My Sister's Schwinn - Page 5 - Pocket Bike Forum - Mini Bikes
Reply
 
LinkBack Thread Tools
post #81 of 120 (permalink) Old 3 Weeks Ago
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Keep up the good work....Take care.....

My taco stand just went out of business.....LOL







Attached Images
File Type: jpg pntrbl.jpeg.jpg (7.2 KB, 4 views)

Last edited by CAM2; 3 Weeks Ago at 08:34 PM.
CAM2 is offline  
Sponsored Links
Advertisement
 
post #82 of 120 (permalink) Old 3 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

Holy Cow, great job, you can be proud of yourself, beautiful and functional. I will tell you I am no spring chicken either, lol.
EPR is offline  
post #83 of 120 (permalink) Old 3 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

You wouldn't believe how ****ed I am at that paint. Rattle can Rustoleum enamel and it's so soft ya can't hardly drop a tool on it. I even tried baking to get it "fully cured" and it's true, a couple days at 150 degrees did make a difference. After baking I can dry sand it and get powder instead of a gummed up piece of sandpaper, but it's still too soft. I can still chip it with a thumbnail .....


I hate to go full auto with hardeners and reducers. It's just a bicycle! So I'm looking for a reasonably priced alternative that I can spray thru my HVLP gun.
pntrbl is offline  
Sponsored Links
Advertisement
 
post #84 of 120 (permalink) Old 3 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

I use engine spray paint, good for 600 degrees and you can heat it with a heat gun to cure it.
EPR is offline  
post #85 of 120 (permalink) Old 3 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

I'm gaining some amount of confidence in my dremel skills. Got this case aero'd out.







Sill debating the base gasket tho. Carving cases ain't the same a raising the ports .020 ....
pntrbl is offline  
post #86 of 120 (permalink) Old 3 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

Looking good, I would put a rounder radius above the bearing where it angles back up so it can flow smooth , just a touch up. I would not try to raise the heights of the ports at this time. Don't try to take on too much at once, and don't feel bad if you wreck something. Keep it simple, every time you mod stuff you will get better. I started with 2 strokes in 2009. A MPR 47cc MT-A1 Cag for $169 and $48 SH, bought it for my then 10 yr old son, he did not like it, so I rode it, I was hooked on pocket bikes after that, lol.. When I saw there X18R Nitro 110cc 4 stroke, 4 speed w/ hand clutch, I was hooked, got to have that, lol.

I am a Honda Man, started after high school with a super sport 50cc 4 speed manual trans. After many different bigger Hondas my last one was a Honda CB1100F , it was wild & crazy, Inline 4 cyld, 4 valves per cyld, dual over head cams, 5 speed manual and four carbs, I put Andrews hp coils and a 4 into 1 Kirker exhaust. It broke the max speed limit in first gear, in San Jose, Ca, I hit 150mph on Hwy 680, 5 lanes wide and no one around.

I have rebuilt BMWs to Cadillac , worked on diesel trucks, went to college for that, lol, so working with 2 strokes engines is easy, and my machine shop/fabrication, plastic and alum work I did does not hurt either,
EPR is offline  
post #87 of 120 (permalink) Old 3 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

Thanx EPR. When you say above the bearing are we talking about what I'd call the 10:30 area vs 12 o'clock? I have some reservations about grinding right thru to the other side! But that kind of knowledge comes with experience and I'm listening.


And yeah. We're all 2 wheeled gear heads at heart. I started on a Honda 90 when I was 12. At 68 I still like to spin the back tire on my 360 and pretend I'm some kinda hero.
pntrbl is offline  
post #88 of 120 (permalink) Old 3 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

I have so many bikes, and parts, my wife said I should open up a Pocket Bike store, and she has a point, so I will reduce my supplies over this summer. Ok, on the lower photo, case half on the right it would be about 10:30, that little section that runs to the case edge inside, round it a little more there and you should be good. Way back I owned a 1015cc Kawasaki Pro Stock drag bike, best time 160mph in 9.45 seconds, that was a Wild Ride, lol.
EPR is offline  
post #89 of 120 (permalink) Old 3 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

Machine tools being another hobby I decided to make me some fancy "upside down" nuts to positively locate my jug in the same place every time, and most importantly, keep it there. 10mm stainless hex stock and some quality zen time communing with my lathe produced these.





All was well until I went to use them and found there was no way all 4 of them were gonna sit in there countersinks at the same time. Further investigation has revealed the threaded holes in the cases aren't exactly located with a high degree of precision. Let's just say at +/- 20 thou they're in the general neighborhood!


