Captain’s log Stardate 09152019 – Started it up and it immediately died. Adjusted idle speed screw on carb to open slide more. Thereafter, idled fine. Experiencing a bit of kickback probably because of the super light rotor on the HPI system.
Captain’s log Stardate 09162019 – Alright, took it for a ride today. Ran great. Acceleration and responsiveness seem better. Got it up to a very similar top speed as in the recent past no problem but was not in an area to give it hell. Wasn’t ready to give it hell yet anyway. I probably need to retard the timing a degree or so and try that. I think I just have to move the stator plate to the left (counterclockwise) to do so.
9/24/2019 – Almost final thoughts on the HPI Ignition System for QT50. I still have some fine tuning to do so these are preliminary conclusions. So I was wrong – I need to move the stator plate to the right (clockwise) to retard the timing. I ended up moving it one click to the right from its initial setting (with piston 2mm BTDC). Temperatures were much cooler with a high temperature of 378F after 20 or so minutes of riding (and that was towards the end in stop and go riding – for much of the ride temps were below 365F). I think this is the main advantage of the HPI system – keeping temperatures reasonable on your performance qt50 setup. In the past, qt50 performance modifications always come with the downside of fighting soaring temperatures. I’ve learned many tricks to deal with this but the ability on the HPI to retard timing and run a CDI with a timing curve makes all the difference in the world. Now I feel like I could take the qt50 to a rally and do a 30-60 mile ride with no fear of heat issues. I could never say that before.
I can also say that after installing the HPI system, I don’t have to constantly look at the temperature gauge anymore as my fear of running too hot and potentially soft-seizing the piston is basically zero or pretty darn close to zero. If you’ve invested time and money into a Malossi cylinder and piston for your qt50 then the HPI system is a darn good way to protect that investment.
I’ve experimented quite a bit with the Yamaha Jog CDI, and it just retards timing too much on the qt50 to really be of any use. In fact, the only way I could get it to kind of work was to run an offset timing key to advance the timing on the bike 3.6 degrees in conjunction with the Jog CDI. Even this combination strangely limited me to 32 mph on a stock qt50 with mlm circuit pipe that normally runs in the low 40s. Strange because it would do 32 mph up an incline and 32 mph down the same incline. The Jog cdi can’t be speed limited, can it? Probably just a fluke. The Jog box allegedly has a timing curve built in but who knows exactly what curve it is. I suppose I could find out with a timing gun – maybe later.
Acceleration seems improved although I kind of overlapped upgrades with the Jemco pipe and the HPI system (the Jemco seems to be a low/mid range pipe and also adds to acceleration). But I think that acceleration has improved despite retarding timing slightly. I obtained a slight gain on top end of about 1 mph and there may be more there.
My next move is to fiddle with the timing some more and see if I can find the sweet spot and then determine what final gains were on acceleration, top speed, and temperatures.
Obviously, or it should be obvious, the 12 volt system is a major improvement over the stock 6 volt system. Lights are brighter, horn is louder, and I have the ability to add 12v accessories like a phone charger.
So I’ll set a goal of a final update before the middle of October 2019 on the HPI system for the qt50. That should give me plenty of time to fiddle with the settings and do a few more rides. And, of course, you can find the HPI ignition system for sale at treatland.tv.