Stationary Cut-Down Test?

[1fastmofo]

I just bought a built banshee (see details below). I know the shop that did the work, they do a good job.

 

The guy that I bought the bike from took it to St. Anthony's in Idaho before he sold it to me and had the shop jet it to run at elevation. I do all my riding in the dunes at sea level. The first time that I took it out, it was flatting out on the top end and the engine was vibrating so much that it either kicked the spark plugs right out or it literally destroyed them. (went through 4 spark plugs in two days).

 

I called the shop and they said that they could re-jet it, tune it up and throw it on the dyno for $200, and that would fix all my problems (with the bike).

 

If I jetted it myself, I do not have the room, locally, to get it up to WOT to do a proper cut-down test. Could I jack up the rear end in the driveway and do the cut-down test or does the engine need a load on it?

 

Should I do the tune myself or eat the money and give it to the shop to tune.

 

Any help would be appreciated.

 

SPECS:'99 black/red, 4 mil, 22cc domes, 35 carbs, p+p, cool head, +4 swingarm, 10 paddle haulers, cpi in-frame drag pipes, and a partridge in a pear tree

Edited April 26, 2007 by 1fastmofo

[Duner440]

I may be wrong but if your plugs are backing out or its "destroying" them, I think it is a detonation problem. Check where your timing is set. Also, what are you running for fuel and what is the compression? I dont think jetting is the issue. I am at around 1000 ft here in Kansas and I go out to St. Anthony every year. I only have to go down one or two sizes on my jetting.

[1fastmofo]

When I took it out, I was running 101, but the guy that I bought it from said that I could run up to 112 or 114. I can't remember what he said the compression was and I haven't checked it. I will check it tonight.

Edited April 26, 2007 by 1fastmofo

[Fireroad Express]

yes, the engine needs a load on it when doing a plug chop or "cut-down"