Triumphrat

thundershortz · 08-30-2009, 09:39 AM

TB states that one can use the MAP sensors to balance the throttle bodies on the 865 twin engines. 'Factory balance' readings reveal an imbalance between cyls 1 & 2, also a comparable imbalance in pulse width between cyls., yet the bike runs nicely with the aftermarket silencer tune. When I adjusted the throttle shaft adjustment screw to even out the MAP readings the bike ran badly. Returning the adjustment to factory settings improved things. My question is: Is the MAP imbalance intentional for this engine?

thundershortz · 09-06-2009, 12:59 AM

Seems I sort of answered my own question. Just for shytes and giggles I downloaded stock tune # 20184, and then using Tuneboy and the adjustment screw, I reset the throttle body balance which was (factory) #1 MAP: 18.7 and #2 Map: 29.2 to a new setting of #1: 22.5 and #2: 24.0. This brought the #1 P/W from 2.01 to 2.53 and #2 P/W from 3.40 to 2.56., evening things out nicely. Had to up idle a bit to maintain 1037 rpm, but throttle % is still zero and idle speed is stable.

Road test was the best so far for all tweaks. No snatchiness at all, no pops upon decell, no gurgling at idle, no stumble at roll-on, rock stable idle speed, but the biggest surprise was at WOT. I wasn't looking for horsepower, just good manners and no popping from my stock engine with TORs. And manners are now there, but my butt dyno says yikes, where did this come from? Power comes on much stronger above 4500 rpm than ever before, with a new solid thump and muffler music to match, right up to redline.

I cannot fathom why factory throttle body balance seems to be so far out of whack. But I cannot argue with the empirical data I just experienced regarding performance. So it seems you can indeed use the Tuneboy MAP readings to balance your throttles. Your results may vary, but I still have this grin......

Dunamis · 09-12-2009, 06:08 AM

Hi Thundershortz.

Thanks for your spirit of adventure.

A few questions ...
1. Which tune you were using prior to 20184?
2. Why did you use 20184 to adjust the throttle body balance instead of the previous tune?
3. Have you disabled the O2 sensor with this latest tune?
4. Have you removed the AI?
5. Where is the adjustment screw?
6. Can you explain the process? Do you use TB merely to monitor the readings of your manual adjustment or are you actually entering data into TB? Or some combination of both?
7. Did you up the idle using the manual adjustment or with TB?

thundershortz · 09-12-2009, 11:59 AM

Adventure is my life; I'm practically Dundee....

Now then:

1) For some insane reason, my dealer "upgraded" my tune to 20187 after I fitted my TORs. This is a stock Bonneville tune and was not brilliant in my America. Also I couldn't balance the tb's with that tune

2) I didn't. I used the adjustment screw in between the carb bodies to balance the throttle shafts to each other. I replaced the previous tune because it behaved badly as it was not the proper tune for aftermarket silencers or my America.

3) No. Also stock airbox and filter. The engine room seems content with the closed loop configurations at shallow throttle positions.

4) No. Removal adds nothing, (how could it, it adds air at the end of the combustion process) and retention causes me no problems. I'll keep it till it fails.

5) Right between the carb bodies. It is a phillips screw with a spring underneath and a dab of yellow paint from the inspector. Turning clockwise richens cyl #1 (port side - 'left' for any lubbers - when seated).

6) I make the adjustment manually using the screw, and monitor my progress with Tuneboy diagnostic screen. Easy does it, small bits each time. I did not modify the tune (yet). I did have to buy a hinky little right angle geared screwdriver (Harbor Freight Tools, $10.) to get at the screw, and it made adjustment a breeze.

7) Manual adjustment knob. The America system does not set the idle speed electronically as other models (triples) do.

For me, it was the 'not knowing what's inside' feeling and the deafening silence from Triumph that compelled me to get and use Tuneboy to converse with my motorcycle. Wayne is a peach, most helpful and spot on with advice, Emma too, and the whole Tuneboy experience has been rewarding. Now we need a Tuneboy to straighten out Microsoft, those buggers....

Best to Fogelfar.

Fair winds,

Dan (Mick)

Dunamis · 09-12-2009, 06:22 PM

Awesome explanation. Thanks Dan. I have a new project

Do you see any benefit in using a manometer as well as Tuneboy to monitor the adjustment? I guess this is similar to carb sync which I used to do on my old bike.

When doing the throttle body balance do you just start the bike at zero throttle and keep it idling throughout the process (I think I read that in another thread)? When doing carb syncing I used to blip the throttle a couple of times to re-settle/check the vacuum reading.

thundershortz · 09-13-2009, 01:14 AM

To use a manometer you would have to remove the existing vacuum lines to hook up the manometer lines. This would disable the MAP sensors and upset the ECU functions. So that is why Wayne recommended using the MAP readings from Tuneboy diagnostic to balance the tb's. Therefore it is not recommended to use a manometer on EFI engines.

The engine should be started from cold and allowed to reach operating temp all at zero throttle position, mostly because the ECU uses that time to acclimate itself to it's surroundings and establish timing and pulse width. Once it's up to temp, I made the adjustments at idle speed and once in a while blipped the throttle to settle it and see how it was responding. I also rigged a large box fan to keep the engine cooled during this period. Plus I found out that the engine will not start or run without the headlight fuse in place, a handy fact to remember.

Tread lightly, have fun, and let us know how you fare.....

Dan

thundershortz · 09-14-2009, 09:56 PM

By way of followup, I took the first real ride with the newly balanced setup, 160 miles through eastern PA with some friends to a hillclimb event. Twisty, 2 lane wahoo PA roads, 2 up, interstate 75-80 mph, the whole magilla, and got an Honest 52.9 mpg when it was all over, using 87 octane. A personal best for my Cory. Your results may vary, but I still got this grin.....

Dunamis · 09-14-2009, 10:15 PM

Sounds betterer and betterer.

I hope to have time this weekend to do the balancing act. I haven't had time to even get a decent ride in (except the daily commute) for a couple of months and even less for maintenance/projects but I'm going nuts without 'cycle therapy'.

Dunamis · 09-18-2009, 10:42 PM

Ok - done the throttle body balance.

Very easy.

Like you I had to get a right-angle screwdriver to get at the screw. Once up to temp my MAP balance was already pretty good (Map#1 25.5 & Map#2 26.2 with 1PW 2.737 & 2PW 2.818). But I got it to Map#1 25.5 & Map#2 25.5 with 1PW 2.540 & 2PW 2.537 with idle at 1102 which looks perfect to my untrained eye.

This is with 20184TuneMod1 from Wayne which has the O2 sensors turned off. K&N filter and Staintune pipes with baffles removed. No Airbox mods and AI intact.

Thanks for your help on this Dan.

thundershortz · 09-19-2009, 01:16 AM

Outstanding. Sounds like you nailed it. It must be running sweet; now rack up some serious miles (sorry, clicks) and see if your grin widens. The adventure continues....I found a tune that has targets nearly all 13.5 A/F straight across the table. Hmmm.....no doubt it will slaughter my mileage but I just wonder.