Non-standard jug and head?

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#1
Anyone know of a good jug and cylinder to use in a 40mm stroke engine? I know people use the puch head but is there a jug with proper porting out of the box?
 


Street Ryderz

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#2
Anyone know of a good jug and cylinder to use in a 40mm stroke engine? I know people use the puch head but is there a jug with proper porting out of the box?
All the cylinder's available will need the ports cleaned up and the area's made to suit your needs.The timming's of ports are good to turn 12k no problem,though most will never see that due to being way under carbed.
 
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#4
All the cylinder's available will need the ports cleaned up and the area's made to suit your needs.The timming's of ports are good to turn 12k no problem,though most will never see that due to being way under carbed.
What would you recommend? Anything specific to look for? Most people on the forums just stick to a stock jug. Specific heads to try?
 
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#6
Vm22 is what they use for the predator 212cc 4 strokes. I would think it would be too rich on a motorized bike engine. I have a vm18 attached to a reed valve and a 48mm jug just haven’t run it yet
63CEA0E5-FE3E-4305-AE88-39C11A0A22CB.jpeg
 
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#7
Vm22 is what they use for the predator 212cc 4 strokes. I would think it would be too rich on a motorized bike engine. I have a vm18 attached to a reed valve and a 48mm jug just haven’t run it yet View attachment 84236
4 strokes take half the fuel so treat it as 100cc 2 stroke and also don't forget 2 strokes rev higher than 212cc 4 strokes. Try it out. If it acts up in the really high revs, go bigger. If you don't rev over 7000, you should be good. Also, I'm running a six petal DIO Reed while you are running a 4 petal. It will limit how high up you can go before the petals can't keep up but I don't know how high the limit is. I need a powerful screamer for higher top speed and a very low gear ratio because of hills around here.
 

Street Ryderz

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#9
What would you recommend? Anything specific to look for? Most people on the forums just stick to a stock jug. Specific heads to try?
1541043468731.png

If dio reed is the way you want to go this one has 3 bores to chose from and is pretty much bolt on.
1541043803681.png

This cylinder is nikisil treated not Chinese chromed and should have a good life span.Then there is the MXS cylinder from vertical minarelli engines also nikisil but requires some machine work to the case and a spacer used at the base.
1541044495648.png
 

Street Ryderz

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#10
Vm22 is what they use for the predator 212cc 4 strokes. I would think it would be too rich on a motorized bike engine. I have a vm18 attached to a reed valve and a 48mm jug just haven’t run it yet View attachment 84236
The vm 18 is ok on the oz reed but a 21 is much better suited.I run a 24mm carb p/p and it's about matching up to your port area's to keep everything flowing correctly.
 

Street Ryderz

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#11
Also, I see you have a banana pipe. Sell it or scrap it and get a tuned pipe.
The banna pipes are crap mostly just a slight improvement if any.A larger chamber with steeper baffle angles gives a more noticable hit at the start of power band though it typical to a dirt bike sharp but shallow,it falls off hard too.
 
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#12
View attachment 84239
If dio reed is the way you want to go this one has 3 bores to chose from and is pretty much bolt on.
View attachment 84240
This cylinder is nikisil treated not Chinese chromed and should have a good life span.Then there is the MXS cylinder from vertical minarelli engines also nikisil but requires some machine work to the case and a spacer used at the base.
View attachment 84241
The first option from falcon 911 is $520. Might as well buy the engine for $200 more.

The second option doesn't look awful at $200 ish but what needs to be done to the case? Widen the hole? Transfer ports not aligned?
 

Street Ryderz

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#13
The first option from falcon 911 is $520. Might as well buy the engine for $200 more.

The second option doesn't look awful at $200 ish but what needs to be done to the case? Widen the hole? Transfer ports not aligned?
The Falcon 911 dio cylinder is $200 U.S +$10 shipping in the U.S. right now and the MXS is closer to $300 but comes with the head,it needs the hole opened yes the transfers cut,and I'd do some stuffing but up to you!
 

