Grubee Clutch Slipping with Wet GB

Discussion in 'Frame Mounted Engines' started by Irish John, Jul 3, 2008.

  1. Irish John

    Irish John Guest

    Today I finally abandoned the wet 50/50 gear oil/engine honey GB. I gave it over 100 kms but it was a heartbreaking experience and the clutch slip got so bad I was down to 12 mph at high revs on hills and pedalling my guts out. It slipped on the flat as well and probably slipped going down hill too. I've taken the cluch out to look at it and include pics below.
    I think it looks OK although I'm sure the clutch pads are impregnated with oil mix and wonder if it will work again. I'm going back to my white lithium grease and I hope the bike gets back to speed. I think I'll be happy if it chatters on hills like it used to and I'll probably be tempted to add a few squirts of oil and cause the slipping to start again.
    The pads are jet black but they look intact. I've forgotten what colour they were originally and I hope I'm not responsible for burning them black as coal!
    The wet GB has worked for others but it didn't for me. If a solution is found I can always return to a wet gearbox. The clutch was getting so hot that you couldn't touch the gearbox casing. If anyone notices anything from the attached pics and can tell me if my cluch looks OK i'd be most gratefull.
    I nearly tried replacing the 50/50 mix with pure 20/50 AMSOIL as per a recent suggestion but couldn't get it here and I'm over experimenting for the time being.
    The desire to improve on good enough has got me into a fix and I'm suffering a blow to my mechanical confidence.
    I wonder if I should lightly sand the pads to give them some grip?
     

    Attached Files:

    Last edited by a moderator: Jul 3, 2008

  2. acronn

    acronn New Member

    I also have this gearbox, and it is getting hot, SEEMS to slip a bit on steep hills, but not too bad, but it does get hot. I have synthetic grease on the gears, no oil. Sure gets hot. I weigh about 180 and there is the Honda 4 stroke 50 cc engine running the bike. I wonder what to do to make it run cooler and hopefully better. It seems too hot to last very long like this.
     
  3. Irish John

    Irish John Guest

    I used lithium grease because the kit instructions said it was probably the best if you aren't going with a wet box. How much grease have you got in there? I put in plenty and then add more.
     
  4. acronn

    acronn New Member

    Clutch Slip and gearbox heat

    I only have the gears coated with grease. Next I am going to pack the gearbox with white lithium grease and see how that goes. I live in hilly country. This Honda 4 stroke is working, I'm peddling, and the motor is not putting out enough. Also I plan to drill a hole in the exhaust, that may help too. When starting off I peddle and then engage the clutch and it always chatters, then it will catch and start speeding off, but I can feel the slipping going on too, and especially if there is any stress on the motor, like a hill.
     
  5. Irish John

    Irish John Guest

    That's not what I wanted to hear Acronn cos I was hoping my bike would go back to fast cruising & no slipping and even on hills I'd rather it laboured & juddered when it gets down to 25 km\hr than revving up and slipping. I take it you have a 48T sprocket and a freewheel drive sprocket. At present I have just greased the gears. I think I remember from the last time that too much grease isn't necessarily that good. The 5/16" hole in the silencer I think has improved accelleration a bit and it sounds better out the back. I'll report back tonight when I take it over the mountain and back. I'm expecting to have to sweat on the big hills but if it starts slipping I won't be pleased.

    Where can I get a 52T sprocket supplied to Australia by express post?
     
    Last edited by a moderator: Jul 4, 2008
  6. acronn

    acronn New Member

    Upon further inspection

    I pulled off the gearbox cover, and the only thing I can see that is out of the ordinary is the unusual wear on the inside gearbox cover from the spinning of the clutch, just touching the cover and lightly grinding into it, so I wanted to stop that from happening at all, and I have to learn how to remove the clutch. There is a blade screwdriver groove at the end of the spindle - and what looks like about a 1.25 inch fender washer also attached to that heavy-duty screw that holds the clutch flywheel into place, and this is just a bit sloppy loose to hold the clutch assembly into place, so I feel like that should either be bushed or the screw tightened, but when I tried to tighten - just tried with no real hope to get it to move, and had the motor switch off, well the whole spindle wants to move so there has to be a method to remove this flywheel/clutch. I have been searching the posts but can't find the approriate instructions. Oh well, it's just a fun hobby for me but I sure would like my bike to haul *me* up the hill.
     
  7. Irish John

    Irish John Guest

    Acronn, Taking the clutch out is easy. I've attached 2 photos with instructions to help you. The clutch & bell housing have a bit of movement even with the bolt fully tightened so that is normal. They make a clanking noise if you push or pull them and that's normal too.
    First you hold a screwdriver through the hole on the bell housing and that will lock up against the gear wheels and allow you to turn the nut so it comes undone. The keyed flange will then prise out easily with a screwdriver blade underneath it. When that slides off the shaft the bell housing and clutch will also slide off. You can get all the oil off the cluch and it will work again.
    To reassemble you do it all in reverse order and Robert is your Mother's brother!
    Hope this helps you.
    My bike is back to form with a light greasing of the gears and no slipping clutch. I am so pleased and it goes nicely at about 28 mph. There's a bit more vibration which might be because the wet gearbox caused a bit of stress to the motor but no terrible rattles. I have to work hard on big hills but that is just what these engines are like with a 48T sprocket. With a 52T my max speed would probably be about 25 mph and I might be able to bear that.
     

