My EASY half-tank lean fix!!!!!

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the-enforcer

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Ok, for all you suffurers of the half-tank lean issues, I have the fix that requires NO cutting, modding, or eighty feet of fuel line. All you need is to buy the fuel tank for the savage 25!!!! Any of the newer savages have a top-feed fuel tank, where the 25 tank is bottom feed.
 
Whatcha talkin about?
HPI has produced two fuel talks for the Savage.
The original tank released with the .21 Savage - part number 87031 - has the fuel pick-up in the FRONT.
The newer tank was introduced with the 4.6 release is part number 87149.
87149 has been the stock fuel tank since then (on the 25, the X 4.6, the X SS, and XL)
It has the fuel pick-up in the REAR of the tank.
Both have the pick-up on the bottom.

87031 - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDLH7&P=7
87149 - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFZN7&P=7
 
Whatcha talkin about?
HPI has produced two fuel talks for the Savage.
The original tank released with the .21 Savage - part number 87031 - has the fuel pick-up in the FRONT.
The newer tank was introduced with the 4.6 release is part number 87149.
87149 has been the stock fuel tank since then (on the 25, the X 4.6, the X SS, and XL)
It has the fuel pick-up in the REAR of the tank.
Both have the pick-up on the bottom.

87031 - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDLH7&P=7
87149 - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFZN7&P=7

This is true but the tank I got with my x4.6 had the feed nipple on the top rear of the tank so it had to push the fuel up, whereas the 25 tank the feed nipple is on the front bottom of the tank. It doesn't matter much thou, just thought I'd put it out there, it worked for me so it should work for someone else
 
I know what you're talkin about now...
You've got the original tank - the 87031 - the one with the plunger on it that came with the .21 Savage.
By the time they got to the .25 Savage, they had already replaced the 87031 with the 87149. That's where you lost me.

Unfortunately the 87031 has it's own set of issues....
One of which is that it's straight sides on the rear of the tank get hammered by the long screw that holds in the shock.
When you tumble, the original shock tower flexes and like a woodpecker going to town, the screw can punch a hole in the tank.
I cut down the shock screw down to the minimum length and it still hit the tank.
I then epoxied a piece of sheet brass to the tank to solve that problem - but it still got dented.
They fixed this with the newer tank and angled the side so the screw can't reach.

Since the pick-up was in the front of the tank, I would also sometimes get a lean condition under full acceleration and it also lacks a stone guard.

You would think that they would combine the best attributes from both tanks though...
Angled side, rear bottom pick-up with a decent well, stone-guard and better baffles to keep the fuel from rushing forward under braking. lol
 
If the HTL issue has been a problem for so long, why is HPI not fixing it?
 
You got me bro...
I switched to the newer tank design (87149) years ago and this thread made me think back to when I switched over from the 87031.
Now that I think about it, I do recall noticing the lean issue more after I made the switch than before, but under different situations (braking with the 87149 versus under acceleration with the 87031).

My fix with the 87149 was to put a permanent backwards tilt to the tank (and I do run a long fuel tube - but it's always been that way).
I played around and was able to fit two o-rings on the front post under the tank and another o-ring on top of the tank (under the clip) on the rear post.

It would be nice it HPI went ahead and revamped the tank, but what I've got's been workin for me.
 
You got me bro...
I switched to the newer tank design (87149) years ago and this thread made me think back to when I switched over from the 87031.
Now that I think about it, I do recall noticing the lean issue more after I made the switch than before, but under different situations (braking with the 87149 versus under acceleration with the 87031).

My fix with the 87149 was to put a permanent backwards tilt to the tank (and I do run a long fuel tube - but it's always been that way).
I played around and was able to fit two o-rings on the front post under the tank and another o-ring on top of the tank (under the clip) on the rear post.

It would be nice it HPI went ahead and revamped the tank, but what I've got's been workin for me.

Does the tilt work pretty good?
 
It forces about a 2.5mm backwards lean and it's a noticeable improvement.
Granted, under braking the front end dive is the killer to the backwards lean, but the only time I ever notice the engine leaning out these days is when it's just about empty.
 
Thanks, I'll have to pick up some fuel line and an o-ring and try that.
 
I just reused some old o-rings that I had taken off of something.
I know some of the o-rings came from a Savage differential - and they look like two different sizes.
Instead of throwing them away I'll clean em off and throw them into a reuse container. They may be too used to reuse on the inside of the diff, but why waste a good o-ring for something like this? I also use these in the diff cup to hold the dogbones in place.

I've also used a nylon bushing on the front post.
If I remember corectly, it came from the throttle mechanism of a Revo when I replaced them with bearings.
 
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