opinion on 120" combination

[dave brode]

Hello All,

Please review my plans for a winter project 120" engine for my '02 FLHT and kick my ass as needed.

[have] Spare set of '02 cases, already bored to 4.310" for Axtell cylinders by Zippers. Will machine for '07 up cam bearings
[need] 120R style S&S flywheels 320-0525 for old cases.

[have] Take out 120R flat top pistons and rings- never run.

[need] HD/SE "bigger bore" 4.060" cylinders. [will buy on black friday -30% sale at dealer] - [unless I find a helluva deal on S&S 4" to bore]
-
[have] Wood 888 cams 246/246 - .575", 100 LSA

[have] Zipper's tensioners.

Heads will be either ported CVO110 with 2.120" intake or blended only MVA/120R/St. Will open port inlets for 1.800" S&S intake.  [have the CVO110s, looking for MVAs]

---


The bike has a 44mm cv done by Wood and a small primary fatcat with louvered baffle. I would consider the perforated baffle, but I'm not going to change pipes. I'm not looking for every horse. I can't imagine that compression down near 10-1 would hurt much. Although, a head cut to remove some of the radius at the quench pad seems logical. I would check piston to valve first though.

I'm looking at [roller] Baisley or S&S rockers, worth it to go to 1.7-1 for .600" or so?

Question:  I hope to use the rings that are on the take out pistons.  Are the 120 engines run in with an electric motor? This would break the rings in to some extent. Would it render them non re-useable?

Thanks in advance for any help offered.

Dave

p.s.- I'll be looking for someone to machine the cam bearing bores and set the main bearing end play. PMs welcome   

[CarlosGGodfrog]

Looks good Dave, I would go with roller rockers before hi-lift rockers though. You are close to .6 lift, so you may as well do it.

[dave brode]

Carlos,
Yes, roller. The question is, would the added lift be worth much? I know the gain would depend on how the heads did at .575" vs .600",  but if it is a matter of 2-3 horse, it's a non issue to me. 
Thanks.
Dave

[Barrett]

Carlos,
Yes, roller. The question is, would the added lift be worth much? I know the gain would depend on how the heads did at .575" vs .600",  but if it is a matter of 2-3 horse, it's a non issue to me. 
Thanks.
Dave

Read post #25 & #28

http://harleytechtalk.com/htt/index.php?topic=91480.msg1054100#msg1054100

[CarlosGGodfrog]

Interesting article. I opted for the rollers, at stock ratio, for the reliability of less side loading on the valve. I did not consider increased lift rollers. That is a different topic, but 6% increase in lift might not be as dramatic a hp booster as we might think. How often are we at v high (over 6000 ) rpm ?

[ThumperDeuce]

Mr. Baisley will convert your stock rockers to rollers and correct the geometry.

[TorQuePimp]

Instead of buying mva heads use the coin to have the 110 heads worked

Get the cylinders from board tracker..... already cheap

Not enough carb

[rigidthumper]

You're looking at ~10.27:1, based on .040 head gasket used and 95cc chamber 110 head, flat tops. 888 should crank ~195 with that combo, and make ~125 TQ/115 HP, with that carb & pipe, @/over 100# from 2.2K to 5.7K.  Very reasonable touring build.

[kd]

Search the 120 builds in the dyno section on here. There's a few good examples.

[dave brode]

Thanks all,

I agree with the Zippers guy, but "responded to add'l lift" is pretty vague. It would be nice to have a A-B number.

I wonder if how the 888 cams would act if a +4 sprocket was used?

Anyone have a comment on the rings?

[GaryLC]

The rings would probably be ok, but for 30 something bucks I'd get a new set from Boardtracker, just to be on the safe side.

[Don D]

Use a cv51. Use a good pipe and dry tc88 ignition.

[dave brode]

Don, How much will the 51 gain over the Wood prepped 44cv?

Have the Fatcat, will keep it.

Have Daytona Twin Tec module with software.

Good thought on rings, Gary.

[Don D]

5-7hp

[dave brode]

Thanks Don,

Huge difference between say 10.2-1 and 10.6-1?

