If you're keeping the stock compression, I think either of your suggestions are good (21 or 203). A 211 coupled with stock compression is a good recipe for very weak low-end torque, and I wouldn't go with the 204 either unless you are willing to bump compression up to 10:1 or more. A stock TC88 has 8.7:1 compression, which means your low-end will likely be weaker with most any performance cams you install, but I think the 21's would be the best fit for a stock engine.

 

I would agree with previously posted comments. However, I disagree on the SE204; you don't need 10:1 CR; detonation prone at that CR but it will perform nicely at 9.6 and would be preferable to the 203 IMHO. Either the Andrews 21 or 26 are also good choices but gettting the CR right to get the most out of whichever you choose is important.

 

I hadn't heard the 204's were finicky about compression, but don't you think these will decrease low-end torque with stock compression? If this isn't important I think it would be fine in a stock TC88, but for my taste I wouldn't want to mess with low-end performance even though the midrange and top-end would surely be improved.

 

Absolutely. Run a SE204 at 10:1 and you'll run into detonation issues. They like 9.2 up to about 9.7. They're a great bolt in cam, good right off idle, with a strong mid range. Pretty much done by 5200 rpm. They're a little harder to find a map for, but the SE203 maps are close enough.

Cams are hotly debated and largely misunderstood by lots of guys. Too many guys focus on peak numbers and lose sight of low rpm performance, where many of us ride. That will leave you with a bike that goes like hell once the cams come into their range, but will be a dog off idle. Others focus entirely on the bottom end, and lose sight of the middle, which isn't as costly, because they'll have a good running bike with a snappy thottle, but it won't be as quick as it might have been.

I've read the Minton article mentioned earlier, and it's good information, but it over simplifies cams almost to a cartoonish level. Intake valve close is a good start point for matching the cams to the compression ratio. ( Or, when you're building up a motor, if you have a cam already, you adjust the cr to the cam's intake close. ) But it sure doesn't tell you how the cam will perform. THe SE204 cams are a good example. Minton says to run the cams as close to 30* intake close as possible, slap in a 4* advance key if needed. However, the 204s have 8* advance ground in, and if you advance them 4* more, you'll have them advanced 12*, which will cause all kinds of tuning problems, and detonation problems even at lower compression rations. I read some of Minton's stuff and try to pick out the good info, but the performance engine builders I know pretty much ignore him entirely. If you read the fuel moto thread on Woods 6 and 555 cams, Jamie pretty much debunked the +4 cam advance as a way of improving low end torque. The fact of the matter is, a few degrees one way or the other really don't make an appreciable difference in the way a cam performs. What the 4* key will do is to help compensate if you've got a cam with too much duration.


By the way, the SE203 cams at 100 bucks are a great, cheap upgrade. They're good low-mid cams, maybe not the top performer in their category, but they work pretty darn good. They are the stage II cams for that motor, usually installed with a BB kit, but even at 88 ci, you'll still have a noticible bump in performance. 203s and 204s were kind of the neglected stepchildren for a few years, but they are good cams. The 203s and 255s get trashed talked mostly because of their popularity, I think.

Andrews 21 and 26, SE203 and SE204 are all used as bolt in cams for stock 88 motors. They all work well, and all would bring back gains across the entire rpm band.

 

Make sure you upgrade the inner bearings to Torrington B-148s. Harley now sells those as Screamin' Eagle parts.

 

I replaced the inner cam bearings with the torrington's earlier this morning and I cannot believe the difference in those bearings. Those torringtons are a FAR superior bearing and I am glad I decided to order those along with the other parts. As for the rest of the debate I figured 100 bucks for a new in box set of decent cams was too good to pass so I pulled the trigger on the 203s. Now all I have to do is get a hold of Fuel Moto and get a power commander on the way with a tune for the cams and I should have all of my bases covered. Hopefully with the popularity of 203 cams (at least they seem to be pretty common) a good map should be pretty easy to come by. I wasn't unhappy with the performance of the stage 1 so this should be a pleasant experience providing everything goes well.

 

I think you'll be happy with this setup. I have two friends who've installed 203's in stock TC88's and both are very happy with them. I rode one of the bikes and it performed well, although low-end torque was less than my stock (at the time) TC96, a tad peppier in the midrange and top-end. I didn't ride it before the upgrade, so I can't offer a before-after comparison, but the owner is happy with the improvement. After all, he is the best judge of that.

 

I think you're going to be pleased with those cams.

 

FWIW I had 203's in my 95" RK and liked them. When I converted to hyd my mechanic bud talked me into Wild Thing TC1's full conversion cams. I didn't want anything radical, I have a sportbike for that. But like you, I figured bump it up a notch as long as your in there. I really didn't know it had 203's until we pulled them out. They felt a tad smoother than the TC1's, but I am getting better mpg now.

I've been told pick the cam you think you need and then go one step less agressive.

 

Good post. Where do the detonation issues most-commonly show-up with the 204's? What is the CCP on these with stock 9.2 compression? How about 10:1? I'll obviously have to adjust my attitude about 204's, as I had heard they were happiest at 10:1 or thereabouts, similar to the 6-6, 555, and 26. You have the 204's, have studied them thoroughly, and would know--so thanks for the clarification.

Speaking of clarification, I think we need some here, as I don't know who is touting importance of low-end performance only and losing sight of the important midrange. I for one like good low-end response and have voiced my interest in retaining or improving the low-end when doing any kind of performance upgrade. That is a very critical area to concentrate on when upgrading cams in a stock engine, as you know and have expressed, as it is easy to over-cam and lose low-end performance if compression isn't right for the grind. The midrange is one area that isn't as much of a concern when upgrading cams, IMO, as almost any cam will provide good midrange and top-end performance, even in a stock engine. BTW I think of the midrange as being in the neighborhood of 2700-4000 RPMs.

I also don't know of any cams that boost or retain the low-end but fall-off in the midrange, as even 255's provide excellent performance up to at least 4000-4500 rpms. Anything above that to me is the top-end, and that range is the least important for my riding style on a bagger. Others may have a different take on what works for them, but I think most bagger riders are most interested in the low-end and midrange.