fatcaaat
Well-Known Member
This crank matches up with the 69mm tall cylinder and piston combo. Figured someone might find it useful. https://www.motorkit.com/en/spare-p...roke.html?search_query=crankshaft&results=866
Found a 54.5mm crank for your square engine builds
- Thread starter fatcaaat
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dirtbkr188
Well-Known Member
Jarred, what is the exact benefit of putting together a "square engine build"?
fatcaaat
Well-Known Member
This sounds like a great question that our beloved RacerX Bob would have really enjoyed answering. However, Ill try to answer it, but I'm going to add bias to it.
First, I typically DO NOT build square motors. When I use the Nice Platform, I am typically building undersquare and when I build small block platform I build oversquares. The former is usually something that has a very wide torque range...think you can put it in top gear at 3k and pull all the way to 10k if it can breathe enough. Its very tough to lug these. Many of my Nice engines are 63-66 strokes with 56-58 bores...tractor like broad torque bands. The Oversquares are usually like to rev more and keep higher in the RPM band. Think about all the 88 and 95cc bore kits that people install. You run them at 7-8k all day long. They usually don't have much down low, but once you get them about 6k they really perk up.
The square is supposed to be the balance between the two ends. Decent off throttle, decent torque band, decent top end. Great all around driver. I have two square engine, a Nice 127cc that is 55.5 stroke and 54mm bore and it was used primarily as a backroad cruiser, and another 127 but running the DOHC head and a lightened rotating assembly that is used a lot more agressively. Both are great motors, but I do prefer the longer stroke motors, hence my most recent 151 on a Nice platform runs a 61.5 stroke and 56 bore with the takegawa dry clutch. I also try to keep my longer stroke motors to under 6500 rpm sustained, whereas I am happy to run a square or oversquare motor at 8000 sustained as long as you can keep the oil cool.
The reason I linked that crankshaft is that for all the folks wanting to build a 124 cc motor on the small block platform usually only have a choice of takegawa or kitaco 54mm cranks which run north of $400 these days. This one is $100 and while it may not be the jewelry of kitaco or taky, it should provide similiar effect for 25% the cost.
First, I typically DO NOT build square motors. When I use the Nice Platform, I am typically building undersquare and when I build small block platform I build oversquares. The former is usually something that has a very wide torque range...think you can put it in top gear at 3k and pull all the way to 10k if it can breathe enough. Its very tough to lug these. Many of my Nice engines are 63-66 strokes with 56-58 bores...tractor like broad torque bands. The Oversquares are usually like to rev more and keep higher in the RPM band. Think about all the 88 and 95cc bore kits that people install. You run them at 7-8k all day long. They usually don't have much down low, but once you get them about 6k they really perk up.
The square is supposed to be the balance between the two ends. Decent off throttle, decent torque band, decent top end. Great all around driver. I have two square engine, a Nice 127cc that is 55.5 stroke and 54mm bore and it was used primarily as a backroad cruiser, and another 127 but running the DOHC head and a lightened rotating assembly that is used a lot more agressively. Both are great motors, but I do prefer the longer stroke motors, hence my most recent 151 on a Nice platform runs a 61.5 stroke and 56 bore with the takegawa dry clutch. I also try to keep my longer stroke motors to under 6500 rpm sustained, whereas I am happy to run a square or oversquare motor at 8000 sustained as long as you can keep the oil cool.
The reason I linked that crankshaft is that for all the folks wanting to build a 124 cc motor on the small block platform usually only have a choice of takegawa or kitaco 54mm cranks which run north of $400 these days. This one is $100 and while it may not be the jewelry of kitaco or taky, it should provide similiar effect for 25% the cost.
dirtbkr188
Well-Known Member
Thank you, Jarred, I appreciate you taking the time to write up a very informative reply
TenderTendon
Member
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fatcaaat
Well-Known Member
Its going to fit any small block engine build matched with a 69 tall cylinder
l c
fatcaaat
Well-Known Member
Ive had daytona parts in my hand and some of them are very high build quality and some less so. I don't know with this crank, but for 100 bucks its an opportunity to test one out. Looks Like TenderTendon is going to tell us what they are like since he ordered one up.
However, what about this here? https://www.motorkit.com/en/japanes...20-20.html?search_query=daytona+lc&results=76
full engine at what seems to be a very cheap price. Thoughts on this?
kirrbby
Well-Known Member
Better deal yet.
For me it shows $418 shipped, signature required, via UPS. I would NOT be afraid to give it a go for that price. Daytona brand + main shaft HD clutch + oil filter + cooler port +12v CDI...sounds like a safe bet for 418. Add only a cooler, carb, and exhaust..?
Will be curious to hear some top speed and performance reports for it...compared to a typical Chinese 125 with a crank mounted clutch.
TenderTendon
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TenderTendon
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TenderTendon
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TenderTendon
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fatcaaat
Well-Known Member
Certainly wont last long with him abusing it starting it that way. I see him busting the kick shaft, kicker gears, and first gear in the near future.
OLDCT on that YX170 hows the vibration at 6000=7500? The last YX motor I had had quite a bit but I did run it for nearly 5000 miles without any issues.
OLDCT on that YX170 hows the vibration at 6000=7500? The last YX motor I had had quite a bit but I did run it for nearly 5000 miles without any issues.
OLD CT
Well-Known Member
Thanks for posting up that crank. That's a great deal. My 170 vibration meter is acceptable at 6400 rpm at 50 mph 
That's the speed limit where I ride. 18-32 gearing, It does 50 smooth and effortless. Fastest I went was 68 at around 9000k. Baffle in the nhrc pipe, keeps it quiet. 7500 shifts get you moving quick. Pulls hard from 3500 and up. I did order a few 31T sprockets from Webikes. Three month shipping plan.
Should be even better and might just hit 70 mph flat out. That's fast enough for me.
That's the speed limit where I ride. 18-32 gearing, It does 50 smooth and effortless. Fastest I went was 68 at around 9000k. Baffle in the nhrc pipe, keeps it quiet. 7500 shifts get you moving quick. Pulls hard from 3500 and up. I did order a few 31T sprockets from Webikes. Three month shipping plan. Should be even better and might just hit 70 mph flat out. That's fast enough for me.
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TenderTendon
Member
Had a nice delivery this afternoon. It all arrived without any damage. Motor was triple boxed with foam. Initial impression is a very good deal for the money, although the word Daytona is nowhere to be found on the motor or box. Let me know if you'd like a better pic of anything. I am going to completely tear down and re-assemble the motor before starting it. I just don't trust the people that would have put it together. If there's enough interest, I will document the whole tear down with pics.
