Interpretation of Charts

[David Jackson]

Hi Mike;

This is a great site; I spent a lot of time looking at the various dyno printouts. Of course there are so many variables that it is impossible to make more than general observations about any particular component, but you already pointed that out.

Here are my questions:

1. I noticed one chart with the S&S reed valve breather installed and removed. Looking at the chart it appears that wet sumping
occured with the reed valve installed and robbed a bunch of HP and TQ. I thought the breather was supposed to keep the
cases empty (relatively speaking). Someone told me that the S&S breather is OK without the Fueling oil pump but I cound not
see any reference to that being on the bike the test was done on. What's going on? Is the S&S reed valve crankcase breather
a real problem or is something else going on?

2. I noticed another chart comparing different gearsets on the same bike; the five speed gearset produced about 5 more hp and tq
as I recall; not a huge difference but significant nontheless. What's going on here? Does that particular 6 speed gearset have
enormous friction losses or something? All tests were done in 5th gear (I think; I could not find the chart when I went hunting
for it a second time.)

Thanks in advance;

David Jackson

[Mike]

Thank you for enjoying our site. By design we published a large number of charts to demonstrate the inherent variability and unpredictable nature of these motorcycles.
?1. We, and others, have run into several cases where bikes with the S&S reed valve installed did in fact have wetsumping. Those bikes we tested had stock oil pumps but in fairness one had an A style pump and was upgraded to the B style when the reed valve was removed. We strongly recommend this upgrade on any bike that still has an A pump. These were not actual tests in the sense that we did A/B testing with and without the vavles. We discovered these problems as part of normal dyno tuning. What we belive is happening is that the reed valve acts like a labrynth type oil seperater which allows the crankcase air pressure to escape but actually causes the oil to be retained in the flywheel chest. S&S did much of the developement of the valve on a Spintron which may not have realistically duplicated the actual engine dynamic environment, especially with respect to oil flow. Also, it may work fine with S&S cases due to design differences vs H-D cases. The Fueling pump might help but may not completely overcome the wetsumping due to oil return restrictions in the cases or actually add to the problem by increasing feed side volume. On our big motors we do install reed valves (not S&S), but they are machined into the cases to increase the overall breathing capability. The S&S valve does not add breather volume. In addition, we modify the oiling system in such a way that the Fueling pump can then provide additional scavenging and thus becomes an advantage. Note also that the Fueling pump can be improperly installed (especially early versions) also causing wetsumping. Until further testing indicates an advantage to installing the S&S reed valve we do not recommend it. The Fueling pump is an option but we do not strongly recommend it unless you have a big motor and the crankcase mods.

?2. Our testing has routinely shown a 4-8 hp loss with 6 vs 5 spd tansmissions. There are many different types, each with different affects. There are three basic causes for these losses. 1, greater rotational mass of the complete gear set. 2, greater parasitic loss due to oil drag (more gears wadeing through the oil). 3, less leverage advantage due to ratio differences. The dyno sees all of these affects. They are real affects and would similary be seen on the street or race track. We see the greatest loss with those that change the primary drive ratio (sim. to the 4th vs 5th gear dyno effect). Note that these effects would be less in the lower gears so "seat of the pants" may not be noticable and the advatange of an overdrive 6th typically outweighs the concern about hp losses. Last, all of our runs are in 5th gear, even on bikes with 6 speed trans (unless we are doing a specific test).
Regards, Mike

[David Jackson]

Hello Mike and many thanks for that exigesis of what is happening with reed valves and 6 speed transmissions.

I have both an S&S reed valve installed in my cases (obviously I thought it was a good idea!) and a BAKER DDDS6 gearset. I could be losing a bunch of power with both those mods apparently. The DDS6 does change the primary ratio I do believe; because while 6th is 1 to 1 the 5th gear ratio is about like stock; the idea being to have an overdrive gear which thinks it is direct.

I live quite a way from your shop (a day's ride) which makes it impractical to bring you my bike so I guess I can just ask your opinion and recommendation.

It seems pretty obvious that the S&S reed valve has to go. I am having the local HD dealer install a 113" kit and the cases have to come apart for that so I suppose the S&S reed valve can be removed then. Can you install your valve if the cases are sent to you or, altermately, can you sell me one and give the local tech instructions on how to install it?

5 to 8 hp is 5 to 8 hp, no matter how you slice it. I would like to get as much power out of my bike (my wife sort of made me buy an '01 Ultra for two up touring, so poor me huh?) as I can so perhaps I should consider having the tech re-install my 5 speed. (I do remember reading, many years ago, Cook Nielsen's articles in Cycle magazine about his drag racing, high gear only, Sportster and I must suppose one reason for high gear only is the power losses with more gears wading through oil.

