Speeddemon Kit, Or Grubee GT5A?

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Intador

New Member
Jan 23, 2014
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Canada

Intador

New Member
Jan 23, 2014
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Canada
Okay so i figured out that the 40mm intake spacing isn't a problem, but which engine is more reliable, I'm stuck on which one to get
 

bgard

New Member
Oct 14, 2013
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Canada
I have 2 of the speeddemon kits. Both kits are rock solid. They are upgraded. Better bearings and all grade 8 fasteners. I am ordering another to make a rocket out of. I had a Skyhawk and it flew a part. Weak wrist pin bearing.
 

Theon

New Member
Jan 20, 2014
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FNQ Australia
You want a 40mm stroke if you can get it!
GT5 from my experience has 38mm stroke and weird piston rod combo.
Center fire head is better ,you can always shave it to increase compression but better the plug is in the center!
40mm inlet is better also, chances are its a better barrel if it has 40 mm spacings.
But not if it comes with a 38mm stroke!
There are better motors out there but you got to know what your looking for, and possibly pay a little extra.
 

Greg58

Well-Known Member
May 1, 2011
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Newnan,Georgia
Since you only have two to choose from my question would be which dealer is rated the best and which has the best supply of parts, the latest grubee engines seem to be of better quality than others. As for the wider intake it has no effect on the carburetor, any carburetor that is for a m/b will fit on the intake. The potential power increase that could be had would lean me to the wide intake model.
 

Intador

New Member
Jan 23, 2014
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Canada
How in particular could one take advantage of the wider intake for a power increase? Same carb just jetted/tuned differently?
 

Greg58

Well-Known Member
May 1, 2011
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When porting a cylinder we widen the intake port for better mixture flow, also if you later add a expansion chamber the added flow should be a plus.
 

sublunacy

New Member
Sep 12, 2013
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ontario
I have 2 of the speeddemon kits. Both kits are rock solid. They are upgraded. Better bearings and all grade 8 fasteners. I am ordering another to make a rocket out of. I had a Skyhawk and it flew a part. Weak wrist pin bearing.

same bearings/ slant head has more compression so its harder to jet correct but makes more power. cool how that works....

the price is better at speeddemon. also they have the new banana pipe i want to try. i need to know if it has a 40mm intake. looks that way. i will try one next just for the low price.
 
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sublunacy

New Member
Sep 12, 2013
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ontario
further they are both grubee kits yes? these are both the new grubee kits w slightly different build kits. both certified epa legal in canada. DO NOT confuse the new 2012 grubee w the old versions not legal in canada as we speak!

i have been all through the new grubee and i wont be switching brands. diy mechanics will not see the difference but i have. i am building tight case/ balanced 3pc crank/ 19mm reed/carb exhaust that will make EVERYONES head spin and its no race bike just my standard setup for torque and midrange you never had before.
l8r

r.ly.
 

doktor

New Member
Jan 24, 2014
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Saskatoon, Canada
I have ordered engines from this vendor, GT5A's only. I have found the quality to be very good. I pulled the head and jug to inspect before running it, all was as it should be. I did sand the head to flatten the surface. Kit included all parts I needed except for an offset intake I needed for my application. Kit also included extra parts, gaskets, spark plug, etc. Engine started well even in the extreme cold we have now. The more it is run, the more power the engine seems to have. Free shipping is a bonus as well.

Grubee GT5A
http://www.motorizedbicycle.ca/bicycle-engine-kits/grubee-skyhawk-gt5a-66cc-angle-fire-slant-head-bike-motor-kit.html