Replacing Hoot Gearbox

Davee930 · Jul 22, 2010

Hey guys, so I'm trying to replace my hoot gearbox with a 4g grubee. The mounting plate I have must be too thin because I can't line my chain up and it will hit my tire. Also how to you get the hoot gearbox off? I don't know how to take the gears out so I can unbolt it from the engine.

Thanks!

cruiser66 · Jul 23, 2010

Break the chain at the master link and remove. Remove all the cover bolts on the Hoot. Pull out the large gear. Loosen the screw or bolt on the end of the small gear on the end of the engine shaft. You may have to remove the pull starter to get to the 14 mm nut on the other end of the engine so that you can stop the engine from turning over while trying to remove the bolt on the clutch end. Pull the clutch bell off. You may have to pry gently around the edge of the clutch to work it off the shaft. Don't loose the key. Remove the two remaining bolts holding the transmission to the engine. You should be able to remove the Hoot then.

66

Bikeguy Joe · Jul 23, 2010

You may want to use a gear or pulley puller (available cheap at places like Harbor Freight) instead of prying it. If you must pry, go in a pattern like you would tighten lug nuts or head bolts.

cruiser66 · Jul 23, 2010

The gear puller (which I have) is a good idea if the clutch is stubborn. Like I said, gently pry going around the edge of the clutch. Sort of like trying to remove the cover off a can of paint. My clutch came out easily using a large flat blade screwdriver.

Bikeguy Joe · Jul 23, 2010

I give up...

Davee930 · Jul 23, 2010

Thanks guys, I got it off with a hammer and flat blade haha. Well it turns out my engine is metric and the g4 grubee is imperial and nothing fits so it looks like I'm screwed.

broHSI · Jul 23, 2010

Davee930 said:
Hey guys, so I'm trying to replace my hoot gearbox with a 4g grubee. The mounting plate I have must be too thin because I can't line my chain up and it will hit my tire. Also how to you get the hoot gearbox off? I don't know how to take the gears out so I can unbolt it from the engine.

Thanks!

Which 4g Grubee gearbox did you get?

What kind of Hoot gearbox do you have?
Does it have gears inside or chain and sprocket?
Does your Huasheng motor have a shaft or the clutch built into the side?

The Huasheng motor that came with the old style "JL Hoot" gearboxes has a 15mm diameter shaft.

I think that the Huasheng motor has a 16 mm or 5/8" shaft same as the Honda GX50 that
works with the newer 4g Grubee gearbox that uses a bushing around the 5/8" motor shaft

eldo · Jul 23, 2010

Can you cut a5/8 shaft on a Huasheng or HF key it for a keyway drill and tap it and use a clutch like Duane has on his Titans? Would not be that hard or do you need the bell housing too?

cruiser66 · Jul 23, 2010

I have the same engine as you. 15mm shaft. I went with the Q-Matic. They do have a shim available to adapt to the 5/8" shaft. Sort of pricey for a transmission, but I like the features and the USA parts. Should be coming in next week. .bf.

azbill · Jul 23, 2010

the shim is actually for the 15mm shaft so that 5/8" pulleys will bolt on

Davee930 · Jul 27, 2010

The shaft on my engine was too small for the grubee g4 trans I got. I got some shim stock for 5 bucks and used 5 layers and now everything is tight and running smooth.

jbcruisin · Jul 27, 2010

azbill said:
the shim is actually for the 15mm shaft so that 5/8" pulleys will bolt on

Bill's right. You can't cut down the 15mm shaft to make it 5/8" because 15mm is smaller than 5/8.

chrisnbush · Sep 13, 2010

Hi folks -

I have a used DAX titan motor on a moon dog, ready to go except for the gear box - kind of stuck I think. I got the Stage III grubee but it doesn't fit the titan stock - the titan has the clutch shoes installed, and looks like the crankshaft has been shortened somehow at DAX.

Even so the clutch bell is too big to fit over the shoes, doesn't fit into the recessed crankshaft + clutch shoes area.

Was thinking of getting the BGF cheapo transmission, the "upgraded" hoot, but read such bad stuff about it here I am not going to touch it. Too tall without a smaller output sprocket, and I have GOT to stop buying crap...

Does anyone know a gearbox that will bolt directly to a Titan, without significant mods ? Since the G4 is the upgrade to the stage III I would think it wouldn't fit. Leaving off the BGF crap, the only others I have heard about are EZM or Qmatic.

