Twin Max - don't own a bike without one!

[macx]

I know it's been said numerous times before, but it was still a most pleasant discovery to find how improved my bike runs after a Twin Max synchro tune! (and after setting the rocker end clearance and the valves first of course, even though they weren't more than 3 or 4 thou max off themselves)

Idles soooo smooth now, pulls very smoothly under acceleration - mild or wild - and from any rpm, even tried it down to 2500 in 6th and it pulled right out as smooth as silk. (I always run premium with an ounce of 104 octane boost per full tank so no detonation worries.)

Nothing was off all that much - about 1/2 turn on one BBS, and 1/8 twist to loosen the left TB cable. Did the TB cable adjust on the center stand at about 4k, then went for a ride. Taped the TM to the tank (on a folded up washcloth of course) to check it out. Just that one little adjustment and it was stable as a rock at any rpm, on or off the throttle to any degree. Needle didn't move the width of the needle at max sensitivity. Couldn't have worked out any better.

Even most of the vibes in the handgrips between 3500 to 4k went away.

Wow!

Now, can't wait for my Techlusion! ; -))

[boxermania]

I have always preached that the TB sync is the most important adjustment on the boxer engine. Based on your expeience, I now have the answer that I was looking for, does the TB adjustment change if the engine is under load at a larger butterfly opening.....and according to your findings the answer is NO.....

The Techlusion will help the response and will make the throttle crispier.....I don't know the type of gas available at your location.....but I think you could run regular grade with no problems.

[jm1515]

Ummm....I think you meant....'TBS...don't own a Boxer without doing one!'
Yep...the TBS makes a real difference...& it's easy to do .
I used to be a 'TwinMax' guy...now my $80 high tech meter sits unused....because I built myself a home-made manometer for about 10bux.
For me, a manometer is so much easier to use...and more accurate. The only drawback is I must hang it from the ceiling in the garage...

[mkmd555]

I had tuned my bike with the home made, 3 bucks manometer, and as a result the bike ran great. However, I had doubts on my contraption, just because it was not 'electronic'.

So I ordered a Twinmax.

I was surprised to find that even under Twimmax's max senstivity, the manometer adjustments were the same as the Twinmax.

Go figure.

I will sell the Twinmax on Ebay one of these days. The home made manometer does an equally good job.

M Khan

[philbytx]

Well, I'd rather own a Morgan Carbtune. Way easier to work and way less complicated than that overcomplicated, fiddly arsed, battery driven Frog Twin Max contraption

[TicTac50]

TwinMax is a very good tool when it works.
Mine did not do the job from the day one. I never did like the results after using TwinMax.
Recently, after adjusting the valves, I put the TwinMax to work and set both sides to the "0". I did not like the way my bike acted. So, I reversed the lines (A to the right cylinder and B to the left cylinder) and checked the settings again.
To my surprise the reading was OFF by at least 12-15 bars. It looks like my TwinMax defective from day one or we all have the same problem with it. I started to look at the BMWMOA magazine and found the main distributor for the TwinMax. I gave them a call thinking that my TwinMax just needs a good calibration. I was told to send my TwinMax and they will take care of it. Even if the TwinMax is out of the warranty, I was thinking that 20-25 bucks would be OK to pay for the calibration. All what I got in the response was: "We did not sell you this TwinMax and go back to the original sellers" I am more then sure that BMW of Santa Cruz does not have the tool to calibrate the TwinMax. Company that sells this TOY does not have repair department to calibrate it. Only when I GOOGLED "TwinMax" I began to read the horror stories about people striping the cable adjusters and so on, trying to adjust the bike by reading TwinMax. If somebody knows the place where I can send this TOY for calibration, I would greatly appreciate the information. Otherwise, anybody wants to buy a used TwinMax, please let me know.

[wjjones]

Only when I GOOGLED "TwinMax" I began to read the horror stories about people striping the cable adjusters and so on, trying to adjust the bike by reading TwinMax. If somebody knows the place where I can send this TOY for calibration, I would greatly appreciate the information. Otherwise, anybody wants to buy a used TwinMax, please let me know.

What! So I'm not the only one to strip out my cable adjuster? That was an expensive lesson, too. I had to buy the whole throttle body for $200+

[boxermania]

TicTac50

I feel for the problem you encountered with the TwinMax, no, they are not perfect but aside from a manometer or vacuum gauges it is just another tool available for the task.

I haven't had one apart, however, I presume that it does have an offset so it can be calibrated.....if you send it to me and if it can be calibrated I will do so for you. If you decide on this course of action, PM me and I will send you the address.

