More work on the rovan 45cc

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Teejay112

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Decided to widen the exhaust port 3mm on each side and ramp the piston and slightly raise the intake side of the piston skirt then painted the crankcase took it out for a test and tune this thing is a real beast even tho I didnt put the new piston ring in yet cant wait to get it out in the summer and race some of the more expensive engines .also need to switch back to pump fuel been running aspen2 at 25/1 because it burns clean no carbon build up


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Teejay112

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Sooo ur not selling it now:unsure:..........nice work btw(y)
Thanks Unsure I know if I sell it I'll want another one by summer and I wont wont to fork out for a other mcd so I'll probably keep it

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Z.hb71

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Decided to widen the exhaust port 3mm on each side and ramp the piston and slightly raise the intake side of the piston skirt then painted the crankcase took it out for a test and tune this thing is a real beast even tho I didnt put the new piston ring in yet cant wait to get it out in the summer and race some of the more expensive engines .also need to switch back to pump fuel been running aspen2 at 25/1 because it burns clean no carbon build up


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Nice 👍 why don't u try to run 28:1 or 32:1 ? I think that would make it alittle faster
 
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Teejay112

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Nice why don't u try to run 28:1 or 32:1 ? I think that would make it alittle faster
I've never been that lean before I'll probably stick to 25:1 so I don't wear out the ring and so the engine doesn't run too hot I think I got 1 spare complete bottom end with bearings seals and piston with a ring but Its plenty fast for me don't want to be doing anymore work anytime soon

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Teejay112

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Looking good, just needs alittle cleaning, but then again u actually run urs
Lol thanks funny thing is was cleaned a couple days ago stripped down scrubbed with washing up liquid and a toothbrush then put together looked new I took it out for 20 minutes on tarmac and its dirty again I give up on cleaning it lol

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Teejay112

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Nice work! Hope it runs well.
Running less oil doesn't lean the mix out of riches it slightly. The oil molecules are larger than the gas molecules so less oil = more gas and vice versa.
I know but I want to keep the engine as lubricated and cool as possible I might try 28:1 when I switch back to regular petrol at the moment I'm using swedish odourless fuel leaves no carbon or anything but Its at 25:1

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1Coopgt

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Nice work! Hope it runs well.
Running less oil doesn't lean the mix out of riches it slightly. The oil molecules are larger than the gas molecules so less oil = more gas and vice versa.
The thing to remember is the oil helps with sealing the ring to the cylinder walls when running . If you go to lean on the oil ratio it has a negative effect on how the engine runs. You actually start to loose power because you're loosing compression.

I have a feeling Rovan recommends 25:1 probably because the tolerances on their engines aren't super tight . Where as OBR recommends 28:1 due to tighter tolerances in there engines.

Now why my Leaf blower uses 50:1 I have no clue . It's probably a disposable engine.
 

Z.hb71

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The thing to remember is the oil helps with sealing the ring to the cylinder walls when running . If you go to lean on the oil ratio it has a negative effect on how the engine runs. You actually start to loose power because you're loosing compression.

I have a feeling Rovan recommends 25:1 probably because the tolerances on their engines aren't super tight . Where as OBR recommends 28:1 due to tighter tolerances in there engines.

Now why my Leaf blower uses 50:1 I have no clue . It's probably a disposable engine.
True, maybe b cuz your Leaf blower revs wayyy lower so it might not matter ?
 

Seandonato73

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Coop were talking about around a 2% decrease on oil here. I have high compression heavily ported chain saws that live for years and years on 40 to1. I depend on them to keep my house heated. And if you look at any consumer product (from pro to homeowner) specs a 50 to 1 ratio. Most also spec full synthetic oil. I digress we've had this discussion already. I just wanted to point out changing the oil ratio also changes the fuel ratio as well..... sorry for the rant
 

bigdipperfred

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It will run hotter with more oil .but will make more power .I know people with high performance two strokes run 18. To1 ratio you have to really get your jetting right. I run 28 1 in temperature above 75 degrees 25 1 below maybe that's just me.
 
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Teejay112

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It will run hotter with more oil .but will make more power .I know people with high performance two strokes run 18. To1 ratio you have to really get your jetting right. I run 28 1 in temperature above 75 degrees 25 1 below maybe that's just me.
I find I'm able to tune mine for higher speeds the more oil I use also and feel safe about it

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Teejay112

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So last night I did some work on my electrics put a new led on my switchblade new switch and this morning i got my ddm dominator and fitted it after spending hours grinding the exhaust header revs are snappy and idle sou d great just need to test it out just waiting on the new spark plug cap now as this one shocked me because it's got a small hole in it


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Z.hb71

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So last night I did some work on my electrics put a new led on my switchblade new switch and this morning i got my ddm dominator and fitted it after spending hours grinding the exhaust header revs are snappy and idle sou d great just need to test it out just waiting on the new spark plug cap now as this one shocked me because it's got a small hole in it


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Looks good. What pipe is that ?
 
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