I'm completely cool with this. Per the original design it doesn't need a high degree of precision in this area. It'll still work. But I'm gonna be asking this little motor to do more than the original design ever intended, and best of all, I can fix it.


My little mill can locate a hole to .001 accuracy. A 1/4" end mill will relocate the holes properly and that's the hole size needed for an M6 heli-coil tap. It'll be better than ever and I get to play with my machines some more.
pntrbl is offline  
post #90 of 120 (permalink) Old 3 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

You can drill out the head fin holes enough that the nuts will slide thru them to the base. I use SS nuts, First you tighten the 4 head allen bolts, then tighten the nuts to the base holes then check the allen's then nuts again and you should be Fine.
EPR is offline  
post #91 of 120 (permalink) Old 3 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

Using a link EPR kindly sent me awhile back;


I've had a look at my balance factor. Here's the stand;



43% seems reasonable for a horizontal motor. There's more information out there on vertical cylinders, which are typically around 55%, and it seems that this is all about controlling which direction the vibration goes vs eliminating it. A single cylinder motor is gonna vibrate no matter what you do. It's just that fore and aft vibration makes for a smoother ride instead of up and down. That makes sense.

But I don't know it all! All comments are welcome.
pntrbl is offline  
post #92 of 120 (permalink) Old 2 Weeks Ago
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Quote:
Originally Posted by pntrbl View Post
Using a link EPR kindly sent me awhile back;

https://www.youtube.com/watch?v=0hoE_MuFpPI

I've had a look at my balance factor. Here's the stand;



43% seems reasonable for a horizontal motor. There's more information out there on vertical cylinders, which are typically around 55%, and it seems that this is all about controlling which direction the vibration goes vs eliminating it. A single cylinder motor is gonna vibrate no matter what you do. It's just that fore and aft vibration makes for a smoother ride instead of up and down. That makes sense.

But I don't know it all! All comments are welcome.
So how is what he did as being balanced?...……….

That tutorial guide seems logical but it kinda isn't...….

You need to realize you need the piston attached to the end of the rod and the bobweight should hang off of the crank pin at the crank not at the rod end...…

He just essentially just balanced the crank and factored in the weight of the piston assembly to get his balance factor number which is kinda inaccurate according to logic..

I didn't see the engine he balanced the crank on running with say a half bottle of water to show the vibes before and after to prove the end result....Everything must be assembled to the crank in order to do it 100% correct...

What you don't realize or ever keep track of this is a tool based engine that's as balanced as its gonna get because its a MULTIDIRECTIONAL engine when it was used as an auger or a brushcutter so slapped on a frame at a 22 degree angle isn't exactly horizontal and it surely isn't vertical so...…..…..

All you have to do is match the piston to the crank except when putting a 44mm piston with 10mm pin on a IE-40 crank then you need to worry about balance factor and the shakes....

Slap the piston on it and see how that crank reacts on the balance beam without the bob weight........Whatever it factors out to is your ideal balance %age as it will vibrate more at idle and smooth out as it revs up and what you want even though isn't ideal for that type of sidestand that bike has....

Unless youre putting a 44mm piston on a crank that had a 40mm piston you shouldn't even have to worry about balance factor.....

Your Schwinn is gonna be a cruiser and the balance %age should reflect on a realistic operating range for maximum comfort and not being fatigued from being buzzed to death...…..Youre gonna need a seat 4" thick with springs aswell as super thick gel grips on the bars at this point...………LOL

Alls you have to do is control side shift from sideloading also the side to side action the wristpin does sitting up in the piston...I use lightweight floater springs for that when absolutely pertinent to get the most revs with least vibes possible at WOT......…

FYI: Weighted flywheels absorbs and deadens vibrations too...……….

Also like I keep saying too My 1913 Harley has a super heavy flywheel which smoothes out the whole thing and gets it cruising effortlessly at WOT cruising at 50mph...…..

One day when Im a decade older Ill get this one sorted out and running....

It has a 7lb cast steel flywheel weight on the primary output shaft...The engine on this model is only 4hp and had a sustained topspeed of 45mph but the piston on this one is also over 3" in diameter.


Last edited by CAM2; 2 Weeks Ago at 02:07 PM.
CAM2 is offline  
post #93 of 120 (permalink) Old 2 Weeks Ago
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Quote:
Originally Posted by EPR View Post
You can drill out the head fin holes enough that the nuts will slide thru them to the base. I use SS nuts, First you tighten the 4 head allen bolts, then tighten the nuts to the base holes then check the allen's then nuts again and you should be Fine.

