building a raptor 3/ 5hp l/C

70stage1

70stage1

Member
hi, i have decided to dig down the rabbit hole of building a raptor 3/ l/C engine

what cam should i use? my parts list is as follows
dyno cams 00-6 maybe a 7x dyno cam
0.27' copper head gasket
arc 6160 dual valve spring kit
arc 6620 billet flywheel
arc 6350 stock replacement rod (3.875")
3DME manuel clutch

is the 7x cam better suited?
im just building a trail engine to withstand the abuse

IF YOU HAVE A RAPTOR 3 ENGINE FOR SALE NEAR MASSACHUSETTS LET ME KNOW
 
89-7 exp or cs2 with 2 new briggs exhaust spring or 2 dyon cams 1 .400 springs
the others will break the lifter bores .
 
what do you want to do with the engine? WKA stock flathead? Limited modified, open, or is this for a minibike
96-3 is best stock cam, 126 or Bud Wilson grinds are best modified/open
raptor 4 is best block
 
Send one of those cams back to DynoCams and have it reground for 107SS or 110SS. Get some heavy single springs and a billet rod. Bump the timing up to 32*, use good oil and go have fun.
 
The 7x is a more aggressive stock cam and it calls for 18-22 lb springs, not the dual springs that you're looking at. I've run several motors with the 7x and it's a good cam. I've experimented with the 043-073, it's also a more aggressive stock class cam that I thought worked well. 96-3 is a very good choice, and Dyno has a pretty wide selection of different grinds.
Dual springs are used with modified cams with more than stock lift. While on the subject of cams, chamfer and weld the lifter bores, use the hardened retainers and lifters. With the thinner copper head gasket, you'll have to watch out for the valves kissing the head, I had one motor that broke a couple of retainers because of that. What carb and type of fuel do you plan on using?
 
All of the cams mentioned with the exception of the 107ss and 110ss are stock “slapper” cams designed to exceed the max lift with controlled valve float, which I don’t think would suit his application, the 107 is a great cam and can be started will the pull rope. See if you can locate on of those cams or call Dyno cams. No need for dual springs and Do away with the copper head gasket unless you have good milling machine capability’s
 
As much as I love the flathead - it doesn't make a good candidate for trail riding on mini-bikes. With the stock carb and tank, you're risking breaking the carb. Before I worried about cam choice, I'd dump the stock carb and tank and replace it with something that can breathe AND live a lot longer on bumpy trail riding. The animal carb or a small slide carb would work so much better.
107-ss, 110-ss, 113-ss, 94-ss - all better choices than WKA stock for your application.
You won't need the billet flywheel as long as you are under 8000 rpm or so. It wouldn't hurt though and obviously is safer.
I agree that you do not want the thinner copper head gasket -- you're not increasing the compression enough to merit its use and sealing should always be a priority.



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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
www.youtube.com
34 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
I assume gas would make a difference with the reduced ignition timing .
I did have one engine with the 110 darg cam that pull started pretty easy .
107 ss if the ignition timing was not too high would be good .
 
a stock cam with a different carb ( mikuni or walbro slide type ) might provide the needed power increase .
 
it should be said for the money you could buy a tillotson or a ducar motor and save a ton of money. 212 or wildcat 223 will set you back 200-250 and makes more power than a WKA built flathead. your gonna pay 200+ for flat head that will need work and $$$. a stock cam for a Ducar 212 is $50 and it comes with an Al flywheel as much as I love a flathead they are money pits. and parts don't come easy or cheap. they are working on a Limited modified clone because they see the writing on the wall. limited classes are WAY down from what they used to be.
 
hi all, thank you ALL for reaching out
one, its for trail riding, i love the flatheads and i have many NOS parts i just wanted to use
i had an old stock 5 horse block that was bored out by some kid (poorly)
i have a ajustable ARC flywheel
billet stock replacement rod
new NOS valves
a 112 ALT cam from dyno
a dual valve spring kit, but im just running the outer springs
and a burris 0.10 over piston

all parts i wanted to use and get rid of and use
 
^ Depends how busy they are at the time a cam is ordered.
If you need anything for your project, keep us in mind.
We still work on these engines all the time here in the shop and we still love them.

That 112-alt cam will need some extra machinework (clearancing done to the lifter bores, crankshaft, and cylinder head for valve reliefs.)
We'd be glad to help any way that we can. We also do align-boring and sleeving if that's what it takes to fix the previous work that was done.
And of course we have most anything in stock for these engines.
Give us a call at the shop if you are needing anything.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
www.youtube.com
34 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
That 112alt is a great cam, one of my favorites. Like Brian said, it will require a bit of work to get everything to clear. If you’re willing to ship the long block I’m sure someone can do the clearance work for you. I’d be willing to help. PM if you’re interested.
 
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