks. This isn't supposed to happen I certainly wouldn't try to start it again until you know. You might seize a main bearing and spin it in the case.

 

[Moss Man]

I can feel your pain man, I hope this can be resolved without too many headaches.

 

[parrisw]

What about the rod bearing on the crank? Did the mains have good, tight bearing retainers?

I was wondering about the rod bearing, its defenaly a possibility, won't know until I break it back down.

What do ya mean by the mains have tight retainers?