are 2 stroke engine kits the same?

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BonusParts

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Nov 28, 2012
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Im not sure if this has been covered.

Pistonbikes.com sells Grubee kits. their replacement cylinders do NOT work properly on a GT5 skyhawk.
Grubee cylinders are milled 1mm on the base.

GT5 Cylinder - 69.5mm
Piston Bikes cylinder - 70.5mm


Matt
 

MadMannArt

New Member
Aug 13, 2013
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LongBeach, wa
I ordered a cylinder last night from zone8cycles for my Brand New GT5, it was billed through PayPal as Nationwides Access, the same people who sell the Grubee... $32.50....
It should fit correctly, I am assuming...
I will be buying a ThatsDax 69cc kit in a couple of weeks to install to replace the Grubee. The G will sit on a shelf, for use if the Dax needs attention....
 

Motorbikenewb

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Mar 19, 2013
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Columbus, OH
The cool thing about these engines is that they seem to run better the more you use them. (That is, until they break down.) Maybe that's because you always have to tinker with them a little bit, and each tinkering session improves the engine a little bit more. Maybe not. Lately I've been stopping about once every trip to make minor adjustments. That's not to mention the aircraft pilot style vehicle inspection before every ride.

Compared to boxy plastic motor scooters, these things are cake to work on. With scooters, road-side repairs turn into road-side piles of plastic cowling and such. I don't like anything that takes 30 minutes just to GET TO the engine. Though I must say, motor scooters seem to be more reliable. Actual mopeds (I mean the vintage ones that actually have pedals.) are easier to work on, but the parts can be quite pricey.

So, yes, you get what you pay for, but I think that dollar for dollar, they're a good bargain compared to other forms of non-licensed two-wheeled transportation.
LOL, aircraft pilot style vehicle inspection... LOL, I thought I was the only one that did that.
 

sublunacy

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Sep 12, 2013
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ontario
waste of time reading this wow. somebody using auto engine oil for premix. another guy puts it in his 600 pound 4 stroke motorcycle w an integrated transmission and wet clutch? is that correct.i have been down that road w knowitall garage mechanics before.
auto engine oil ruins wet cork clutch plates end of story!
dont argue w me to restore your ego!
 

CARider

Member
May 20, 2013
165
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San Rafael, CA-Mesa, AZ
There are these two strokes- some may know all to well.

Let me just say- glowing silver paint, smiling factory workers on the instructions, 3 piece cranks, textured two tone paint on sprocket and chainguard.

Well, as soon as I thought they were gone, they are back again. These motors are fine besides for the fact they shake REALLY bad.
 

goofyfoot2001

New Member
Aug 16, 2012
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South Carolina
Not sure why I'm still subscribed to this thread since it's been about 3 years since I bought a sportster and ditched bike. But let me tell you, you do not know vibration till you hop on a '95 rigid frame 1200 sportster.
 

fatdaddy

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May 4, 2011
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San Jose, Ca.
waste of time reading this wow. somebody using auto engine oil for premix. another guy puts it in his 600 pound 4 stroke motorcycle w an integrated transmission and wet clutch? is that correct.i have been down that road w knowitall garage mechanics before.
auto engine oil ruins wet cork clutch plates end of story!
dont argue w me to restore your ego!
I know yer right about the clutch plates, As for regular oil for premix, what do you think they use in China AND Russia, Most of the time it's used crankcase oil. Yeah, tends to foul plugs and smokes like a oilfield fire, but the thing runs fine on it. I told a friend about it a couple months ago just in passing, I just found out the other day he's been running it since I told him. The engine sounds good and runs pretty good for a old engine that he beats on pretty hard. I still use 2 stroke oil myself but it seems regular motor oil WILL WORK just fine. If his engine blows up I'll get back to everybody with an update.
fatdaddy.usflg
 

piper

New Member
Jun 20, 2014
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san luis obispo,california
I know yer right about the clutch plates, As for regular oil for premix, what do you think they use in China AND Russia, Most of the time it's used crankcase oil. Yeah, tends to foul plugs and smokes like a oilfield fire, but the thing runs fine on it. I told a friend about it a couple months ago just in passing, I just found out the other day he's been running it since I told him. The engine sounds good and runs pretty good for a old engine that he beats on pretty hard. I still use 2 stroke oil myself but it seems regular motor oil WILL WORK just fine. If his engine blows up I'll get back to everybody with an update.
fatdaddy.usflg
I have a chainsaw from the 1950's and it specifies non detergent 30 weight motor oil mixed with gasoline. The old maytag 2 stroke washing machine engines also used non detergent 30 weight oil mixed with gasoline. Yes this was the method of 2 stroke lubrication before they came out with specific 2 stroke oil.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
I've been running 40wt non detergent oil mixed at 25:1 in one of my bikes, runs great, I have 107 miles on the engine since the switch, I road it 26 miles today, I dont putt around either, most of my 26 miles today were between 30-37mph on a bike with 24" wheels, the carb is actually jetted a tad fat still because I have gone up to 43mph and when I get to that speed it will start 4 stroking so I know its a bit on the rich side at really high rpm but for how I typically ride it does just fine like it is.

I have a Puch Hi Hi70cc head on it now, a free flowing home built exhaust, RT Dellorto clone carb, and just some minor port work as well as shaving down the jug for a bit better compression since the engine is what we call a "Half Breed" type that is 38mm stroke like a GT5 but uses Pk80 type low pin piston and has the short 110mm rod.

Balance isn't as good as I'd like with this engine, but it has improved some since it hit the 100 mile mark.

