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Post by boostnjuice on Feb 21, 2015 9:59:42 GMT -5
A little background
I moved back to FL last November. My work was about 10mi from my home. So in an effort to save a little cash I picked up a Wolf Brand RX-50. Worked pretty good with the route I travled @37-40mph top speeds.I got 90-100 mpg on average. So once/week fill ups were cool. About a month later I got a much better job which was 20mi from home and by way of roads with higher speeds and more traffic. Some modifications were in order.
0mi- brand new stock
300mi- first oil change
800mi- upgrade to 20mm carb, main jet=95
1200mi- Added 50mm bbk, head w/23/20mm valves,A9 cam, perf. vaireator 6.5g rollers, 2k clutch springs, 2k contra spring, CDI, perf. Coil, perf. exhaust, open element air filter,main jet=100, oil change.
1250mi- no-start, found ex valve to tight
1350mi- broke stock belt, found rollers flattened, Added Gates belt, 5g rollers
1850mi- Added 49-17t final drive gears, found belt overheated and damaged, Added new Gates belt.
2000mi- no-start, found burnt ex. Valves, returned all engine & trans parts to stock
So that's where we are. I have ordered new valves and should have them next week at which time I will give it another go. This commute is horrendus with stock acceleration. The power was great @82cc the cvt needs help tho, the clutch is slipping and causing lots of heat which is eating belts. A new clutch is in the works. What is the word about the Hoca full kits? They look good. Also the next big move will be the Ecotrons EFI setup, and then a crank which leads to a turbo. (Please save me the comments about "just get a 2t if you want to go faster" I have no interest in 2t's and this is more of a fun thing/toy for me so I'm good with spending some cash on it.)
I look forward to discussions about these fun little scoots.
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Post by 2TDave on Feb 21, 2015 10:59:22 GMT -5
Welcome. Where in FL? I'd love to see a fast boosted 4t. What speeds where you seeing before you burnt the valve?
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Post by dan50 on Feb 21, 2015 11:47:41 GMT -5
How about some pictures.
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Post by 90GTVert on Feb 21, 2015 11:52:43 GMT -5
Not sure if the 4T version is the same, but the Hoca 2T clutch bell is knurled inside and really grips well.
I've also been dreaming of trying out an EFI system on a 4T, but mine has so much to be done before then that I have no idea if I'll ever do it. Very interested to see how it goes if you do the conversion. Same with the turbo. I can't say I've seen a lot of good results out of turbos on these small engines, but it would be an interesting endeavor and made easier with the EFI installed.
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Post by boostnjuice on Feb 21, 2015 13:04:30 GMT -5
I'm in the Sarasota/Bradenton area.
I was 50+mph pending wind & terrain.
I am excited about the EFI kit. I go a lot of miles and better fuel economy would be cool. I'm only getting about 60mpg with mods. @40mi/day I have to fill up every other day. But @$2-$3 a tank its not so bad. Also I believe I was running at peak cylinder temp, thus the burnt valve. Now I know I'm going to shake every one up here but lean mixtures do NOT = higher cylinder temp. So in my case I need to go richer, or leaner as to lower the CHT. I'm running a #105 main now and my plug looks the perfect ivory-tan it should. I have lower jets so I will lean it up to cool it down. Point being this would be easier if I had better data, and better control. Ecotron's setup looks perfect for me. I don't think the MBE one is quite as refined so I'll avoid it. I have crunched the #'s and I believe I can get the VZ21 to spool up. How much I am uncertain, but I only need 4-5psi. Any more an lots of things go wrong, like bent rods, need for higher octane fuel, superheated air charge(need intintercooler) overheated engine(need water cooling) ect....
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Post by niz76 on Feb 21, 2015 14:40:03 GMT -5
Sounds like a cool project Boostnjuice. I'm in the process now of tuning a new carb on my scoot (it's a 2t) and finding that even though I'm rich on the MJ, it still gets hotter at WOT than mid throttle... Have you seen "the list"? We need some fast 4t's on the list! Lots of people here wanting to make their 4t's fast. Speaking of that- I saw a Naraku performance exhaust for a 4t last night... www.scooterdynasty.com/exhaustnarakufor50cc139qmbscooters-1.aspx |
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Post by dan50 on Feb 21, 2015 14:56:11 GMT -5
All of the turbo kits that I have seen for sale state that they are for 150cc or larger. I've seen warnings not to install them on 50cc scooters.
