10mm Serval tuning help

[CrashRyan]

I just build a 10mm Serval cub (465) as cast. I'm running pods, 35mm carbs, chariot intakes, VF4 reeds, chariot cool head with 24cc domes (kicking compression 155lbs), shearer SB in frames. Timing is set at +5 with all stock ignition minus the timing plate. Fuel of choice right now is Avgas mixed 50:1 with  Amsoil. Leakdown test held 6lbs solid for 1.5 hours.

 

Right now I'm running into a problem that im hoping you guys can help me with. 

 

Im running 42 pilots, 135 mains, cgm needle on top clip. My machine is acting rich but i feel like im way to low to go any leaner. When my machine gets under heavy load like when hill shooting it has a hard time staying in the powerband. as if my pipes can't clear and its bogging out. 

 

Here are a few video clips of me out testing and tuning let me know what you guys think. 

 

 

This was with a 148 main

 

this was with the 142 main

 

I picked up more speed with a 140, 138, 135.... but im worried about being way to lean. Any other issues you guys might be able to lead me toward or is it just a jetting deal is all?

 

[special06shee]

Are you losing ANY trans fluid?

[CrashRyan]

Are you losing ANY trans fluid?

No still right where i was when i filled the trans.

[sprinklerman]

The only time I had weird jetting issues similar to what you are describing, is from a dome profile issue.

I'm not saying that's what it is ( might try cel needle)

 

Sent from a van down by the river

[dirtydownunder]

X2 with the cel needle. Also try mixing the avgas with pump fuel 50/50.

Dome issue could be there.

 

How do the plugs look ?

[CrashRyan]

X2 with the cel needle. Also try mixing the avgas with pump fuel 50/50.

Dome issue could be there.

 

How do the plugs look ?

To new to get a good reading on them. haven't had them in very long. i pulled one plug and it was wet the other was dry but both carbs are set up identical and the cylinders kick exactly the same. I'll try a different needle and mixing down though. That was one thing we talked about trying.

[WINDYCITYJOHN400]

Your carbs are too small for that motor. (I know. I tried) Your main (thanks to an unbelievably stong signal strength) is going to end up around 130.

You can chase the jetting.....but you should just jump up to 39-41's.

[trickedcarbine]

^ was actually typing something similar then read your post john. That is exactley what I thought was going on. The only 10 serval around here has incredibly low jet number on some 34mm PJ's with power jets.

 

OP, definitely try a different needle profile. The CEL, CGL, and DGH seem to work really well in the PWK's.

[trickedcarbine]

Any one running 38mm PWM's on one of these yet?

[sleeper06]

Like windy said and also check into electrical , ive had people lean there machines out chasing jetiing then when I got it it was electrical

[locogato11283]

Your carbs are too small for that motor. (I know. I tried) Your main (thanks to an unbelievably stong signal strength) is going to end up around 130.

You can chase the jetting.....but you should just jump up to 39-41's.

Windy hit it right on.. You need a bigger carb. And yes, a bigger motor pulls fuel more efficiently resulting in the smaller main jet. That's why I can run the same size main jet in my 18DM as people do in a 10mm Cub.

 

The other thing that could be causing you some issue is your pipes. Shearers just don't make the same power and torque up the curve like CPI and Sniper do. Unless you're riding that motor around at 10,000 RPM you're not going to see max performance from them.

 

[CrashRyan]

Tyler any idea what the stutter at the top of the sniper pipes is here on this dyno chart that Cam did on Ryan's 10mm serval?

 

http://bansheehq.com/forums/index.php?showtopic=171645

 

That is one of the big reasons i stayed away plus the fact that i have heard and seen that they burn the crap out of your pods which isnt great out in the sand. 

 

I've been thinking about new carbs for a while and just about bought a new set the other day but then saw chariot is coming out with new carbs and decided to wait. Messaged them just yesterday and they said they are out about 4 months on those. Is there any harm in running a 35mm carb on this motor till i can pick up a set of 39mm chariot carbs?

[locogato11283]

Tyler any idea what the stutter at the top of the sniper pipes is here on this dyno chart that Cam did on Ryan's 10mm serval?

 

http://bansheehq.com/forums/index.php?showtopic=171645

 

That is one of the big reasons i stayed away plus the fact that i have heard and seen that they burn the crap out of your pods which isnt great out in the sand. 

 

I've been thinking about new carbs for a while and just about bought a new set the other day but then saw chariot is coming out with new carbs and decided to wait. Messaged them just yesterday and they said they are out about 4 months on those. Is there any harm in running a 35mm carb on this motor till i can pick up a set of 39mm chariot carbs?

 

I don't remember exactly what it was. Cam wasn't concerned with it if I remember correctly. He made several pulls with them and they were all the same.

 

I am not sure about the filters but I could have rjdgriff post some pictures of his new Snipers on his 10mm Serval.

[Strm Trpr]

I asked Cam about the dip too, and he said that you wouldn't be able to feel it.

CPI's or Snipers and in that order.

[locogato11283]

I asked Cam about the dip too, and he said that you wouldn't be able to feel it.

CPI's or Snipers and in that order.

 

Snipers out-performed CPI from top to bottom on the 10mm Serval. They also revved about another 400RPM. They are the hands down best pipe for the motor they were tested on. I'm guessing they will be similar on other 10mm Servals as well.