Anyone Running The New Grubee 66cc Yet

[cannonball2]

I have been wanting to try a genuine Grubee for some time now, but they have been impossible to find(at least for me).

Found the latest 2015 models for sale on ebay and bought the complete engine.
Its not cheap @$188, but am curious if the quality that China Gas hypes is true. If so this should be the top of the heap of the currently available CGs out there. I have a Grubee 48cc round head that is an extremely fine little engine its a 2010 model. Hopefully this is worth the extra $$. Decals gotta go though!

http://www.ebay.com/itm/281824140193?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[Rudz]

You could have gotten the engine only for $50 less

 

[crassius]

reading the stickers, I see they are still claiming to be chainsaw motors

 

[cannonball2]

You could have gotten the engine only for $50 less

I saw that from the same seller, however I wanted the complete engine set to gave it a fair shot.

The one thing I know from my 48cc is that the carbs are different sizes(smaller than the 66cc) and jetted differently. The other kits I have had use a one size fits all carb and jets.

Am hoping Grubee has actually done what they say and is selling a fully developed product. If not then its just another CG engine and $188 isn't going to break me.

Check the website its a wealth of info. http://www.grubeeinc.com/index.html

 

[crassius]

looking at the links, I'm wondering why the grubee is sold by mzmiami instead of grubee

 

[cannonball2]

China Gas the actual company I believe operates thru a distributor net work. I believe Nationwide LLC(Gas Bike, Kings etc) was the last distributor in the US. If you read on the site CG indicates that the above was selling products under their name that were not of their manufacture and ended their relationship. To my knowledge the only Grubee stuff showing up in the recent past was NOS and often a few years old.

MZM must have some agreement with CG, ordering direct from them or is buying from another distributor. The investment for a distributor required by CG was pretty stout, requiring some serious desire to handle their products.

Who knows, just glad to see them back on the market in the US. A least we know who makes them and at least they seem to try for a quality, if not pricy product.

I suspect KC Vale could clue us in a bit.

 

[cannonball2]

After looking at the ID tag on the engine it clearly shows MZMs website. So MZM must have ordered spec engines in some larger quantity.

The thing is MZM has been dealing with CGs and parts for some time, I have bought a lot of stuff from them, good folks. With this background they must have some faith that the CG/Grubee engines are worth the effort to obtain and the higher cost.

I got curious enough about my 48cc to remove the head. Not only was it properly torqued, but it has the nicest bore and stock ports of any of the CGs I have seen either first hand or in pictures.

Also look at this link( click year 2008), it indicates that the Gen 2 engines have a steel cylinder liner. What a great thing that would be.

I am in no wise a Grubee groupie just hoping that somebody will build a decently made/ running CG out of the box. Maybe this is it.

http://www.grubeeinc.com/Aboutus.htm

 

[sbest]

I have a new Grubee.
Happy with it, 37mph on a 44t sprocket. The supplied black muffler was loud and restrictive. What would you like to know?

 

[cannonball2]

I have a new Grubee.
Happy with it, 37mph on a 44t sprocket. The supplied black muffler was loud and restrictive. What would you like to know?

Thanks for the reply. Am wondering about the general running and smoothness. The muffler is a catalyst so restrictive is a given I imagine.
Still your top speed calcs to around 8500rpm which is great for a stock engine(if its still stock).

My interest is in a good running stock motor out of the box. I have had some where close to 10 of the CGs over the years and they have gotten better. A good many of the ones I have had were so poorly made that they were a rough casting kit for the buyer to finish. No where have I seen a manufacturers website like Grubee that shows/explains their engines. Seems they have nothing to hide and take some pride in their product.

