Hello everybody, greetings from Italy! It's freezing cold right now and so it's the rigth time to break the toolbox open and get to work!
A couple of years ago a did the big bore conversion to my 2006 FLHRCI.
All SE off the box, big bore cilynders and pistons plus 203 cams, Big Sucker and recalibration through SERT. Left the heads alone although I put .030" Cometic head gaskets and stayed with chain drive.
Happy overall but now I would like a bit more and I once again will do all the work by myself.
Again I would like not to touch the heads (I might polish the exhaust and maybe lap the valves just because I have the heads off) but I am thinking of increasing compression a bit maybe to 9.5 or more (in any case below 10) and changing cams to something a little more aggressive.
For what concerns the cams I am not sure what is the maximum lift that the stock heads will be ok with before having to work the springs but I was looking at a set of Zippers 557 (lift is .557) and was wondering if that would be too much.
Any suggestion?
Is there a combo pistons/cams that would work well together?
Is it worth looking at the 50mm SE throttle body?
Thanks everyone for any ideas or pointers!
Ciao!

 

I know you said you don't want to touch the heads but I would think that they would be your next item to work on

 

I know and I tend to agree with you but I have made a point to always do all the mods on the bikes in my garage and I have always understood that even the most basic work on the heads is a kind of magic art that cannot be tought and should not be tempted lightly as the results are likely to be disastrous.
That's why I'm looking somewhere else.....unless of course someone will tell me that it can be done in my garage!

 

What Tat said. I can't answer your question about the Zippers 557 cams but I don't think you'll gain much HP or torque over what you have, particularly when you consider what you'll spend. You might move the curve left or right, that's about it. If you want more out of that engine you'll need head work, maybe a different cam, and I'd be looking for somebody over there in Italia who you can trust to do your heads. Engine work is Science, not art. Nice bike btw. Buona fortuna.

 

Set the compression @ 10.0 cr, with an Andrews 37, and get the heads working would be a HUGE boost!
Last spring, 3 different tuners, 3 different bikes, all had our 98"/37 cam/Stage II head combo, from Fla, to NY, all showed 106-108 hp, and 108-111 ft/lbs.
Scott

 

I agree. Bump the compression and do some head work. The Andrews 37 is a hot set up for 95" builds.

 

Ok, I will look into the head work with the Andrews 37. There's a couple of guys over here that I might talk to about that.
Three questions then:
1) is there a recommended combo 98" cylinders/pistons to go with the worked heads (presumably the case is still stock)?
2) if I stayed at 95" what pistons would you guys recommend to give me the 10 cr that I am looking for?
3) would the Andrews 37 work with stock springs?

Thank you and sorry for asking so many questions!!!

 

If you go to a 98" you'll have to go to a forged piston. Personally I like the cast SE pistons. They are lighter and you can set them up tighter and they run a little quieter. I don't see a need to run forged pistons at the compression ratio needed for the 37's. Another thing is the cast are cheaper. When you have your heads worked, they need to be cc'd and milled to set the compression ratio. Stock springs would be fine but you may want to replace them if they are getting some milage on them and starting to fatigue. Go with a good head porter and it will be money well spent. When you pull the trigger, you'll also want new lifters, inner cam bearings and may want to go with the updated and much superior cam plate with hydraulic chain tensioners also. This is the way I would do the build but others will have their opinions as well. If you want to go further, you could split the bottom end and have the crank beefed up by having it trued, welded and balanced but I don't see a need for that with this build unless your runout is bad.

 

You can stay with the 95"er, and install the 37's, with headwork.
Just using the 98"ers as examples.
The myth that sorrounds forged piston noise, in this day and age is that, a myth.
With the piston design, and specific alloys used in these, most times .0025" is the standard piston/wall clearance, leaving .00125" per side for lubrication.
Very, very, quiet, stock-like operation, from what we see here.
Scott

 

Your heads will accomodate .575" lift without issues and the OEM springs are up to the job. Personally, I would not bother with boring for 98". You can see 100TQ and near 100HP with the 37s and 9.8 static compression without headwork. Heads could use some cleanup, ccing and decking for the target compression. Of course, some porting, perhaps a 1.9 intake valve would help but not necessary to see significant gains over what you have. Might consider 1.7 rockers to increase the lift of the 37s. No need to over think this upgrade. JMHO.