I've never seen an 18T freewheel output sprocket on any 5:1 4G. I've seen 10T solid, 11T freewheel, and 12T freewheel.
Try actually reading the thread. I've had the bearing mod for 2 years now and it's been awesome.
New kits at Kings "Ghost Racer 7G"
- Thread starter knightscape
- Start date
I'm sure I could find a bearing solution for the bushing but your link don't look right...
That is a 13x20 x4mm Blue Rubber Seals Ball Bearings ABEC-3.
The bushing fits a 15mm shaft for a 20mm clutch bell hole, and it's 22mm long!
Considering the clutch bell is the only freewheel on the whole drive train that thing really needs to turn with ease.
Though a big fat needle bearing would be best I suppose a couple of thinner bearings would work...
Guess I'll see when I have something to put it on.
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KC, that write up uses 6, 4mm bearings in the hole to get 24mm wide, then the output shaft on the engine is turned down to 13mm from 15mm to get inside the bearings so that's the right size.
Well, I'm not going to be grinding shafts and buying 6 bearings and such just to replace a bushing.
Either their is a 1 or 2 bearing solution replacement or I'll just lube it with dry graphite between the clutch bell and bushing as that is all that matters.
I was just wondering, wouldn't it be easier to use these 15x21x4mm bearings
http://www.ebay.com.au/itm/RCS-Mode...Radio_Controlled_Vehicles&hash=item5d4c91236b
You would only have to bore out the clutch bell by 1mm without touching the output shaft. If you mess it up it's a lot easier to buy a new clutch drum. It also makes it backwards compatible if you change your mind and decide to use an EZ Motorbike tranny instead. I don't see any reason to use the 13x20x4 bearings. Any thoughts?
http://www.ebay.com.au/itm/RCS-Mode...Radio_Controlled_Vehicles&hash=item5d4c91236b
You would only have to bore out the clutch bell by 1mm without touching the output shaft. If you mess it up it's a lot easier to buy a new clutch drum. It also makes it backwards compatible if you change your mind and decide to use an EZ Motorbike tranny instead. I don't see any reason to use the 13x20x4 bearings. Any thoughts?
My point exactly.
Clutch bells are cheaper than new engine cranks shafts and I can widen one of those on the drill press.
What I'd really like to find is a couple 15x20x10mm needle bearings, then it would only need 2 but hey, 15x21x10mm would work just fine with a little easy drill press work on the bell and the 2mm would work, just need more of them, thanks for the link bud ;-}
Well that was easy to find...
Bearing-Belt and Chain, Inc.
http://www.bbcarizona.com/products/
15x21x12mm wide HK1512, $6 each delivered and 2 will do the job with a quick drill press 21mm bit ream of the clutch bell.
That local store does not stock that size at the moment but I ordered half a dozen and they should be on their way direct to me today as he was just placing orders.
Thanks for the help guys.
Bearing-Belt and Chain, Inc.
http://www.bbcarizona.com/products/
15x21x12mm wide HK1512, $6 each delivered and 2 will do the job with a quick drill press 21mm bit ream of the clutch bell.
That local store does not stock that size at the moment but I ordered half a dozen and they should be on their way direct to me today as he was just placing orders.
Thanks for the help guys.
Jezz, neither of my kits came with a throttle either!
So the list of missing parts needed so far for this Macargi Panera with 1-piece cranks is:
Bottom bracket 3-piece conversion cups.
BB cartridge crank shaft (note stand width is fine)
5/8" pedals.
Throttle.
If I didn't routinely stock all those items I'd be pissed.
So the list of missing parts needed so far for this Macargi Panera with 1-piece cranks is:
Bottom bracket 3-piece conversion cups.
BB cartridge crank shaft (note stand width is fine)
5/8" pedals.
Throttle.
If I didn't routinely stock all those items I'd be pissed.
