Grubee Gearbox- running "wet"

[HoughMade]

So that's what that is- a fuel pump. I have one too....somewhere.

The 250 weight gearlub should work fine. I don't thing a tapped hole on top is necessary as you can just add lube through the place where the engager arm is, but to each their own. I would really like to hear a report on how the 250 works for you...as you can tell, I'm always looking for what may be better.

I did tap a 6mm hole into the bottom to drain it some day.

 

[motor puzzle]

Houghmade and Jimraysr, thanks for the reply. Just purchased the engine from small engine warehouse. Spoke to several vendors including Five Flags and no one has a frame engine mount, let alone a "mounting kit", which aparently are made from parsed out complete kits. It does seems that there are still plenty of the Grubee Gear Boxes out there. Might have to wait till Dax starts selling his engine mounts or make my own....

 

[Irish John]

Wet gearbox runs hotter with 56T

Since I started running my GB wet using 50/50 gear lube & engine honey I notice it runs much hotter. It used to be just warm after a 25 km run but is now quite hot - not too hot to touch but very noticeably hotter.
I think this is because I changed back to the 56T sprocket from the 48T.
My top speed with the 56T is 27 mph and the revs are too high at that speed for me to keep it up for long. The vibrations are just too worrying.
I like being able to climb hills that were previously an effort but I can't take having to sit at 23mph where the revs are bearable. The fuel consumption has gone up markedly because of the increased revs and I just know that the motor will wear out if I keep using this sprocket.
I think the only satisfactory answer is to get a 52T sprocket and I don't know where I can get one. If I can't get a 52T I would go back to the 48T I got off an old HT kit but 48T is too small and when the speed drops below 18 mph on a long incline the motor doesn't like it.
I've also noticed that the clutch slips more with the 56T because there is much more torque on the back wheel.
So my questions are these:
Where can I get a 52T sprocket that has the right holes for mounting?
Can I fix a slipping clutch or do I have to buty a new one and where can you get a clutch for a Huangsheng? The clutch is OK now but won't last if I keep using the 56T.
The smaller the sprocket wheel the less comfortable the motor is at lower speeds. The larger the sprocket wheel the less comfortable the motor is at higher speeds. I've tried 44T, 48T and 56T and I reckon 52T would be about right.

 

[cheap ride]

Hi Irish, I am in Perth, W.A. and have the same setup as you, Huasheng with Grubee box and 56 tooth rear sprocket, i agree with what you are saying about the 48 tooth and the 56 tooth, it would be nice to have a sprocket in between like you suggest a 52 tooth, then you have the best of both worlds, i think kings can do one of these sprockets, they had an advert on the forum, on the left side, however they are quite pricey, and i think they are aluminium, may not last long, i am not shure, I have a sturmey archer internal geared hub(3 speed AW) and i plan on mounting it between the engine and the rear wheel, I have done all my gear calculations using a downloaded calculator from member J pilot only thing stopping me from going ahead is my indecision about whether to mount it the normal way, and get 3 gears or do it the easy way and just turn the hub the other way and have 1st and second gear, second gear is 1:1 ratio , 1st gear is 25% less, good for take off, i have every thing i need, maybee i will start this weekend. Irish i am keen to know how your success continues with the 50/50 mix in your box, and please tell me what brand of stop smoke did you use, I think your box was hotter because your mix is more a liquid now, and therefore has the ability to transfer heat alot more effectivley where only using grease, it's only on the cogs so only the air within the box is heated and alot of that is expelled out of the hole on the top of the box where the gear engager lever is. Another way you could possibly change your gear ratio is to change the output sprocket on the other end of your chain, but i don't know who would sell a sprocket for it. Good luck with your hunt for a sprocket.

 

[Irish John]

Thanks CheapRide,
The Stop Smoke engine honey is made by Nulon and it's Aussie. Need to microwave it first after mixing so you can pour it in the engager hole. Kings do a 50T not 52T and if it's aluminium it won't be any good at all. Who would make a sprocket out of aluminium apart from the Chinese? might as well make one out of pastry! I could change the output sprocket to another one that you can get but I think it might be 1 tooth smaller. Anyway a freewheel srocket is a total necessity to life & limb so that option looks closed.
This sturmey Archer hub - please explain cos I have a 3 speed one lying about. The good thing with Sturmey Archer hubs is you can service them etc. Not like Shimano. I'm very interested in your hub idea. A 50T sprocket would be marginally better but 52T is the answer. There are bike chain rings of 52T that could probably be welded onto an old 44T to sort of make up one that fits on the wheel with the 9 holes for fixing. If the 50T is aluminium it would explain why they sell for about $15. Thanks for the heat transfer info - I think you are right. Oh yes, don't forget the silicone gasket gunk around the GB casing or you'll leak oil over the garage or even the bedroom carpet if you sleep with your bike. Sorry it's Spooky Tooth that have the 50T. What's the URL for Kings?

 

[jimraysr]

Making a copy of the gaskets

Good information on the GruBee gears.

