80-90-100MPH is this for real?

[SamM]

During the maiden voyage yesterday and before the tank problems, I had my Viva up to 60mph @ 7000rpm. It was very smooth and ran great. I was afraid to go much faster the first time out. Maybe next time! I have done the 520 conversion with new 12/35T sprockets and a new 520 D.I.D. chain.

[AZ200cc]

Well Sam After the new tank and she is all broken in she might do 70 or more..Pretty darn good for one of these bikes.

[IronFist]

If I fill my pockets with quarters I don't weigh 125LBs. If I rode the 2nd fastest bike, it would be the fastest.

[justinkr58]

yea the bike has to be broken in...
one day my bike was sluggish and topped at 40 mph, and i gave my girl a ride around the neighborhood and the next day it took off (at around 200 miles on odometer)
does anyone think the extra weight on the bike had anything to do with the sudden mood change the next ride.?

[shammash55]

sam what would be the 428 sproket size to match your speed, im trying to get my bike at that speed.

[IronFist]

justinkr58 I don't know, but every oil change I did, the bike got faster, more responsive, and each gear had a little more travel than it did before. Well except the last oil change, OD says 1200K, I think its broken in now. After 200k I stopped babying it, the pro's may tell you different but that's when I started noticing the bike getting quicker. Just my experience, for what it's worth. Might be a valve thing, but I don't know enough to tell you "why", just what I experienced. I've only got a 150cc with a 15/46 sprocket set up, but I'm getting a very good top speed at WOT 95 kph depending on wind.

Question, did you find metal bits in your oil filter/screen the next time you did an oil change, after your double ride? I only found grindy bits once, after my first 100k+ ride. Seemed stronger after that. N2r.

[zacstewart]

I noticed that my bike got faster and faster with each oil change too. It feels like it sheds some of it's sluggishness every time. I'm at 1200 miles right now and I ride it at 70+ miles per hour regularly.

[SamM]

Posted by: shammash55
sam what would be the 428 sproket size to match your speed, im trying to get my bike at that speed.

The stock sprockets on my Viva were 56/17 which works out to a 3.29:1 gear ratio.

An American Lifan has 46/17 sprockets. These work out to a 2.70 gear ratio.

My new 520 sprockets are 35/12 and they provide a ratio of 2.91. I wanted a good compromise ratio for on and off-road use. When I downsift into 1st gear it slows the bike RIGHT now! It should work great off-road.

Personnally, I'd go with 50/17 if you want to stay with the stock type 428 sprockets and chain. You should be fine with the stock chain. It your stock rear sprocket a 56T? If so, you're golden with a 50T rear sprocket. The ratio would be 2.94:1. That's as close as I could get you to my ratio.

My front sprocket is rather small for my bike and is eating into my plastic chain guide. If I had it to do over, I'd go with a 38/13. These gears have a ratio of 2.92:1. Maybe a bigger front sprocket like a 15T and a rear sprocket about 40T would be a good compromise between on and off-road too! that would be a 2.80 ratio.

I hope this helps!

[katoranger]

I tried and I could only get about 68mph with the 17/45 setup. Might need to get some more miles on it.

Allen

[STcoldcrzy]

yesterday i took a Gps with me bike speedo got to 65mph Gps was at 57mph i am sure it was heading to 60
34mph on speedo was 30mph gps... 45 was 40 and so on 17/46 sprockets

[tzrider]

Originally Posted by fatboy250

Yeah I guess it won't be too long before Discovery Channel comes a callin' on me and Dad.

Did any one see this episode? A 250cc two stroke breaking the top speed record going something like 129mph??

My 1977 TZ250D yamaha was clocked at 141 at the 1981 Daytona and the top 250 went 158. Modern 250s can exceed 175 mph. Record? Give me an RS250 Honda or a TZ250 Yamaha and I'll shatter that record bone stock!

That TZ was a pure race bike. The old ones like mine were piston port, needed a top end every 300 miles (piston kits) and a crank about ever 600 miles, not really viable street transportation. Modern ones have twin cranks, V twn lay outs, and get about 500 miles on a top end and about 1300 miles on a crank set. The one purpose these things have is racing, going fast on a closed road circuit, nothing else. You can see what I'm talking about if you tune in MotoGP 250 on Speed sometime. Evem my RS125 would aproach 140 mph top speeds at Texas World Speedway and my rider weight was around 190 at the time.

Looking at that picture, the chassis I don't know about, weird, but the motor looks like an old rotary valve Rotax or KR250 Kawasaki, either of which would push 150 mph in a GP chassis.

I don't have any pix of my old 250s, but here's a shot of the RS125. It's a 96 model. sold it in 2004 and I race minis only now. These things are too expensive on my post working budget to play with, but they sure were a lot of fun to ride. Nothing handles like a GP bike.

http://imageigloo.com/images/5295spphoto.JPG

[tzrider]

BTW, every tool has it's purpose. My LS200 is a trail/around town bike. My SV650 is a 135 mph fun on the back roads and track day cheap sport bike. My Goldwing is my 1000 mile day in the saddle two wheeled car. I ain't takin' the wing off road in the mud and I ain't takin' the Diamo to a track day or on a trip to Aridzona. :wink:

That said, the Diamo will do a little over 100.........KPH......

[katoranger]

I am happy with the speed I can get. It can keep up with the traffic and not old anyone up and the roads I need to travel. I sure I can get it to 80 though. I just need to put it on the trailer.

Allen

[tzrider]

When I was gearing mine, I went from a 54 rear to a 44. That got me up a little over 60 mph where before it wouldn't do 50 without sounding like it was going to float a valve. I've decided to keep it there, not gear any taller. Against a stiff wind, I have to lean into it and it'll get up to 55. And, too, off road, 1st gear is about as tall as it can be and be useful. I don't wanna get into tight stuff and have to slip the clutch or something. So, my gearing is a compromise for the uses I have for the bike. I have other bikes for other uses.

[mdsuave13]

before i modded my bike at all, i was able to get it to 78-80mph.

After i modded, it seems to pull better in the mid and high, but tapers off at around 70-75 now.

I weigh 160 and am 6'3". Its really not all that bad for top speed on a 200cc.

I've been looking at sv650's and kawi z1000's for riding around the back roads. either that or a yamaha road star warrior for bombing around... we'll see. I just got a card from my dealer saying that i could get financed for whatever i wanted... Which is veryyyyyy tempting.