    Attached Files:

  8. Irish John

    Irish John Guest

    Pleased to say that going back to grease has totally solved my clutch slipping and the bike runs as normal again. It's no noisier and it only gets warm now and not hot to touch.
     
  9. cheap ride

    cheap ride Guest

    Hi John, i agree the grease works good enough, i weigh about 95kg and i'm using a 56 tooth sprocket, hills are no problem and the g/box is quiet at 50 kpm, however i think if i can get my sturmey archer hub idea to work that should fix the grabbing at low speeds.
     
  10. Irish John

    Irish John Guest

    Acronn, are you sure the grinding mark on inside cover of GB isn't from yhe bolt that holds the first gear wheel on. That is a very common problem and you may need to use a thinner washer or replace the bolt with one that has a thinner head or file off the head of the bolt or at least two of the above. Sound very much like this is the case.
    Incidentally I cannot belive that you can do 50 km\hr with a 56T sprocket. Your front drive sprocket must have less teeth than mine. I weigh 84 kg and I cannot get that speed out of a 56T - no way.
    Sorry Acronn it's Cheap Ride that gets that speed not you - I muddled the messages up.
     
    Last edited by a moderator: Jul 5, 2008
  11. Irish John

    Irish John Guest

    How many teeth on your front drive sprocket Cheap Ride? Is this 50 km\hr on the flat without a big tailwind or running out at the bottom of a steep hill?
    I can't see how you get that speed but HoughMade does as well. You must have the Honda and not the HuaSheng - am I right?
     
  12. acronn

    acronn New Member

    Clutch slipping and bell housing removal THANKS UNC

    I'm not sure how fast I'm going, on level or slight uphill I can get maximum speed but the digital speedometer isn't correct, when I walk with the bike the speedometer was showing 6 mi per hour so that isn't working right. It feels about 30 or a bit faster. I've seen it saying 60! I took some pictures of that grinding, the clutch, etc. It is much smoother, the gearbox is running cooler - the picture of the gearbox cover inside shows the grinding. I don't know if it is still touching the cover or not, but it is sounding smoother, using the white lithium grease and the bike will go fast now. White Lithium Grease - from an old can - The new Lithium Grease I got is red and says it's for disc brakes. Didn't mention the color of the grease on the outside.. That grab and surging feeling is still there with the start up, and if I try to start up a bit slow, or uphill, then the motor really sounds like it has to work and the ride is bumpy as the clutch is engaging, what I would like is a way to get that start up smoother, with the engine not sounding like it is working so hard, with me peddling easier and more feeling balanced, and also as long as I'm dreaming bike has a fast running top end, as it is now, the top speed is more like there might be a fuel starving or filter clogging at max, but otherwise the motor runs great, with the idle very slow and quiet. Your description of Labored and Juttered The gearbox is quieter, but still very loud to me. From the pictures - there was grease in the clutch, I cleaned off the pads and reinstalled. This only had grease, no oil in it, but it was not white lithium grease. I wonder what that grinding is from, the pictures show the housing damage. This is fun project, bell housings that you can hold in one hand.

    The first picture is the gearbox cover, second shows the clutch and that keylock pin that I couldn't get out, third pic shows how the muffler exhaust actually touches the bike, I have worked on the motor mount and have fastened the motor more forward, running 1/4 inch bolts all the way through, as the existing metric were stripping out.

    Irish John- I got that clutch bell housing off, there was a sleeve that I had to pry off once I got the screw loose. I held a fin from the flywheel to be able to unscrew that first screw, it was not very tight at all, and I put loctite back on that screw when I put it back together. I tried to see how to get the clutch actually off, but I just cleaned it up, took these pictures and put it back together, because I could not get that pin out that fits in the slot that seems to hold it all together, it looks like it was hammered in there tight. I would like to be able to remove the clutch pads and isn't there something that is lubed in the back there? This bike has a 46 tooth sprocket. 56 tooth seems like it would give a better ride while climbing hills.
     

    Attached Files:

    Last edited: Jul 6, 2008
  13. Irish John

    Irish John Guest

    Acronn, I thought I answered this but maybe I didn't. I posted how to do it pics for you to follow. The clutch itself prises out. You don't have to touch the steel key slotted into the shaft. It says there. The clutch slide out with a bit of help. There's wear on the inside of your bell housing and it must be from the clutch. I think you need to take it out and have a look. The head of the bolt has worn into the inside of your gear casing and you need to fix that by the methods I described above. You shouldn't need too much grease just a good amount. If you pack it solid it probably won't work well. I've tried and it didn't stop the gears from throwing the grease off but it's a good sound insulator. I think your clutch is too far out along the shaft and is rubbing against the bell housing. There's a reason for this and you need to see what's causing it.
     