I am still in the build stage. Haven't found a 3 piece crank to fit my 1.5' lower bracket yet. Also waiting for a clutch with the correct keyway slot.

My clutch has a slot (4mm), but the race bushing for the bell housing and the engine shaft have a 4.5mm slot. Go figure for the China folks to ship two different size keyways to make my life complicated.

Anyway my contribution to this is I copied the gaskets for the gearbox on our all in one printer. A couple of times on plain paper and a couple of times on folder stock.

When a kid, I saw my dad make new head gaskets for refrigeration compressors from folders when we were out in the sticks. He used a ball peen hammer to cut the new gasket on the compressor cylinders. Of course those were cast iron so no damage was done. Would not suggest doing that with the aluminum gearbox case. ) I have put a layer of RTV on both mating surfaces of the gearbox and the engine, so might not need a gasket?

I also would think the oil would do a better job of transfering gear heat to the case?

Jim

 

[cheap ride]

John, the sprockets from kings are aluminium unfortunately, and are 46 bucks U.S. incase your still interested type in this url and go down three quarters of the page and on your left is an add for kings, click on the add (picture of sprockets) her is the url http://motorbicycling.com/ as for the three speed hub info, type in a search on this forum worded, a new geared experiment idea maybe ? read all the way through this thread it's quite informative john, When you get about half way down the first page you will see a post from member Dan, (i ride customs) he has put some great pictures of a custom made bike of his that he fitted a three speed hub to, and he mounted it opposite to the way it normally goes, this is where the idea originated from ( Dan ), since then i have seen a few others on this forum do similar things with internal geared hubs, i like the old sturmey too, cause you can lube it on the oil port.

 

[Irish John]

Thanks CheapRide, I'll try one of those special anodised aluminium hubs but all the geared hub stuff on that thread left me a bit lost. I'll try reading it again tomorrow and see if I can comprehend it all. I like pictures and I'll look at those to see if I can fathom it all. Andyinchville seems to know his gears and it's great read about ideas like this.

 

[Irish John]

Yesterday my petrol tank sprang a serious leak at the rear left threaded post. Can't see how I could fix it because soldering is all I could think of so I ditched it and put on the larger tank that came with the kit. I loved the teardrop tank from my oldHT (actually it was less than 3 months old) and I had done a special paint job on it to match the blue bike frame and spayed clear varnish over the MBc lettering. Shame to see it rendered useless after spending about $30 on painting it.
Anyway back to wet gearboxes - I decided to drain my 50/50 gear lube & stop smoke engine honey out which had only been in for a couple of days because I used too little silicon gasket sealant and didn't do a good job so it leaked. I took the gear box apart and degreased everything as per HoughMade's method. I put plenty of silicon on both surfaces and put the original plastic gasket between the cover and the gearbox casing. I drained the 50/50 gunk into a jug so I could reuse it (it's expensive!) and I took the clutch apart to look for wear. It looks OK which cheered me up cos It had been slipping a bit with the 56T sprocket and I was worried about it.
I also drilled a 6mm threaded hole for a drain plug in the casing at the bottom near the front and installed a short 6mm bolt with 2 flat washers & a split washer.
I used red loctite stud lock on the bolt threads and a dollop of silicon to help seal the bolt. I haven't filled it with 50/50 mix yet because I'm taking advice from this page and letting the silicon harden for 24 hrs. Tomorrow I'll fill the GB and I'm hoping it wont leak. The last leak only occured when the engine was running. From the start I saw minute bubbles coming through the silicon sealant which I reckon were caused by two things:
1. The pressure in the GB must be quite high when the gears are spinning fast and I reckon the gunk was so tacky when cool that it stopped air escaping fast enough from the engager hole which accounted for the bubbling through the casing gasket.
2. The silicon hadn't cured and wasn't on thick enough to stop it behaving like bubble gum and letting air and oil bubble through.
After stuffing the first attempt up I expect to fail again and am apprehensive about what will result. I'm worried about the drain plud cos its only a thin threaded hole and I daren't tighten the steel nut too much cos it would definitely strip the aluminium threads on the hole. I'm keeping my fingers crossed but if I fail again I could always revert to lithium grease. Meanwhile I'm back on the HT which is quite fun going up hills the 4-stroke can't handle but the top speed is slow and noisy and I'm quite rough with because I hate it so much!

 

[Irish John]

Help! Clutch slipping on Grubee

Tried my new sealed GB out today and no leaks but the clutch is slipping badly even at speed. the top speed is down due to the slipping. I wonder will I have to go back to grease. I've got 3.5 fluid oz of 50/50 in the gear box and it must be making the clutch slip. Any ideas from anyone as to a remedy. I have a 48T sprocket on it now and I thought that ran well on Friday night and saturday but is slipping badly since I cleaned the gearbox and refilled it with the old oil. The clutch pads looked good when I saw them yesterday but if it continues to slip it will wear them out. Would it help to take the clutch out and sand the pads?