Dave

[Hillside Motorcycle]

S&S G carb/ Thunderjet, and 1" spacer block would be a STRONG set-up.

[dave brode]

Update, input welcome;

Don [HD StreetPerf] did the bottom end and supplied the 120R style S&S flywheels [320-0525] for old cases. He also bored the cases for '07 up cam bearings, Thanks, Don. I have the 120R pistons and 4.060" cylinders. CR will be 10.3-1 or so.

I ended up with a set of CVO110 heads done by Baisley, their basic work, 1.800" inlet, 2.12, 1.65", etc.
[Thanks Mike]

I decided on these cams;

Arsenal Racecraft [by Andrews]
248/252 - .610" [.645" at 1.72*]
101/109 centers
.213"/.178" TDC
23/45 - 55/17

I have a set of 1.72-1 S&S rollers, and a pair of 1.625s. Split or 1.72s on both?

Dave

[HD/Wrench]

Myself would go with a S&S carb  Easy simple will get you there all day long .

As for altered rocker ratio its a test thing I have seen it work and i have seen no change as well I have seen power loss . Use of them on te intake side only would be the safest bet . EX side can be very tricky

[dave brode]

Thanks, GMR,

I was leaning toward 1.72s on the intake only, you convinced me. I have a CV spigot style S&S intake that will fit my Wood 44mm cv, I will probably see how it does. I do have a super G intake too if I decide that I need more carb.

Dave 

[Rsw]

Listen to Steve (GMR) he knows his Sh%#{t

[HD/Wrench]

Thanks, GMR,

I was leaning toward 1.72s on the intake only, you convinced me. I have a CV spigot style S&S intake that will fit my Wood 44mm cv, I will probably see how it does. I do have a super G intake too if I decide that I need more carb.

Dave

The 44 is a good carb but it is way too small on an air pump of that size my guess is that you will struggle to jet it. I built a 117 woods 6 combo bakc in the mid 2000's  well customer had a 42 Mik on it .

I could not jet it down far enough air pump plus high signal strength .

The S&S all though simple is a great carb tons of parts for it , works very well . 

[dave brode]

Thanks, GMR, Rsw, and Hillside too,

Gmr, I understand, it's like a 600 holley on a 496. The signal is very strong. 

I'll study the S&S carbs and try to muster some love for them. I've never more than glanced at one. I was thinking of a 48 mik, but I do despise that slide rattle.

Dave

[dave brode]

Veering off, it is interesting how testing with the manifold greatly reduces the flow differences. Especially between the stock G and the 48.


[attach=0,msg1292948]

[HD/Wrench]

the 48 is costly as a complete kit dont forget the 110 dollar jet kit you will need plus the https://secure.vulcanworks.net/store/Carb-Spacers-Adapters/ and its a large carb in size many times it will hit the fins based on what you are using .

peak vs drivablity is something to look at as well


XXX carbs does a bore job on the G and I have tuned a few of them one was the S&S 126 set up and man it ran well the guy did have a 48 on it peak to peak about the same but  low speed transition the S&S was much nicer . engine kits will vary for sure .


Zippers does a nice ready to go set up as well .

[Mattbastard]

Don't ya have to raise the tank to use a 48 as well?

That's a BIG carb. 

[dave brode]

I am studying the G carbs. The XXX guy had bypass surgery, I wish him well, but not much going on there.

I had a 48 on a '99 FXDL with a +.200" tall cylinder deal. Fit under tank, but was close.

GMR makes going points. The 48 mik has gone way up in price, adapters and tuning parts are pricey. Maybe I should have bought a 51 CV that I passed up some months ago. Then again, I ready that some parts for them are hard to find nowadays. 

Thanks!
Dave

[dave brode]

How often does a G need a thunderjet?

[jrgreene1968]

Are the s&s carbs hard to tune?
I had read long time back somewhere, that they tend to run rich  and have to have thunder jets. Etc. I never really studied up on them much, I just bought a mik 45 because they are so easy to tune

[harpwrench]

When I put an S&S V111 in my bike about 5-ish years ago, John Sachs bored a super G and made the main air bleed external. It has been a great/reliable carb, easy to dial in, and runs hard. He told me that a t-jet wasn't necessary for this anyway. You might ask John what he thinks, he'd know.