I'm not a bit worried about using the 40wt non detergent in it, runs just as good as it did when I was running it on a premium 2 stroke oil that actually mixes @ 100:1 and once it gets warmed up there is very little smoke.
 

Davezilla

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Mar 15, 2014
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San Antonio Texas
Yup... people have been using standard non detergent oils in their 2 smokers for decades before all these specialty oils came out with no trouble at all... I remember growing up everyone just bought regular motor oil and mixed it up for their dirtbikes and nobody messed up their engines. The new synthetic oils are really good and do the job quite well but nobody's ever messed up an engine running between 20:1 and 40:1 with regular non synthetic motor oils... that's all we used about 30 years ago.
 
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mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Yup... people have been using standard non detergent oils in their 2 smokers for decades before all these specialty oils came out with no trouble at all... I remember growing up everyone just bought regular motor oil and mixed it up for their dirtbikes and nobody messed up their engines. The new synthetic oils are really good and do the job quite well but nobody's ever messed up an engine running between 20:1 and 40:1 with regular non synthetic motor oils... that's all we used about 30 years ago.
Yeah, I been wanting to experiment with one of these engines on an old school oil mix for a good while, Im NOT recommending people to do what Im doing with this one, but since this is pretty much how all 2 stroke were run for years and other countries still use whatever oil they can find for the 2 strokes.

Ya know how us tinkerers are, always gotta be messing with something just for the heck of it, Im just having a little fun with this one and after pulling the head off yesterday and replacing the little round pancake head for the Puch Hi Hi 70cc head I can tell the engine is getting plenty of protection, bore looks very good, piston has no buildup on crown, just a dark slick shiny plating of carbon.

I guess the biggest surprise to me so far is the lack of smoke, I was actually hoping fo a good smoke screen @ 25:1 on the 40wt non detergent but this thing hardly smokes at all accept when it first starts up and even then there isnt that much unless I really rev it out a few times, this leads me to believe a lot of oil is staying in the crankcase and kepping things lubed up good.

Another good thing is I have several quarts of the 40wt non detergent, bought a bunch a couple years back at Big Lots because thats what I like to use in my chainsaws for bar &chain lube, never liked the thick stuff.

Im gonna run this engine like this for it lifetime is the plan right now, heck it might outlast me....lol!
 

fatdaddy

New Member
May 4, 2011
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San Jose, Ca.
waste of time reading this wow. somebody using auto engine oil for premix. another guy puts it in his 600 pound 4 stroke motorcycle w an integrated transmission and wet clutch? is that correct.i have been down that road w knowitall garage mechanics before.
auto engine oil ruins wet cork clutch plates end of story!
dont argue w me to restore your ego!
Don't seem to be any argument at all, NO ego bro, Just facts. I've been down the road a couple times too. And when someone says, Don't argue with me I'M RIGHT, Well, I gotta at least look into it. It seems regular 30wt or in some cases (in Russia and China,) even used crankcase oil works OK. I'm just glad yer not one of those knowitall garage mechanics. And I hope ya didn't waste too much more of yer time reading this.
fatdaddy.usflg
 
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steveanson

New Member
Oct 2, 2014
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Houston, TX
Yup... people have been using standard non detergent oils in their 2 smokers for decades before all these specialty oils came out with no trouble at all... I remember growing up everyone just bought regular motor oil and mixed it up for their dirtbikes and nobody messed up their engines. The new synthetic oils are really good and do the job quite well but nobody's ever messed up an engine running between 20:1 and 40:1 with regular non synthetic motor oils... that's all we used about 30 years ago.
Non-detergent motor oils have worked well in many 2 stroke applications for a very long time. Plug life suffers though. Heck, I still have my old Sears spark plug cleaning kit...
 
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Aug 17, 2011
313
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Springfield IL.
It seems to me that the 80cc ebay kits come with either the "speed" carb , with the rectangular air filter opening or the NT carb with 4 round openings.

Anyone just purchase a ebay kit and care to share photos?
 

CARider

Member
May 20, 2013
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San Rafael, CA-Mesa, AZ
I bought one recently to compare it to my own engine kit I sell. I was pretty far from impressed. Don't buy those kits! The one I got had a 3 piece crank with bolted on steel plates, and was really a piece of junk.




 

crassius

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Sep 30, 2012
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kits I get have good chain, also have tensioner that locks for one-hand adjusting rather than reaching thru spokes to get to adjuster bolt, has same angle-cut balanced muffler, has longer clutch arm for easier pull, has wide front mount for fitting to cruisers, and best of all, has NO pink carb
 

Raincloud

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Feb 19, 2017
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Peoria,IL
How can one tell which kit is best? My kit came with absolutely no manufacturers name or number, not even as much as an assembly instruction booklet. Thanks to You Tube, I have it together , but never have gotten it to start.
 

crassius

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Sep 30, 2012
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many sellers have the manual online for download instead of printing it out all the time

except for some connecting rods and carbs, none of the parts from any seller have any markings

any and all info you might need can be found right here
 

Kartooo

Member
Nov 18, 2016
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MA
How can one tell which kit is best? My kit came with absolutely no manufacturers name or number, not even as much as an assembly instruction booklet. Thanks to You Tube, I have it together , but never have gotten it to start.
they are like snowflakes, no 2 are alike. 2 wire/3 wire mags, different carbs, short/long clutch arm, different strokes, different case bolts, port size, smooth castings/crappy castings, etc etc etc. no 2 run alike, some smoooth/some vibrate. you have to jet and needle clip according to what they like. they look similar but come out of many different factories with varying quality control.