640 cam who has it?
- Thread starter TCALZ06
- Start date
Black Dawg
Active Member
What are your performance goals?
Scott041804
Member
Its a really good cam for high compression. It pulls very hard for a long time lol. my rev limiter is set at 7500 and it pulls like a freight train!!
Scott041804
Member
I would not just put a .640 in a stock motor.
jwoolf
Well-Known Member
I've heard some good things about those cams. Stroker's is telling me the same thing but, I didn't ask too many questions at the time.
About what's the cost for one of those and, how do you get the right cam - cam gear combo correct with them? Are the cam and gears purchased separate? Can we re-use the cam gear that's on our S&S stock cam? I've read that the cam gears are color coded on the S&S that's in the bike and you have to match the right color to get the right size so, you have to know in advance what size to order or re-use your old gear.
I'm just going by the service manual but, I'm about to change the cam in my own bike and, would like to know.
Also, what are you putting in the 05 117" motors and, do you need a spring replacement? I've also heard the the S&S lifters are suspect of not flowing oil as well as they should and should also be replaced.
So, what I'd like to know as your opinion on what I should drop in my 05 117" motor that's already got pipes and, I've also got a 45 dcoe Weber side draft carb I'll be adding at the same time. ( thanks, Sul ) The heads are stock with stock springs with stock cam right now.
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R&B_Cycle
Member
You have to determine the spring before changing to any cam. Without good on seat valve spring pressure you run the risk of the valves hitting each other or the piston. Low valve spring pressure will result in the valve bouncing when it hits the seat & the roller not staying in contact with the camshaft as the rpm of the camshaft increases. The more aggressive the cam lobe design the more power and torque the engine will make without changing the static compression ratio at all. Cams help make cylinder pressure through their opening and closing timing designed into the lobe. So you can make more compression just by changing the lobe design. The 520 lift stock cam in the 117 is not big enough to make good power in a 117 but is great for a stock "80 evo motor. We are not a big fan of high static compression ratios because when coupled to aggressive cam shafts you will most likely have to run race gas to stop the spark knock. So with all that being said the 117 needs a large cam to make good power because it's such a large engine and large cams require good valve springs to control the valve as it travels through it's opening and closings to and from full lift. So the first thing you want to do is put in the camshaft and valve springs the motor likes and then you can go through the carb and exhaust pipe combos that have alot to do with the way the bike looks until you find an arrangement that you are happy with.
jwoolf
Well-Known Member
I know cam shafts can be a big technical discussion with lift, overlap, duration. What RPMs are you trying to affect? etc. etc. etc.
Are you having good results with your 656 cams in otherwise stock motors ( heads wise... I mean with a stock heads set up ) by just changing the cam and springs?
Again, I'm just looking for the low fruit right now. I don't want to shave the jugs and heads ( yet ). I'm just looking for a fairly aggressive cam that I can use now until the time I decide to do a top end on this bike.
Are you having good results with your 656 cams in otherwise stock motors ( heads wise... I mean with a stock heads set up ) by just changing the cam and springs?
Again, I'm just looking for the low fruit right now. I don't want to shave the jugs and heads ( yet ). I'm just looking for a fairly aggressive cam that I can use now until the time I decide to do a top end on this bike.
pink chopper
Member
On the 05 you HAVE to change the springs to change the cam...that year had smaller springs....If you use the 640 springs you'll be okay(they have an orangish/red strip on them to distinguish)...
I used to do this combination and got between 120-130 HP...
1. 600 cam
2. 640 springs
3. cut the cylinders back to the correct height...
4. port but not polish the heads-they have a sand finish which atomizes the fuel better
5. bigger valves
6.shave the heads
The machinist that I have used for 30 years used to be a top fuel HD racer so he's real familar with getting big power out of tried and true combinations...
this isn't too much of a radical change but does give you significant more power for the buck...
His price for the whole job is 879.00 and that includes springs...
Just to give you an idea of what combinations I've used before...
If you ask Jim on the forum about his bike...I did the motor work on his and he LOVES it...course it all depends on carb/pipes/ac etc...but this will be a noticeable difference and it's still street rideable..
Just my 2 cents...
I used to do this combination and got between 120-130 HP...
1. 600 cam
2. 640 springs
3. cut the cylinders back to the correct height...
4. port but not polish the heads-they have a sand finish which atomizes the fuel better
5. bigger valves
6.shave the heads
The machinist that I have used for 30 years used to be a top fuel HD racer so he's real familar with getting big power out of tried and true combinations...
this isn't too much of a radical change but does give you significant more power for the buck...
His price for the whole job is 879.00 and that includes springs...
Just to give you an idea of what combinations I've used before...
If you ask Jim on the forum about his bike...I did the motor work on his and he LOVES it...course it all depends on carb/pipes/ac etc...but this will be a noticeable difference and it's still street rideable..
Just my 2 cents...