2016 FLSTFBS 124" currently sitting at 10.4-6:1. I've got the Star Racing 650 cams in it now but it's not very squared up and I feel as if I can get her from 144TQ/135HP to 150-160HP with the CR651. 91 Octane should be good to run at 11:3.1. My problem lies in how to get to 11.3:1. I have the .0020 base gaskets and .035 head gaskets. When I CC'd my heads they Where 98CC. Im assuming this is due to the MVA valves I had put into them. Would it be cheaper to just get different heads like MVA's and trim those or different pistons? BigBoys without using base gaskets and cutting down my heads to 95cc would put me at 11.26:1. Is it smart to use no base gaskets and have .020 out of the hole? What would you do?
In reading through some history on HTT I seen Don d. Doesn't like .020 sticking out the hole and I can get why. I'm studying but still would love some direction. I seen Ohio HD did get away with .008 and gave a good reason as to why this would be good for some builds and sounded like piston design played the biggest factor. Of course this is MY understanding and may be wrong. That's why I'm here and love this site.
You can use 3M 1104 (Yamabond) or 3M 08672 (Ultra pro high temp silicone gasket) to seal the cylinders/replace the gasket, but- if you were at 0 deck before, the piston would now be proud of the cylinder by .020"- potential interference between the piston/head/valves, and any carbon build up would result in contact, so that's an issue. That would also change the intake manifold clearance.
IMO, +5 to +6cc dome pistons would put you right where you want to be, without having to re-do all the intake stuff.
I don't know if you have seen these sheets, these are from Ray's 124" running CR651 cams.
He was running a good set of heads, S&S 66mm TB and a Burns pipe with these cams.
CR 651 in a 124" (https://harleytechtalk.com/htt/index.php/topic,78430.msg868546.html#msg868546)
I have seen them and stumbled across his YouTube channel also. They sounded great and I understand why he named it Duracell :teeth: I was looking at pistons as I figured that would be the route that made the most sense and didn't create more issues. Allot of the pistons are for 7.660 Rod lengths. I have 7.670 which would add an extra .010 to the equation? Just confused on that part. Any recommendations on pistons that would work? Axtell? I would prefer CP or KB as they are the standard. Should I get oversized to refit them?
CP pistons are top notch. The compression height for 124" TC are 1.050". They've always measured that when I 've used them. There's always the possibility that the deck height of the cases are not perfect, the cylinder lengths not perfect, etc. So all you can do is shoot for as close as you can, then make adjustments to the components if needed.
Should you use std. bore pistons? That depends on what the cylinder bore actually measures, and if the cylinders can be precision honed to get a starting point for new std. pistons and rings without making too much clearance. I figure why take a chance, and I'd use 0.005" oversize. The cylinders need to be measured before ordering new parts. Also an experienced machinist that has the equipment to precision hone the cylinders can help decide what size piston to use.
Ok thanks, I appreciate the help and knowledge.
How'd you like those Star Racing cams?
Did you find a good source for pistons? I can't really wrap my head around $700 for a coated set
Quote from: HighLiner on August 12, 2022, 05:57:19 AMHow'd you like those Star Racing cams?
I liked them but all things considered I wish I would have kept the Star Racing 680's. It's my understanding they have a short duration. The intake Close is 40 so super early. Star Racing doesn't post or share the Cams events. I did recieve the Cyclerama CR651. I did have a interesting conversation with Cyclerama about others STEALING or copying cams. Wes is a good guy and I get why alot hide their numbers. They came on about 3200 and don't die out but don't climb either they feel like they pull to redline just not scary enough :scoot: The reversion is something fierce on them that's for sure. I would say if a guy is building a 117 they would be a great cam. 124 maybe great but leaving some on the table. IMO
Quote from: donk_316 on August 13, 2022, 07:36:58 AMDid you find a good source for pistons? I can't really wrap my head around $700 for a coated set
It seems expensive but you gotta pay to play. I want the best. I haven't found a good +7CC pistons supplier except Tman has them with a 1.049 CH. I haven't called CP either yet. I'm still looking. I'm not sure what manufacturer Tman uses for their pistons either. Do I get them with coatings? Anyway, I'm going to start it in November so I'll send off my cylinders and pistons to someone and let them pick or tell me what to use. Can't wait to ride them 651's though. This is addictive
Randy @ Hyperformance can get you the CP pistons your needing. If you send him your cylinders he can also fit the cylinders to the pistons for you and even gap your rings for you too.
(515)266-6381
At the time I bought this set for a build, Randy didn't have any oversize. Customer had NIB S&S cylinders. I verified the domes @ 6.1 cc.124 CP pistons.jpg
I'll give him a call. Thanks for the information.