MotoPsycho's Meager Mod's - Ofna tank install

[MotoPsycho]

This mod explains installing a 125cc OFNA fuel tank to help in defeating the tank half lean problem.

Note: THIS MOD REQUIRES RUNNING NO MORE THAN TWO (2) REAR SHOCKS

For a printer friendly PDF: Clicky

Tools needed:
Normal disassembly tools
Drill
13/64" (fits tighter) or 3/16" drill bit
X-acto knife
hacksaw

Parts needed:
Fuel line of your choice
Ofna Tank - Tower Hobbies P/N: LXBM24

Step 1: Drill out BOTH mounting holes with a 13/64" or 3/16" bit

Step 2: Install both fuel fittings into tank.

Step 3: As you can see, the Ofna tank mounting tabs (left) are much thicker than the stock Savvy tank (right).

Mark the new tank across the tab with a sharpie in line (red arrows) with the bottom of the mid tank seam (yellow arrows).

Step 4: Carefully saw (I used a hacksaw) on the line, down close to the tank body (obviously, don't saw into the tank!)

Then score the underside of the tab with an x-acto knife and remove the bottom 1/2 of the tab thickness (red line).

You should now have this:

Step 5: Remove stock fuel tank, fuel lines, exhaust pipe & header, both forward rear shocks, and the rear tank bracket.

Note: I have GPM tank brackets. Rather than having 1 threaded mounting hole and 1 alignment stud, they have 2 threaded mounting holes. If you use stock mounts, I recommend cutting off the stud and drilling so you can have 2 mounting screws instead of 1.

Step 6: You will need to fabricate some sort of stand-off bushings for the rear mount. (I cut down some shock eye bushings)

These stand-offs (red arrow) will keep the tank parallel with the TVP, and prevent rubbing.

Step 7: Install the tank bracket on the outside of the TVP using the stand-offs you made. The screws will be installed from the engine side of the TVP. (This is why you removed the pipe and header.) Reinstall tank, fuel lines, pipe and header, and tighten rear shocks. VOILA! (Va-Whaa-laah; for those of you that don't speak French)

I also run a fuel filter, and attached the bracket for it on the forward side of the rear shock mount with the shock bolt.

Here is my review

1. - I have presently run 3 tanks with this setup, and have not experienced ANY leaning problems.
2. - The run times are somewhat shorter, but that was expected.
3. - It is impossible to fill the tank with the body on, without hacking on it some more.
4. - For about $12 and 45 minutes worth of work, this mod is well worth it.

 

[Double-O-Zilch]

Beautiful Moto! I saw you were posting a new thread and couldn't step away till I saw it. I like the suggestion of removing the stud and and replacing with a screw, that would also work on the stock exhaust mount with which I have problems. Keep'em coming bud, by the time I start receiving paychecks again I'm gonna have so many ideas to implement. By the way, how's it handle with two rear shocks?

 

[MotoPsycho]

By the way, how's it handle with two rear shocks?

I am running Integy MSR8's. I have done some custom valving on the pistons, and I am VERY happy so far. I only have 3 tanks on those as well, so I am still kinda testing.

-Moto

 

[Double-O-Zilch]

How's that steel spur working out for ya? I got one just been affraid to run it. You know how my luck is.

 

[MotoPsycho]

How's that steel spur working out for ya? I got one just been affraid to run it. You know how my luck is.

I've been happy with it.

Just make sure you run a hardened CB or you will end up with this:

 

[Double-O-Zilch]

That's what I'm affraid of, besides the tranny. Supposedly the stock HPI cb is hardened steel but I've run it down with the plastic spur. Back to the topic peolple come on! LOL

 

[lifter37]

Great job on the tank switch Moto. Very good idea and very nicely done. Hey Parker, I have been running my HPI steel spur and HPI vented CB for quite some time now. Have had no problems what so ever. Just make sure you get a good meshing and believe me, I am very hard on my trucks.

 

[k0m0d067]

Hey Moto...any chance you can get the fuel line fittings in a 90 degree elbow version? I need to point my fuel lines a different direction, and have been wondering...

 

[Jeremy]

Great thread moto .. I think we need to start your own mod section ..

 

[lifter37]

I second that SJ

 

[Double-O-Zilch]

I third! Moto rocks! Thanks for the info on the spur gear guys, I just need one more part to get it running, and a good cb. I was told it would trash other stuff but I ain't scared no more!

 

[MotoPsycho]

Hey Moto...any chance you can get the fuel line fittings in a 90 degree elbow version? I need to point my fuel lines a different direction, and have been wondering...

You mean like this?

Clicky

 

[rex_hvn]

love da mod I'm having lots of trouble wit 1/2 tank lean how much shorter is the run time love da post very heplfull

 

[k0m0d067]

You mean like this?

Clicky

once again Moto...YOU DA MAN!!!

 

[X]

I tried that tank out but with the kit from New Era. I found that if you mount the tank with the fuel lines going forward you can still run both rear shocks (stock hpi shocks). We'll see how this tank works.

 

[MotoPsycho]

love da mod I'm having lots of trouble wit 1/2 tank lean how much shorter is the run time love da post very heplfull

It really depends on tune.

I went from about 12 minutes on the stock tank to about 8 on the smaller one.

if you mount the tank with the fuel lines going forward you can still run both rear shocks

I mounted the tank the way i did because it put the fuel pick-up to the rear.

-Moto

 

[X]

I mounted the tank the way i did because it put the fuel pick-up to the rear.

-Moto

I guess I've never asked, does it make a difference if its pointing to the front or back?

 

[MotoPsycho]

I guess I've never asked, does it make a difference if its pointing to the front or back?

I'm not sure, but i assume that since you are going forward most of the time, the fuel would be at the rear of the tank more often.

 

[X]

Thats true, but there is a splash barrier in that tank in the middle to keep fuel near the pickup. I should really test it both ways to see if there is a difference.

 

[MotoPsycho]

Let me know if you see a difference!