Sync virginity . . . LOST!

[Troutluck]

Twinmax came Friday, and I did the deed this afternoon. Was significantly off 3k out of a 24k service. HUGE difference. Heck, I think it even shifts better now. :) Also got some feeler gauges, so I hope to improve it even more when I do a valve adjustment.

Autolites+Twinmax=Oilhead Nirvana (or Pearl Jam, whatever).

[BubbaZanetti]

welcome to heaven!

the twin max is so easy to use i'll break it out any time things are feeling off. not just at valve adjustments

[Screamineagle]

In addition to being new to BMW I am also ignorant and stupid. What is twinmax? :bikes

[bubbagazoo]

In addition to being new to BMW I am also ignorant and stupid. What is twinmax? :bikes

It is a tool for synchronizing your throttle bodies or carburetors. Some info can be found here. (http://www.ibmwr.org/prodreview/twinmax.html)

[deilenberger]

Twinmax came Friday, and I did the deed this afternoon. Was significantly off 3k out of a 24k service. HUGE difference. Heck, I think it even shifts better now. :) Also got some feeler gauges, so I hope to improve it even more when I do a valve adjustment.

Autolites+Twinmax=Oilhead Nirvana (or Pearl Jam, whatever).Just as a suggestion - it is better to do the sync AFTER doing the valve adjustment. If the valves are out of adjustment, the vacuum will be different due to the difference in breathing efficiency in the cylinders.. using the TwinMax when they're out of adjustment misadjusts the throttle bodies to compensate for the valves being out of adjustment. Not the optimal thing.

Valve adjustments only take a few minutes (well - for me about an hour for both sides) once you learn how, and may well make any TwinMax adjustments unncessary once they're set right.

[SNC1923]

OK, I want one. I did a brief search and now have the following questions:

Is there more than one kind?

Do I need to buy adapters?

Is <$90 a good price?

Where should I order it?

Thanks.

[BubbaZanetti]

90 dollars is a reasonable price,

yes, make sure you adjust the valves FIRST

usually, i won't pull out the twin max at all between valve adjustment checks, but occasionally, if things feel "off" i will adjust a little between the 6000 mile valve checks.

[Troutluck]

yes, make sure you adjust the valves FIRST.
Good advice, and I would have, given time. After I hooked it up just for S&G and saw how off it was, it was irresistable to tweak it. Even though it is only 3k out of a 24k service, I could see some definite "lumps" in the calibration through the RPM range, which, to me, indicate some valve adjustments may be necessary. That being said, it synched up quite well with the "two turns from stop" base adjustment of the Big Brass Screws. Minimal adjustments from there, and big improvements in driveability. Who's working on the patent for a solid TB linkage retrofit? :)

[jwhite518]

Do I need to buy adapters?


Thanks.

I bought some adapters but they didn't fit. The guy at California Sport Touring didn't know diddly about fitting the thing to a BMW. I ended up buying $2 worth of parts at Kragen - a bit of vacuum hose to fit onto the TBs, and some tiny plastic adapters that connect the BMW-size hose to the Twin-Max size hose.

[JimMoore]

If you're cheap, try this instead of the twinmax. Costs about $10 and is more sensitive than the twinmax.

http://www.rightspin.com/motorcycles/LowCostMano/mano.html

[BubbaZanetti]

Good advice, and I would have, given time. After I hooked it up just for S&G and saw how off it was, it was irresistable to tweak it. Even though it is only 3k out of a 24k service, I could see some definite "lumps" in the calibration through the RPM range, which, to me, indicate some valve adjustments may be necessary. That being said, it synched up quite well with the "two turns from stop" base adjustment of the Big Brass Screws. Minimal adjustments from there, and big improvements in driveability. Who's working on the patent for a solid TB linkage retrofit? :)


the two turns seems to be a good baseline for acheiving optimal idle. i'd never bothered to "set" my brass screws when i first got the bike, rode it a year and a half and noticed the idle below 1000 rpm most of the colder months. turned the screws out this summer and discovered they were both about 5 turns in. backed them off a bit, balanced them and now the bike purs at 1150 rpm no matter the weather.

[Burnszilla]

So, how do you go about syncing a three cylinder bike with the Twinmax?

[BubbaZanetti]

So, how do you go about syncing a three cylinder bike with the Twinmax?


pick one, maybe the left one, oh, right, K bike, maybe the "front" one and synch the other 2 with that. it works the same for all multi cylinder engines. one fuel injector/carb is the "standard" to which all other are equalized (i know it happens to be the left one on most japanese multis, my friend uses the left one on his triumph tripple)

[PUDGYPAINTGUY]

Or just get a multi cylinder mercury gauge. I have used one of these for years and as long as you don't drink the mercury it is safe...lol. They have the fine graduations on the scale to get an accurate read on the cylinders. I know that you can't attach it to the tankbag, however, it still works good.

[BMWRich58]

So, how do you go about syncing a three cylinder bike with the Twinmax?

I'm a big believer in "Carb Stix" over the Twin Max.
Found the Twin Max to be off much more than the Stix.

And besides,the "Stix" has four columns....good for up to 4 cylinders!!! :brad

[deilenberger]

I'm a big believer in "Carb Stix" over the Twin Max.
Found the Twin Max to be off much more than the Stix.
Not sure what you mean here.. if the TwinMax shows smaller deviations from being balanced to me that's a GOOD thing. I have both, the carb-stix work OK for quick adjustments.. but I prefer the TwinMax to really dial it in to being exactly the same. I've checked the TB's with the TwinMax after balancing them with the CarbStix. They come out needing some more adjustment. When I do the reverse - adjust with the TwinMax and then check with the CarbStix - they are perfect on the CarbStix. I suspect you're seeing the result of a more accurate reading with the TwinMax.And besides,the "Stix" has four columns....good for up to 4 cylinders!!! :bradTrue - and when I had a K100 - this was useful, but since this is an oilhead forum, and AFAIK - BMW hasn't made a production 4 cylinder oilhead, the TwinMax would work fine for the vast majority of people here.