Ignition system and ECU

The Wolf ignition system is still in use on this engine. It controls a 3D advance curve by taking RPM and throttle position inputs. It automatically swaps to a milder advance curve in 6th gear (reads a gear selection sensor) to stave off detonation. It controls the water injection system on/off points and checks switching RPM to throttle position. it has built-in control for quickshifter operation. Unfortunately, the TZ requires a very large amount of ignition advance, more than I can get from the Wolf igntion when the stock timing mark (on the crank) is used. This winter we’ll relocate the timing notch to about 45 degrees BTDC so I can get a full advance curve on the engine. So far I have been as much as 10 or more degrees behind what a stock TZ needs for advance. Hopefully this will help to wake the engine up, next spring. We plan to swap crank wheels from side-to-side, and cut a new notch in one of the currently virginal crank wheels.

Pipes

Thus far, I’ve been using modified “Darcy pipes” , which were designed around the OEM RG barrels and at 113mm are much too skinny for TZ application. They were also too long, and I had to shorten them considerably. Actually, they’ve been chopped and modded about 3 times, now. We have a new pipe spec sorted, which is very similar to a std TZ pipe, which should also help to wake up the engine next spring. The plan is to allow the pipes to run up to 11500 or 11750 rpm, and use water injection to fill in the lower part of the powerband.

Water injection

Water injection is a big part of this package. Still controlled by the CDI, it should be able to reduce peak torque rpms to 9000/ 9500 RPM when activated. Hopefully we’ll be able to get a very wide, and high, plateau of torque in the 70 ft-lb range, while still revving out to 11700 or so. In theory, that ought to be good for 155 hp.

How it ran

Frankly, I had no idea what to expect when I got this thing running. Initially, I had to deal with crazy low-end carburetion. But, that didn’t prevent me from riding it. What I found was, the motor made better power in the 5000-6000 rpm range than my old RG setup. I attribute this to the excellent powervalve, which drastically reduces the height of the exhaust valve to something more suited to a trials bike. It ran well on top but oddly enough, still peaked at 10300 or so, like my old motor. None of the screaming, 12,000 rpm power I had been expecting. Now, I knew my pipes were designed to peak at 10.2 or so, but I figured that with all this extra exhaust port height, it would still rev out higher than the old barrels. No dice. A trip to the dyno revealed 125 HP and 65 ft-lbs, but much less upper-midrange than my old setup. Damn! Were the pipes so long that they were beyond some critical threshold, where the ports just didn’t work like they were supposed to? I cut the pipes down a few inches. Bingo- 12,000 rpm power- but was it any faster? Another trip to the dyno. Still at 125 HP, but now it had to do 11000 rpm to do it. This time, though, I had overrev to end all overrev. It would easily do 12k, and even with the powervalves set in the low rpm position, it revved to the moon. Anyhow, it was no real improvement.

Next, I cut the pipes a bit more, in the headpipe, to try and bring the vacuum vace back into synch with the stuffing pulse. result? 125 hp, but now at 11500 rpm. Shit! Powerband was considerably narrower than what I had when using the RG barrels.

I rode it like this for the rest of that year. The next spring, I planned to go to Daytona and contest the Brute HP shootout at AMI. I had a few mouths to shut, and I did call out Mr Lance to bring his best bike down to Daytona and run against me on the dyno in front of everybody, as he had been investing quite a lot of time and energy telling people that I had been falsifying my dyno numbers.

Brute HP shootout

Preparation- Pete bored the carbs to 36.5mm and I enlarged inlet passages, and advanced timing another 4 degrees by altering the location of the timing pickup in the case. Still a good 10 degrees from where it needed to be. but, it was all I could do. UNFORTUNATELY (and this is a big one) the shrouds surrounding the main air bleed entries had been machined off as part of the carb boring process. I didn’t realize that those babies HAD to be on there for it to run right. And so...

