going case inducted!!!

[Davezilla]

Got some goodies on the way and got my Rocket CDI today in the mail, I'll install it and see how it goes after I put my engine back together so I can get a "stock" baseline before I duplicate it and upgrade some of the resistors to a higher watt rating and get some different caps & a 10 turn precision pot to change the timing curve.

For a carb, I went with the Tillotson HS254B since it has the same 21mm bore with a 19mm venturi. I also got some aluminum bar stock coming in so I can make a manifold adapter and possibly design a reed box, I may need some more bar stock for the reed box depending on the design I come up with and what reed cage will work best. I'm thinking the GY6 scooter reeds will work with the Tilly carb I ordered, then mill the intake side of the cylinder down to mount at the intake port similar to the Arrow setup, then buy another set of cases or bottom end with a 40mm crank to cut an opening on for a true case inducted setup. With the Tilly or Walbro floatless type carbs, we're not limited to runnnig them completely side draft so it will be possible to mount it at a 45 degree down draft eliminating any bends in the intake tract which would offer a more compact high performance induction system for bikes like mine with limited frame space.

I like the idea of the teflon bushings on the lower end as they would effectly keep the bearings from creeping out of their bores under extreme conditions without any way to harm the engine as well as like you mentioned it could help prevent the crank from bending from the stress of high power and rpm, these could also be made oversized to help occupy space and add some case compression, they may need to be chamfered a little tho if oversized to allow some of the fuel/oil mix to reach the bearings. oversizing them may also help dampen out any high rpm harmonics as well, depending on size, shape, and how much room there is in there...

 

[Goat Herder]

When we were making custom intake manifolds from Alluminum block, we would do them up Mad Max style with carfully crafted fins carved into the block with a band saw.
Just as busy as the fins on the jug or the head!

Have not seen anybody on the forum do one up that way yet?

 

[Theon]

http://www.arboristsite.com/community/threads/mcculloch-chain-saws.71126/page-964
This looks the same as the old saw I got my carb from.

 

[mech_engineer]

Davezilla... yes you can make them bigger to increase case compression this will increase transfer air velocity and increase the intake suction capacity. Also some people using aluminum plates to increase the compression. Theon is using aluminum but he can use teflon... the bad news for me is that the only person in ebay selling the teflon parts needed dont send them outside US without increasing the s&h to $$$30 for a part that cost only 14 with free shipping

 

[Davezilla]

Man too bad on the shipping... I know it costs more but a lot of it is just buyer's greed as I've sold stuff on ebay and shipped it out of the states just as easily as shipping it within the states... and the cost really isn't that bad... maybe $5 to ship a few sheets of teflon at the most...

 

[mech_engineer]

I going to buy a cutting table made of teflon this will be cheaper

 

[Theon]

This next lot of stuffing plates, will have a second layer protruding into bearing recess in the crank. I have some Nylon bread board plastic, wondered how it goes with fuel though?
I like the alloy, and thinking about Daves suggestion to screw them to the cases, But been considering getting another RSE crank for the engine as it will gain better Crankcase compression with the flywheels closer together, Leaving more room to stuff.
But should build two of these while I'm at it, and the hole I have in my Test Cases, looks as if it will work, only really missing a clutch assembly and a better crank to get a second motor together.

 

[mech_engineer]

I recommend you use teflon because the teflon as it has the lowest coefficient of friction known to man; turn is excellent holding temperatures and is resistant to chemicals. If one plate moves out of place it will not cause any damage to the engine components. My only problem is the price and the fact that i do not possess the machinery to make parts . in my college there is a 3 axis cnc lathes and milling machines but are used by new students only.

