A question about power and reliability

[Papalala]

So I am really confused about their relationship. For example, a well assembled stock cylinder ported well with stock pistons will it be more reliable than say a 392 cc cylinders ported and assembled well? Or would they be the same. Like would it heat up quicker because of the extra power, or will it be the same? I ride for 40 minutes and more on a completely stock engine and I am fine. If i replace it with a ported 392 would that make me unable to ride for long periods of time?

 

 

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[ZillaFreak]

There are 3 parts to this. 

Money + Power + Tuning = Reliability.

If you put 100hp on stock parts, you wont be reliable.

If you put 100hp on good aftermarket parts, but can't tune, you wont be reliable.

You can easily run 100hp on a 392 top end for hours if you build it correctly. You will also need to tune it correctly. 

[Papalala]

There are 3 parts to this. 
Money + Power + Tuning = Reliability.
If you put 100hp on stock parts, you wont be reliable.
If you put 100hp on good aftermarket parts, but can't tune, you wont be reliable.
You can easily run 100hp on a 392 top end for hours if you build it correctly. You will also need to tune it correctly. 

I am thinking of running 392 CC ported cylinders with Wiseco pistons and a stock crankshaft from driveline with coolhead and 21 cc domes. Tuning shouldn’t be a problem for me. What do you say?


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[ZillaFreak]

8 minutes ago, Papalala said:

I am thinking of running 392 CC ported cylinders with Wiseco pistons and a stock crankshaft from driveline with coolhead and 21 cc domes. Tuning shouldn’t be a problem for me. What do you say?


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So 68mm driveline cylinders, ported by driveline with their wiseco pistons? My only thing would be the stock crank. Are you having the crank rebuilt? Make sure it is trued and welded and it should be ok.

Just don't skip over the clutch, make sure the transmission is good and the coolant system is working fine.

[Papalala]

So 68mm driveline cylinders, ported by driveline with their wiseco pistons? My only thing would be the stock crank. Are you having the crank rebuilt? Make sure it is trued and welded and it should be ok.
Just don't skip over the clutch, make sure the transmission is good and the coolant system is working fine.

My crank is junk currently and due to money purposes I am thinking of buying the stock crank from driveline as well. The clutch I will replace with also driveline STD heavy duty ones, coolant works perfectly currently and the transmission is fine. Would really love a shift star mod, but I am way too lazy to split cases haha.


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[ZillaFreak]

Don't need to split cases for shift star.

 

Also you will need to split for crank.

[Papalala]

Don't need to split cases for shift star.
 
Also you will need to split for crank.

Really? I read somewhere on the forums that you should just replace the shift star when you split cases. And oh yeah I completely forgot about that since I usually buy a top end without crank, been running this crank for years haha which is way it is currently junk. So, if I do buy I will probably purchase these items:
1-Driveline 392 cc cylinders ported
2-Wiseco Pistons
3- Coolhead with domes
4- Trued and Welded stock crankshaft
And yeah that looks about right.
Also for those that helped me buy my previous engine about 2 weeks ago and are wondering, I recieved the engine but still didnt assemble it. This engine is gonna be bought by me and 3 of my buddies for our banshee since not one of us alone can buy all this stuff currently.


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[RagunCajun]

I often think about ryan griff's old 10mil serval. That engine had hundreds of hard hours. Ran fine.

[ZillaFreak]

19 minutes ago, RagunCajun said:

I often think about ryan griff's old 10mil serval. That engine had hundreds of hard hours. Ran fine.

Perfect example. A well built, well tuned engine can run for a while.

[kawa110]

I have a very low hour stock stroke hot rods crank I’ll sell you.
I’ll even sell you brand new OEM outer crank bearings with it.

I also have Never ran new trinity stage IV head ready to run I’ll sell you.

Also have a modified shift star and shift shaft if your interested.

[2004LEBanshee]

My trail bike is a 10 cub on race gas. Didn't cut any corners on parts though. Billet crank welded. 

[BigRed350x]

I ran a 4mil dune ported stock cylinder with shearer pipes, high compression, 7 or 8 deg advanced timing, etc  for 3 or 4 years on methanol and beat on it almost every weekend all summer long, rode every chance I got after work and any time the temps were above about 45deg.  Beat on that bike a lot.  It ran awesome until I got a batch of bad methanol from a tank at the dunes I rode at the time and blew my top end.  The more power you make the harder it is on everything.  That's why the little 35hp stock bikes lasted for years and years...  Just take your time and build it properly and they will last for quite a while.

[ban421shee]

It's been my experience the shape of the exhaust port dictates the reliability of the engine. OEM cylinders with wide, square exhaust ports will catch the rings, A wide squared off exhaust port on a Cheetah Cub/DM will take out the intake bridge eventually. A cheap Chinese crank with the 29L rods have no reliability at all. It's best to use a builder, they will sell parts that are reliable and known to be good, along with port jobs that will last a lifetime.