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Old 10-08-2018, 08:32 AM
subarumafia subarumafia is offline
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Default Streaker torque converter questions

I've got a Streaker fun Kart I'm trying to get sorted out. Its got 22" tall tires in the rear, a 60 tooth sprocket on the drive shaft and I just installed a predator 212 engine with a 10 tooth centrifugal clutch. This gear ratio doesn't work. The Kart has a hard time taking off and reaches frightening speeds. Thinking the Kart may have had a torque converter on it in the past. The question is will a torque converter provide more reduction? If not, should I just go to a larger driven sprocket?
Thanks
Chris
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Old 10-08-2018, 08:49 AM
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Yes, for the 212 a 3/4in shaft, you will need a 30 series torque converter. With 6:1 ratio with 22" tires may be pushing it but someone will I am sure give you a better answer. I would go away with the clutch and put a TC on there as it will give you even more reduction on the low end. I forget the actual reduction on the low end but it also gives you a 1.1 overdrive.

--Dan
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Old 10-08-2018, 09:13 AM
subarumafia subarumafia is offline
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Thanks for the reply Dan. I'm sure the kart is supposed to have 22" tires because its level with them on there. I tried some smaller tires I had kicking around and it pointed up hill. I've got a 301 predator as well. Would that be a better motor choice? Could it just be an issue of not enough torque?
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Chris
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Old 10-08-2018, 09:22 AM
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I would still go with a TC even with the 301. Although with the 301 you have a 1" shaft so a 40 series would be recommended although probably could get away with a 30 series with a 1" driver unit. If it were me I would do TC no matter what, you will be much happier with it.

--Dan
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Old 10-08-2018, 09:27 AM
subarumafia subarumafia is offline
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I think I'm decided on the torque converter. I'm just not sure if it provides a lower ratio or not. I'd like to use the predator 212 if possible. I like the idea of the smaller hot rod motor. Plus I've got a bunch of them and only one 301 which I wanted to use on a 2 man Kart project I've got going on. Can someone chime in and tell me exactly what kind of reduction the torque converter will give me?
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Chris
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Old 10-08-2018, 10:21 AM
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The TC does provider a smaller take off ratio... I believe (do not quote me on this) that the take off ratio is 2.7:1 on top of the 6:1 already on the kart from jackshaft to axle. The overdrive is .9:1 if my memory serves me right... so off the line you would have the 2.7:1 and the 6:1 reduction. If I remember how to calculate compound gears you should have 16.2:1 off the line with the TC and 5.4:1 in overdrive. With 22in tires that would mean a top speed of 44mph assuming governor is still in tact (3600rpm) and the engine has enough umph to get to the speed.

--Dan
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Old 10-08-2018, 10:43 AM
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Thanks Dan. So all said and done. In your opinion is that a functional set up with the TC. Do you think that the Kart will have enough low end grunt to work as the manufacturer intended?
Chris
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Old 10-08-2018, 10:58 AM
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2.7 and 0.9 are correct for a series 30 with 6" driven unit (the TAV Kit for example)

BUT 6:1 is still a bit of a stretch for wheels that size..
you might need a taller rear sprocket to lower the gearing down further (7.5:1 recommended)

6:1 is a good value for 18" rear wheels (WITH TC!) not so much for 22" I'm afraid

'sid

PS if you want to play with numbers and inbetweens:
visit app.kartcalc.net with your phone and click on quickcalc
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Old 10-08-2018, 11:18 AM
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Ok, Thanks for the help. So I think I have space for a 70T sprocket. The problem is I cant seem to find a 41 pitch 70t sprocket with matching hub on any of the go Kart sites. Also struck out on amazon and Ebay.
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Chris
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Old 10-08-2018, 01:39 PM
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Just found a post on forum about literally the exact same thing with exact same Kart. The Kart came from the factory in this configuration. How could it not work?