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#14
The Falcon 911 dio cylinder is $200 U.S +$10 shipping in the U.S. right now and the MXS is closer to $300 but comes with the head,it needs the hole opened yes the transfers cut,and I'd do some stuffing but up to you!
Could you show me where you are getting $200? That's not bad at all for it being nearly bolt on. Because right now, the website I saw is cylinder and head = $520
 
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#17
Just out of curiosity, I see he raised the intake port to create a boost port. Has anyone else tried this on the Chinese jugs with a reed valve? You would think it wouldn't hurt if the piston window closes off the crankcase before transfers open which seals some crankcase compressed mix in between the reed and piston which would release once the piston goes down far enough to uncover the boost port and thus releasing this pressure. Since I changed my timing back to stock, I got my power back so I want to experiment on the stock garbage I got until she seizes or loses compression. I still have alot to learn. My jetting that was running perfect yesterday is too lean now that it is raining (plus surging possibly due to foaming and oil not mixed extremely well). What I thought was bad compression turned out being awfully advanced timing.
 

Street Ryderz

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#18
Just out of curiosity, I see he raised the intake port to create a boost port. Has anyone else tried this on the Chinese jugs with a reed valve? You would think it wouldn't hurt if the piston window closes off the crankcase before transfers open which seals some crankcase compressed mix in between the reed and piston which would release once the piston goes down far enough to uncover the boost port and thus releasing this pressure. Since I changed my timing back to stock, I got my power back so I want to experiment on the stock garbage I got until she seizes or loses compression. I still have alot to learn. My jetting that was running perfect yesterday is too lean now that it is raining (plus surging possibly due to foaming and oil not mixed extremely well). What I thought was bad compression turned out being awfully advanced timing.
Alot of people do the boost port above the intake thing,but is it really? does it do anything down low? Again if you think about whats going on, this booster opens after the transfers and the pressure is allready blead off and trailing the exhaust pulse.That means that this port allows more area for scavaging and thus deffinatly requires a tunned pipe to put it back and be of any affect as it doesn't really have any thing to do with initail charge introduced to the case.
 
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#19
Alot of people do the boost port above the intake thing,but is it really? does it do anything down low? Again if you think about whats going on, this booster opens after the transfers and the pressure is allready blead off and trailing the exhaust pulse.That means that this port allows more area for scavaging and thus deffinatly requires a tunned pipe to put it back and be of any affect as it doesn't really have any thing to do with initail charge introduced to the case.
My theory is the crank case pressurizes everything in the crank case to the Reeds. Once the window on the piston (if low enough) is closed there is still pressurized mix between the Reed and the piston. This extra "charge" could be utilized by venting it off via a raised intake port/boost port. This not only means potentially more charge, it also means less charge stuck in the crank case and after the Reed's so in theory more power and possibly better scavenging. Now if the window doesnt close before transfer open, the pressure would vent as you said.

Now that I say all of this, I really wonder if it makes a difference....

But then crank case pressure would be higher because it would no longer be vented by the piston window but it also means there would be vacuum as the piston rises. Doesn't mean the Reed is useless... but wouldn't this reduce the length of the intake stroke?

My God... People weren't kidding when people with 4 stroke backgrounds will be lost at how 2 strokes work
 

Street Ryderz

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#20
Yes intake vacuum duration would be less,and the window cant close because of the boost port being open,and beause the piston is windowed there is no charge trapped between the reed and piston.From bdc as the piston is going up above it is positive pressure that works as a blocker to the open ports until their closed that allows vacuum to be made below the piston before the ports are actually closed through to tdc as the piston starts it down stroke again a positive pressure is made below the piston that closes the reed and pushes the freshly acquired charge up the transfers building pressure until they open as they open the pressure is realeased and the so called boost port opens but now with no pressure behind it as the fresh charge has allready shot into the cylinder via the transfers,so this means that it's only real purpose would be to aid in scavenging where if the velocity of the tail end of exhaust was able to pull open the reed.Witch IMO just makes it more likely to flutter.
 

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