GT2 vs 2A and GT5 vs 5A???

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mapbike

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
rogergendron1 said:
your right man and i fell for it too... i am not a victim of advertizing though i am a strait up idiot for not doing more research, i did not get ripped off... i wasted money buying a gt5 that could have been better spent on a dax kit that was 100$ more. i saw that 100 more and the big grubee ads and fell for it.... its nobodys fault but mine for wasting my money on something i could have done more research on.

now if i could go back in time i would spend that 225 $ plus shipping on the dax kit and with the same work i put into my gt5 (just to get it to run the way i want it ) i would have had a friggin beast of a motor !!!!!

fact is thAT those biggger bearings and the better cdi and seals are probably all junk anyway lol ....


aahhhh Damn it i should have bought a dax !!!!

srsly though i am ok with the money i spent on the grubee gt5 i am not ok with the amout of work i put in to it to get it to run like a dax would have out the box ~!!!!

i honestly recomend the dax kit to anyone who asks about building a bike !!! and when my gt5 goes kaboom.... it replacement will be a dax balanced lower and top end seperate so i can mod it before it goes together and back in my bike .
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If you have your engine running the way you want that is all that matters, but I can honestly say that my dax lower build is the fastest and smoothest china girl I have had hands down, the smoothness is what is so nice, being a single cylinder engine bolted solid on a bike it isn't butter smooth with zero vibes but it is comfortable to over 8000rpms on mine, the way I did my porting hurt my bottom end a little but midrange and top end speed and power make it a good trade off for me since I dont put around town on my bikes much, I live in the country several miles form the nearest town, being several miles from anything but country roads causes me to enjoy good mid to upper speed and power for longer distance cruising and my dax build is the best I've had for it because I like to cruise at 35+mph so it dont take me so long to get where I'm going.
As soon as someone has a balanced crank for purchase I'll invest in that so I can smooth up a couple more of my HT engines and get them to at least a nice comfortable 35+mph cruise speed.

Huffydavidson said " once you go dax you wont go bax" and I have to agree that I feel the same way now.
I have roughly $125 in my engine since I already had all the other hardware.
Map
reddd
 
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maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
The only extra cash I'll ever spend will be on a Dax balanced lower assembly.
(or hopefully a crank kit! hint hint for us poor guys)
I have no reason to spend more. Ming gives me great motors at a great price.
Never saw a grubee that was any better than my $150 kits.
 
mew905

mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
rogergendron1 said:
here u go other than the cdi and magneto the crank is a little diff and the jug has larger intake port and the studs are 6mm not 8 like the standard gt5

i wanted one bad because the cdi and mag are all in one and suposedly make more power. it would have given my bike a cleaner look with less wires and also tthe intake port would require less work to get ported and can be ported a little larger. pluss the puch head will fit this motor no drilling. but nobody can find one aanywhere they are not makinmg them anymore
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You're referring to the Super Rat, which is a bit different than the GT5-a. The built in CDI is irreplacable (aside from OEM parts), so you have no choice with that, the magneto is larger and yes, the crank is slightly different.

The OP asks what the diff is between the A variants, and you're right, larger intake *bolt spacing* and port. However the I.D. of the manifold is the same, so offers no real extra power. However this does mean you can port larger and put larger manifolds on (up to 3/4" I.D.) if you have fabrication skills. The manifold is also better made IMHO, rather than a welded steel tube, its a full on bored out aluminum cast manifold. 40mm intake AND 40mm exhaust bolt spacings mean you can truly port match, though it already is from the factory.

