General Lee minibike.

#42
I just thought it was an option to look at is all. Trying to think outside the "normal" box.
It's good to think outside the box!
I am new to torque converters and I can't find any info on people who have already modified or changed theirs to get rid of the vibration.
It seems like they just run it and can live with the vibration. That vibration is bad for everything.
I know it should be able to run much smoother and I will get it figured.
 
#43
If you want less vibrations try a salsbury 330 or comet 340 (same clutch) hard to get but from what I've herd the driver is balanced nearly perfectly and has little to no vibration and its set up for more power and rpms than a comet 30. I think GTC sells a copy but its nearly 400$
 

delray

Well-Known Member
#44
If you want less vibrations try a salsbury 330 or comet 340 (same clutch) hard to get but from what I've herd the driver is balanced nearly perfectly and has little to no vibration and its set up for more power and rpms than a comet 30. I think GTC sells a copy but its nearly 400$
looks like josh let the cat out of the box. wasn't going to bring it up,but i did mention earlier in this post about a unit that will work with a billet flywheel and a lite billet flywheel too. but your not going to find the correct parts to make it work. it was the salsbury/comet 340 unit. but it has to be a certain kind and not just the standard cast aluminum they made.
it was a billet aluminum part they use back in the day on jr dragster stuff when engine produce only 20hp or less and it work real good. when the jr dragsters started to get into the much higher hp motor motors the unit wet to the waste side and every body jump on the band wagon and started to get into the big dollar billet torque converters that where made with a much larger belt and the units where made for big engines and not for a small block honda/clone ….etc.
here is a heavy use part I purchase off of ebay and was told buy the seller that was a good working part and soon found out after getting it the part was damage and that he was a member from here,but I won't though him under the bus. he did refund me money back.
totally cracked


here was the second design they came up with and fix the problem. two piece unit. the spine piece was made out of steel and the pulley half was billet aluminum.

picture of a stock unit back half pulley. cast aluminum. they will explode under any good amount of power.

so when josh talks about 330(5/8 belt)or 340(3/4 belt) it can be just little misleading on how great they are. just not any kind of salsbury. it was a certain kind of unit that was very good and it was called a jr dragster salsbury unit. maybe the best unit that was every made and now that there is a new era of built engines being made with lite aluminum flywheels and people want to drag race with a torque converter or just have fun on there bike and hot rod around. this would be the torque converter that would fix the problem with vibration that people are experience with there billet flywheel engines when using heavy unbalance 20 or 30 series units. also the GTC unit was never made. they post it in there web site and when you call them about it. they will tell you straight out that they will probable not make it and if they did? it would only be cast aluminum.
I do have a new nos 340 salsbury unit that I can take measurements and make a new steel spline. I will need to get a Indexing Dividing unit with a 3-Jaw Chuck and Tailstock to make it if I still want to use this unit. no one makes this parts anymore and they don't want too. I have call two different places that made them and they both said no...……..
here is how it works. you can set it up with different weight rollers and springs and the the unit is spot on every time it engages.

also this unit was rated at 8500 rpm's. that was only the jr dragster models that I know of.
 
#45
Very informative.
This unit looks like it uses arms with weights on it. Just like I want to make in a 30 series clutch.
I don't want to spend that kind of money as I will use it just for fun riding applications.
I just want the clutch driver as I have it and then create a part for it that is easily bolt on and makes close to zero vibrations.
 

delray

Well-Known Member
#46
Very informative.
This unit looks like it uses arms with weights on it. Just like I want to make in a 30 series clutch.
I don't want to spend that kind of money as I will use it just for fun riding applications.
I just want the clutch driver as I have it and then create a part for it that is easily bolt on and makes close to zero vibrations.
I think one of the reasons why the 340 jr dragster billet pulley works so good when it comes to not having vibrations. the whole unit is machine out aluminum allowing it to spin 10x's better(spin true). something that is hard to get away from when using a comet unit because all the parts are just casted or stamp out metal and none of that will spin true. something you can maybe do and it will help just little but probably not enough, machine the back lip of the steel stamp pulley until it's true up on your lathe. that area does not get use for the belt or anything else. i ran enough comets in the past and that area defintely does not spin true from bring stamp out from the factory.
good luck,i really like to see what you come up with.
 
