The best for fuel consumption is 41021 and 51006M
But now the Novarossi launched in new exhaust 2135 that maintains the same fuel consumption as the 51006M, but with a better performance.

When you run the tank empty and next on you have tuning issues my 1st thoughts will be a damaged plug because that happens when running the tank empty.

Carb is clogged?

put some fuel in the tank ...... remove high speed needle keeping it clean ...... blow though pressure line to push fuel though carburetor intake ...... fuel should come out of the high speed needle housing for 2-3 seconds .... install the high speed needle .... run all the way in and back out to 4 turns form all the way in ..... start again ..... i agree that your plug may be toast as well

2135 pipe
 

ya...... that is not good ... there is an oring in the base of the block that creates the seal against the neck of the carb ...... it will not run properly at all if its not seated proper

Honestly not to sure what to do. I have - sealed around my HSN and replaced the O-rings.
- New Plug
- Fresh Fuel and Fuel line.
Still is lean on top at open throttle to the point where can see air bubbles in the fuel line between fuel filter and carb. I don't understand how the engine is running at 100deg perfect for 3 race days to running our of fuel and being super lean?

if your getting air bubbles in the fuel line then its NOT the engine its either your tank or fuel filter... check the tank.. submerge under water and blow into the exhaust nipple while having the fuel line plugged where you have it on the carb nipple.. yes check the complete fuel line and filter on the tank as you run it in your vehicle and see where the bubbles are coming from.. also double check that the exhaust is getting into the tank from the muffler.. ive had a pipe go bad from getting hit and it stopped putting pressure into the tank.. jeremy

hhhmmmmmm.. that's not good as air in the line is generally the tank or clunk in the tank... does it bubble all the time or just around half tank?

Well this is weird. You can see air bubbles in the line between the Fuel filter and HSN.

I just done what Monty suggested. Marked the carb with a pen and measured with verniers as well as wound the hsn all the way in and counted the turns back out to its original place. removed HSN all together, blew some fuel through and wound HSN back into its original spot. I also pulled all the old fuel line off between tank and motor and replaced it with brand new tubing. Car started straight up and ran. Didn't suck air like before (before would suck air to the point the engine would cut in and out). Just ran for 9 minutes and came in at 102degrees. very very bizarre. At WOT at the moment there is only some small pin head bubbles and only at the HSN where as before they were all along the line from the filter to engine and were the size of small stones.

I feel dumb as Ive never seen this happen before or know why as my fuel tubing had no holes that I could see when submerged

bubbles does not alwys mean an air leak, they can also be caused by vibrations, that is why most fuel tanks are placed on rubbers with a non tightened screw.

probably the fuel filter has a leak then

it should... but run it without the filter if the engine is running good..

Ive had tanks that dont show bubbles when submerged but would seep fuel from the seams and leak out. Imo anything extra added to the fueling system is just another point for a leak to happen, the simpler the better.

hsn being clogged will wreak havoc on tuning .... the engine will not run properly guaranteed

this will be the biggest help

Still having this problem... any suggestions? End points are correct. Carb fully closed and fully open. Tune does not change on brake.

I agree. Sounds like lean HSN for sure, likely also with an overly rich LSN to compensate.

CLEAN OUT HSN .... then reset HSN to 4 turns from closed ..... adjust LSN and idle gap while HSN is still a bit rich ..... then lean HSN until desired runout


airleak?

sometimes you just need to start at a base setting

5 turns from full closed on LSN 4 turns from closed on HSN

be sure to pull linkage open before running LSN in

Have any of you guy,s ran the mephisto yet just curious to hear any feedback.

jack im thinking about getting one of these also.

OH YEAH !!!!!!!!!

According to the Novarossi website the Mephisto is a Mantra with a different crank and carb, so unless they did some changes to the crank besides DLC it should run the same.

So you mean that the Mephisto is a little evolution of the Mantra?
Is Mephisto better in terms of fuel consumption versus Mantra?

I have no idea, I haven't used the Mephisto, just pointing out the possible difference if there is any.

they made the crank a tick bigger per novas site. different glow plugs. different carb. 3 needle like the rolling. and better cooling head and they say different exhaust to use.. I can give more on this when it shows up Friday and I can put the 2 motors side by side.. jeremy

I was looking at the mantra for awhile but got mephisto when they came out, Drake has it now doing the break-in. The BTT square stroke was my favorite buggy motor ever, so I'm hoping this is similar

They both say they have a bigger crank bore, and though glow plug isn't exactly engine specification it is the same on the exploded view.
The only thing that make any real difference is if they have changed the crank in timing or bore etc, all the rest is the same between them. The carb could have slight difference in how it feels and tunes, but not in power.
But measure the timing and get back to us.