I thought I would start my own thread. I stated building my first case inducted motor yesterday. I did some mill work on the intake and some porting. Today I ordered the reed valve from Rocksolid. I'm going to have a piston port with the third port above the intake port. This will eliminate having cutting the cutting the intake port down to the bottom of the cylinder. It should have more crankcase pressure that way.
Going case inducted too!!!
- Thread starter Ron344
- Start date
I don't understand, if you are going case inducted don't you have to cut into the crankcase? Curious what you are doing.
Cool.. I remember some of your past posts and those engine pics you posted. I'll be following along to see what you come up with as well. this should be interesting
Thanks Davezilla and Curt, I was going tell Davezilla that I was going to buy a Dax motor for this project but I had this one on another bike so I stated with it. For now I'm not going to spend a lot of money on this I just want to see how it works first. I will use mostly stock parts.
Last night I took the cases apart and milled the area where the reed valve will go. I also started trying figure away to fill some of area in the case to get more pressure today I hope to show that later today.
Davezilla I hope you get back to work on yours it sounds like a nice motor.
Last night I took the cases apart and milled the area where the reed valve will go. I also started trying figure away to fill some of area in the case to get more pressure today I hope to show that later today.
Davezilla I hope you get back to work on yours it sounds like a nice motor.
Interesting, I am going to be building a 31cc weedwhacker motor that already has case induction. But I'll need to replace the carb end which will increase the crankcase volume. I am curious to see the effects of messing with crankcase volume.
Are you leaving any of the original intake route intact?
Are you leaving any of the original intake route intact?
You almost can't get too much compression are too much crankcase pressure the less room in the crankcase the better. That way every time the piston comes down the more fuel will go into the transfer ports and boost port. This engine had about 160lbs. compression with a sock head but there was alot of work done to get that. The cylinder was decked and the head was milled down also remade squinch band. The only part of the original intake will be the boost port the rest is covered with the plate. When I took the bike to Bonneville a couple of years ago to ride in the pits it would go almost 40mph but in Colorado it only does about 35mph. The motor was very fast before these mods. The carb will go on the reed valve like an Arrow engine.
Sounds like you got a plan and those spacer cups you made look like they'll take up a lot of the dead space, just be sure to leave yourself enough clearance to compensate for heat expansion. About .020 away from the crank should be plenty, and if you can, clean and bead blast the surfaces before applying the Devcon so it'll have a really good grip on the metal. I've used the black devcon to fill small dents in aircraft wing and cowl leading edges and that stuff is a mother to try and sand, waers out the sandpaper almost instantly and ruined a vixen file I was going to use to shape it down but it cured on me too fast.... lesson learned. But garnet or bead blasting the surfaces right before mixing up a batch will ensure more than enough grip onto the metal even tho that stuff is near impossible to get off once it starts to set.
Yeah, I still got all my parts from my old engine that I took out to true the crank then decided to go case inducted, got the crank nice and true but that's about the time I realized this project was gonna take longer than expected and I bought a Dax bottom end and put my jug on it, After milling everything to fit the old bottom end the piston was sticking almost 1mm above the deck so I had to make a spacer at the base, then used different thickness copper gaskets at both the base and head to get a 0.75mm squish clearance. This also put my port timings about 12 degrees more duration and more advanced than I planned for but surprisingly the engine didn't lose nearly as much low end torque as I thought it would (I'm sure the 12.7:1 compression ratio helped some too), but I also added 4" to the belly of my pipe's expansion chamber which helped too. The end result was a nice smooth acceleration from a dead stop and a top speed just under 40mph with the 44 tooth rear sprocket. this is part of the reason I back burnered the case induction project back then... The temporary engine ran way better than expected.
I got all my old parts and different reed valves to experiment bagged up in my stock room here at the shop and got the old bottom end temporarily assembled since I've decided I want to weld the crank pin in place since it can be knocked out of true way too easily, then it'll be checked and trued one final time after welding and then off to balancing. Bought another jug and piston for this engine but need to buy another Fred head or get a Puch head... one of the good ones for sure.
I made a set of stuffing plates for the case that press fit in and then I drilled thru the case and the plates, tapped the plates for M5 screws, then drilled the holes in the case slightly oversized so the bolt threads won't interfear when they grab the plated from outside the case... just 3 extra screws is all that's seen outside the case on one side.
I'm still planning on cutting right behind the cylinder to put the reed valve, but I've been looking at under the engine as an option if there's enough room for the reed block and an offset carb, but I hadn't decided for sure I'll mount the reed block down there since it looks more conventional behind the jug and there's enough room for a good sized carb there too. For the intake port on the jug it's self I was thinking about melting some Alumaloy into the port to fill it and then brazing it into place from the outside or making a plug like Theon did on one of his builds... Undecided there too since brazing may heat it up too much and warp the bore.
