203 VS 204 cam

[roofeditor]

I have a 06 Ultra with SS/SPO pipes and a SERT tune and the Stage one filter. Thinking of a cam change. Big bike big guy on big bike so which is more appropiate a 203 or 204 cam or what the heck a 21G. Is there that much difference.

Thank you.

[Totenkopf]

Wow, there are a lot of previous threads on this perpetual topic. I guess you haven't caught any of those.

My stock answer is to consider not only a cam change but to get the heads, cam and exhaust all working in harmony and optimized for the mission at hand.

I'm also not a big fan of either the 203 or 204, considering all the other great choices available. If I had a gun to my head, I would choose the 204 but even then it would be with street ported heads and adjusted for optimum compression to get that cam to bite. And even then, for the cost of boring the cylinders for a 95" build (around $50 - $75/hole) and the SE cast flattops at $109 makes that decision a no-brainer.

By the way, the 26g is a better choice and the 37g is even a lot of fun and very well mannered.

Good luck with your decision!

[George C]

Richard, where have you been?

Stick a 26G in that thing. If you want to stay with the SE line, I would probably go with the 203 for your bike. I have the 204, perfect for a lighter bike because it will make it run, but it's a little lumpy for a bagger.

You don't really need to touch the heads on an 06' because they flow pretty darn well from the factory.

[roofeditor]

I would choose the 204 but even then it would be with street ported heads and adjusted for optimum compression to get that cam to bite. And even then, for the cost of boring the cylinders for a 95" build (around $50 - $75/hole) and the SE cast flattops at $109 makes that decision a no-brainer.


I'm a little new to the site and I'm learning. The dealer obviously wants to do the 203 and stage II 95 kit. I was wondering what the difference was in the 203 VS 204?

While on the subject I noticed many threads recommending a 98 kit VS the Harley 95 kit. Is there an advantage other than 3 more inches which in theory might be 3 more HP?

As to street ported heads....what is that? Harley has some sort of ported high compression heads from the SE book. I have also looked at Dewey's and Zippers for heads.

As to optimum compression.....what is optimum?

We have a pretty popular builder in Florida http://www.cycle-rama.com/ which is about a 2 hour drive away.

Thanks for the reply. There are so many opinions on cams it's confusing.

[nw_guy4_fun]

If your bike is EFI I suggest you decide and do the research on tuning solutions 1st.
Anything you do to the motor that effects airflow that is outside of the Harley canned builds will require custom tuning to get it right. There is no Harley stage map for a big bore with 204 cams to the best of my knowlege. Buying and having motor hardware installed is the easy part. Many viable options.

[Totenkopf]

Originally Posted by roofeditor

I would choose the 204 but even then it would be with street ported heads and adjusted for optimum compression to get that cam to bite. And even then, for the cost of boring the cylinders for a 95" build (around $50 - $75/hole) and the SE cast flattops at $109 makes that decision a no-brainer.


I'm a little new to the site and I'm learning. The dealer obviously wants to do the 203 and stage II 95 kit. I was wondering what the difference was in the 203 VS 204?

While on the subject I noticed many threads recommending a 98 kit VS the Harley 95 kit. Is there an advantage other than 3 more inches which in theory might be 3 more HP?

As to street ported heads....what is that? Harley has some sort of ported high compression heads from the SE book. I have also looked at Dewey's and Zippers for heads.

As to optimum compression.....what is optimum?

We have a pretty popular builder in Florida http://www.cycle-rama.com/ which is about a 2 hour drive away.

Thanks for the reply. There are so many opinions on cams it's confusing.

First off, nw_guy4_fun is correct. Getting the new build tuned "properly" is half the battle. Find out from Cycle-Rama what their preference is.... our preference is the SE Race Tuner but it can be difficult to find someone that is good with it.

Now, if you are like everyone else, you want a good bump up in performance and no loss of reliability. Being that you have a bagger, you probably want really good torque down low and your probably have never and will never hit the rev limiter. Please correct me if these assumptions are incorrect.

The typical 203 build has a decent bottom end response(read that as okay but not as great as it could be) but the motor will start to lay down at around 4500-5000rpm, iirc. The 204 has a similar bottom end response but stays around a little bit longer than the 203 and makes better hp.

A good 203 build dyno sheethttp://www.latus-harley-davidson.com...mid=1307#M1307

An exceptional 204 build dyno sheethttp://www.latus-harley-davidson.com...4&mid=260#M260

A Andrews 26 cam dyno sheet http://www.latus-harley-davidson.com...4&mid=983#M983

My neighbors nicely tuned 37g build http://www.v-twinforum.com/forums/at...2&d=1142117847

There are certainly other cam choices that work well in baggers, it all depends on what you want.

With regard to the 98 vs 95, they would be pretty similar in performance with a slight edge to the 98 in potential. The difference is that the HD jugs are iron lined and retain heat. The 98" cylinders are Nikasil plated aluminum and run up to 20* cooler. That's a good thing.

Ported heads is a big topic and I won't go into all of the detail here except that a good porter, like the several we have on the site (Big Boyz, GMR, Dewey, Atwood) can take your '06 heads and clean them up from the casting process, improve the ports, equalize the combustion chambers and then mill the heads for the correct chamber volume for the cam that is chosen. Hard to get that from a catalog.

Optimum compression ratio is going to vary depending on the cam. Some examples would be 9.6-9.8:1 for the 37g, 9.2-9.4 on the 26g, you would need to work with whomever is doing the heads to get this correct for the chosen cam.

Again, it's really important that you get the whole system from intake to exhaust tip working together and finally, to get it tuned properly.

