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Post by christopher on Oct 11, 2019 10:18:13 GMT -5
My Google fu found a few options but no real reviews. With the 70cc kit I can make the temperature climb into the mid 300 degree range. Dottie aftermarket fans help? I see a few listed as oversized etc. Does removing the fan grate or slots help? Curious if it's something easy cheap and worth pursuing or not? In Minnesota the riding season is about over, so it is cooler and not hot.
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Post by 190mech on Oct 11, 2019 11:41:11 GMT -5
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Post by christopher on Oct 11, 2019 16:06:36 GMT -5
while looking at those fans I noticed the cylinder head covers were different.  I have this style, the 90cc heads that square has been removed and there’s a cross to hold the four sides square but not the bulky piece in the middle. I was wondering about removing the deflector for better air flow.  |
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Post by 190mech on Oct 11, 2019 16:51:08 GMT -5
90cc stuff is taller than 70cc(apples vs oranges),so dont try to out think the engineers!Most of the cooling is thru the cyl head and the top 20mm of cyl..Run the 50cc shroud and bigger fan...  |
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Post by christopher on Oct 14, 2019 18:12:27 GMT -5
Looks like I have clearance for the larger fan and I have one on its way. Found some data under project 90 that is encouraging I'll find out, if it is for me. If my temps drop near 20 degrees like it did in in previous testing I should be good to go.
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Post by christopher on Oct 25, 2019 15:05:33 GMT -5
Just a little thicker and it fit right in.   |
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Post by Zino on Oct 26, 2019 7:53:59 GMT -5
Measure your top speed and acceleration 0-35 and temps before and after the Fan Swap
My Zuma tops out at 340 ish for temps with the stock fan with a 90 jet and pushes closer to 360 with a 85 Mikuni jet if I am wide open a few miles.
With My riding style alot of 45 mph plus roads very little city driving I also found going up a heat range from a Br8hs to Br9hs plug also brought my temps down about 10 degrees .
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Post by christopher on Oct 26, 2019 9:14:58 GMT -5
My idle temp dropped from 155 - 160 to ~145°F. I warmed it up with the old fan, turned off took maybe 5 minutes to stick the new fan on, started it up and watched the temps again.
Around town temps I saw 198 a few times, used to be mid 220 or so, definitely runs cooler. Most of my riding is around a small town, population less than 2000. I did go out to a county road and I can still get to 50mph. My 0-35 times didn't change noticeably the times are mixed in the list with previous times. Definitely didn't do something like add a second to my times. Maybe with a stock setup that struggled to get to 35.
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Post by Zino on Oct 26, 2019 9:41:02 GMT -5
Good to know
I run 200-240 when I am running around town under 35 mph and under 8000 rpms at mid throttle.
When I go wide open for over a mile i drift up to over 300 .
Where did you get the fan and did you use your stock shroud or did you have o replace it or mod it .
I might want to do this to keep my temps under 350 degrees when I lower my squish up my compression and raise my peak rpms with my next set of upgrades .
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Post by christopher on Oct 26, 2019 9:53:11 GMT -5
The fan is a Polaris sportsman 90cc fan. As far as fit goes, depends on your shroud, found information in the 90cc project posting about this. I looked through my fan shroud inlet and had a good inch of space between my fan and the shroud opening. I figured why not give it a try.
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Post by christopher on Oct 26, 2019 9:58:49 GMT -5
I think if I were going to do it again I would find a Polaris 90cc in good shape and mount it in a scooter. 90cc with no BBK or anything else to install. The price of a 70cc BBK in a midrange sport setup is $150.00, you are still 20cc smaller than this stock setup. The posting on the 90cc project has information about the swap.
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Post by Zino on Oct 26, 2019 10:07:53 GMT -5
You get to having over a thousand in these builds real quick .
Couple hundred in motor couple hundred in pipe couple hundred in carb 300-500 in trans ,new tires
Rinse repeat
It gets addicting modding these things .
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Post by aeroxbud on Oct 26, 2019 12:05:08 GMT -5
Yes the parts are cheap. But they soon add up in price. Even little things like jets.
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Post by repherence2 on Oct 30, 2019 21:16:33 GMT -5
I think if I were going to do it again I would find a Polaris 90cc in good shape and mount it in a scooter. 90cc with no BBK or anything else to install. The price of a 70cc BBK in a midrange sport setup is $150.00, you are still 20cc smaller than this stock setup. The posting on the 90cc project has information about the swap. yup, as was once said to me after spending over $1k on 70cc parts. "get a jog90 block and add upgears. you'll run with the DIOs and SYMs all day long, full stokers and all." I found it to be true. 90 block with 83cc 50mm cast bore was $350. malossi upgear kit $100. I got a sweet deal on a 54mm Taida aluminum bore kit and a jog90 sectional V8 pipe for $450. now at 94cc, I smash DIOs and SYMs for fun now on the streets in Honolulu. it's tuned for WOT racing. I can hold WOT all day long @350°F. the set up has not failed yet. |
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