Need help - how tight on REALLY worn 420 tracks?

[TI420]

Hi - OK, the crawler is operational! Rebuilt the steering clutches and they are working well - also had to rebuild the carb and starter, debug a million other little things too, but now have been able to drive and turn it. AND - quickly slipped a track... Luckily, it wasn't too tough to get back on - just slipped sideways off all 5 bottom rollers.

So here's the deal - I'd like to eventually get all new rollers and pins and all that but it's just not in the cards right now - and this is more a toy than anything else although I would like to be able to use it to move stuff around...

I had adjusted the tracks per the manual to about 1" of sag between the top roller and sprocket or front idler (5 roller with curved top roller...) Anyway - after I drove it a little, the sag seemed to get a little more but not too much. Then, was going across the field in third gear and made a turn and that's when it slipped off...

I see crawlers working with as much sag as mine so it must be that my rollers and chain are worn to the point to make this happen. So my Question is this - Can I compensate for the heavy wear by tightening up the tracks more? I see pictures of crawlers with almost no sag and thought I remebered a post a while back where someone said you just tighten them up. I am thinking about tightening them to the point where all play is taken out but the springs are not compressed yet - but just a hair away from starting to compress them...

Like I said - my stuff is worn but I don't think it's ridiculous - the rollers are just starting to "kiss" the pin bosses of the chain but there's really no wear there yet - here's a photo of what I'm dealing with. I do have at least 1/8" of wear in the pins and bushings - I see Lavoy refer to "the snake" - is this the side to side slop and is that what my issue is? AND - will tightening the tracks help?

BTW - there is currently more sag in the chain than this picture shows but this gives you an idea of the current wear on my chain links...



As always - Any help is greatly appreciated - could not have done this without Lavoy's parts and the help from this site! - Thanks! - Chuck

[dlplost]

if the bearings in yer bottom rollers are worn out the rollers will tip sideways and let the track out from under, thats my guess as to whats letting them out.
Worn out tracks dont help any either. Keep them as tight as you can, but I think its a loosing battle, keep yer eye out for better rollers and a better set of chains. I lucked out at an auction once and got a good set of MC chains for $60 cause nobody there knew what they fit on...I did.

What ever you do , DON't run on a side hill, you'll lose both sides real quick, BTDT with the MC in the mud on a side hill. Took 2 weeks to get them back on..

[Lavoy]

Running them tight will only help a little, plus it will accelerate the wear on the sprockets because with worn chains you are way out of pitch so the bushings are trying to climb the sprockets.
Lavoy

[Tigerhaze]

Then, was going across the field in third gear and made a turn and that's when it slipped off...

I see crawlers working with as much sag as mine so it must be that my rollers and chain are worn to the point to make this happen.

I found out very early on with my worn 2010 undercarriage that moving in a higher gear across uneven ground is a recipe for having the track slip out from the bottom rollers. All it takes is for the track to get out from underneath one bottom roller and the forward motion can quickly get it out from all of them. Pulling a turn, especially a sharp turn, is also problematic with worn track, as it seems to want to come off the front idler.

I since only operate in low gears, especially on uneven ground and stop if I hear any unusual noise from the undercarriage. It makes distinct sounds when it is trying to slip off. I also try to keep from pulling sharp turns and instead make a bunch of smaller turns.

Hope this helps.

[Howard Yoder]

Your rails don't look completely worn out so if you could get them rebushed and new sprockets on them plus replace what rollers need replaced you would have a good undercarriage. These rails are allmost impossible to find unless you go to the 350 style.