Bored G much better than an HSR48 : V-Twin Forum: Harley Davidson Forums

Bruce Woltz · 07-12-2009, 08:32 PM

For slide rattle anyway..

After swapping the 48 for the G the very first thing I noticed was an rear exhaust leak.. Got to tighten down the rear stud and guess what??

The absolute best way to pull a broke stud...

Bought 4 studs only used 2 on the rear head..

Go to tighten down the pipes and ..

Oh well bought 4, used 4.. Not sure with the originals came from but they were pretty easy to snap and pretty easy to drill out.. Trick on using the Snap- easy outs, drill the hole all the way through the stud..

Max

Bruce Woltz · 07-12-2009, 08:33 PM

BTW,

Found and issue with the bike.. The gas cap vent don't flow enough air.. On the HSR48, it cased the lean cough. With the G, it hates not having enough fuel in the bowl. They have a real distinctive behavior when running out of gas. Mid throttle starts spittin and sputtering. On the HSR48 the only time you can tell it's out of gas is when the motor dies like someone hit the kill switch.. Did about 140 miles today on it.. Within first 3, it started behaving like it was out of gas... OK stopped at the station.. cuz it was low.. 30 miles after that same thing.. Pop the cap and it'd run fine..

May drill a hole in it and add a vent line.. Need to take it apart..

Going to upgrade the fuel filter also.. It's got one of those glass ones with brass screen.

Max

oh1deuce · 07-12-2009, 08:39 PM

Pingle high flow?

Bruce Woltz · 07-12-2009, 10:10 PM

Quote:

Originally Posted by oh1deuce

Pingle high flow?

Yep, Just installed it.. Bruce

TXCHOP · 07-12-2009, 10:30 PM

Bruce, what heads are on your 131? Just curious.

How do you think the throttle response/power will be with the G compare to the Mik?

pwmorris · 07-13-2009, 01:26 AM

Bruce,
No matter the diameter flow, as you know it still needs a healthy venting to force feed the beast-I have had that locking style cap before. I drilled and tapped the cap Buell style, ran a line to the bars, secured it , and then to atmosphere with a tiny filter-cured.

Have you flowed the bored G vs. the 48? How big was the big G and what if any jet changes? T jets, main, modified in any other way?
Thanks!

Hillside · 07-13-2009, 05:53 AM

We have seen a poorly vented cap raise all sorts of hell before.
Good you nipped it in the bud.

Scott

Bruce Woltz · 07-13-2009, 10:01 AM

Quote:

Originally Posted by TXCHOP

Bruce, what heads are on your 131? Just curious.

How do you think the throttle response/power will be with the G compare to the Mik?

It's got the RP cast heads.. (Ultima?) I can't tell any difference on the response.. Both work fine. The G sucked as far as response goes when there was a vacuum in the tank..

Paul,

The G is the Davinci that has been de-bomb sighted. I moved the air bleed outside and am using a keihin 140. No Tjet yet. 31 int, 78 main when I rode it but I've up it to an 84. You can still go pretty fast in the twisties with this guy and not get too far into the main..

Thanks Scott,

I think the bigest thing for me was not understanding what the 48 was complaining about before.. The G realy lets you know whats going on...

Bruce

Bruce Woltz · 07-13-2009, 11:59 PM

Quote:

Have you flowed the bored G vs. the 48? How big was the big G and what if any jet changes? T jets, main, modified in any other way?

The D manifold had a 1.8 port..

The carb right now is a 1.86 bore by davinci..without the bomb sight. I changed the air bleed to external (aka zippers).. I need to add Tjet if I plan to keep it ob the bike.. Bruce

Bruce

dog155 · 07-14-2009, 06:08 AM

My 124" is sporting a modified G with Tjet,and have a 45 HSR ready to bolt on.It's hard to get motivated to do because the G works so well.Have thought about boring the G,the word is it will really wake the topend flow up.

Bruce Woltz · 07-14-2009, 09:09 AM

Another thing to look at with SnS carbs is the air cleaner.. Going from a stock late setup with SnS paper to a +1 inch green (KnN style AC) and a slotted SnS cover, you will pick up 5-7% flow on a stock G with a 1.8 manifold.. This means that the port can get that much more air if it can take it.. Boring the G on top of that is 2 pretty cheap performance upgrades.. May give you warp 2.. Bruce

TheNowhereman · 07-14-2009, 07:26 PM

The biggest restrictor to fuel flow is the manifold.
You can talk, bore, add more jets, do anything you damn want but, if the manifold isn't developed also, your not getting what you think your getting.
That's one reason why a smaller carb will actually out fill cylinders at all but high rpm applications with HD motors.
If top end is what you want, then get a *** bike.
If you want rip snortin torque that will win you beers at your local stop light to stop light GPs, run a v twin, and stick a well jetted Mikuni on it and you will win most of your 0 to 100 drag races.

skidmark316 · 07-14-2009, 07:54 PM

Quote:

Originally Posted by TheNowhereman

The biggest restrictor to fuel flow is the manifold.
You can talk, bore, add more jets, do anything you damn want but, if the manifold isn't developed also, your not getting what you think your getting.
That's one reason why a smaller carb will actually out fill cylinders at all but high rpm applications with HD motors.
If top end is what you want, then get a *** bike.
If you want rip snortin torque that will win you beers at your local stop light to stop light GPs, run a v twin, and stick a well jetted Mikuni on it and you will win most of your 0 to 100 drag races.

Welcome to the forum!!

dog155 · 07-15-2009, 05:10 AM

There is also a happy medium we all strive for.Granted most of our riding is done at a lot less than wot,and most street battles do not last long.It still is a joy searching for that last ounce of hp/tq combo.That search never ends,isn't that what it is all about.