[turboprop]

How often does a G need a thunderjet?

There is a common misconception that the need for a Thunderjet is somehow linked to engine displacement. Not true. Wether it's a Supper or G carb is also somewhat irrelevant. The Super carbs have three circuits that prove fuel, with the main jet doing most of the work. The issue is simply bandwidth. Tunning the main jet for optimum AFR at high RPM will produce a very rich at the lower RPM in which the main jet operates. Adding a Thunderjet effectively splits the operating range into two, with the main covering the lower portion and the T-Jet covering the upper portion. Some carbs are even set up with two thunder jets. Again, this is not to provide more fuel, but simply more control of the fuel delivery at various sections of the RPM range. The additional T-Jets require their air bleeds to be drilled to a size that brings them in at the correct vacuum draw. A larger air bleed brings the T-Jet in at a higher RPM. The air bleed for a T-Jet is at the base  of the jet holder and has to be drilled to size. That being said, it is almost impossible for the typical rider to set one of these up on their own. This really requires a dyno with an AFR sniffer to re-align the main jet and its air bleed  as well as the jet and air bleed for the T-Jet.

To give you an idea of what is involved, my Smack-A-Hoe TC124 was originally setup with a bored and retimed Super G with one T-Jet. After many pulls on the dyne it was decided that a second T-Jet was in order. Again, not to add more overall fuel but to flatten the AFR in the mid to upper RPM areas. We spent almost a week on the dyno and went through quite a few bases for the T-Jet (the part that is drilled for the air bleed) until we got it right. We also changed carb bodies to try different locations for the T-Jet (Closer to the butterfly provides more draw, closer to the Ac provides less draw). There are also different size nozzles for the T-Jet. My carb runs combination of one standard and one large nozzle. The nozzles alone required about six pulls to dial in.

Bottom line, T-Jets are not really for the do-it-yourselfer and are better left to a professional tuner. Done right, they provide a much flatter AFR line that produces great power and improved fuel economy regardless of the size of the engine.

[jrgreene1968]

Thanks TurboProp, I did not know that 

[dave brode]

Thanks turboprop,

I don't doubt a word of that. It seems to me that the placement of the t-jet, as far as distance from the venture would be very critical. Now I'm more skeered LOL.

--

Maybe I was lucky, but the 48 that I had on the 118" TC with Wood TW-9Bs and Boarzilla worked really well. Great throttle response, needed only a main jet change. Decent on gas. Repeat: I hated the rattle, and it spewed gas on decal on the dyno.

Dave
   

[jsachs1]

RE: T-Jet.
Some do and some don't. I tend to install them several thousands closer to the butterfly, and more of an angle to the right looking at the front of the carb.
Takes dyno time to see if your combo is better or worse with it. 
John

[prodrag1320]

most don't even know how a t jet works,let alone tuning one.we ran 1 to 2 in each carb on our pro gas bikes bikes in the day,CID motors from 114" to 167"

[speedzter]

Maybe I was lucky, but the 48 that I had on the 118" TC with Wood TW-9Bs and Boarzilla worked really well. Great throttle response, needed only a main jet change. Decent on gas. Repeat: I hated the rattle, and it spewed gas on decal on the dyno.

Dave

Not lucky, they always work well !!

Also, the HSR48 is no taller than the 45/42, I don't know where that came from ?.
http://www.mikuni.com/carburator/hsr_group_l.jpg
A manifold is cheap from S&S  - 160-0001A , no adapter needed, and no need for a jet kit, maybe a few single jets, and a needle.
I run one on my custom 120 in a Dyna.
You can barely hear the slide rattle, and only really at idle.
A modded "G" will be more expensive.

[dave brode]

Thank you Mr. Sachs, and speedzter,


I didn't mean for this to be a 48 vs G thing, but it's ok.   speedster, you might remember the 48 on S&S manifold thread.

Dave