I just put all the cap bolts with washers through the cap first then I thread the nuts up the bolts so theyre touching the cylinder flange at the last couple turns of the bolts to basically pre-locate the cylinder as the nuts wont bind against the bolts without an extra jamb nut so-but may have slight resistance so I usually go to 13.5-14 inch lbs depending on whether you use a locking style nut or a plain style non nylon locking style nut in order to to get the correct 13 inchlbs that's recommended then after the bolts are properly torqued I tighten down the base nuts then I recheck the torque if using a basegasket as the nuts will squish the basegasket even further making the bolts looser..
CAM2 is offline  
post #94 of 120 (permalink) Old 2 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

I wasn't looking to change the balance CAM. I've got this idea I should drill two holes in the piston to feed the boost ports and wondering what affect that might have on the balance. Based on what I've learned ... I'm thinking not much!


So whaddaya think? I can accurately index the holes to the ports so I'm thinking I'll be able to keep them small. Should I drill away?
pntrbl is offline  
post #95 of 120 (permalink) Old 2 Weeks Ago
EPR
Banned
 
Join Date: Aug 2009
Posts: 24,102
Re: My Sister's Schwinn

I not the one that sent that too you, but I watched one not sure if that is the video or not. He had 2 bars like you do, He had a hook thru the rod end, and kept adding nuts and washers till the main rod bear was at the top and the crank did not turn either way or balanced. They he weighed all the stuff, and tried to make the piston pin & piston and parts the same weight buy drilling the center of the pin and what ever else, CAM2 knows about stuff like that.

That's why me and CAM2 on the billet case engine went with a 40mm cyld and FC crank with a 10mm pin and piston that are both lighter. I am starting to search for a 10mm and 12mm Titanium pins, have some 5 and 6mm bolts here, there very light, the pin would remove a lot of the weight.
EPR is offline  
post #96 of 120 (permalink) Old 2 Weeks Ago
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Quote:
Originally Posted by pntrbl View Post
I wasn't looking to change the balance CAM. I've got this idea I should drill two holes in the piston to feed the boost ports and wondering what affect that might have on the balance. Based on what I've learned ... I'm thinking not much!


So whaddaya think? I can accurately index the holes to the ports so I'm thinking I'll be able to keep them small. Should I drill away?
The weight lost from the addition of the holes wont be a negative for what extra torque they bring to the table...The holes will be adding back the additional revs it loses kind of like a tradeoff as it reduces the parachute effect while traveling down to BDC.

On one 4 port cylinder piston I used it was cut into an ovalized rectangular shaped hole to catch both boost channels over the bridge of the ports...

Two separate holes will work too if the bridge between both isn't small enough to fracture and fall out into the engine...

I say if you can do squarish shaped windows youd be golden....

In the main part of the end result you'd be enhancing the torque and that's what you need..

Last edited by CAM2; 2 Weeks Ago at 07:17 PM.
CAM2 is offline  
post #97 of 120 (permalink) Old 2 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

I was doin' the top end on the family KDX80, which is a reed valve motor, when the new piston showed up with no window in it. It wasn't hard. I just duplicated the window in the old piston.


It's a 1980 model and we still got it and it's still going strong. I think the whole family learned how to ride on it. My brother scored the last rod kit in the country a decade or so ago! Good little 40 year old bike.


I'll pop a couple of holes in and see what it looks like. I'm thinking I should keep them on the high side. Maybe a 1/4" below the bottom ring groove?
pntrbl is offline  
post #98 of 120 (permalink) Old 2 Weeks Ago
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Quote:
Originally Posted by pntrbl View Post
I was doin' the top end on the family KDX80, which is a reed valve motor, when the new piston showed up with no window in it. It wasn't hard. I just duplicated the window in the old piston.


It's a 1980 model and we still got it and it's still going strong. I think the whole family learned how to ride on it. My brother scored the last rod kit in the country a decade or so ago! Good little 40 year old bike.


I'll pop a couple of holes in and see what it looks like. I'm thinking I should keep them on the high side. Maybe a 1/4" below the bottom ring groove?
Im partial to being more towards the bottom or a tad past half point so they end up as low as they can go on the boost port grooves on the downstroke but the spot you quoted will work great aswell as it will give a lot more bleedoff higher into the transfers on the downstroke..

One time I tried just two 1/2" long 1/8"wide slits dead middle of the piston skirt aswell as boost port channels which worked pretty killer...