One more question; I am using the cam everyone seems to love to hate, the SE 264. Maybe I am just too stupid to know any better but with it the bike (now a 103" with SE HTCC CNC heads, and a 51mm DV carb) starts easily, idles fine, runs in traffic just fine, and at the upper end of the powerband it really seems to work. Do you have any experience with this cam in a 113" motor? (Bike is an '01 Dyna T-Sport).

Back in the old days (the 1960s) I had a KR wheel and a stack of sprockets and so could fool with final gear ratios to my heart's content. Hard to do with belt drive. I like the ease of use of a belt; is there any earthly reson in this day and age, to go to chain drive, aside from gearing flexibility, in your opinion?

Your thoughts and comments please. thank you again very much, in advance.

Regards;

David Jackson

[Mike]

The DD6 idea is that when in sixth gear it is a direct drive through the main shaft to the drive gear and the rest of the gears are simply freewheeling on their shafts thus reducing drag. But to accomplish an overdrive final ratio the primary ratio is changed and we believe this is where the dyno sees an hp loss. I would not advise anyone to remove a six speed because we have to remember why the six speed was installed and what the intention was. It's a substantial investment. Although maybe a swap from the Dyna to the Ultra may be an idea (if I have your bikes correct).
We would be happy to machine your cases for our reed valve. We would want both halfs because we do additional changes to the scrapers and oil passage. Expect to pay $112.50 labor plus the cost of the valve, $22.00. This is a propriatory service and cannot advise others.
The 264 cam seems to be too much for even a 120 (stock in the Jims motor) on both paper and the dyno, unless you have the compression or RPM's to support it. I believe Jims uses it to help starting and to keep cylinder pressures low. We've had much better luck with cams similar to the 258 (timing wise) when using 10-10.5 compsession. T-man's 650 works really well as does Redshift and Wood Auto Knightprowlers in these motors.
So far the belt drives have not been a big issue. We are putting 140 ft lb tq through stock belts on a number of bikes without failures. On the drag strip we may want to see chains for ratio changes and the shock loading seen when launching from a dead stop with VHT on the track.
Regards, Mike

[David Jackson]

Hi Mike;

You have my bikes right. I just got the Ultra and before that, when I bought the 6 speed, I was planning to use the Dyna for everything. Now I might rather use the Ultra for long rides and the Dyna for just short joyrides so the overdrive feature becomes less important. What becomes important now is the 5 to 8 hp I lose. I still have the 5 speed gearset.

Cases and breathers; do you also machine the cases for 113" HD jugs? If so, could that be done at the same time? Might save a little money that way.

Tell me; what is the real scoop on the S&S breathers? I remember what you said about how they were developed and what can happen, is that a universal? In other words, do ALL S&S breathers in ALL HD cases cause a significant power loss?

I understand you have found the SE 264 cam to be too much for even a 120" motor and you like the timing of a SE 258 better. Would that be a superior cam for HTCC CNC Ported heads with 113" jugs, a 51mm CV carb and V&H ProPipe?

I realize most favor gear drive but it is expensive and some say, noisy. Eventually I might consider a Wood 408HG I think it is; which is supposed to be available this month; however I have nothing against using parts made by HD. I also like the idea of perfect fit pushrods as they don't ever come out of adjustment!

Right now its winter, my bike is at the shop being worked on, and its the best time I can think of to make changes.

The tech at the dealership where I go tells me he feels the 51mm CV may be too big, even for a 113" motor. He favors a Mik instead; perhaps a 48 mm if they make such a thing. That and a velocity stack might solve the leg room problem.

Thanks for taking you time to consider all my questions, Mike.

Regards;

David Jackson

[Mike]