Chris
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Old 10-08-2018, 02:18 PM
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I guess that you found my thread. I've yet to solve this problem on mine. I thought of using a jackshaft, however I would need two to align the sprockets. The two solutions that I am thinking about are switching to 18 x 9.50 - 8 inch Carlisle Knobbys (similar to factory tread pattern), or ordering a live axle online and using a larger sprocket.
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Old 10-08-2018, 03:15 PM
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Two problem here. I have found only one larger sprocket. Go power sports has a 72T aluminum sprocket that will barely fit in the frame and doesn't get you to the desired ratio. I don't think anyone makes one bigger one but even if they did it just wont fit. Going to smaller tires is going to put your Kart in an uphill stance. I tried it. Its goofy. Plus the sprocket drags on everything. I'm going to try a 301 predator and 30 series torque converter on mine. I'm thinking this Kart must have come with a bigger motor. Only way this configuration works.
Thanks
Chris

---------- Post added at 01:49 PM ---------- Previous post was at 01:32 PM ----------

I'm getting ratios between 16.2 to 1 and 5.4:1 in the calculator. Is that likely to work with the predator 301 motor?

Chris

---------- Post added at 02:03 PM ---------- Previous post was at 01:49 PM ----------

KartInfo by kartcalc.net:
Code:

KART
Kartname : Streaker RW diameter : 22 in Weight : 450 kg
ENGINE
Engine type : Predator 301 HP : 8 Torque : 10.5 ftlb | 14.24 Nm RPM : 4000 Governor removed : false
TRANSMISSION
System : Torque Converter TC type : series 30 6" driven TC sprocket : 10 Axle sprocket : 60 Final Ratio : 6:1 Lowest Ratio : 16.2:1 Highest Ratio : 5.4:1
PERFORMANCE
Min Torque : 56.72 ftlb | 76.9 Nm Max Torque : 170.15 ftlb | 230.69 Nm Acceleration : 3.41 fps | 1.04 m/s Top Speed : 48.48 mph | 78.02 km/h


---------- Post added at 02:15 PM ---------- Previous post was at 02:03 PM ----------

The app suggested a final ratio of 6.8:1. We are getting a lot closer.

Chris
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Old 10-08-2018, 03:23 PM
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Quote:
Originally Posted by subarumafia View Post
Just found a post on forum about literally the exact same thing with exact same Kart. The Kart came from the factory in this configuration. How could it not work?

Chris
CHICAGO BULLS SHIRT!

The KenBar Streaker came with 13" wheels all around (13x5 on 6" rims)
and a simple centrifugal clutch not a Torque converter

'sid
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Old 10-08-2018, 03:38 PM
subarumafia subarumafia is offline
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Sid,
So I'm very likely completely wrong but I'm thinking there is more than one streaker model. I know the DD9 streaker came in a similar but 2 seater config. Looks like J.S. has exactly the same set up as mine. I'm also seeing a lot of pics that look like mine online. My frame wouldn't work with 13" wheels. I know I'm missing something here. I did some calcs and my final drive works out perfectly with 9hp. I'm gonna try my predator 301 stage 1 and see if I can get the thing moving. Am I missing something?
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Chris
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Old 10-08-2018, 03:42 PM
Tpdingo Tpdingo is offline
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I know it was very popular to put on 18" rims and 6:1 ratio with a T/C, so that is a possible setup it could have come with.
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Old 10-08-2018, 04:14 PM
J.S.@SMS J.S.@SMS is offline
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Not sure if my engine is factory (no reason it wouldnt be) but my kart has a Tecumseh OHH60 which last I checked is a 6.0 horse 195cc engine.
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Old 10-08-2018, 04:23 PM
subarumafia subarumafia is offline
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J.S.
You're issue is that you are not getting the top speed you want? Does it take off ok and run ok? Do you burn up belts?
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Old 10-08-2018, 04:38 PM
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The engine runs great, the acceleration could use some work (my stock minibike could beat it in a race), and my top speed is not where it is capable of going. But I have yet to burn up a belt.
However I am using a brand new torque converter from gopowersports (since the old one blew up).
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Old 10-08-2018, 04:45 PM
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Yeah, I'm thinking the only solution is more HP.
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Old 10-08-2018, 06:22 PM
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That's something that i'm thinking of. I am currently trying to decide between a Duromax XP7HPE and a Tillotson 212 with e-start. The Duromax has 7hp (1 more than the original), and an electric start. However the Tillotson has 10hp (4 more than stock). I'm leaning more toward the Tillotson ($250) than the Duromax ($200), since I feel that 3 more horsepower is worth $50.

But for you I would hope that a predator 301 has enough power to move this kart. However if I were you I'd use a 40 series instead of a 30 series.
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