Big-bore engines

[rayo1]

have a 96 cu bored to a 107 & stage 4 work. is there any particular maintainance to periodically perform or double check with a big bore motor?

[dog155]

Nothing needs to be focused on other than regular maintenance and keeping a good tune in the motor.

[rayo1]

does the tts tuners hold tunes pretty good. I know the old pwr commanders would drop out a lot.

[MilesToGo]

Originally Posted by rayo1

does the tts tuners hold tunes pretty good. I know the old pwr commanders would drop out a lot.

I have a 107 build with TTS tune also. Maybe one of our resident pro tuners will chime in on this question. I would say unless you make some significant mods to your bike then your tune should hold indefinitely. At least i hopes that's the case. I sure don't want to pay another $400 to have this thing retuned. If that's the case then might as well spend the money on an auto-tuner.

[rayo1]

only change I have made after my dyno was going down to a 31 tooth trans pully and a 139 tooth rear drive belt. don't know if it was significant enough to need retuned but it is a definite change with the launch. Any pros or con about redynoing>

[jeffsglide]

From what I heard,some of the bikes that were tuned years ago either with the TTS or Screaming eagle tuner are running slightly lean now due to the Quality of the Gas (ethanol) that's going in our tank. Most bikes need to be richened up about 2% to make them run right again. Quoted By Doc.

[dog155]

Pull the plugs and take a peek,if they have a little color on them you will be fine,best to read fresh plugs.

[rayo1]

Had 50 miles on bike and had a big bore engine build. had the dyno at 900 miles. never really got into the bike for its worth more than 3 or 4 times now have 6500 on bike. should I get another dyno since it is well broke in?

[dog155]

Pull the plugs and take a peek,as long as the bike runs clean and makes you happy no need for another pull.

[FXDRYDR]

+1

Watch for heat.

[rayo1]

With 124 HP and 127 TQ, will there be noticeable drop off on the big end speedwise when going from a 32 tooth trans pulley to a 31 tooth and a shorter 139 tooth rear drive belt

[dog155]

Not enough to worry about,you might feel a little more tug in seat of the pants.Our big inch bikes were geared up from 32 to 34 for better cruising.
This is the fun of having power like this, experimenting or in better terms dailing them in.

[FRANXNBEENZ]

Getting back to your original question, there really is'nt any special maintainance needed for a big bore engine. The most important thing to remember is that these engines are hard on oil. Be sure to change yours regularly, and use a good filter too. Not some bargain brand.

[guydoc77]

Just regular maintenance as mentioned. Nothing dramatic.
I'd add that, if you're using forged pistons, make sure you let the motor become warm to touch before you start using much throttle or getting the revs much above 1500 or so.

Does a TTS "hold a tune"?
The TTS system is not like a Power Commander. A Power Commander is installed inline between the engine's ECM and the injectors and ignition system. The "tune" is whatever is in the ECM. The Power Commander just alters the ECM's signals inline before those signals get where they're going. With a Power Commander one can make changes to the alterations that the Power Commander makes to those signals so it is a tuning device for sure.

TTS comes with a little plastic box called a dongle. The dongle is nothing more than a key to allow access to the ECM from a computer. Of course, along with the dongle, the TTS system comes with software to download onto said computer. Using the software, you can change the parameters of engine ignition timing and fueling and then download them into the ECM. When done, your ECM is reprogrammed, you unplug the dongle and ride away. There's nothing left on the bike as far as any TTS hardware, etc.

Now here's the tricky part. If you have a newer bike with oxygen sensors from the factory, then the factory tune is closed loop. When you modify your bike, you have to retune it. If you leave it in closed loop, there is a feature called "adaptive fueling" which enables the ECM to "learn" from data, good or bad, obtained, largely, from the oxygen sensors. If any of the data is "bad", which is likely to be the case in a modified engine and because the oxygen sensors are narrow band, then yes, your tune will degrade.

So, in summary:

When you modify your engine you do need to get it tuned. In my opinion an open loop dyno tune is THE most cost effective way to do that.

In order to tune the bike, you, or whoever tunes it, will need a tuning device, be it TTS or another.

[DEW2112]

I was under the impression that you can no longer read spark plugs like the old days due to todays fuels.