Those old KDX 80's are pretty cool...My brother had one.It was orange and I think an 83 model..I had an older model Yammie MX100

We got my nephew a lil KX80 when we got him riding....LOL

He said the first time he hit the powerband and wound it out he held his breath and thought he was going into a time warp......LOL



Last edited by CAM2; 2 Weeks Ago at 12:08 AM.
CAM2 is offline  
post #99 of 120 (permalink) Old 2 Weeks Ago Thread Starter
PBP RACER
 
Join Date: Feb 2019
Age: 68
Posts: 126
Re: My Sister's Schwinn

I liked CAM's suggestion of slots instead of holes in the piston. I can do that ...





Yeah! That's cool! I can't see where the piston got much weaker over that.

Probably could've made 'em lower but I've had recent experience with a skirt breaking in my Grandson's YZ250. That was ugly ... Don't wanna go there.
pntrbl is offline  
Banned
 
Join Date: Mar 2008
Posts: 21,721
Re: My Sister's Schwinn

Quote:
Originally Posted by pntrbl View Post
I liked CAM's suggestion of slots instead of holes in the piston. I can do that ...





Yeah! That's cool! I can't see where the piston got much weaker over that.

Probably could've made 'em lower but I've had recent experience with a skirt breaking in my Grandson's YZ250. That was ugly ... Don't wanna go there.
Those slots look lovely....very nice job....

I hear ya on the piston debacle even though the pistons are pretty strong mainly due to their size and thickness..

I dremel out the extra castings n such from underneath to super lighten certain pistons too...

I beat this piston to death inside a 5 port cylinder and it stayed together but sometimes safer than sorry is the way to go.....



This one was one hell of a ripper.....For some odd reason with this style piston with round window and side reliefs instead of just enhancing bottomend power but with the right porting also a rocket key set retarded it actually enhances all 3 powerbands pretty nice with a cylinder with only 1 boost port...Oh split transfers too



some random pic with the amount of pistons I went through in a very short time also the different cranks I did it with too....

I tried quite a few different window and crank configurations that week....

The data I got that week was eye opening for sure...

Especially when I did the 34mm stroker crank mod from the piston ported engine into the reeded engine and used a 40mm 1pc cylinder w/3rd boost port and windowed piston the power was very very torquey and quite surreal..........LOL.

Attached Images
File Type: jpg 008.jpg (38.4 KB, 2 views)
File Type: jpg 20160922_112508_zpsm9i06mzy.jpg (222.3 KB, 2 views)
File Type: jpg 20180723_180849.jpg (293.7 KB, 2 views)
File Type: jpg danscylinder029.jpg (75.8 KB, 2 views)
File Type: jpg 086-1 (2).jpg (57.4 KB, 2 views)
File Type: jpg pistondifferences006_zpsabb64d98d.jpg (75.3 KB, 2 views)
File Type: jpg piston031.jpg (75.8 KB, 2 views)
File Type: jpg 022.JPG (15.5 KB, 2 views)
File Type: jpg 071_1.JPG (100.6 KB, 2 views)
File Type: jpg 100-0404.JPG (68.3 KB, 2 views)
File Type: jpg 074 (3).jpg (90.7 KB, 2 views)
File Type: jpg 001-4_1.jpg (116.9 KB, 1 views)
File Type: jpg 098_1.jpg (151.1 KB, 1 views)
File Type: jpg 016-1.jpg (171.9 KB, 1 views)
File Type: jpg 002.JPG (64.0 KB, 1 views)
File Type: jpg 6e2e36ca-e518-4afe-b804-52013791d543_zpspsfmtcf9.JPG (127.9 KB, 1 views)
File Type: jpg 034.jpg (69.9 KB, 1 views)
File Type: jpg 030.jpg (72.8 KB, 1 views)
File Type: jpg 034-3_1.JPG (220.7 KB, 1 views)
File Type: jpg 020-2.JPG (98.2 KB, 2 views)
File Type: jpg 008-1_1e.jpg (96.2 KB, 2 views)
File Type: jpg 304.jpg (196.7 KB, 2 views)
File Type: jpg 318.jpg (103.7 KB, 2 views)
File Type: jpg 121_1e.jpg (137.1 KB, 2 views)
File Type: jpg exhaustflange039.jpg (175.1 KB, 2 views)

Last edited by CAM2; 2 Weeks Ago at 02:30 PM.
CAM2 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pocket Bike Forum - Mini Bikes forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome