Tunnel Ram Tune

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RB,
Once again in post #44 you show you have no idea how the MAB size controls the start of the main system. I have provided you 3 or 4 examples from carb experts/ engineers...& you still don't get it.
 
Update: I haven’t been able to plot the timing curve yet, but I have put about 60 miles of in town/county road cruising on it with a couple of WOT runs. (Secondaries still disconnected) One roll into wot and one stab to wot. It’s running extremely well! Afr shows fat (12.0) at under 35mph, and 14+ above 35 at any cruise speed. If I stab the throttle to wot it’s showing 12.5ish and if I roll in slowly it gets pretty lean. Will probably put the 10.5 PV back in eventually. I’ve got a couple of out of town cruise in events I’m planning to attend over the next couple of weeks so I’m going to leave it alone and continue to monitor and note any new developments. I’m really happy with the way it’s running. Here is one of the plugs @j par after the 60 miles. I messed up the electrode taking it apart.


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Update: I haven’t been able to plot the timing curve yet, but I have put about 60 miles of in town/county road cruising on it with a couple of WOT runs. (Secondaries still disconnected) One roll into wot and one stab to wot. It’s running extremely well! Afr shows fat (12.0) at under 35mph, and 14+ above 35 at any cruise speed. If I stab the throttle to wot it’s showing 12.5ish and if I roll in slowly it gets pretty lean. Will probably put the 10.5 PV back in eventually. I’ve got a couple of out of town cruise in events I’m planning to attend over the next couple of weeks so I’m going to leave it alone and continue to monitor and note any new developments. I’m really happy with the way it’s running. Here is one of the plugs @j par after the 60 miles. I messed up the electrode taking it apart.


View attachment 1715812662

View attachment 1715812663

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View attachment 1715812665


That’s lean at WOT.
 
Ok folks, got this thing running really well now. Super reliable, very responsive and cruises great.
Now because I’m not one to leave things alone. I’m curious as to what it might run like with a pair of 600 mechanical secondary carbs vs the 750’s I’m running now. Keeping in mind this is a street cruiser that gets the occasional beating, what do y’all think I could expect with the swap? I see that FST has a nice looking 600 dp at a reasonable price. It looks to have all the bells and whistles, replaceable bleeds, quick change jet bowls etc. Just tossing it out there. And heck, I’d even consider the vac secondaries.
 
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Ok folks, got this thing running really well now. Super reliable, very responsive and cruises great.
Now because I’m not one to leave things alone. I’m curious as to what it might run like with a pair of 600 mechanical secondary carbs vs the 750’s I’m running now. Keeping in mind this is a street cruiser that gets the occasional beating, what do y’all think I could expect with the swap? I see that FST has a nice looking 600 dp at a reasonable price. It looks to have all the bells and whistles, replaceable bleeds, quick change jet bowls etc. Just tossing it out there. And heck, I’d even consider the vac secondaries.


Skip the VS. Waste of time and money.

Obviously you’ll need to calibrate the FST carbs. I’ve done several of them, and they are nice but like a box of chocolates, you never know what’s in them for a tune up.

In the end (IMO) you spend some money and time to maybe break even on power and driveability. Maybe. And your chances of going backwards are better than punchers odds.

But WTH!!!. No one would learn anything without trying. If you have the time and resources I say give it a whirl. The worst that could happen is you have a pair of TR carbs to sell.
 
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