I guess you are going to put a sleeve on your crank? I personally would rather have sealed ball bearings with no need for a sleeve. For $9.85 I can get 10 of them here http://www.ebay.com/itm/10PCS-6702-...Control_Parts_Accessories&hash=item43c04de171 and have 4 spares. I just need to order a 20mm drill bit at the same time.Well that was easy to find...
Bearing-Belt and Chain, Inc.
http://www.bbcarizona.com/products/
15x21x12mm wide HK1512, $6 each delivered and 2 will do the job with a quick drill press 21mm bit ream of the clutch bell.
That local store does not stock that size at the moment but I ordered half a dozen and they should be on their way direct to me today as he was just placing orders.
Thanks for the help guys.
Correction: I meant 21mm drill bit.
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http://motorbicycling.com/showthread.php?t=37410
i believe in this thread of cobra's goes over all this stuff of needle bearings an drilling out the bell to each his own however after much thought i still believe cobra's way is the best way of doing this
as aleman stated he has had his with cobra's setup for a long time without issue an with everything i've read on here from aleman i think if he thought of a "better"way he would of said so by now
as for the needle bearings though they would last they aren't sealed an will get chewed up from the keyway that'll also act as a "dirt port" allowing dirt to easily eat those bearings ...............
i believe in this thread of cobra's goes over all this stuff of needle bearings an drilling out the bell to each his own however after much thought i still believe cobra's way is the best way of doing this
as aleman stated he has had his with cobra's setup for a long time without issue an with everything i've read on here from aleman i think if he thought of a "better"way he would of said so by now
as for the needle bearings though they would last they aren't sealed an will get chewed up from the keyway that'll also act as a "dirt port" allowing dirt to easily eat those bearings ...............
Those look really good and cheap at $1 each, good find!
I didn't know if the needle bearings were sealed or not, I had the guy on the phone find me what I needed to replace the bushing and order them before I looked them up and grabbed a pic.
I like needle bearings but you are right, the keyway is an issue I didn't consider, I'll give BB&C a call when they open and find out.
21mm ;-}
Blast that keyway, this would have been ideal.
http://www.mscdirect.com/product/details/09015520
15x21x22mm caged needle bearing for $16.
http://www.mscdirect.com/product/details/09015520
15x21x22mm caged needle bearing for $16.
I took the time to get some pics so everyone is on the same page.
This model of the HS 142 has the 17mm (5/8") output keyed shaft tooled down to 15mm after it clears the case lip with the end drilled and tapped for a clutch bell retaining bolt and NOT the 5/8" straight shaft as claimed in the gasbike ad.
That tapper provides a stop for the clutch which leaves 17mm of 15mm key shaft for the clutch bell.
The thing is, the clutch bell with T-belt pulley is 22mm wide...
In order to have enough shaft the end bolt has a collared washer that goes into the bushing 5mm and butts up against the end of the drive shaft.
That gives the 22mm shaft area for the bell housing to freely rotate on the bushing which is semi-attached to the drive shaft.
I say semi-attached because the bushing is just sort of pinched in place hoping the clutch bell will do the turning on it's outside and not turn it.
(continued below)
This model of the HS 142 has the 17mm (5/8") output keyed shaft tooled down to 15mm after it clears the case lip with the end drilled and tapped for a clutch bell retaining bolt and NOT the 5/8" straight shaft as claimed in the gasbike ad.
That tapper provides a stop for the clutch which leaves 17mm of 15mm key shaft for the clutch bell.
The thing is, the clutch bell with T-belt pulley is 22mm wide...
In order to have enough shaft the end bolt has a collared washer that goes into the bushing 5mm and butts up against the end of the drive shaft.
That gives the 22mm shaft area for the bell housing to freely rotate on the bushing which is semi-attached to the drive shaft.
I say semi-attached because the bushing is just sort of pinched in place hoping the clutch bell will do the turning on it's outside and not turn it.
(continued below)
(continued)
It looks like this with the bell in place.