#47
Looks like that clutch is similar to my Polar except-
The Polar is a straight drum, with ramps with different angles that can be switched out, whereas that clutch uses a slanted drum with a predetermined slope that cannot be changed.
That clutch has 5 sets of arms with weights/rollers while the Polar only has 4.
Other than that they seem to be of relatively the same design.
I will say that by altering the angle of the ramps and the size and weight of the rollers, there is a ton of clutch tuning that can be done.
My drag bike also has an old technology digitron device installed with a speed sensor on the jackshaft. Monitoring this rpm VS the engine rpm enables you to fine tune the clutch.
That type of info might be valuable to you for you to see what is going on with both the driven and the driver.
 
#48
Well...
As I have searched for springs that might fit my design; they are being sold for €4,-/each. I need 4 of them and then I am quite certain they are not strong enough, so I might need stronger ones, again €4,-/each. If they are not strong enough, I'm done, because there are no stronger ones with the right dimensions, or I need to have them custom made (and that's not for €4,-/each). So my plan to come up with a modified part is in the fridge and I will go another route.
I might try to machine a drum driver, which is beefier as the stock one. The stock drum driver is just 1,5-2mm thick and like Delray mentioned; they do not spin true. And the way they are mounted against the splined hub driver also isn't very good.
But I don't think it it will help a lot as the 2 weight are only held in place with 2 garter springs. When they start to come apart, they will follow the way of least resistance.
Spend my hard earned money to something else and try to live with some vibrations.
 
#49
Another thought and just thinking out loud:
When I take a look inside the stock driver the weights are perfectly centered around the splined hub driver and they are flat with both sheaves. No problem and vibrations at this point.
With the gartersprings removed I can move them outside, like they do when rpm increases, the weights at this point are no longer flat with both sheaves and only touch the sheaves at a single spot (most likely at the middle of the weights). But there's a lot of play between the 2 shafts/pins and the holes in the weights (5mm pin in a 7mm hole), which can cause the weights to move freely. Possible unequally friction of both gartersprings, might cause the weights to twist a bit, which can cause more friction to 1 weight as to the other weight. See the problem?
I don't think that eliminate the play between the pins and weights will work, as that might cause the weights to get stuck or have to much friction to move.


I know: this is a centrifugal clutch and the weights will touch an outside drum. But if this principal is build inside a TC clutch modified moveable sheave and when the weights move outside they touch the outer drum driver (perhaps with small roller bearings) and force the moveable sheave to slide over the splined hub driver?
It will require another outer drum driver and another moveable sheave (needs to be flat on the side of the weights). But the weights are held in place with the solid pins. Maybe not with 2 weights, but with 3 weights.
Clutch tuning: weight can be added and springs can be changed.
Just thinking out loud and I'm starting to like this idea.
 
#50
Here's some things that have been going on in the workshop the last couple of weeks/months.


I've done a bit of cleaning in the workshop.


I had these parts ordered and already at home, and I was curious if there would be any interest in them over here in Netherlands. So I put them for sale at a large Dutch website where people can trade stuff.
It is sold with profit and I already ordered new rods and this time I ordered 2 aluminium GXV 160 flywheels (double the fun for the price of 1 billet flywheel). When they have arrived I will see if I can make an adjustable steel hub in them with the use of the stock recoil starter. That would make it easier to adjust the ignition timing.


This is 1 of the first 3 GX160 engines I bought.


From the other side. Ready for disassembly.


Stripping down the engine. It's engine code is QMD6, meaning it has lighting coils and an oil alert. Both will be removed.


When I took the cylinderhead off, I noticed it's chamber looked different as to the other engine I first disassembled. Also the piston is different; it is dished, while the other was flat. The first engine I disassembled had an 18CC cylinderhead, so would this be a 14CC cylinderhead?...


...Yes. 14 grams of water filled the chamber.
Not sure what to do with this head, yet. I don't like the narrow space between the opened valve and the cylinderhead sides. There's almost no room for proper flow. I think there's room for improvement, but first I will see how it performs stock.