Other than the intake and manifold, there is no difference between the GT2 and GT2-a, or GT5 and GT5-a. The SR and SM (Super Rat (GT5SR) and Super Mouse (GT2SM) respective) have the built in CDI's, larger magnet, different cranks:confused: and the same, larger intake as the A variants. You should, in theory, be able to swap the GT5, 5-A and SR cylinders between them (However not having an SR I cant say for sure, I only have 5 and 5-a's)
 
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sublunacy

New Member
Sep 12, 2013
90
0
0
ontario
the gt5a is stroked to 40mm and is the gt5 replacement since 2012. you dont even know what you got! shady use of old engines to take peoples money.... youll see
 
mew905

mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
sublunacy said:
the gt5a is stroked to 40mm and is the gt5 replacement since 2012. you dont even know what you got! shady use of old engines to take peoples money.... youll see
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my GT5a has a 38mm stroke, though. I'm fairly certain the only ones with the 40mm strokes are the Super Rat and Super Mouse. There are several differences between the SR/SM and the GT5/a, but the A and the vanilla variants are only differed by their intake size. Port matched out of the box, I plan to get another 5A cylinder later on because IMO the two absolute biggest power killers on these little motors is the transfers and the intake (both carb and manifold). 1/2" I.D. just isnt enough, alot of 5hp 50cc engines come with 3/4 to 1" intakes, and larger carbs than our 15mm toys... and the transfers are just straight up terrible, short circuiting like crazy.

EDIT: CONFIRMED! GT5-SR does indeed have a different crank. Utilizing a 6203 bearing, this means the crank CAN be swapped out with our GT5 engines to get the extra displacement, however whether or not the magneto will fit is a different question. However as stated in my HT compatible parts thread, this means the Super Rat has a crank the same size as most standard moped engines.
 
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Ouch that Hurt

New Member
Jul 27, 2013
38
0
0
Port Alberni, BC, Canada
thanks for all the replies guys!!!

I live in Canada, and the laws are different here. I got the 48cc to stay within the law. I'm pretty sure they can impound your bike here if it is larger than 50cc and goes faster than 32 km/hr; assuming you aren't registered/insured/licensed. Impound would be for a week and you would have to prove your documentation before you could have your bike/vehicle back. Impound fees would run around $300 too. Just not the a hassle I need for a few more cc and km/hr.

It has been a great lil motor so far.(knock on wood) It has been my daily driver all summer. And I plan to ride straight on through winter.

I believe I have the GT-2A; not the SM. It does have the external CDI, not the internal. But on an up note it does have the 40mm intake and exhaust stud spacing. So bolting on after market parts is a breeze.

I do have the "banana" expansion chamber w/ exhaust. It is a lil quieter than the stock exhaust and now I have a power band I can feel when it hits the pipe. Also, live in a pretty hilly area at sea level so the pipe really helps. Lil motor hauls my 200lbs a$$ up a 35-40% grade for about 10 city blocks to home everyday.

I get what I want from it so I am happy with it. I will be trying a boost bottle in the near future. Just trying to get the 4 stroking to stop at WOT. Which is most of the time cause; heck, its only 48cc.

peace
 
mew905

mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
Ouch that Hurt said:
thanks for all the replies guys!!!

I live in Canada, and the laws are different here. I got the 48cc to stay within the law. I'm pretty sure they can impound your bike here if it is larger than 50cc and goes faster than 32 km/hr; assuming you aren't registered/insured/licensed. Impound would be for a week and you would have to prove your documentation before you could have your bike/vehicle back. Impound fees would run around $300 too. Just not the a hassle I need for a few more cc and km/hr.

It has been a great lil motor so far.(knock on wood) It has been my daily driver all summer. And I plan to ride straight on through winter.

I believe I have the GT-2A; not the SM. It does have the external CDI, not the internal. But on an up note it does have the 40mm intake and exhaust stud spacing. So bolting on after market parts is a breeze.

I do have the "banana" expansion chamber w/ exhaust. It is a lil quieter than the stock exhaust and now I have a power band I can feel when it hits the pipe. Also, live in a pretty hilly area at sea level so the pipe really helps. Lil motor hauls my 200lbs a$$ up a 35-40% grade for about 10 city blocks to home everyday.

I get what I want from it so I am happy with it. I will be trying a boost bottle in the near future. Just trying to get the 4 stroking to stop at WOT. Which is most of the time cause; heck, its only 48cc.

peace
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Where I am (Saskatchewan) the limit is 80cc, but the police here feel its safer to be able to keep up with traffic, rather than limiting them, so my limit is 50. I'm also considered a bicycle here, so I fall under bicycle laws, not moped laws (no helmet required, stay off sidewalks, lights at night, etc. etc.)
 
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