After building a "Hot Rod" Zilla, I feel in love with this motor. I was very curious to see what a stock Zilla performs like. I never rode one. I went right to all the mods building Shirley. I do alot of trail, route, play riding in Michigan. My main quad for this was a YFZ450 with some work.
I found a 1987 Zilla that was stock except for the FMF pipe. I really wanted to try a small reed motor after hearing about better torque and throttle response. I replaced the cylinder, head, and carb to a small reed set-up as you would see in a 88 plus Zilla.
Motor Work:
- Fresh Bore and Piston
- Head Squish Cut
- Oring Head
- 88 + style TM Carb
- Stock Airbox and Lid/Foam Filter
- FMF Pipe with Spark Arrestor Version
I had some seat time on this quad last weekend after breaking it in. Here are some observations:
- Smooth and powerful right off the bottom through the midrange. I mean right off idle!
- Very powerful midrange thrust - FUN
- Tractor like torque
- Smooth like mother butter
- Fast through the gears
- Short shifts and ride the torque wave
- Very little topend thrust (I am jetted alittle fat on my main but this pipe tells the tale).
Stock Milked Out 87 Big Reed Motor vs. Fresh Small Reed Motor - The new small reed motor had noticeably more power.
- Added compression, head work, etc I assume.
- The small reed motor seemed much smoother at low speed. It had no carb or strange issues at very low rpms and speed. Is this the difference between the small and large reed motors?
Fresh Small Reed Zilla vs. my BB, Cammed, Ported YFZ480- I think this Zilla may be faster.
- I think this Zilla has better torque and power delivery than the YFZ.
- I rode the YFZ a few weeks ago at the dunes, so the butt dyno is pretty fresh.
Small Reed Stock Zilla vs. Shirley- Shirley is Ported, Big Reed, 41MM carb, Big Filter Beast with a Q Pipe
- These are two different motors
- Shirley is violent and angry. Does not like going slow. Hits hard in the midrange through the topend.
- The small reed motor is torquey, happy to put along. Doesnt seem to ever fall off the pipe/powerband.
- Both are still 500's and fast as hell.
I really like how this motor turned out. I think I will have alot of fun riding it in various terrain. Its got big power that's useable. I was surprised how well it runs and have no doubt that it will smoke a stock to modded 450.
My advice to others building a 500 is to take a hard look at the riding that your do. Dunes - no doubt big pipe and HP rules. Everything else, a fresh stock 500 properly set-up is alot of fun.

Small Reed Play Quad

Hot Rod