I ran into a great deal some time ago. Someone had an used GX160 engine for sale and mentioned he had more of them, so I offered him money for all 3 engines. They've been used in go karts and 2 of them had the clutches still on. It were 20T #219 chain clutches, so I couldn't use them and by now the clutches have been sold, which leaves just the engines. I have 7 GX160 engines by now.


Before I sold them I tried the clutches on the General Lee minibike. 20T front sprocket, 85T rear sprocket; 1:4,25 ratio. Once the clutch engaged it was fun and scary at WOT. It was fast and I had to hold on tide to the handlebars, because it felt like it wanted to wobble.
I'm not sure about the speed (no tacho- and speedometer) but with this ratio 5000 rpm's already means 50mph.


I noticed the oil fillercap leaked a bit of oil. With a torque converter installed the diameter of this oil filler cap is to big, so I used the lathe to make it smaller. This oil filler cap is ordinary M20x2,5 thread, so if I would take a stainless M20 bolt and do some modifications to it, it will fit and be a lot beefier as this plastic one.


Engine taken apart.
 
#51
If you run the flat top piston with the smaller head, that would bump your compression up a little.
As long as you have enough piston to valve clearance!
 

delray

Well-Known Member
#52
did you cc the head with the gasket still on? or still little dirty. correct cc's would be a clean off surface without the gasket. the small cc head works good with stock or mild cams only. small chamber head design with not flow as good as the large cc head unless you do a lot of rework. still a good bolt on hot rod trick to help with compression and for mild built motors.
 
#53
If you run the flat top piston with the smaller head, that would bump your compression up a little.
As long as you have enough piston to valve clearance!
The flat top piston is in the engine with the 18CC cylinderhead. I replaced the stock "thick" headgasket with a thin metal headgasket.
With the 14CC head I can replace the thick headgasket with a thin one, too and keep using the dished piston.
 
#54
What I am getting at is
Using a flat top piston with a smaller chamber head will bump compression kind of like milling a flathead head.
If you are looking for that to make more power.
Not sure how high it would raise the compression ratio though.

But I forgot, you’re building two engines right? So that would make sense with the gaskets
 
#55
did you cc the head with the gasket still on? it looks like it. correct cc's would be a clean off surface without the gasket. the small cc head works good with stock or mild cams only. small chamber head design with not flow as good as the large cc head unless you do a lot of rework. still a good bolt on hot rod trick to help with compression and for mild built motors.
Well, the gasket was off, but I didn't clean the surface. I just wanted to quickly know how many CC's it was. If it is 14CC or 14,5CC my scale doesn't say anything lower as a gram. But it's clearly not a 18cc head.
To help with the compression ratio, I use thin metal gaskets, as my stock GX160's have the "thick" head gaskets. The difference between the gaskets in cc's is about 3cc. No need to mill the head to get a higher compression ratio.
 
#56
What I am getting at is
Using a flat top piston with a smaller chamber head will bump compression kind of like milling a flathead head.
If you are looking for that to make more power.
Not sure how high it would raise the compression ratio though.

But I forgot, you’re building two engines right? So that would make sense with the gaskets
At the moment I'm just building one engine. The other is already on the General Lee minibike.

I will make a excel sheet with the calculations for the compression ratios. I wrote it down somewhere, but can't seem to find it anymore.
As I recall: a thinner headgasket would increase the ratio about the same as installing a flat top piston with the stock headgasket. So a flat top piston with a thin gasket would increase it even further. I'm not sure if I want to do that or I don't feel the need to do so.
 

delray

Well-Known Member
#57
Another thought and just thinking out loud:
When I take a look inside the stock driver the weights are perfectly centered around the splined hub driver and they are flat with both sheaves. No problem and vibrations at this point.
With the gartersprings removed I can move them outside, like they do when rpm increases, the weights at this point are no longer flat with both sheaves and only touch the sheaves at a single spot (most likely at the middle of the weights). But there's a lot of play between the 2 shafts/pins and the holes in the weights (5mm pin in a 7mm hole), which can cause the weights to move freely. Possible unequally friction of both gartersprings, might cause the weights to twist a bit, which can cause more friction to 1 weight as to the other weight. See the problem?
I don't think that eliminate the play between the pins and weights will work, as that might cause the weights to get stuck or have to much friction to move.