I do not know Cycle-Rama but in looking at their website, I see they build some winning drag bike motors. That's a good indication that they know how to make power and tune. I would investigate them and see what they know about reliable bagger power and what proven combinations they recommend.

[djl]

I would choose the 204 but even then it would be with street ported heads and adjusted for optimum compression to get that cam to bite. And even then, for the cost of boring the cylinders for a 95" build (around $50 - $75/hole) and the SE cast flattops at $109 makes that decision a no-brainer.

As others have said, there are plenty of after market cams that make good power. However, if you want to keep it simple, I think you are dead nuts on with the SE BB Stage II approach instead of a 98". Totenkopf has clearly stated the difference in the two cams. I run the 204 in my SE BB Stage II build and my brother runs the 203 in his; I like the 204 better; he likes the 203. He gets out a little quicker than I do but in a 1/4 mile race, I reel him in. Could be technique? could be cams? could be pipes? I don't know.

As to street ported heads....what is that? Harley has some sort of ported high compression heads from the SE book. I have also looked at Dewey's and Zippers for heads.

BigBoyz offer a street port job; he retains stock valve sizes and develops sufficient flow and velocity to support boltin cams. If you select bigger cams outside the boltin family, you should consider a full port job. There is a dyno in the HTT Dyno Room of a straight up SE BB Stage II build with 203 cams and BigBoys street ported heads; 108.7TQ/95.3HP; very respectable numbers. There are many with more cam and more headwork that won't put up those numbers. So, you can make plenty of power with the 203 or 204, it is a matter of matching up the components and tuning.

[roofeditor]

Sounds like the 203 makes it's power a little sooner and the 204 comes in a little later and hangs in a little longer?

As to gear drives. In some other threads in the twin cam section there is some concern of deterioration of can tensioners and cam chains. Obviously this will happen eventually but how soon does this typically happen and how often are there problems? I have read that if this assembly lets loose all hell breaks loose $$$$$$$?

More cam questions. Given a Andrews 21 or 26 cam, is there a HP advantage by going with a gear drive VS chain drive? I have built stock car engines with gear drives and in the upper rpm's there are some noticeable advantages. What I'm eluding to is, are the advantages apparent with a relatively low RPM engine like the TC-88.

Assuming the gear drive makes a little more power and is more reliable, I wonder why HD factory doesn't include it as standard equipment. It can't cost all that much when mass produced.

[nw_guy4_fun]

No HP gain from gear drive, just reliability and piece of mind IMO
TW26g or TW21g can be considered equivalent to what the MOCO would have used if EPA and federal noise were not an issue as a stock cam for the 95" and 88" respectively.
Life of tensioners, on a case by case basis
My theory, major contributors to the problem are:
· High oil temperatures (won't elaborate to avoid the brand name syn vs dino wars)
· The uneven surface of the linkbelt type chain
· Chain slap due to valvetrain dynamics
I would check the tensioners every 10K and if they look perfect two inspections you may extend the interval.
They are a sacrificial part and the crud from the pads ends up in the oil and not very often filtered out the way it is supposed to happen in la la land. If a pad goes south it can and often does affect other parts.

[nw_guy4_fun]

BTW a FYI
In a few weeks when they release the new 2007 model line we will see if they adopt the hydraulic tensioner, roller chain setup for all of the models.

[xkvator]

roofeditor...you are lucky to live close to a highly regarded, highly knowledgable builder in the Orlando area...Doc
If you're interested in someone doing the work for you...no brainer...use him.

If you're really interested...I'm sure someone will PM you his #

[autococker07]

Originally Posted by xkvator

roofeditor...you are lucky to live close to a highly regarded, highly knowledgable builder in the Orlando area...Doc
If you're interested in someone doing the work for you...no brainer...use him.

If you're really interested...I'm sure someone will PM you his #

Ummm, is there anyway someone could put me in contact with "Doc"? I live in NW Florida, but was thinking about using Cycle-rama also... I don't mind the ride down and back, but I am beggining to wonder if I really want a PCIII on my ride.... Just trying to keep all options open.... Thanks for any info! Jim

[route66paul]

Originally Posted by nw_guy4_fun

No HP gain from gear drive, just reliability and piece of mind IMO
TW26g or TW21g can be considered equivalent to what the MOCO would have used if EPA and federal noise were not an issue as a stock cam for the 95" and 88" respectively.
Life of tensioners, on a case by case basis
My theory, major contributors to the problem are:
· High oil temperatures (won't elaborate to avoid the brand name syn vs dino wars)
· The uneven surface of the linkbelt type chain
· Chain slap due to valvetrain dynamics
I would check the tensioners every 10K and if they look perfect two inspections you may extend the interval.
They are a sacrificial part and the crud from the pads ends up in the oil and not very often filtered out the way it is supposed to happen in la la land. If a pad goes south it can and often does affect other parts.

to add to this some other statements I have heard:
1. 4hp from a gear drive(I am very skeptical)
2. timing bounce with chain and tensioners. I have heard up to 2% +/- depending on accel or decell with a chain.
3. A gear drive cam must be installed by someone who knows what he's doing. the tolerances of a gear drive must be tighter than with a chain. if the gears are installed to loose or to tight there can be problems. S&S makes some slightly oversized and some slightly undersized gears to combat the loose tolerance of the hd engine in regards to cam bearing alignment.

[roofeditor]

Thanks for the replies.....lot of good info. Does Cyclerama only do PC-III tunes and not the SERT? I have the SERT box and hookup.

As to the bounce theory. In bigger race engines cam timing does bounce all over the place with a chain and gears are the way to go. They do have a sound of their own.

BTW I did try calling DOC will no success.