[Sunbeemer]

I use the TwinMax to synch the throttle bodies initially at idle with the BBASs and then under load (4000rpm in second gear) on a fully warmed up engine by taping it to the tank with the hoses running down to the TB's and make small throttle-cable adjustments between 1/4 mile sprints. Takes about three times to get it spot on, and then it feels sooo good
I couldn't do it that way with a manometer.

[boxermania]

Sunbeemer

Did you ever go back and checked the TwinMax reading at 4000 rpm with the bike on the center stand?

I have been wanting to know if there is a difference as a result of the engine being loaded in your case and unloaded in most cases. I would really like to know....maybe you can just check with the TwinMax after a ride to find out.

[TicTac50]

boxermania.
Thanks for your offer to help. From what I was reading on the WEB it looks like the older models had only ONE sensor built in and the newer model was somehow modified. My ridding buddy just got a brand new TwinMax and I went to check how it works against mine, or how much my TwinMax is off. At 1100 rpm mine was about 1,6 to the right and at about 4000 in the 6th gear was about 0.3 also to the right. It took me four tries to set the cables right. I've adjusted everything using brand new TwinMax. Rode home and stopped at Home Depot. In about 10min I had my self a home made CycleRob version of manometer. Went for another little ride, just to get the engine hot and checked the setting with my new tool. At 1100rpm my bike is spot on. Now I have something to compare my TwinMax to. I did read some more on the WEB about the TwinMax, I think I will try a new battery and see if that will help. If everything fails, I will take it apart just to see where the legs are growing from.
I will post my discoveries.

[Sunbeemer]

Boxermania

Did you ever go back and checked the TwinMax reading at 4000 rpm with the bike on the center stand?

No. Good idea. I'll try it this weekend and let you know how it turns out.

TicTac50

I think I will try a new battery and see if that will help

I read somewhere that using a fresh battery is critical to getting a good reading with the TwinMax. In fact, the author (it might have been Anton Largiader??) even recommended cutting the instrument light out of the circuit to reduce the parasitic drain and get more voltage to the sensor and metering circuits!

[boxermania]

Sunbeemer

Hey, thanks as I have been wondering if there is a difference on the TB’s adjustment between load and no load of the engine. It stands to reason that under load the TB butterflies will open more and if so any error at a lesser opening (like under no load) will be magnified.....now with your help the issue will be resolved.

Titac50

You are on the right track....Sunbeemer is correct, a fresh battery is imperative for accurate and repepetive results as it appears that the TwinMax electrical load depletes the battery after a few uses to the point that the instrument is no longer accurate

[CycleRob]

The TB synchronization is very important to smoothness and fuel economy on any big twin cylinder bike. The 2 carbs/TB's must fill both cylinders equally for any throttle setting.

I think the TwinMax is disappointing for it's high price. It's biggest weakness is their choice of a 9 volt battery to power it and the wizard of smart that added the unswitched backlight. As if we'd be setting the synch in a dark room! The 9V batteries are not intended for medium or high current drains and won't last long in that application.

I used to be a Mercury CarbStyx advocate, but after using the differential water manometer, there is no better calibration tool at any price, let alone the water manometer's under $3 price. It's only weakness is when it's hooked up to a bike with a large error in it's TB synchronization. That's when I hook up the Mercury filled unit to get it in the ballpark. Then I switch it to the water unit because it's the most accurate.

.

[Boxer]

I have to agree with the majority finding the manometer to be more accurate. I've used both and the little homemade device served me better in some ways and the Twinmax is better in other ways. I like having the Twinmax right there handy on the seat to view, and my personal issue with the homemade device was the plastic tubes would get warm and bend on me if they were stressed in the slightest, decreasing or altogether cutting off the air flow from that side. Very annoying to me, and instead of modifying it, I just went with the Twinmax, only to find it doesn't do any better job than the cheaper alternative...Its just handier to use. I also had an issue with having to hang the manometer above the bike. I was not always in a place where I had somewhere to hang it. I think Rob's version doesn't require "hanging". If I remember, his just leans against the bike. Mine wasn't long enough...a problem I seem to always have had.

[TicTac50]

Just like I anticipated!!!
Twin Max - don't own a bike without one! turned into
CycleRob - don't own a bike without HIM!

Every thread I read, CycleRob puts in his 2 dollars and the whole thread is upside down.
So far nobody on this board was able to prove CycleRob wrong or contradict his opinion.
I personally owe him so much beer, if I start paying, he should be drunk for the next 3 years.
I think it is time to make a new section on this board with the PayPal option and call it
CycleRob's Play Garage, don't own a bike without HIM.

[wncbmw]

Re: TB synchs

Boxermainia did mine at a demo at Bash II (2005?). Never did one again until this year, when a fiend and I checked it out. Perfect still! Nothing to change!

Nice work Al!