Autonerdz forums

autosparky wrote on Oct 26^th, 2017 at 9:32pm:


Okay, busy looking @ burn time ect, what is the vacuum on this engine?, can we do a COMP wave form?

Ye tweaked the exhaust, have no idea the ramifications on that, but can this engine breath???

As far as I know it can breathe. I went back to basics last night and checked compression again. Both cylinders even at 150 psi. I also performed a cylinder leakdown test. Front cylinder 5% leakage from the crank case and the rear cyl 2% leakdown from the crank case. In the motorcycle world that would qualify as a tight engine and in theory it should make power.

I would like to do a compression waveform but I do no have the tool to do so :/

Well guys we got it figured out!

It took some hours last night but we got the horsepower back. Some of this was me being a novice to the scope but the scope was able to confirm a lot of suspicions I was having.

After I got the scope dialed in and hooked up the current clamp correctly  I was able to prove that everything on the ignition system was working. I also was able to prove that the bike was advancing timing like it should. (For a little while I was thinking that maybe the TCI was not advancing timing which would definitely cause hp loss.)

I learned alot this time around on the scope. I learned how to set things up that I never have before and I was able to use previous bikes to prove good signals on this bike.

Enough chit chat, I am sure you guys are wondering what did all this!
Like I said, we checked compression and leak down, couldn't have been fuel because no matter how much fuel we added or took away it would not change and spark, after much debate, was also working like it should! If I had the compression waveform tool, this would have gone much faster. The customer had made, or he had someone make them for him...a set of "custom" baffles for the exhaust that are apparently extremely restrictive! After all things that make an engine run properly checked out, all I could think was that it was something outside of the engine so I started to look at the exhaust and waaay up there was these baffles. Removed them and did another run. The bike sounded so much healthier and you could definitely feel the seat of the pants power.

This was a challenge and really one to log away in my brain for later! I really appreciate all your guys input! I will post the hp/torque graph for you guys to see and also the known good ignition waves. 

Zoomed in view

RedlinePowersports wrote on Nov 4^th, 2017 at 6:44am:


For these after repairs did you move the amp clamp location and/or orientate it differently?

StitchB wrote on Nov 3^rd, 2017 at 6:27am:


Redline, good on you.

Yeah, if you had WPS would have seen the high pressure as the exaust valve opened.  But all that is hind sight, 20/20 and as always, it is.

New ignition captures also look great, now for posterity we know what a good one looks like for other times. The beauty of all this is forced you to hook up, unhook, ect and with that comes what I call muscle memory and the ability to hit it quicker next time, and there will be a next time.

Good job

StichB