Note the bell turns independent of the drive shaft at idle be sitting still or rolling, when you rev it up the clutch shoes come out and grab the bell.
From there the bushing is simply keeping the bell centered as everything spins with the shaft.
The burn with the 7G is it has no freewheel anywhere else but the clutch bell, and that bushing wears in short order making it very noisy.
When you need to pedal with the engine off you have to pull the whole drive train to the clutch bell and why a simple cheap bearing replacement for the bushing would sure help.
The 20 tooth T-belt pulley is held to the bell by the belt teeth on one side, and just a flare on the other.
My plan is to replace the bushing with sealed ball bearings.
The ideal size would be a bearing 15x20mm but they are not made.
A previous design uses 6 13x20x4mm sealed bearings all shoved in the clutch bell and tooling the 15mm output shaft down to 13mm.
I am going the other way with just 3 15x21x4mm bearings.
With a 21mm drill bit I can just drill 3mm deep into the 20mm hole on the inside of the bell and insert a bearing there with 1mm sticking out,
and a 21mm hole 7mm deep at the pulley side and put in 2 bearings leaving 1mm out but going far enough to go past the 5mm long end screw and not compromise the engine shaft.
It looks like this with the bell in place.
Note the bell turns independent of the drive shaft at idle be sitting still or rolling, when you rev it up the clutch shoes come out and grab the bell.
From there the bushing is simply keeping the bell centered as everything spins with the shaft.
The burn with the 7G is it has no freewheel anywhere else but the clutch bell, and that bushing wears in short order making it very noisy.
When you need to pedal with the engine off you have to pull the whole drive train to the clutch bell and why a simple cheap bearing replacement for the bushing would sure help.
The 20 tooth T-belt pulley is held to the bell by the belt teeth on one side, and just a flare on the other.
My plan is to replace the bushing with sealed ball bearings.
The ideal size would be a bearing 15x20mm but they are not made.
A previous design uses 6 13x20x4mm sealed bearings all shoved in the clutch bell and tooling the 15mm output shaft down to 13mm.
I am going the other way with just 3 15x21x4mm bearings.
With a 21mm drill bit I can just drill 3mm deep into the 20mm hole on the inside of the bell and insert a bearing there with 1mm sticking out,
and a 21mm hole 7mm deep at the pulley side and put in 2 bearings leaving 1mm out but going far enough to go past the 5mm long end screw and not compromise the engine shaft.
After looking at mine (see the link for a picture) it looks like I have at least 2.5mm of wall thickness and am willing to bet removing .5mm of that material won't weaken the crushed spline interface, especially if the bearings are a tight fit. If it fails, I can always try having the spline interface tack welded.
https://drive.google.com/file/d/0BxnT0SDiN2hvNklFNmtMRjB5RUU/edit?usp=sharing
KCvale, another thing you would want is two washers with an inside diameter of 15mm and an outside diameter small enough to not touch the outside race of the bearings. These would go on either side of the clutch bell up against the bearings to keep the bearing's outer race from contacting anything other than the clutch bell. I was thinking of trying to make them using the brass bushing but I'm not sure how to cut thin slices of it. Maybe I can find some copper washers that are the right size.
Exactly, I don't know what the material is but it is used in the skinny black washers in SBP kits between the bearings and sprockets. A 'first part' kinda thing.
Like bikerider the 10-pack of $1 a pop Chinese bearings I ordered will take a month to get here but BB&C can get me 3 Japanese bearings like them in a couple of days, but at $21.80 a pop ($65.40 for 3) certainly not an economical way for a mod.
If anyone has 3 15x21x4mm sealed roller bearing they can get in the mail so I have them 10-3 I'll give ya $25 so I can see if this works or not as I have a bike in the bay now.
Ohh..
I have a bunch of other build pics with details to help those of you with this kit other than the clutch which even stock given the right adjustment and lube lets the bike roll pretty free so far, but this mod is because we al know it won't last.
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