I ran off to my local dyno guy to test ignition curves, disc valves, and my next generation pipes. I also took a can of VP-MR2 oxygenated fuel. I had to leave for daytona in a few days! What happened was, the bike would pull on the dyno up to 11,000, then suddenly go so lean that it would begin barking and backfiring out the carbs. No matter what I did with jetting, it just would only run to 11,000 rpm. All the rest of my testing was rendered moot by this development. I returned home to try and sort it, and came back day or 2 later.

Shit!! Still ran to 11k and stopped. It pulled 132 Hp (134 on one jagged run, but that stuff doesn’t really count) at 11000 with the power curve climbing sharply, but at 11k it was all over. After exhaustive tests, I dragged out of there, with nothing to show for it but new problems. We even tried the MR2 on the low CR heads, and it hurt power. Damn!

I talked to a few guys, including some vary sharp tuners, and got suggestions that covered everything from alien electronics to fuel frothing. I went to Daytona with car wheel tape weights to stick to my float bowls..

A few days of struggle in Daytona revealed no solutions.

The bike just would not run above 11k. I was even trying to alter the main air bleeds by epoxying them shut and retapping to a smaller size. I tried to find air jets: I searched all of Daytona, IN BIKE WEEK, FOR GOD’S SAKE, and could not find air jets. I tracked down the Mikuni guy at his giant trailer outside of Harley Davidson of Daytona. O Mikuni Guy, I said. I need and assortment of main air jets! And I listed the sizes. “Nobody’s ever asked me that before”, he said. And sure enough, he had no fricking air jets.

I called Darcy in a panic. By this time, I was considering whether the loss of the main air bleed shrouds was causing a problem. I had managed to contact My Favorite Journalist (Kevin Cameron) and he pointed out that many bikes use controlled airflow across the air bleed entries to create certain effects at high intake airflows. Removing the shrouds would certainly have an effect. Thanks, Kevin! Darcy recommended epoxying aluminum tubes back into place to shround the entry to the air bleeds. Voila! it ran perfectly. Too bad I had completely wasted two trips to the dyno back home. I slapped it all together and ran off to AMI to run it. My water injection system was dead because of rust in the steel lines, so I was running without. The guy asked me where to gas it, so I said 6500 or something like that. He got it to 6500 and gassed it.. and it fell right on its face. Remember that rich hole? Instead of getting off the throttle, like we would do, he held it open hoping it would clear out.. but instead, it fouled a plug or 2. I think it registered 50 hp or something like that. I had to limp home on 3 cylinders.

I thought boost bottles might help. I had calculated the volumes and hose lengths for boost bottles to help with the rich spot, and had already made the bottles, so I installed them. They actually worked pretty well, till the gasoline fumes melted the plastic I had used. Damn!

I decided to fix the crippled water injection. I spent tuesday night installing new stainless lines, a new pump, and cleaning out all the fittings and injectors. I installed the 16:1 heads and filled it with MR2 fuel. One test ride- it worked like a charm. No flat spot with that little blue water injector light winking. And it was faster than holy F%^&. Wed I was back to AMI bright and early. The top 600 had posted 103 HP, I believe. We ran my bike up on the dyno and it ripped, spinning the back wheel on the drum but posting something like 118 HP. You only get 2 pulls, so that was that. With the shootout lead, I ran off home. I rode around all day and decided that the high CR setup was really no better than my low CR setup. I burned up the rest of the stinky fuel, which was now enough to make me sick with one whiff, flushed it out and changed back to Amoco 92. The 102 is too slow-burning for my low CR setup, I had seen that before when running high octane Swapped on my 14:1 heads. Went back Thursday and insisted that they strap the bike down really tightly. It banged out 128.6 Hp on the Superflow, still climbing sharply at 11750 when the rev limiter kicked in. The correction factor for that day placed it at 138 dynojet HP- I was pretty happy with the result, and also with the correlation of my dyno back home, with the superflow in Daytona. Whatever the absolute numbers, I beat all the GSXR750s there and was 4 Hp behind the top R1, which had posted 132 HP. Vindication! ! whew. An exhausting week. I think I worked as hard as any racer at the track. Friday I came back to AMI and took the win with a bye in the 600cc class, at 128.6 HP, as the 103 Hp ZX6R was not likely to challenge. See the results HERE

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