  14. acronn

    acronn New Member

    Grubee Gearbox, Honda Engine whose clutch?

    Today I pulled off the Grubee gear box cover and wanted to get at the clutch, to pull it off and to find out where the problem of the grinding inside the gearbox cover is coming from. It looks to me that the clutch mounting should be further on the shaft, and the keystock is jammed in there, nothing will move it so far, but I didn't want to force things at all, perhaps someone has seen this before, I wonder what to do to get that piece off of the crankshaft, or to get it all the way on, either way would be alright to me. Here is a picture of the problem.
     

    Attached Files:

  15. Irish John

    Irish John Guest

    Acronn, The key piece looks damaged. You need a new one. should be easy to get. tell me you can get the screw out & washer and then the flange and then the bell housing but you can't get the clutch off. It looks like the clutch needs to slide ove that key piece to come off. You might need to try prising it from both sides at once to get it to go over the key. The key may need filed a bit to help. My JL Hoot arrived just now. That tray won't fit my Merida so I need a bike to fit the kit. The one sahown in the picture is a Walmart Schwinn of a type I can't get in Australia. It has no freewheel hub & a very small fixed drive sprocket and an HT 44T sprocket. The tank is badly dented as well but it has a better exhaust than the stick straight out type I've seen other kits. The HS engine has a 15.8mm X 33.5mm shaft and it says it's the same as the Honda GXH 50. I'll check that cos that's not whatit says on MBc postings.
     
  16. acronn

    acronn New Member

    It all fits now

    Well, got the clutch piece off, the key out and what it turned out to be was that that clutch piece was backwards - and it must have a little bit of a taper on the crankshaft hole because it fits much better now. That's how I bought it- used - good thing I found the problem, thanks for the help. Tomorrow I will put it back together, the Grubee gearbox and I'm looking forward to the difference. It will prbly be quieter. I read where some sound proofing was used on the cover, and I just couldn't see how it would fit, but now there is enough room for something like that.
     
  17. Irish John

    Irish John Guest

    Acronn Don't worry about sound proofing the Grubee the rocker arms make more noise than the gearbox. It really isn't an issue with stage 2 grubee GB.
    I thought that clutch looked funny but assumed it was a JL Hoot clutch when all along it was the wrong way around. I think you need a new key.
    Are you fitting a grubee GB onto the HS motor that had the Hoot Gb. I didn't know the shaft size allowed that but am very keen to find out if that's so.
     
  18. acronn

    acronn New Member

    Irish John I don't know exactly all the parts on my bike yet, but I do know that this is the Honda GHX 50cc 4 stroke - It has the Grubee GB but as far as the Hoot GB I don't know the past history but I doubt it. The bike was near new when I got it, had about 50 miles on it. Later on this morning I will get the bike back together and see how it goes. No other extra parts came with the bike. I couldn't figure out how to get the clutch spring in as it is very stiff, so with 2 8" C clamps that lightly held the clutch spring in - grabbing from the other side of the engine - and then pried the spring over into the recess for it, it worked! No way I can see how it could be done in the field without some good tools, so if that screw loosens up, you're toast. The locktite held it well from a few days ago, and now there are more threads in there, as the whole assembly is about 1/2 inch deeper onto the crankshaft now. Have fun with your new ride.

    ----- later today ---

    The bike rode much better. Much less chatter and clutch surging problems, smoother. Now for a bit more power, you have some experience in pulling off this governor, when I had the gearbox off, I got a good look at it, will I get more top end RPM's with it off? That may help climbing hills. I now have several good *tester* hills, and so far this is the best performance.
     
    Last edited: Jul 15, 2008
  19. jimraysr

    jimraysr Member

    I have two of the GruBee boxes and both have a large headed screw to hold the bell housing bushing onto the engine shaft. I think that gives better clearance than the bolt and washer shown in the instructions.

    Proof will be when I get on the road. I am waiting for a new 56 tooth driven sprocket. I tried everything to get the one in the kit to run true, but it has two high spots so no amount of adjusting the mounting pads would get it under around 75/1000s run out. It would actually rock on a flat surface. I tried to correct it but it has more problems than just not being flat.

    I assume to get the 56 tooth to run faster would require a larger sprocket (than the std. 11 tooth) on the gear box?

    I see where dax in his instructions suggested turning the teeth in towards the spokes to give the chain a better torque alignment? Also after taking the sprocket on and off a few times I am inclined to turn the bolts around and cut off the excess to give good clearance to the bike frame. My Schwinn has two jam nuts on the driven sprocket side which gives around 3/4" to the frame mount lug.

    Has anyone tried turning the bolts?

    Jim

     
  20. acronn

    acronn New Member

    If you have the room I don't see any reason why you couldn't put the nuts on the outside of the hub, it would pinch just the same and that is the reason they are there. On my bike the clearance is too close to do that, I don't even have a washer between the head of the bolt and the sprocket. Some people have to counter sink the bolt heads to fit their bike.
     
Loading...