Problems with 93 Blaster

[J.D. Shipp]

I have a 1993 Wave Blaster with the following setup:

Pro Tec Recreational Head @ 170 lbs.
Pro Tec Pump Gas Ported Cylinders.
Pro Tec F-Series Exhaust Manifold / Pipe.
Pro Tec Intake Manifold.
K&N Flame Arrestor.
1mm overbore.
2 Hours on new top end.
Running 93 Octane Gas (32:1 for break-in, 40:1 normal)

Dual 38's with 102.5 Mains, 65 Pilots, 2.0 N&S, 20 lbs Pop Off, both high & low adjusters are at about 2 turns out.

Now for my problem(s):

1) Throttle Response - Good response from idle to 1/4 throttle (Smooth and Strong), but any throttle past 1/4 throttle is like instant WOT and acceleration will rip your arms off.

2) When running over 1/4 throttle for 3-5 minutes, the engine will either suddenly shutdown completely, or almost shutdown (I can sometimes catch it right before it shuts down by feathering the throttle, but it has no power and has a low "WAAAAA" sound to it for about 10 seconds, then power returns).

I am not sure if I am leaning out and having mild seizures or loading up and killing the engine.

Any help is appreciated,
Justin

[ July 31, 2002, 03:30 PM: Message edited by: J.D. Shipp ]

[polaridoo]

Sounds lean in the high speed circut, or even possibly fuel starving (like fuel pump or fuel lines)

[Bryan Glynn]

You definitely sound like you have a lean situation, obviously in the mid-range. I would try larger high jets to start with, but you may have already been doing damage by seizing it.

[J.D. Shipp]

Alright.. I have some 125 mains I will try.

Would lowering my pop off to 17 lbs help richen the mid?

Thanks,
Justin

[Bryan Glynn]

No it won't. Pop off is coupled to the signal of the carb, not the mixture requirements.

[J.D. Shipp]

Welp, It is definitely lean.



Here are some more pictures.

With advice from Pro-Tec and others, I am going to rejet to: 110 pilots, 150 mains, 1.5 S&N, 115g springs.

I don't think there was any damage to the cylinder, so I am gong to hone it and put in new Pro-X pistons.

Thanks for the help!
Justin

[ August 01, 2002, 10:39 PM: Message edited by: Bryan Glynn ]

[Bryan Glynn]

That *could* be detonation damage, but it's hard to tell anything from that grainy pic. I check your others and non of them clearly show what we need - the top, expecially the dges, the bottom without the bearing and wrist pin, and all the scoring, without all the wash from a flash.

From what I can tell it looks like a clearance/overheat problem, not detonation.

Good luck with Pro-X.

[J.D. Shipp]

OK, here are some better pictures.











[ August 02, 2002, 08:05 AM: Message edited by: Bryan Glynn ]

[Bryan Glynn]

I stand by my overheat diagnosis.

[ August 02, 2002, 08:06 AM: Message edited by: Bryan Glynn ]