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CVO Technical => Twin Cam => Topic started by: Farm boy on May 19, 2018, 07:45:15 PM
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Machine work question: I am looking at upping the compression in my 03 serk and installing cams. It was recommended to port and polish and install ACRs in them. It is going to be $950.00 plus the ACRs. Is this a reasonable price to do this work ?
Note: 10.5:1 comp with Woods TW400G cams.
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Sounds pricey to me for our area of the country. Also, the larger the cam, the less need for compression releases due to the later intake closing. TIMINATOR
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That is a short cam, just high lift. Noisy as hell.
Bad choice in my opinion and I have used it in the 110 before.
The cost to do the heads? Well others can provide more for less, by that I mean all new parts and including the ACR drilling. It is a bit tricky to install ACRs in these heads, I have done that too.
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I went with S&S EZ start compression release cams. No drill needed.
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The S&S 570 is a good cam in that motor with head work. An EZ start would work. Best to get rid of the early chain drive at the same time. That cam will require domes pistons to work best, the heads have 98cc nominal heads.
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I like the 570 in mine. Nice long powerband throughout the rpm range.
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Everyone, thanks for the info and advice. Does anyone have a dyno sheet they can post on the 570g cams ? Also, how much do I need to bump the compression for these cams ?
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Ideal is 10.25:1, honest fluid measured as opposed to advertised.
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https://www.cvoharley.com/smf/index.php?topic=115440.0
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A wise move would be to contact Don (HD Street Performance) for a quote/further advice.
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At $950, without knowing what all they're doing and putting in them, it's hard to give you a straight answer.
If you're getting a good port job with quality valves* (Manley, Ferrea), new intake seats, bronze guides,
and machining for ACR. I'd say that's in the ball park and not a bad price.
(*I'd expect a 1.94/1.61 valve combination or similar)
Allot of people will put a 1.9 intake valve on the stock seat, but I don't recommend it. There are so many variables
and combinations, the price can vary greatly. You didn't mention the engine size, bike/rider weight or intended use.
So basically, it depends on what all you're wanting and how good the heads are. I'd say it's not a bad price if you're
getting all the good stuff put in them. If it's just a fluff-n-buff with small valves, not so much.
P.S: Nobody "polishes" ports anymore. That went out of style with hula-hoops and bell bottoms. lol
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Matt these heads come stock with ferret valves and the intake is 1.9"
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If you are going to larger valves, be aware of your pistons valve notch size. You may have to flycut them for larger valves. Aftermarket piston notches are usually cut for larger valves than stock ones. This is an issue with the 2.08 valves in the CVO 110 heads and especially in the MVA 2.120 valve heads. CVO pistons have larger notches than stock pistons, but maybe still not enough for what you intend to install. Better to check. Do it before you try to install the heads, or decide to purchase or rework. It is an extra expense that many overlook. TIMINATOR
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Again not all that applicable. The heads have a 27 and 31deg angles and you will have hell and a huge chamber volume to get even a 2.08 in there, valve to valve issue. And why? Stock compression is about 8.6:1. 90% solution for 50% money is add compression, minor porting, guides and better seals, and a cam such as the 570eg. Not everyone wants to go wot most of the time.
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Matt these heads come stock with ferret valves and the intake is 1.9"
New seats I hope.
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Ferrea valves, 1.9 & 1.625 as they were sold by Harley.