All that said, my spending nearly $200 for an engine only is a last effort to find a decent out of the box experience. If this one doesn't make it or get close I'm done. Might be here today

 

[sbest]

Mine is a GT5A made 5-10-2015 at the Yuan Dong factory, bought from a Grubee dealer in Canada.
It has 6mm mount bolts, 40mm intake stud spacing, NT carb and angled 3 prong plug and Allen bolt hardware.
I checked the bolts for tightness, installed it and ran it with 20:1 oil as recommended by Grubee.
Only mod at this point was the "Z" intake to clear the frame.
Break in was 3 tanks of this mix, using short bursts of full throttle and coast with stock carb settings.
Fuel mileage was terrible, about 20 kms on the first tank. Oil dripped from the exhaust, top speed 30km/h range.

By tank 4 it was running much better, speed and power increased. Cut oil back to 40:1
Replaced the stock black exhaust pipe with a chrome one from the dealer, quieter and more power.
Made jetting corrections thru plug chops and getting much more kms to a tank.
Top speed with the stock 44t sprocket is just barely 60km/h with 55kph always achievable on a flat.

I had some problems:
1) with plug forward it detonated and warped the head likely from the plug running hot. Even with plug to the rear the engine would run hot on hills at WOT with a "popcorn popping" kinda sound. Sanding the head flat and sanding more squish area right out to the edges solved this.
2) The air filter let grit through, scoring the piston and bore. I now use a better filter.
I am still running this scored cylinder but have a new top end ready too go.
This scored cylinder runs better on 32:1 oil, no more or less.

Even scored, my top speed is still in the 55-59km/h range and will run at WOT for hours.
Vibrations are not bad but I have it on a very solid bike.

My Grubee sticker did not withstand my boots, mostly ripped off. Sorry for the photo quality.

Kind of muddy due to the trails and back roads I ride.

Steve

 

[cannonball2]

Great write up sbest! Thanks for sharing your experience. The cylinder head you have is like the one that came with my Flying Horse, its not really a GT5
head. It ran very hot on the FH like yours. I replaced it on the FH with a center fire and the problem was over. I included a pic of the GT5 head. No telling how it got on the Grubee.

Well maybe same but different is a good description.

The bad: The only thing really negative was my cylinder head has an impact gouge right in the seal "ring" area that would have sooner than later been a gasket leak. It an issue of quality control and nothing else, but that can affect the end product ruining the end users experience.

The same: Ports are a bit cleaner than most but still have some minor flashing that could be quickly cleaned with a Dremel or even a bit of carving with an Xacto. For a stock motor I will leave them alone.

Different/better: The bore is very nice. I think its Nikasil, doesn't appear plated. Has very visible hone marks in the right pattern. I like the round exhaust port, will be very easy to match.
The crank is heavily counter weighted and very nicely machined. The rod has numerous oil holes/slots is marked ZAE80.
The entire engine/"trans" turned extremely smoothly spinning with the
jug off.
The case is like none other and very stout.
Absolutely no debris in the engine, very well oiled, nice gaskets.
Have not opened the reduction case, but the gear lash turning the output sprocket is the least I have had. Long clutch arm is nice too.
Head nuts(big!) properly torqued.
Nice stock transfers.

So what about it? If the head wasn't dinged Id probably give what I see 5 stars. Otherwise its the nicest out of the box engine I have had yet.
The proof is in the running though and I don't have a build done for it yet.

Is it worth the money? Wont know until I run it. I do know this one will not get the usual final straightening out that my previous engines have gotten. I should plane the head on my glass sheet, but don't want to change the compression.
Will JB weld the gouge and run it til it blows if it ever does.

 

[cannonball2]

More pics.

Sbest. After looking at your head again It may be the GT5 head, it looked flatter like the FH head. My computer stretches things a bit to fit it on a 21" screen that may be the deal.

 

[crassius]

More pics.

Sbest. After looking at your head again It may be the GT5 head, it looked flatter like the FH head. My computer stretches things a bit to fit it on a 21" screen that may be the deal.

Was that first pic done with the barrel raised a bit, or does your intake open a bit at bdc?

 

[sbest]

Was that first pic done with the barrel raised a bit, or does your intake open a bit at bdc?

