Dyno Results

[slickta]

We dynoed the 520 yesterday. It made 55 rear wheel horsepower and 35 lb/ft of torque. We made 5 pulls with it and every pull the horsepower increased. What I am trying to figure out is the graph. The bike made max power at 8500 rpm and went into a sharp decline after that all the way to the 10500 rev limiter. The A/F ratio stayed good across at wide open. What could be causing this drop and low rpm power max? I am wondering if the carb is not big enough or if the port job is not enough? This was done on an air brake dyno. What would you recommend to remedy this problem? I am very unhappy with it at this point and know there is much more potential.

Falicon billet stroker crank
athena big bore cylinder
JE 12.5:1 piston
cylinder is zero decked
ported head
+1 intake and exhaust valves
Web Mysto cam
Kibblewhite springs guides and valves
LRD Pro 4 exhaust
Magnum cdi
Edelbrock 40mm carb
custom air intake (no air box)
K&N filter

[chad502ex]

i'd have to say that the cam should be twisted back a bit retarded cam timing. that's good power though. If you can push the curve 1000 rpm higher by retarding your timing you could probally make a bit more near limit.

got a picture to show of the plot?

[slickta]

There printer was broke and we tried to burn it to a cd and the burner would not recognize the file. We tried changing the file extension, but still wouldn't work. We did it at the TT nationals over the weekend. We degreed the cam in straight up. Thanks for the reply.

[370kingR]

Originally posted by slickta
We dynoed the 520 yesterday. It made 55 rear wheel horsepower and 35 lb/ft of torque. We made 5 pulls with it and every pull the horsepower increased. What I am trying to figure out is the graph. The bike made max power at 8500 rpm and went into a sharp decline after that all the way to the 10500 rev limiter. The A/F ratio stayed good across at wide open. What could be causing this drop and low rpm power max? I am wondering if the carb is not big enough or if the port job is not enough? This was done on an air brake dyno. What would you recommend to remedy this problem? I am very unhappy with it at this point and know there is much more potential.

Falicon billet stroker crank
athena big bore cylinder
JE 12.5:1 piston
cylinder is zero decked
ported head
+1 intake and exhaust valves
Web Mysto cam
Kibblewhite springs guides and valves
LRD Pro 4 exhaust
Magnum cdi
Edelbrock 40mm carb
custom air intake (no air box)
K&N filter

For a stroker motor i think its way down on torque when comparing to a bore only 520 that i ran which had 38 ft lbs or torque. 3 ft lbs is alot. The 520 had about the same horse @ 55 though. I just think the stroker would do better in the torque department. Oh and those numbers im speaking of were with the HRC cam, and not the Mysto.

Thats a big cam, make sure you dont do too much tweaking without clay checking. You never know, if worse comes to worse id stick an HRC cam in there and see whats doing. Its not the limiting factor in making more power in these motors, its actually a very good cam. Bolt in none the less.....



Im thinking get rid of that CDI you have and put on a dyna and try a different pipe like the Rossier (mayby someone you know can lend you the pipe).

Im not sure what that Edlebrock carb is doing for you too. Not saying its hurting or helping, i just dont know anything about it but its obviously 2mm smaller than stock. It may flow as much as stock because of the butterfly but no one i know has really tested them or even run them. I think the stock carb is pretty decent myself.

Dan Lamey is a porting wizard, i bet he could scratch out some more ponies in that head if theres room. I was extremly impressed with his port work on my engine.

All more $$$. Expensive hobby isnt it?

[slickta]

I am wanting to put a 43 FCR and the crf igntion in it. The head is not ported very much, mainly around the guides. The edelbrock made a difference when the motor was basically stock, but now I don't believe it's the best choice for the application. I was thinkin the same thing about the cam. It is a big cam. The motor has .100 on the exhaust and .080 on the intake for valve clearance. The motor already has alot of money in it, so might as well go on and spend the money to make it right.

[370kingR]

Originally posted by slickta
I am wanting to put a 43 FCR and the crf igntion in it. The head is not ported very much, mainly around the guides. The edelbrock made a difference when the motor was basically stock, but now I don't believe it's the best choice for the application. I was thinkin the same thing about the cam. It is a big cam. The motor has .100 on the exhaust and .080 on the intake for valve clearance. The motor already has alot of money in it, so might as well go on and spend the money to make it right.


I think the CRF ignition out weighs the FCR IMO after now having owned both. The CRF ignition just feels great.

I think you have PLENTY off room to up those numbers. I wouldnt be surprised to see it get to 39 or so ft lbs or torque with the right combination of things. 58 horse or so i believe is achievable no doubt.

This is when it becomes $300 a horse power. The first dozen ponies are rather cheep comparativley :devil:

[BSTURDIVANT]

The stock carb will make more than the Edelbrock! Definately dump the CDi and go with a Dyna.

Get FCR that is bored to 43mm and install a Dyna box should give you 3 or 4 on torque and HP. Retard the cam 4 degrees and it will move your curve up about 800 RPM's

[slickta]

Thanks for the reply. I am now figuring out where I want to get the carb from. I have talked to Mark Baldwin and would like to talk to Dan Lamey now. I really need to get my rpm all the way up to the rev limiter. We run tt on a big track and need the rpms. We were running the same gears over the weekend, but would not run all the way to the rev limiter. I could change the gear but I know something is not right and that would just be masking the problem. The head is coming back off this weekend. I guess that wasn't bad considering we built the entire engine in 10 hours so we could get it running for the nationals.

[370kingR]

Definetly talk to Dan Lamey of Dasa for the carb. He is soooooooooooo much cheaper than where i bought mine from (pinit motorsports) and got robbed blind. Good price and excellent work from Dan. I see the dyna on Ebay offered @ 339.00, thats a pretty darn good price if your interested.

[R3Concepts]

You'll be 10 times happier with the CRF igntion and it'll rev to the moon.