Today fred's sent me the 5.3cc head and digikey sent me the components for the cdi just need to wait the arrival of the components. One of the pieces that worries me is the lower rod bushing is an oil filled bronze plain bushing this means that the oil layer created because of the loads that receives , I do not know how good they are at high revolutions have looked if someone used in engines but there is nothing written about this use.

right now I'm very busy and I work by day and study at night which leaves me little time for my new hobby and my girlfriend. I hope that within a month have the bike running and so end several of the posts I've done since they are incomplete. Excuse me for doing equations on paper since it is not professional , but it is practical for the little time I have. theon I hope you achieve your project if you have any questions just send me a private message yet I think you should somehow restrict airflow. since the time area could come out of the parameters and this is not good. I do not know how accurate are the parameter given by yamaha but with this is what we have to work. this quarter I met an old friend from my first university he is finishing his degree in mechanical engineering with a minor in aerospace. he owns a workshop with several machines. My friend proposed to make high performance parts for bikes like the intake manifold to go inducted case and a few more parts for sale but designed by me; also he wants that I design an ultralight aircraft to develop the first aviation factory in my country. this sound good but rigth now the economy here is not the best. there are less people in my country every year due to economic crisis here. i dont know what to do but the parts is a must go. So for now i have created a few post they will remain the same but from now new post will not include equations.this desicion is because some forum users who pretended to know what they were talking without knowing anything they offended me. I will not be the smartest person in the world but my post was created to share knowledge.

 

[mech_engineer]

theon have any picture of the 40mm crank i want to see it.

 

[Theon]

I will get another, as the crank is in the Goat's motor so until I pull it down again.
I assume your referring to the RSE crank.
I lost all my photos to a dodge SD card.

 

[mech_engineer]

Did you use 2 lower gasket for the 40mm

 

[mech_engineer]

A little preview

 

[Trix]

nice!!!!

 

[mew905]

what piston is that? Looks like a Hoca or similar.

 

[mech_engineer]

Is a minarelli 47mm 10mm pin

 

[mech_engineer]

 

[mew905]

different rings on that piston? last time someone tried it, the chrome rings stripped the cylinder plating pretty rapidly. You may want to invest in different rings, proper plating or extending the top ring gap just a tiny bit to relieve pressure. The problem is the harder metal will damage the softer one, being that those rings are properly plated and our cylinders arent, the cylinder plating goes first. exhaust pressures on the downstroke will push that ring into the cylinder pretty hard too, especially with the stock CDI. A retarding one will boost reliability significantly by reducing high-rev pressures. The choice is basically: Deal with stripping; Different rings/plating; or reduce pressure.

Then again... the cylinders on these motors is almost cheaper than the proper rings, but the question is will the stripping of the chrome plating affect performance to such a degree in such a short amount of time that it would justify different rings?

A little off topic, I just dont want to see this destroy your motor. It's a great plan and if you find success in it, and are willing to produce cases like this, I'd be willing to buy it. I'm just not willing to pay the $700 Arrow asks for their "race" motor

 

[mech_engineer]

The rings create too much pressure maybe increase the ring gap could help... the clearances of this piston are much smaller than the stock this may cause more friction too also the skirt finish is going to create more friction too. The piston came with 2 rings and a fine wire ring. I think the wire is for the second ring like the oil control ring in cars. I have the stock piston at home and try the minarelly piston with a cylinder that came damage from factory; have a spot without the chrome and have casting air cavities this is critical because increase the provability of loosing compression. The good one leaved china today.


Exhaust clearance without bottom gasket

at TDC without bottom gasket and the ss head stud

 

[Davezilla]

That piston looks good and the clearances at TDC and BDC are definitely workable as well. For the rings, what thickness are they? they do look thinner than the China Girl rings which is good for friction reduction. If you need some iron rings, I believe I saw them on Treatland's site where they have some 1.5mm thick iron rings (for Puch pistons) that are 47mm, they may even have some that are 1.0mm but I didn't go thru all their products links.
The piston skirt clearance can be fixed the old fashoned way by hand lapping or you could lathe cut .05 to .1mm to reduce the final diameter. I remember seeing in Garahm Bell's writing where he was talking about reducing the diameter of the top half of the piston by .06 to .1mm to compensate for heat expansion and prevent seisure or excess scuffing. It does look like everything you got in that setup is workable tho.

 

[mech_engineer]

they are 1.5 mm... for now i cant do anything... a frien have the crank to balance it and the cases are at he shop for the case indution manifold manufacturing.