It has to be Crassius.
The piston is WAY below the exhaust port.
I bought my Grubee GT5A from these guys;
http://www.motorizedbicycle.ca/
Wonderful service, Highly recommend them to Canadian customers.
My only complaint is wanting more aftermarket selection.

My gaskets don't look as nice as yours. Otherwise, looks similar.

I would recommend sanding the chamber dome squish area out to the edge of the head gasket. Note the little corner pockets in this sketch:

And my sketchy little representation of what those gaps do to cause detonation:

Steve

 

[cannonball2]

Was that first pic done with the barrel raised a bit, or does your intake open a bit at bdc?

Yeah the cylinder was sitting on the rings when the pic was taken. It was a shot mainly to show the bore. The second pic is BDC

Sbest, I will later plane the head. I assembled it with a dab of JB Weld on the gouge in the head to be able to run it stock first just to see what out of the box runs like. Thanks for taking the time on the graphics!

I went ahead and pulled the side covers. The mag according to Grubee is their own version. Looks like some of the better ones I have had with the external ground jumper soldered to the laminations. Was kind of surprised to see the white wire, a lot of mags have dropped them. Interestingly enough there is a metal shield over the mag oil seal between the mag and case. The rotor looks nicer than most. Stated timing is 28 BTDC. CDI looks like a standard version

On the gear side nothing spectacular, but the gears look nicer than most of the CGs I have had. The crank gear is well seated and runs true. There was a minimum of grease.

Grubee states the carb is a new more efficient emission version. Looks externally like an NT. Havent gone into it yet. According to the excellent manual that came with the engine is a compliant PE14 carb using the smaller 14.4 mm slide. They list a larger 14.95mm carb for performance.

So from a purely observational non running stand point I'm more Impressed with this engine than any I have had before, but I'm not blown away.

The nicest thing is between the manual and the website they pretty much tell you everything there is to know about what you have unlike most CGs that come with very little to no information leaving the buyer to figure out just what you got and what fits and what doesn't--usually the hard way.

 

[sbest]

I have the white wire also and will probably use it to charge a 4 pack of NiCad AA cells to keep lights on at night and a motion activated alarm. The trickle charge should not drain the ignition.

My gears were noisy for the first few tanks of fuel but have quieted nicely. Every other tank of fuel I wipe off the excess grease and apply a matchstick dab of hi-tack EP2 grease spread over the center of the gear teeth.

I did buy the CNS performance carb but have not tried it yet. So far the NT has been sufficient.

My bore is chrome for sure, not nikasil, like my KTMs are.

Yes, these are not a Honda or KTM, but a hobby of their own. Their simplicity and availability of cheap parts make them an experimenters dream come true.

Steve

 

[cannonball2]

Its good to hear your engine is doing so well.

That's the carb that came with my 48cc. Runs very well. I ran the course with different carbs on my Flying Horse. Was not real fond of the SHA type. I finally settled on a carb for a 50cc Yamahopper moped. Its very similar to the carb you have there. I like the adjustable idle/low end.

I agree about the hobby aspect of these things. I really like the concept of a small very lightweight motorbike/motorcycle. I rode many 50cc small Japanese MCs in the late 60s and they I guess set the standard for good running. If some one would make a decent top end with broad porting with good tractability and a cast iron cylinder. This would make a great little engine.
Cast iron cylinders are all over ebay for various engine for low bucks. I'm sure the Chinese CG manufacturers could do the same for these engines. If they could get smooth runability like a small M/C engine, I would have no problem spending $300 or so for one.

 

[crassius]

metal shield is really just a trans shaft bearing with the inside seal pulled off

 

[cannonball2]

metal shield is really just a trans shaft bearing with the inside seal pulled off

This engine actually has a large metal plate bolted under the mags frame. The parts list calls it a seal retainer. Must be some reason to go to all that trouble. Ive never see a seal pop out. Who knows.

 

[crassius]

that's new, never seen that plate yet, but have seen those seals pop completely out

even since the large mains got changed to small, there have been seal changes