top end swap

[rinferno]

Does anyone know if you can swap 32cc thru 36cc top end and piston with 30mm crank? Refering to Rovan engine or has anyone tried different combinations.

 

[Seandonato73]

@Polar_Bus may know, he has had a few apart I think.

 

[Polar_Bus]

Sorry for chiming in so late to this thread but i'm actually down and recovering from a recent hip replacement surgery. Anyway back on topic looks like the 23cc - 32cc CY's all use the most common 28mm stroke crank. Starting with the CY 34cc the stroke is 30mm. **note that the 34cc family of engine uses a different crankcase configuration from the 23cc-32cc family and are not comparable with "some" types of internal parts). The 45cc engine uses a 31mm stroke. Dam, it's a ROYAL PIA to successfully categorize and research CY engine specifications, but I think I finally got it :

23cc = 32mm x 28mm ( Bore x Stroke)
26cc = 34mm x 28mm
27cc = 35mm x 28mm
29cc = 36mm x 28mm
30.5cc = 36mm x 30mm
32cc= 38mm x 28mm
34cc= 38mm x 30mm
36cc = 39mm x 30mm
42cc = 40mm x 33mm
45cc = 43mm x 31mm
46cc = 42mm x 33mm

**Guys keep in mind the mfg's play games with "advertised" engine CC vs actual. A perfect example is the Zen GR270RC engine. The engine description suggest it's a 27cc engine yet per the specs it's actually a 25.4cc displacement , so good luck with understanding that aspect. The GR260RC engine IS in fact the same 25.4cc displacement engine. So always measure your bore and stroke and caculate your final displacement. It can get REAL confusing ! Lastly, if I have an incorrect spec by all means correct me and lets all get this right for future quick reference. Hope this helps.

 

[Thrasher]

The engine description suggest it's a 27cc engine yet per the specs it's actually a 25.4cc displacement , so good luck with understanding that aspect. The GR260RC engine IS in fact the same 25.4cc displacement engine.

Isnt this illegal? I am pretty certain that if our socialist overlords knew about this they would crawl up Zenoah's ass and lay eggs for 'mislabelling'. The EU is pretty fuzzy about this so how do they get to do this and get away with it? Is it the same as "HP" where everybody and their dog has their own way and place on the drivetrain on which to measure?

 

[Polar_Bus]

Isnt this illegal? I am pretty certain that if our socialist overlords knew about this they would crawl up Zenoah's ass and lay eggs for 'mislabelling'. The EU is pretty fuzzy about this so how do they get to do this and get away with it? Is it the same as "HP" where everybody and their dog has their own way and place on the drivetrain on which to measure?

You may , or may not be correct. I honestly don't have an answer. One could argue that the advertised engine "model designation" is simply "numbers and letters" and have NO direct correlation to the actual engine displacement.

 

[Thrasher]

And someone would be willing to buy that argument because in this case its as clear cut as can be. However, it doesn't feel that fulfilling to just let it hang there. There must be some reason as to why its not mislabeling. At any rate. Thank you for being a towering light of solid technical information and knowhow in our little social swamp of entertainment and nonsense.

 

[John Parks]

Most vehicles, and off road vehicles like ATV and dirt bikes do the same. Not a big deal in my book, 1.6cc or 30-40cc on a larger atv isn't a big deal. It's the "norm" and has been for many years.

 

[Thrasher]

Since nobody is complaining, there probably isnt an issue but what gives? Do you know? You know how fierce the EU is about mislabelling anything.

 

[Striikar]

They call it "Rounding".
Whatever makes the consumer think their getting "More" for their money.
It's the same with hard drives - 1000 vs1024 been fighting that battle forever.

 

[Seandonato73]

This has been normal in any small engine since their inception. Many small engine manufacturers label a engine under 3 or 4 different hp configurations with the same displacement, hell I've seen 46 cc engines called 50cc engines. Really ita more about the power it puts out then just displacement. don't matter what it is, you pay for more power.

 

[Polar_Bus]

*post deleted, incorrect info.

 

[mark35]

Note that both the 29cc and the 30.5cc both have the same bore and stroke ? So clearly it's a "advantage marketing game" for the advantage going to the 30.5cc . It's a mental thing "more cc's must = more hp" .

Same 36mm bore but the 30.5 uses a +2 stroke crank ??

 

[evssv]

..same crank i fitted to my zen29....?...so now i have a zen 30.5?

 

[Polar_Bus]

Same 36mm bore but the 30.5 uses a +2 stroke crank ??

Ok, so the 30.5 uses a 30mm stroke, not a 28mm ? Then i need to correct my specs. Let me know. Thanks

 

[mark35]

Ok, so the 30.5 uses a 30mm stroke, not a 28mm ? Then i need to correct my specs. Let me know. Thanks

Correct ??

 

[buzzkill]

really want to know the ACTUAL displacement ?? DO a liquid displacement test , this accounts for squish etc.

 

[Z.hb71]

really want to know the ACTUAL displacement ?? DO a liquid displacement test , this accounts for squish etc.

Bud this thread is almost a year old a completely dead ?‍?

 

[buzzkill]

Bud this thread is almost a year old a completely dead ?‍?

Not anymore !!!

 

[Z.hb71]

Like ur attitude ??

 

[mark35]

Since this thread has been resurrected the g240 and g270 are 4 bolt versions of the 2 bolt g230 and g270 respectively ?.
Put that in ya pipe n smoke it???