I know: this is a centrifugal clutch and the weights will touch an outside drum. But if this principal is build inside a TC clutch modified moveable sheave and when the weights move outside they touch the outer drum driver (perhaps with small roller bearings) and force the moveable sheave to slide over the splined hub driver?
It will require another outer drum driver and another moveable sheave (needs to be flat on the side of the weights). But the weights are held in place with the solid pins. Maybe not with 2 weights, but with 3 weights.
Clutch tuning: weight can be added and springs can be changed.
Just thinking out loud and I'm starting to like this idea.
more material you ad on farther out on the driver you may also experience a unwanted vibration. especially with that type of clutch setup.
when mentioned early about the weights moving outward and the pins springs creating a problem with balance, another problem could be occuring. when the weights are traveling out against the pulleys they are just stamp steel and if one weight feels less resistance because of the shape of the steel or weight it self that could affect travel totally different then the other one.
 
#58
You are right about the weights moving different from each other.

Here's another thought: instead of the 2 weights, why are there just 2 weights? Why not make 3 smaller weights in the clutch? A table with 3 legs is always stable. A table with 2 legs falls over...
I think the total weight of 3 would have to equal the weight of the 2 stock weights. Or would each weight (of 3) have the same weight as each weight (of 2)? Same gartersprings to be used. The weights will need to be made and I think that's do-able.
3 weights; each weight has to be 120 degrees, so they'll be closed at idle.
 
#59
Today I measured 2 camshafts and put the data in 1 diagram.
One camshaft was the original GX160 camshaft (orange and blue lines in diagram).
The other camshaft is a new Chinese aftermarket camshaft (green and yellow lines in diagram).


Valve lash was set at 0,15 and 0,20mm with both camshafts.
To me it seems that the aftermarket camshaft has more duration. Up to 20 degrees for the intake and 10 degrees for the exhaust.
Nice to know, I might want to try this cam later and see if I can notice any diffrence.

Last week new parts have arrived.
2 New cast aluminium flywheels.
2 New ARC billet rods.
Stainless steel valves, bronze valve guides, 18Lbs springs aluminium retainers with keepers and HD lash caps.

For the stainless steel valves it was stated that it was lightweight, high flow... But they are 1 gram heavier as a stock valve?!
And they look the same as a stock valve. If they're high flow, a stock valve is high flow, too...
They are stainless steel, that's true.

The bronze valve guides; they are 0,1mm (0,004") bigger in diameter. I think I need to heat the head before I put them in? They need to be reamed after installation.

The aluminium retainers with keepers looks good.

The aluminium flywheels look good, too. They are 1450 grams/each. I'm not sure if I can fit a steel adjustable hub in them, because they are not as thick as I expected them to be. There needs to be enough material to make threads. If an adjustable hub is a no go. I will use them as they are.
 

delray

Well-Known Member
#60
I wouldn't think even if the cast aluminum was thick enough it would be safe to bolt a steel hub to it without worry the cast aluminum fracturing from the bolt holes. but I have machine Tecumseh cast aluminum flywheel before and was very impressed how solid and dense without any voids after machine the starter teeth off.
Li'l Popeye do you have the ability to harden the stock cams? if so you could also run set of stamp 1.3 rockers. that would help the performance by using a stock cam. also might be able to get away with not harding the cam by a couple different ways. I know from the pass some guys ran stock cams in there builds with 18 pound springs and didn't have a problem with eating up the lobes,but anything more you could chewy up the lobes. cams are not harden very well from the factory. 18 pounds could still work with 1.3 rockers if there is no coil bind and set at the correct spring height. engine should pull good up to 5000+ and at that rpm your not going to float the valves and it wouldn't hurt to run a good zinc oil. make a good little hot rod engine with just stock parts and couple mods.
 

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