Carb Synch and Enrichener Circuit

[LoHo]

After extensive labor on the old beast, I finally got to the synch and did a pretty fair job of lining them up and getting a smooth idle. I find now that I often don't need the choke (enricher) to get started on warm days.

Does that mean I have it dialed in, or is it too rich to start with and constantly doing the enricher's job? My plugs look fine.

[DGXSER]

If your plugs look good after a couple minutes running at idle speed, your mix us fine.

[Schming]

When your engine is fully warmed up, after a few miles of riding, You should be able to do a full throttle roll on, in 5th gear, from approx. 10 mph, to redline, with no hesitation or bogging down.

If you can do that, your in good tune.

[BA80]

After extensive labor on the old beast, I finally got to the synch and did a pretty fair job of lining them up and getting a smooth idle. I find now that I often don't need the choke (enricher) to get started on warm days.

Does that mean I have it dialed in, or is it too rich to start with and constantly doing the enricher's job? My plugs look fine.

I never need the enricher if the temp is above 50º. I use the throttle lock to up the idle 'till it's warmed up but it'll start right up.

[vedgar]

10 mile an hour full throttle 5th gear ?

Schming,
I think your intention was good, but lugging the engine like that in 5th can lead to bad ju ju. Excessive strain on the clutch, trans, wont hurt the rear end at all. i might suggest moderate to aggressive accel through 2nd and 3rd and banzai full throttle after that.
P. S. kind of like French kissing your granny. You can do it ; But why would you want to ?
Vance

[IanDMacDonald]

After extensive labor on the old beast, I finally got to the synch and did a pretty fair job of lining them up and getting a smooth idle. I find now that I often don't need the choke (enricher) to get started on warm days.

Does that mean I have it dialed in, or is it too rich to start with and constantly doing the enricher's job? My plugs look fine.

Maybe a silly question, but aren't we speaking of two different things here? Vacuum sync, vs. Air/Fuel mixture settings? Wouldn't the mixture screws have more of an effect on use/disuse of the "Enrichener" over a sync?

Also, have you perfected the tune by highest vacuum level yet via Carb Tune? I hope to try this again this season.

[Schming]

Schming,
I think your intention was good, but lugging the engine like that in 5th can lead to bad ju ju. Excessive strain on the clutch, trans, wont hurt the rear end at all. i might suggest moderate to aggressive accel through 2nd and 3rd and banzai full throttle after that.
P. S. kind of like French kissing your granny. You can do it ; But why would you want to ?
Vance

I suggested this for test purposes, and a full throttle roll on is what was stated. Also if your engine lugs it's out of tune.

And I can't, 'cause both my Granny's are in a better place than I.

[LoHo]

Yeah, Ian, I wasn't trying to link the two. Just asking if a good synch job might eliminate the need for the enricher, or if not needing the enricher indicated a too rich condition.

I have never heard of the 5th gear roll on test. I guess if one does it gently and allows each curcuit to get online as the bike speeds up using throttle only, each curcuit would be sampled for tune. A stumble at some point would indicate a fuel curcuit that was too rich/lean. Is there a consensus on the efficacy of this idea, or is it an internet rumor?

[IanDMacDonald]

No, it's no rumor, definitely true. However, each person comes to a point where they say their tune is "good enough". And, I can guarantee that "good enough" for some does not allow a full-on throttle from 5th gear without bogging, including my bike. It's an ideal tune that mandates that each circuit has been tuned perfectly. Main jets, pilots, float, needle clip setting, air idle, etc.

What it comes down to for me regarding tuning is cracking throttle wide open in the beginning without stumble. That, and MPG's. If you're happy with those two things, and you have no bogging near the top, you should be good to go.

Another thing I believe someone said for another way to do a plug chop when I did mine, was to ride in 5th for a few miles, going no faster than 25 mph.

[DGXSER]

Tuning and synching are two different things, but effect each other. Synchronized carbs will eliminate bad synch being interpreted as out of tune mixture. A poor mixture could be mis interpreted as a bad synch.

The mixture screw mostly effects low end RPM. Once you start pulling the slides up and the mains are in heavy use, that mix screw setting is almost of no effect at all. So really, low end and idle running will show the plug color based on mixture screw setting. Whatever method you want to use, keep the RPMs low and the load on the engine low, and your running on the mix screw and pilot jets more than the mains.

As to the 5th gear pull test, not one I have heard or done.

HERE is a link to a tuning method that I like and believe in.

[IanDMacDonald]

Hey Don- Just a quick question, I've always followed that guide on my other bikes. Never really had to use it on my 11, as I've always been close.

My question: Have you ever really had to mess with the needle clip position using mostly stock parts? I only had to one time on my 750 using pods instead of jumping the mains.

[jetmechmarty]

Mine starts up just like Greg's does. It will cold start instantly without the choke. Mine was running extremely well with the mixture screws guesstimated and a very good bench sync. I used a Morgan Carbtune to fine tune the mixtures and sync in the idle. The bike seems to run perfectly at all throttle settings. I should add that the valves were recently adjusted and the cam chain replaced. Cold or hot weather, low or high altitude, the bike performs very well. My only gripe is that I'm looking for fuel at 80 miles. I get 25 to 30 mpg.

[DGXSER]

Honestly Ian, I have never fussed much with the earlier carbs, and the later ones do not have adjustable needles. So, no, I have not messed with the needles.

You might just be heavy handed Marty. I get 35 ish most of the time. On longer rides it goes up to about 40mpg or so.

[Schming]

Yeah, Ian, I wasn't trying to link the two. Just asking if a good synch job might eliminate the need for the enricher, or if not needing the enricher indicated a too rich condition.

I have never heard of the 5th gear roll on test. I guess if one does it gently and allows each curcuit to get online as the bike speeds up using throttle only, each curcuit would be sampled for tune. A stumble at some point would indicate a fuel curcuit that was too rich/lean. Is there a consensus on the efficacy of this idea, or is it an internet rumor?

Yes, a gentle non stop twist of the throttle and not a quickly cracked open motion is what I use.

Actually the "test" , for me, is the way I can tell if I have all bases covered, as in valves and cam chain adjusted properly, all electrical systems checked, and all fuel and air delivery systems in proper order. The last adjustment, for me, is the synch and color tune, which usually yields favourable 5th gear roll on throttle results.

A low throaty bog, while "testing", usually indicates a rich condition and a spit or hesitation will be lean.

[MaximPhil]

Yes, a gentle non stop twist of the throttle and not a quickly cracked open motion is what I use.

Actually the "test" , for me, is the way I can tell if I have all bases covered, as in valves and cam chain adjusted properly, all electrical systems checked, and all fuel and air delivery systems in proper order. The last adjustment, for me, is the synch and color tune, which usually yields favourable 5th gear roll on throttle results.

A low throaty bog, while "testing", usually indicates a rich condition and a spit or hesitation will be lean.

Hi Schming.
Just curious how many"Redline in 5th gear" episodes you have survived ? on public roads?
Phil