Maybe I'll pull my parts out after hours or on the weekends to sort thru everything again and re start my project in the near future, but I'll keep tabs on yours for now... Excellent work so far.
Yeah, I still got all my parts from my old engine that I took out to true the crank then decided to go case inducted, got the crank nice and true but that's about the time I realized this project was gonna take longer than expected and I bought a Dax bottom end and put my jug on it, After milling everything to fit the old bottom end the piston was sticking almost 1mm above the deck so I had to make a spacer at the base, then used different thickness copper gaskets at both the base and head to get a 0.75mm squish clearance. This also put my port timings about 12 degrees more duration and more advanced than I planned for but surprisingly the engine didn't lose nearly as much low end torque as I thought it would (I'm sure the 12.7:1 compression ratio helped some too), but I also added 4" to the belly of my pipe's expansion chamber which helped too. The end result was a nice smooth acceleration from a dead stop and a top speed just under 40mph with the 44 tooth rear sprocket. this is part of the reason I back burnered the case induction project back then... The temporary engine ran way better than expected.
I got all my old parts and different reed valves to experiment bagged up in my stock room here at the shop and got the old bottom end temporarily assembled since I've decided I want to weld the crank pin in place since it can be knocked out of true way too easily, then it'll be checked and trued one final time after welding and then off to balancing. Bought another jug and piston for this engine but need to buy another Fred head or get a Puch head... one of the good ones for sure.
I made a set of stuffing plates for the case that press fit in and then I drilled thru the case and the plates, tapped the plates for M5 screws, then drilled the holes in the case slightly oversized so the bolt threads won't interfear when they grab the plated from outside the case... just 3 extra screws is all that's seen outside the case on one side.
I'm still planning on cutting right behind the cylinder to put the reed valve, but I've been looking at under the engine as an option if there's enough room for the reed block and an offset carb, but I hadn't decided for sure I'll mount the reed block down there since it looks more conventional behind the jug and there's enough room for a good sized carb there too. For the intake port on the jug it's self I was thinking about melting some Alumaloy into the port to fill it and then brazing it into place from the outside or making a plug like Theon did on one of his builds... Undecided there too since brazing may heat it up too much and warp the bore.
Maybe I'll pull my parts out after hours or on the weekends to sort thru everything again and re start my project in the near future, but I'll keep tabs on yours for now... Excellent work so far.
Great to see this subject come up again.
A thought in hindsight,
I have two Reed valved engines, the Mongoose, and Frank,
Frank is my favorite, not as fast as the Mongoose, but a nicer ride, and fast enough.
The Mongoose has a top speed that I'm scared to do!
Over 10 000 RPM on a 26" wheel and 36t sprocket is around 50MPH!
I guess what I'm getting at is, a well (boost) ported, reed valved CG motor with a decent pipe is enough power for me on a push bike.
And if you can find a good barrel with the wide inlet port, Drilling piston windows and using the existing inlet is a much easier way to go, giving very nice results, with pipe!
But, the Mongoose looks cool, is fast and was/is a fun project.
Looking forward to seeing your progress.
A thought in hindsight,
I have two Reed valved engines, the Mongoose, and Frank,
Frank is my favorite, not as fast as the Mongoose, but a nicer ride, and fast enough.
The Mongoose has a top speed that I'm scared to do!
Over 10 000 RPM on a 26" wheel and 36t sprocket is around 50MPH!
I guess what I'm getting at is, a well (boost) ported, reed valved CG motor with a decent pipe is enough power for me on a push bike.
And if you can find a good barrel with the wide inlet port, Drilling piston windows and using the existing inlet is a much easier way to go, giving very nice results, with pipe!
But, the Mongoose looks cool, is fast and was/is a fun project.
Looking forward to seeing your progress.
Davezille, I spent most of the day trying to get the clearance right on the cups I made but will need more time. 20 thousands sounds about right, But bought some davcon but it's not the two stage stuff. It is metal filler though, buy I'm not sure if it will work. Bead blasting is a good idea my son has a bead blaster I can use.
I hope you can stat work on yours soon Theon has replied to this thread and he is one of the experts in this area he has some real nice bikes.
I just wanted to say that I'm trying to make a bike that will go 50mph. I just want something that sounds really good and look different. I had a near fatal crash on my first bike going about 35mph. when the rear brake came off and went into the spokes. I didn't crash but came very close. It did scare me half to death. I will not be going that fast on a motorized bike anymore.
I hope you can stat work on yours soon Theon has replied to this thread and he is one of the experts in this area he has some real nice bikes.
I just wanted to say that I'm trying to make a bike that will go 50mph. I just want something that sounds really good and look different. I had a near fatal crash on my first bike going about 35mph. when the rear brake came off and went into the spokes. I didn't crash but came very close. It did scare me half to death. I will not be going that fast on a motorized bike anymore.