I am stuck on the direction to go. My bike sits in the basement looking cool, minus only a gearbox to get rolling (I have a 56 tooth rear sprocket).

Any advice would be appreciated

cb

ocscully · Sep 13, 2010

There a re a number of primary reductions that will fit your Titan motor. There is a version of the Grubee G4 that is made for the HS-142CC motor that will fit. 4G T Belt Transmission Only (78mm) [4G-TBELTTRANS] - $119.99 Dax also has Duplex Chain Drive reduction box that will fit as well ENGINE_KIT_PARTS_PAGE_4 (midway down the page) This reduction unit is a 3.25:1 unit and should be in the range of a good ratio for a in-frame mounted 4-stroke. Stanton Inc also make several reduction gearboxs that would be direct mount/blot up to your Titan motor.

ocscully

chrisnbush · Sep 14, 2010

Thanks Ocscully !

Been talking to Duane at DAX on the DAX unit, that would be my preferred except that at 3 to 1 with my 56 tooth sprocket it is too tall. Also, DAX keeps the output shaft nice and short (compare to the one BGF sells, long output shaft - seems like it would be too much stress) but that makes it so I would have to drill new holes in my "grubee" mounting plate. So I am excited to here about the Grubee transmission that might fix the DAX, I'll look into it.

BigKid

MotorBicycleRacing · Sep 14, 2010

chrisnbush said:
Been talking to Duane at DAX on the DAX unit, that would be my preferred except that at 3 to 1 with my 56 tooth sprocket it is too tall. Also, DAX keeps the output shaft nice and short (compare to the one BGF sells, long output shaft - seems like it would be too much stress) but that makes it so I would have to drill new holes in my "grubee" mounting plate. So I am excited to here about the Grubee transmission that might fix the DAX, I'll look into it.

This gearbox will fit your motor.

only $34.95 with shipping already included !!!

Gas Scooter Mini Moto Bike Parts Transmission Moped: eBay Motors (item 180360796487 end time Sep-16-10 01:06:19 PDT)

chrisnbush · Sep 14, 2010

Well that looks nice on price, and being for karts I would think it would hold up, right ? The only thing is that if I line up the DAX, the G4 and this one, only the G4 has the output sprocket so that it will line up with the rear sprocket - kind of makes sense since I have their mounting plate. Otherwise I have to cut new holes and move the motor to the right side of the bike (sitting on it). That may be worth it considering the price difference ($35 vs $119, hmm...). But also on the G4 is the adjustability of the belt.

Thanks

ocscully · Sep 14, 2010

chrisnbush said:
Well that looks nice on price, and being for karts I would think it would hold up, right ? The only thing is that if I line up the DAX, the G4 and this one, only the G4 has the output sprocket so that it will line up with the rear sprocket - kind of makes sense since I have their mounting plate. Otherwise I have to cut new holes and move the motor to the right side of the bike (sitting on it). That may be worth it considering the price difference ($35 vs $119, hmm...). But also on the G4 is the adjustability of the belt.

Thanks

Chris,

Dax offers a 10t output sprocket for the 3.25:1 Reduction Box (May need to be purchased seperately?) so you have a 3.25:1 primary times a 5.6:1 secondary for a total overall reduction of 18.2:1 maybe a little tall?, but not much, and maybe right where you want to be? There are a lot of members here that are running 48t - 50t rear sprockets on their 50cc 4-stroke motors.

ocscully

Smoothe · Jan 2, 2011

Excuse me for digging this up, I found it doing research.

Would a 40T rear wheel sprocket work okay with a 3.25:1 gearbox? What kind of speeds could I expect?

wayne z · Jan 4, 2011

Smoothe said:
Excuse me for digging this up, I found it doing research.

Would a 40T rear wheel sprocket work okay with a 3.25:1 gearbox? What kind of speeds could I expect?

I have an 11 teeth drive sprocket on my 3.25 box and a 48 tooth wheel sprocket. Overall ratio is 14point something. I need pedal assist to take off. Clutch fully engages with full throttle about 15-20 mph.

Have trouble pulling hills but about 42mph topend , feels like motor is too loaded and can't reach full rpm. cruises nice at around 30-35.

I ordered a 56 tooth, I want to have takeoff without pedaling a the ability to pull moderate hills esaily.
kinda big jump though, prolly shoulda ordered a 52 or 54.

Wayne Z

Wayne Z

Smoothe · Jan 4, 2011

Thanks Wayne, it looks like I'll be contacting Jim about a 56 toothed sprocket.

Replacing Hoot Gearbox

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