View Full Version : I was right! (...again!!)

01-05-2003, 05:04 AM
Today I had the opportunity to do acceleration tests between my near-new (1800km) Sr50 Ditech and my brother's 1995 Honda Dio (with over 18,000km on it!!) and guess what? I was right all along. The Dio out accelerates my Ditech! Bloody amazing...but not completely surprising considering that in the month that I've had my bike I've often thought it didn't feel very fast at accelerating. Of course, my bike has a faster top speed...but all the same, how does a high mileage 7 year old, ancient technology moped out-accelerate a new, high priced, modern technology scooter? Am I missing something here or what? Have we all been conned? Should we all go back to our old mopeds and be done with it?

It was also the first time I've had a chance to listen to my bike whilst being ridden by someone else. And you know what? The rattling type of sound that comes from around the back of the bike under acceleration is even more noticeable when you stand behind the bike and listen to it ridden down the street. I can't work out if it's coming from the gearbox (rollers and variator look fine, clutch looks OK) or if it's from the motor. Despite my best attempts at trying to hear it whilst parked on the centre stand, I can't discern it over the exhaust noise. Yet on the road it's quite noticeable.

I guess I'm feeling a bit deflated at being beaten by my brother's bike, and feeling even more deflated when I realise that my own Dio that I traded in on this Ditech was an even quicker accelerating bike than my brother's!! Maybe I should've just saved the money and bought a Derbi!!

01-05-2003, 06:19 AM
my friends honda x8rs used to rattle like this under acceleration. It turn out to be the stand vibrating against the frame, thats why we couldn't hear it when it was revving oin the stand, check this out

01-05-2003, 06:28 AM
somehow I don't think it's going to be the stand...but I will check it out to eliminate the possibility. It just doesn't sound like a stand sort of rattle. The rattle increases under hard acceleration and is not subject to bumps (like a stand rattle might be). The rattle either stops or is unnoticeable at a constant speed, but appears again as soon as I open the throotle some more. Makes me think it's the gearbox rather than the motor...it just sounds like a gearbox rattle.

I'm wondering whether to wait till my 4000km service (which is another 2000km away) or take it in now and see if they can find anything.

tiba karotsu
01-05-2003, 06:46 AM

is your brothers Dio the horizontal engine or the vertical engine? the Dio with a horizontal engine has a rev limit of 10,000 rpm plus the thing is geared for stop & go city riding plus it has smaller 10' wheels. it can go a bit faster with cheap mods like racing CDI, overdrive pulley & a 16 x 42 gear up kit. all the Dio ZX models including the older vertical engine have a power of 7.2hp. add some mods like a tuned pipe, P & P, CF reeds, lighter rollers, carb tuning and it can do 100+ kmh on a 50cc.

add to the fact that the Dio is much lighter than the DITECH it's very easy to see why it out accelerates your DITECH plus the current mapping is limited to 9,000 rpm. so i'd get the new mapping & tune the tranny to suit and have it tested against the Dio. also the Dio has a longer 39.2mm stroke compared to the DITECH's 37.4mm stroke so the Dio has more low end to mid range torque.

as for the rattling noise just pull out the stand and listen if it still rattles.

Aldo Steptoe
01-05-2003, 05:01 PM

I have a DERBI Atlantis 100.
<img src="http://www.sumeko.fi/derbi/kuvat/atlantis_100_1.jpg"/>

You wanna swap?:rolleyes:

I just wanna bugger around with a Di-Tech, slow or whatever.

01-09-2003, 12:37 AM
I must admit that the Derbi's look like excellent value 4 money and if I'd known about them before I bought my Ditech, I might just have ended up with one. But now that I've committed myself to the Ditech, I'm going to stick with it for the immediate future (probably for years I hope!)

It's interesting to note that the reason I became interested in it was because my local dealer was advertising it in the paper every week as being able to do 100km/h. So I went along to try it and although he was exaggerating enormously about the top speed, after I'd ridden it I was hooked. I only found out that there were other alternatives (Derbi, Piaggio, Peugeot, etc) after I'd bought it!!

How fast does a Derbi really go anyway? There's a dealer in Brisbane advertising a second-hand Derbi 50 (with about 2,500km on it) and in his ad he quotes a top speed of 110km/h. is this guy kidding himself big time or what?

01-09-2003, 12:40 PM

I had a very strange nois, perhaps like you have.
The workshop did not find anything, but after a while the shaft was worn out, you know the axle where all the variator weights are. The small disc behind the variator was worn out as well.
Check if thats the problem.