ARC Billet Rod for 196cc Clones

[Atvroles]

I haven't posted here alot and when I made this account I didn't know how forums worked Now I do(obviously).

I am wondering if anyone knows anything about ARC Billet Rods, I know there is the Stock length (3.303) then an extra .010(3.313) and an extra .020(3.323). I am wondering if any modifications need to be done to the valves or crankshaft with a 3.323 Rod? I am going want to put a different rod in(I am going to be removing the governor) and I was thinking it would be more useful to put a longer rod in rather then a stock length rod. I am probably going to be using this forum alot more since im getting back into the mini bikes again.

 

[jesse8931]

you need to use a flat top piston but thats it.

 

[Atvroles]

you need to use a flat top piston but thats it.

So This Piston would need to go with it:
DJ-2295 Honda Flat Top Piston; Std Stock GX200

 

[rmm727]

No. The .010 and .020 over rods are to be used in blocks where the piston sits below the top of the deck. Some of the Harbor Freight blue engines were like this. Using a longer rod would raise compression. You can use the Honda flattop piston with the std. length or .010" or .020" longer rods. The 3.707 rod is the true long rod and is for use with a Wiseco piston that you mill flush with the top of the deck.

 

[r_chez_08]

Use the long rods to get your deck height as close to level as possible (preferably a little in the hole than out IMO.
Then use gaskets to get .030 squish.
The flat top piston is NOT required, but improves compression.

 

[Dragbikemini]

So I would like to see this thread go somemore. Just picked up a Greyhound, I can pull the head see if the piston is down in the hole at TDC? Measure and see if I can use a .010 over or .020 over rod? If so I can still use flat top but no less than .030 head gasket?

 

[Dragbikemini]

Also I don't have a dial gauge and wouldn't know how to use one even if it fell from the sky and hit me on the head. Could I measure for fit this way? I would lay a straight edge across the deck and slip a .010 and .020 feeler in between the piston and the straight edge? That could tell me if my Greyhound is down in the hole.

 

[rmm727]

So I would like to see this thread go somemore. Just picked up a Greyhound, I can pull the head see if the piston is down in the hole at TDC? Measure and see if I can use a .010 over or .020 over rod? If so I can still use flat top but no less than .030 head gasket?

Yep, pretty much. I for get what the piston to valve clearance number should be but you could put some modeling clay on the piston and put the engine together with your head gasket of choice. Torque to spec and crank the engine over by hand. Tear it back down and check for interference.

 

[rmm727]

Also I don't have a dial gauge and wouldn't know how to use one even if it fell from the sky and hit me on the head. Could I measure for fit this way? I would lay a straight edge across the deck and slip a .010 and .020 feeler in between the piston and the straight edge? That could tell me if my Greyhound is down in the hole.

Seems like a good way for people who don't have an indicator. I use the depth gauge on a caliper but that is not the best way. Your way seems better.

 

[Dragbikemini]

In theory more cc would be added from a .010 and .020 over rod?

 

[JamnJM]

^^^ no, the crank still travels the same amount....just a little farther away for a better rod angle....and piston stays at TDC longer for a better burn.

 

[Dragbikemini]

^^^ no, the crank still travels the same amount....just a little farther away for a better rod angle....and piston stays at TDC longer for a better burn.

:thumbsup:

 

[65ShelbyClone]

All the longer rod will do it make the trapped volume above the piston at TDC smaller, thus increasing the compression. A +0.010 or +0.020" rod will improve the rod:stroke ratio, but not enough to make a measurable difference in how the engine runs. The bigger gain comes from increasing compression.

 

[N-gin]

Length of rod changes how long the piston will dwell at top or bottom dead center, and it changes how fast the piston accelerates at different points along its travel from top to bottom and back.
It effects cylinder fill as well during overlap.

In other words the connecting rod can change the profile of the cam.

 

[N-gin]

I will also add that longer dwell time will slow the intake charge causing less ram effect of the AF mix.
On the compression stroke the longer TDC dwell time could produce spark knock especially on air cooled engines.

 

[davidlamb78]

I have a blue 196cc greyhound with the 20 over rod. I am also running the flattop piston. It will fit. It will raise the compression. You may want to run a little higher octane gas with it. Some say it doesn't matter. I am also running a 14cc head with mine. What other mods have you done to the engine?