... and lean the HSN a little

A little history from my local track:

One of the members bought a BTT last year from a LHS (parallel import...). There was a fault on the tip of the crank (due to the loss of the motor on the floor???). Because of the parallel import it took several moth to get a new crank...

The member maaaayby hasn't the biggest patience, so the break-in was done as follow: 3 tanks of fuel in break-in bench at idlespeed. It was done in the winther time and the engine never reached 85º C... Then into the car and off to a practise weekend. The ambient temp was approx. 0º C all weekend. Without a sock, alu tape etc. around the head, he started leaning the engine after the very first start at the session. Screaming lean all weekend...
Some month after he started racing on our outdoor track and he really hated the mill... It was impossible for him to find the right tune, so the engine kept flaming etc. etc.. We told him to stop those 1/8 to 1/4 adjustment on all screws, because he would never get the tune right... He never listened so he finally gave up, and gave the engine to another member... for free! It had only 2 3- gallons on it.

Without ANY part replacements the engine is a killer on our track. The new owner has 100 tanks of fuel through it so far. When he got it, he put in a new C6TGC plug in. That plug lasted 90 tanks of fuel... ... I tried to convince him the try a 9901 or RB 2045 pipe insted af his 2057 with an insert so he could get some more topspeed... But he is happy as it is, and thats just fine with me

BTW: The new owner has been racing Sirio engines for the past few years. He is impressed with the Novas smooooth powerband - much easier to drive the car...

just a quick question. I ran my buggy for a 5 min qualifier, then we got rained out....

Novarossi BTT, C6TGC plug, 9901 pipe, 41020 header, 6.5 venturi, Byrons 30%, about 1 mile above sea level, 100 degrees out....

But during the qualifier my motor was flaming out at the end of the long straight away. Basically, after a high speed run of about 7-10 seconds and went zero throttle and rolled the turn it flamed out. The tune other wise LSN is about 1.25 turns in from flush no drop on the idle and steady, the HSN was about 1/2 turn out from flush.

The plug was a little brown, coil shiny. I had good smoke from what I could see. Temp was about 240. Clutch was just rebuilt, was good, no problems there. Where should I start to fix the flame out?

Hoosier
Had a similar problem about a month ago on my plus 4. Ended up being slightly lean on the lsn. My Carb ended up being a little out of balance. Sounds like yours is doing the same thing mine was.

So, you richened up the LSN? I did as per Monty's instructions. Maybe not enough. I am thinking since my location is El Paso and the air is thin, less oxygen it may be influencing this maybe, maybe not...

But, my HSN was above flush when it was doing this stuff. I hear people are below flush on the HSN. I know it varies, I just want to get this tune down. I was thinking that I needed to richen the HSN too. I am going to restart from stock settings and try again. Just wondered, thank you.

Yes on the lsn. As far as the hsn I was about the same until my engine dropped its nuts. How many gallons are through the motor? I tied the stock setting before it fully broke in and they were way to lean. Just use caution with the stock settings. I am currently about 4 turns from closed on my hsn needle and I am just finishing my 3rd gallon.

You must be reading my mind. I have about One & 2/3rd's of a gallon, just about 2 gallons through the motor. It still has massive pinch left when its cold, but after I run it (235-240*) I check the pinch by turning the flywheel through the chassis with my finger and it still has a noticeable amount of pinch.

I would just richen the LSN just slightly, maybe a 1/8 to a 1/4 turn at most. Was it bogging down low at all? not lke a lean bog, much shorter or not making a smooth transition from low speed to high speed? You may just be trying to get to much out of it to early. I just grabbed my buggy and tried to turn the fly wheel over and its tough to do when cold. I always preheat up to at least 190 before starting. I am a firm believer in preheating. Like I said my motor is starting its 4th gallon next weekend it its in top form even after loosing a pressure line for the first 4 laps of a main and having a hole in my fuel line another time. Even with those two instances of being run pretty lean my motor is still in top form and I think it has to do with preheating and quality fuel. Not to mention what we all know, the best engines in the business have the Novarossi name on them!

Also try the 7mm insert. You will find it runs better then the 6.5. When I go to big tracks and need power I switch to the 7.5.

Thanks Brother, I will try a 7.

I was there too. I can imagine going from El Paso to here would be a bit irritating tune wise. It needs to be richer here. For example, the low speed should be close to flush, and the top just outside flush, sounds like you may have been lean on the bottom. I thought mine needed to be a little leaner on the bottom too, but it was so hot when it warmed up it went too lean on the bottom. I should have known better. It was a challenging day at the track for sure. Was it the b main open buggy class. I was in that too.

I'm confused...I'm in El Paso, you were here? We actually got rained out after the first qualifier. But, thanks for the advice Merdith.

I thought you were from El Paso and went to the Texas State Finals in Alvin. My bad.

No, I wish...lol

Anybody remember this engine?? we will be running it in a losi 2.0 buggy, what pipe works well with it?? thanks