Bonneville America Forums Forums Technical Forums General Tech EFI Notebook - Tunes

Did the Group Buy for Tuneboy and it was brilliant, installed fine and runs sweet. While exploring my ECU, found that the dealer had installed tune 20187 to slow the popping I was getting on decel with TORs. This tune is a base tune for Thruxtons, and the installed tune for Bonnevilles with stock power units, and is not recommended for use in America/Speedmasters. The bike ran ok with that tune but had terrible manners - snatchy throttle, rollon stumble, irregular idle speed, and surging between 3000 and 4500 rpm.

I downloaded tune 20184, which is the standard America/Speedy tune for aftermarket cans, and installed it with no problems. Gave it a 160 mile test yesterday and happily it is the tune that should have been installed from the giddyup. Good manners, snatchy throttle not there, power band seems broader, no abrupt shut-off when released twist grip, and also less severe engine braking on decel. And just a hint of grumble @ 2000 rpm on decel, no popping. It is very happy at low rpm's, and you can shift very nicely at 2500 revs with no arguments from the engine room, and a smooth power curve as well, to as high a speed as your comfy with. This Tuneboy is like an MRI for your ECU, and lets you see that is going on inside your little Univac. And, you can, if you dare, modify the stock tunes to whatever you like, and reverse it if you are not 100% pleased.

Kicking and screaming into the future.....

My BA showed 20187 also when I first checked with Tuneboy. I asked Wayne about it and he sent me an updated version of TuneEdit which then recognized the tune as 20184 (I had not installed any new tunes at this point). In other words the tune always was 20184 but it was not recognized by TuneEdit - now it is. Actually now I have 20184TuneMod1 but prior to that TuneEdit saw the tune as 20184. So I don't know what tune Triumph had in yours to make such a difference - because maybe you had 20184 to start with and just reloaded it. Sorry if that confuses the issue Dan. Maybe an email to Wayne would be in order to see if he can explain.

Not sure I want to put too fine a point on it, perhaps I'll let sleeping dogs lie; next time I hook up I will poll the ECU and see if it tells me what actual tune is in there, knowing what I installed. It runs much more to my liking now, and I'll probably try a few other tunes as time goes on anyway. But I may send off for an update of TuneEdit if one is available.

One question I asked 'support' for is how to balance the throttle bodies, as the diagnostic tables in Tuneboy showed my bike had an imbalance in both the MAP and P/W values between #1 and #2. I didn't get an answer from OZ, but reading the Triumph manual it seems that an imbalance in MAP values may be inherent in the 270 degree firing order, and that the delta value between bodies is ok provided it is within their unspecified tolerance. The engine ran like crap when I matched the MAP values, so I returned the setting back to factory marks, and it runs good. Understandably, Tuneboy would be hesitant to offer tuning advice, other than about their product, and I'm ok with that. Also I imagine they are pretty busy setting up all the new owners. But empirical data from us owners and any TB guidance shared here is most valuable, and hopefully together we can build a working database to understand these mysterious critters.

Also, it seems a few more rpms of idle speed makes my and others engines lots happier, shifting better, etc. They do not like the tractor/Harley low idle speed. 1120 rpm works for me.
Quoted from Wickipedia, FWIW:

Crank Angle (270 degrees)

A development in recent times is the 270-degree crank, pioneered by the Yamaha TRX850. The TRX used a modified version of the Yamaha TDM850 engine; but the TDMs 360 crank became a 270 crank in the TRX. A 270-degree crank imitates the sound and feel of a V-twin, and there are other advantages. In contrast to the 360 and 180 parallel twins (above) the 270 crank gives a compromise that allows a more regular firing pattern than a 180-crank, and less vibration than a 360-crank. There are two extra benefits as well. Just like a 90-degree V-twin (but unlike the 180 & 360-cranks) the 270-crank never has both pistons stationary, and this gives a dynamic benefit. Also, although the firing interval is not as uneven as the 180-crank or 90-degree Vee (which both fire 1-1-0-0) the 270-crank avoids being perfectly even. This feature is said to allow better power delivery to the rear tyre, giving two fairly close power pulses followed by a "recovery gap". This "big bang" concept has been adopted for the 2009 Yamaha R1 engine, which has a 4-cylinder "cross-plane" crank. The 2009 Triumph Thunderbird 1600, which has a massive 1600cc parallel-twin engine, has adopted a 270-crank to obtain such special benefits; and it is quite probable that 270-cranks may become the norm for parallel twins in future.