Theon I'm glad you replied to my thread I was wondering if you were still on the forum. I got a lot of ideas from you while you were building your bikes I've been wondering how they are doing? Your kind of the expert on reed motors. I think the boost port will work pretty good. I'm going to try my hydro-formed pipe I made it was on this motor before I took it apart. I'm going to put a bigger carb. on it but I don't know what size yet.
My friend thought that the port in the piston was a little big but I'm not sure. I will try it and see.
Hope your having lots of fun on your bikes.
My friend thought that the port in the piston was a little big but I'm not sure. I will try it and see.
Hope your having lots of fun on your bikes.
Cheers Ron,
I have been having a bit of a break from bike building, having more bikes than I can ride, lol.
So need to sell one, before I go 'invensting' anymore.
My Dual suspension bike is by far my favorite, The Soft tail next and the Mongoose is still awaiting a new top end I built for it, with a little less duration on the ports, for a 'smoother' power delivery.
I tried selling my 'Goat' localy, but the only interest I got was from a 120+ Kg(not pound,KG!) 14 year old, who I talked out of it. Dirt Bikes and Quads are easy to sell here, but I'm the only one I know with MB's, Been waiting for Xmas to be over before readvertizing, I figure there will be a few that lost there licence here over the season.
But, I'm due to pull the Mongoose down, so if you want any 'inspiration', I will post up some more pics when I do.
I have been having a bit of a break from bike building, having more bikes than I can ride, lol.
So need to sell one, before I go 'invensting' anymore.
My Dual suspension bike is by far my favorite, The Soft tail next and the Mongoose is still awaiting a new top end I built for it, with a little less duration on the ports, for a 'smoother' power delivery.
I tried selling my 'Goat' localy, but the only interest I got was from a 120+ Kg(not pound,KG!) 14 year old, who I talked out of it. Dirt Bikes and Quads are easy to sell here, but I'm the only one I know with MB's, Been waiting for Xmas to be over before readvertizing, I figure there will be a few that lost there licence here over the season.
But, I'm due to pull the Mongoose down, so if you want any 'inspiration', I will post up some more pics when I do.
I don't know about 'the expert',
But some of the more 'expert' don't seem to like to share too much.
But some of the more 'expert' don't seem to like to share too much.
I know exactly what you mean there Bro... There is good reason for the secrecy too, one of the biggest reasons is because they sell some really powerful engines and if they told everything they would lose out on sales because some of their customers would be capable of building their own at those power levels, but the other part of it is once they start divulging out too much info it gets into the wrong hands and next thing you know there's 8, 9, and 10hp engines all over ebay selling for next to nothing and that's what really hurts... All their R&D and time spent to make something really nice then others stealing the idea for profit... similar to what hpaaened to Fred wen he sold an order of heads to one of these vendors. Yeah, they sold most the heads they bought, but sent some to China and there's copies all over ebay and other places now.
Well, I got nothing to lose sharing my research and development, The time, skill and understanding to build a really fast motor is likely above the average builder anyway, but for those that do, I am happy to help in any way!, and if I can help lift others understanding and skills, I will.
Teaching/sharing is one of the most rewarding exchanges.
Even if all you get in return is the chance to learn from others and their appreciation.
I very much doubt that I can tell anyone anything they can't find themselves through looking, and my advice is do the research your self, as this will give a better understanding than I can ever give.
I do understand the concept of profit from 'intellectual rights', But not sure that I agree.
Teaching/sharing is one of the most rewarding exchanges.
Even if all you get in return is the chance to learn from others and their appreciation.
I very much doubt that I can tell anyone anything they can't find themselves through looking, and my advice is do the research your self, as this will give a better understanding than I can ever give.
I do understand the concept of profit from 'intellectual rights', But not sure that I agree.
I'm the same way, I got nothing to lose or gain by sharing what I know other than knowing I helped someone get past a part they might be stuck on etc... but I still respect those who don't share for the reasons I've stated. Most of us would never use the info for profit or try to take credit for someone else's work, but there are just enough of them out there to keep these guys quiet.
Now when it comes to what I do at my shop fixing other people's cars and doing a lot of work for the dealerships in my area, if I was to tell them everything there would be a chance they could pass the info to their mechanics and some of them not need me anymore... but that's a different story. In here it's just a fun hobby for me so if I do something and it works really good I'm always happy to share.
Now when it comes to what I do at my shop fixing other people's cars and doing a lot of work for the dealerships in my area, if I was to tell them everything there would be a chance they could pass the info to their mechanics and some of them not need me anymore... but that's a different story. In here it's just a fun hobby for me so if I do something and it works really good I'm always happy to share.
