RadialFin's AKRA Build up Thread

R

RadialFin

Member
Looking to take my "out of the box" clone to the next level now that I have some laps on it.

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I've been keeping peak RPMs around 5600RPM and it seems to run out of puff there. Don't think it would pull anymore than 5800 anyway. All that has been done so far is a degovern, set lash to .003", drilled the main out to 035 and pilot to 021 and installed an NGK B7ES plug.

So, what changes do you think you would make next? Keep in mind this has a stock flywheel (Yikes!)
Weenie pipe broke yesterday, so I guess I can go change that now..
What about springs? Trick rings?
Not looking to spend megabucks just interested in seeing how I close to ballpark I can get this thing by myself, incrementally.

I'll be sprint racing this on asphalt and I guess I need to get it as close to a LO206 as I can. Driven back to back I would say the 206 has about 1.5s (on a one minute lap) over my clone in it's current state.
 
Big exhaust pipe, replace springs, ARC billet flywheel, Holy Moses carb from Dover Power, CL-1i or CL-2 cam, lap or change valves.
 
Can I run the "big" pipe with AKRA rules? I've heard good things about the dover carbs so that's on the list. I'd like to do things incrementally for my wallet but also to compare things...
Any specific recommendations for the springs, seems to be a lot of choices.
 
if you can, get the bigger pipe! get a better flowing carb like the one from ARC or a Dover Power Holy Moses. cut the gaskets to match the intake and carb ports. cheap way to clean up the flow a little. if you can, get stiffer springs (maybe in the 20 lb range) anything other than the 10.8 or stock! this will give you a little help in the rpm range. take the head and clean it up (if you haven't already)....smooth out all the rough edges and do a little cleaning in the combustion chamber area. anything that you feel is rough or kinda sharp needs to be smooth....the idea is to flow the air/fuel misture better into the combustion chamber. i would go ahead and lap the valves. some say it's not necessary, but it just helps to make a positive seal and oly takes a few minutes. definitely look at the billet flywheel...if nothing else, for safety. if you can get a higher lift cam without going against the rules, a black mamba or a f275 would wake the motor up a lot!! and if your going to do the mod's that you'd like to get more power out of the motor....then you're gonna have to get off the duckies and buy a billet rod....

jsut my thoughts!!! :D
 
mikey56 said:
jsut my thoughts!!! :D
Click to expand...

...and I appreciate them....But, can I clean up the head and so on for a AKRA Stock motor? Not looking to get big power in terms of modding it. , just make it competitive for a BSP type class. Blueprinting I guess? For power I have some smelly two smokers from 100-250cc

I'll lap the valves, maybe do a leakdown beforehand out of morbid curiosity so see how they are sealing after 100 miles without being touched....
 
i guess it depends on what akra calls porting and polishing....to me, cleaning the head isn't the same....then again, they are probably trying to prevent folks from hogging the head out. shaving the head, cleaning it up, different cam, better rod, shaving a lilttle off the top of a dished piston....all of it is going to make a difference in the way the motor runs.....now whether it's legal to do it or not depends on them rules!!
 
I do believe any evidence of work in the ports or combustion chamber should get you tossed according to AKRA rules.
 
LO206 has a better cam and 6100rpm rev limit, they are faster on our sprint track too, compared to a legal AKRA ish clone.
If you are staying AKRA Legal, trick springs, aluminum flywheel maybe, and a holy moses carb will get you close.
Where do you notice the LO206 pulls you?
 
Everywhere, bottom mid and more overrev but thats to be expected considering next to zero has been done to the clone. But looking at my data I think there's 14 teeth on my driver, not the 15 like the P/O wrote on it. So that's and embarrassing, rookie mistake but good at the same time. My top speed is around 70KPH at 5700 which equates to 14:60 gearing. I think my low RPM is about 3400. What sucks is that the track is probably done for the year now...
To be honest I was expecting it to be so slow that I never questioned it haha.
 
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