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Post by katastroff on Feb 21, 2015 18:54:48 GMT -5
Sounds like a cool project Boostnjuice. I'm in the process now of tuning a new carb on my scoot (it's a 2t) and finding that even though I'm rich on the MJ, it still gets hotter at WOT than mid throttle... Have you seen "the list"? We need some fast 4t's on the list! Lots of people here wanting to make their 4t's fast. Speaking of that- I saw a Naraku performance exhaust for a 4t last night... www.scooterdynasty.com/exhaustnarakufor50cc139qmbscooters-1.aspxIts a nice pipe, but the description.  Its a 4T, an exhaust is an exhaust. But its still some nice bling bling shinny expensive stuff. |
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Post by FrankenMech on Feb 21, 2015 20:02:51 GMT -5
Get an exhaust and head temp gauges. While you are at it a nice wide band O2 sensor would be nice. A single belt drive is only good for about 5HP continuously. We get away with pushing that because of the duty cycle we use. Unfortunately long high power runs can melt a belt. The 50cc variator setups only seem to have splines at the outer end of the crank which means that the variator is only truly driving the belt on one side. The aluminum half is just along for the ride. This also limits the power that can be transmitted through the belt by about half or 2.5HP. It is a bad situation but I have not figured any way around it. Maybe someone here has. CVT case ventilation is very important to reduce heat but water must be kept out. Some people are bleeding some air off the engine fan to help cool the CVT. A small 12V computer fan may also help. Just hook it into the headlight circuit. Good luck and keep us posted  |
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Post by boostnjuice on Feb 24, 2015 6:21:33 GMT -5
New valves arrived yesterday, so the bbk and big head/cam are going back on today. I will post lots of pictures. I am running a #105 main, and I believe I was at peak( 14.7:1 or peak CHT)Thats why I burned the valve, and I was going to lean it up to help economy. But after some thought, I need the power so I ordered a #108, #110, and #114.
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Post by scootinredneck on Feb 24, 2015 16:44:17 GMT -5
Frabkenmech I like the fan idea...that would be pretty neat and in theory should work
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Post by boostnjuice on Feb 24, 2015 19:01:42 GMT -5
Got her back up and running!  ?. What a beast!! Completely stock CVT save for a new set of 4g rollers, she hit 11,000 RPM. ? The speedo needle was buried against the bottom of the gauge housing. Basing the position of the needle and factoring in the inaccuracy of these speedometers, I know I was 50+ mph. List here I come, I should be able to move to 7th if I'm not mistaken. More when I put the 2.66 gears back in. If this wasn't my daily driver I would put a shot of N20 on her...... I will post some GPS data and videos when I can. On the down side, I found a bad bearing in my rear pulley of the cvt, and I broke a baffle in the muffler on the way home today, too much power!!! |
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Post by 2TDave on Feb 24, 2015 19:48:56 GMT -5
Congrats! That's a lot of rpms on a stock 4t bottom end. We have member in Boca iirc that has a 150 he runs on juice.
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Post by iwiketuddlz on Feb 24, 2015 19:52:45 GMT -5
My new Polini crank is only splined on the end like a 4t and I have estimated 25hp and don't have any problems...
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Post by boostnjuice on Feb 26, 2015 13:47:12 GMT -5
So this morning it started right up as soon as I hit the start button then died. Took a while to get it running again so I zipped away trying to get it warmed up. It stalled at the first stop light and would not start again. So I pushed it home and got in the car to go to work. It is acting just like it did with the burnt valve. I believe I may be running it too hard for this cheap Chinese head. I don't have a CHT gauge so I don't know how hot it is getting but I think it is too hot. While 11k is great for power and top speed, I don't think the ex valve is closed enough to transfer much heat to the seat which causes the valve to overheat. The answer? I think I need to spend some cash on a higher quality head. Something with better valves.
I will check the valve lash when I get home tonight.
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?. What a beast!! Completely stock CVT save for a new set of 4g rollers, she hit 11,000 RPM. 