Yes, we can machine the cases for the 113 cylinders or any others (Axtell), we do this in house. We charge $150.00 for this.
All I can say about the S&S breather's is what our experiance has been. Those motors with them installed that have come through our shop have all had wetsumping problems. This was also confirmed by two other engine builders who we talk to routinely, both in the mid-USA. When the reed valves are removed, the wetsumping stops. I have seen reports on the web from owners who have installed them with no problems. I have two of them and if time and opportunity permits maybe we can do a true A/B test on a mild 95 build. With the race season coming up, this may be awhile.
Yes the gear drives can be noisey (especially with fast cam ramps) this is why H-D uses chains. If you are looking at .650 lift cams I would recommend gear drives due to the high valve spring pressures required to control that lift. The TW408's look OK so long as your compression is 10.0 or less. These are very short duration cams for a 113 and would be torque oriented than hp. Carnking cylinder pressures would be high so compression releases and possibley a high torque starter would be required. Also consider the Rivera 66t starter ring and pinion gear (stands up better to starter kick back). Conversly, more hp cams would require more compression but be easier on the starter.
I really like the Mikuni 48, and this would be a good choice for a 113. I do not agree that the 51cv is too much. It is routinely used on 103's with good results and is very user friendly. With good heads, the 44cv will not make the hp of the 51. The problem with the Mik 48 is getting the manifold, air cleaner mounting and carb support correct. T-man performance has a very good kit for this combo, as does Zippers and Rivera.
The VH Pro pipe may not be the best choice for a 113. We really need stepped primary runners to a large volume muffler/collector. The VH is very good on 95 motors but seems to pull down H.O. 103's and larger motors. So far the only pipe that seems to work is the DD Fatcat (with the performance muffler) or their Borezilla. The Borezilla, however is pretty loud.
The Bassanni Pro Streets also work really well but do not develope the torque of the DD.
Many of these choices will be based on what you want the bike to do. If it's hp, then big cams/compression/pipes and gearing changes to take advantage of it. If it's lower rpm torque, then short duration cams, lower compression (to avoid detonation) and more restrictive exhaust (gearing changes may still be condsidered).
Regards, Mike

[David Jackson]

Thanks for the most informative comments about the Wood torque cams, high cranking pressures at start up, and the possible need for a different starter or starter parts. All those mods are more money than I have this year.

I have the HTCC Heads and matching pistons, according to HD 10.5:1 CR (assuming accuracy here by HD). I am wondering about the 260 cam with the 113" and this set up if the 264 cam is a bit much. It seems as though with the 258 cam (which you mentioned as being a good one) I would have about .066" less lift; and the 260 cam only about .026" less. The 260 might still have strong top end (which I like) but more torque than the 264.

D&D recommends Fat Cat with the Big Boar baffle. I guess that is the same thing you said?

This may seem a silly question and one you have already answered; I am guessing that you would not recommend the Super Trapp with a 113" motor? My apologies for asking for the same info twice!

If I use the 260 cam I can use the same perfect fit pushrods I am using now; and ... with about 5,000 miles on them is it safe to use the same lifters I have been using? I have the good guy SE tappets, pn 18562-02 or do I need to replace them when using new cams?

I might go with this set up for this year. Next year, who knows?

I like the idea of using HD parts mostly as they should all fit, be readily available, and be relatively reliable.

Thanks again for reading my posts.

David Jackson

[Mike]

I know we covered some of this in our phone conv. but I wanted others to see some of it. Your tappets will be fine with 5k on them. We recommend new if more than 7k and STRONGLY rec. if 10k+, with a cam chainge (same for chains and tensioners).
All will see us (Latus Motors) taking a more pro-active stance with respect to exhaust and noise issues. One manifestation of that would be my recommendation to use the Supertrapp system vs the D&D. I know that the D&D will make better peak hp/tq but the Supertrapp will be quiter (depending on baffle count) or can be made quiter. When given choices, we will be erring to the quite side. A spin off benefit will be better overall torque curves (higher average numbers) especially in the 2-4k rpm area's and "seat of the pants" feel should be better.
Regards, Mike

[David Jackson]

Hi Mike;

I very much enjoyed our phone conversation. I learned a lot; particularly about the transmission situation.
Believe it or not; I do have some budget constraints and so, partly based on our phone conversation, I think I will run my 264s for one more season; though I have not completely decided not to get a set of 260s a guy has.
On pipes; quiet is probably something more attention should go towards. Sadly, budget comes up again and I have a V&H Pro Pipe which I bought a couple of years ago and so will probably use that for one more season.
Of course all the pipe makers tell me that their pipes work great in all motors, even to 124"; but I don't know if that's true or not.
One other alternative for quiet power is the RB Racing Black Hole. Have you any experience with them?
My cases are coming your way for the vent set up we talked about; the tech at the local shop will send them up next week (I hope).

Regards;

David Jackson

[Mike]

Sorry. no experiance with the RB Black Hole. The RB LSR and Thunder header are good examples of pipes that work very good on 80-95ci motors but seem to fall off on larger motors. This would make sense due the volume increase in motor size but not exh. This is also why stepped primary's have become so popular with the proliferation of large motors (but may not work as well conversly, on small motors). None of this is new and it is still all about creating the best combinations. The problem with exh is that it is a moving target in that there are constantly new pipes introduced on the market and our inability to test them all. In most cases, our testing is based upon the opportunities our customers present to us when dyno tuning their bikes. Noise will now be part of our conversations with customers when talking about exh options.
Regards, Mike