Originally Posted by BlackDangerous
Well, I just finished my 98 CI upgrade on my 01 FLTR and I am really happy with it and I do think that with this bike that I am going to stay put and not increase the CI displacement. However, with that being said, I do need to have a new project. I have been thinking of this for a long time that I would like to build a 113" or 120" Twin cam engine. I know that there are a lot of people that have done this so I thought that this forum would be the only spot really to get complete information. I am really looking forward to this thread as I am sure that there are just endless possibilities that one can choose from.
I am going to start the thread by saying that I am a person that likes to build things for practical purposes, meaning that I am not a straight line rider by any stretch of the imagination but I require that my bike has the power that it needs for all situations. My intentions for this engine as of now is to build it, then sell it.
This engine will be an A engine and I am looking for it to perform at 3000 rpm and up. I know that people will use the cliche, "there is no replacement for displacement," but I do not subscribe to that line of thinking all of the time. What displacement do you think is the most reliable? Why? I am looking for responses that exhibit real world experience. Remember, 120 CI is the max that I want. What cam shaft then would you recommend?
Thanks in advance to all who participate and lets have fun spending virtual money. Please give legitimate reasons as to why you are making the suggestion. Thanks. Lets have some fun but serious at the same time.
Bob Lobenburg, the tuner for RC Cycles Hayward, California recently tuned a 117"er of ours, and in spite of the small diameter primary tubes on the Thunderheader, it still ripped 129/137 in touring form.
Oznog on the HTT, runs one of our 120's that showed 141/144, in more hot-rod form, and Splitting Lanes on the HTT, has also 40,000 miles on his 117"er, with a tiny Wood 6 cam,(that we built the 117" around, as he already had it) and popped 119/136, tune by Bruce @ Horsepower Express, in the San Fran Bay area.
Too many others to mention, that have as much power and miles on them.
4 3/8" stroke, 4 1/8" hole, with an off-shelf cam and a set of heads that roll off the needed air, with the proper t/body and pipe, tuned. That straightforward, that simple.
No need to re-invent the wheel, and no rocks will be turned over, finding something new, 'cause it just ain't there.
It's already been done......