Dynoing on the rollers?

[binge]

My speedfight should be ready by tomorrow but Ive been wanting it setting up again professionally for a while... Would taking it to be dynod on the rollers encourage it to blow up again?
I just want some first hand advice on scooters which have been tuned like that and what their experience was. Thanks...

<|Binge|>

[sickpup]

2 stroke + dyno = bang

[Keith]

Correct me if I'm wrong, but hasnt your scoot just had a complete rebuild and new top end?

If so, It'll obviously need running in first, unless you feel like seizing it.

I have seen videos of 2 smokes on the dyno and they didnt sound like they enjoyed it very much!

You should get some advice on scooter forums, buy a handful of main jets and just a process of trial and error IMO.

Get in contact with John at www.moped-spares.co.uk and he might be able to point you in the right direction.
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Aprilia RSV Mille R Edwards Replica - Aprilia RS250 - Suzuki GSXR600 Supersport Race Bike

[binge]

Yep, just had a complete rebuild...
I have a feeling that the carb not been set up great helped the engine towards death row
Thats why I want it setting up properly...
I suppose it dosent "Need" to be dynod, just the carb setting up correctly...

<|Binge|>

[stevo as b4]

I had my speedfight 100 set up on Taffspeed's dyno. Its the best way of setting up the carburation from tickover to full throttle, as you cant ride the bike constantly at different throttle opening as well as look at an AFR monitor. It might take 1-2hours of dyno time to set up, but they will do everything, like set up the clutch and fit the best compromise rollers for the whole speedrange. My SF100 went from 9.4bhp with all the bits i had fitted at home, up to 10.6bhp after being set up on the dyno. i think you might be able to get the main jet close by riding and testing the bike, but to get the pilot, needle, and needle jet functions set up perfectly for faultless carburation, a dyno set up is a must. Ask Divuk83 he can probably find you a dyno graph of someone with a dragster172 thats a before and after a dyno set up be a proper tuner.
there's no reason why a 2stroke should blow up on they dyno, if its tuned correctly!

[binge]

Yea, Ive seen the dyno graph of the wacky racers dragster... Its somthing like 27bhp...

Ive got a malossi clutch what I really dont like because its a race clutch and it doesnt engage until the scooter is reving at about 7k ...
Its horrible because when it does ingage, the scooter takes off at about 20mph...

I dont want it tuning to "Go faster", I just want it setting up so it rides smoothly again, and also so I KNOW that the carb settings are correct. Because I really dont think they are as my plug is always sooted up!

<|Binge|>

[Fortuna]

Dude run it in first, then run it in some more before doing a dyno run.
Go over the recommended run in miles as it's going to get caned at a dyno.

[binge]

Ok, 500 miles is about the right running in distance right?
So ill do about 800 miles (about a month)

<|Binge|>

[sickpup]

[divuk83]

[Fortuna]

Good 2T oil as well

[cagiva gezzer]

Had my 50&125 set up on the dyno. As long as the person using it knows how to use it, it should be fine. I would rather know that my jetting is spot on and risk the very slight chance that the dyno will push the engine over the edge, than guess using a plug chop.

+Dynos are fun! Hearing your ickle engine having the life screwed out of it!
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"because one stroke isnt enough and four strokes waste two"

[Kickstart]

Hi

The other problem with dynoing a 2 stroke is that most of them run slide carbs. If you just give these full throttle (which you would do with a CV carbed bike) then the only thing that is affecting the mixture is the main jet. Basically you need someone who knows what they are doing so sort the jetting out on different throttle openings.

The other problem is that 2 strokes tend to be more prone to spectacular failure when thrashed from cold, and few dyno sessions are going to be long enough to get it up to temperature before each run.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Fortuna]

[binge]

Ok, Ok. I might skip the Dyno...

[sickpup]

[Kickstart]

[sickpup]

Yes your right. As I said 2 stroke + dyno = bang.

[divuk83]

All this stuff is only a problem if your at a crappy garage who don't know what there doing. Take your bike to somewhere like Chiselspeed, PSN or Taffspeed or any of the other 2stroke or scooter specialists and you won't have any problems.

Dave

[sickpup]

Yes I am sure they have never had a bike blow on there dyno.

[divuk83]

A few have gone pop, buts its pretty rare.

Dave

[Fortuna]

Two stroke racing bikes are more highly strung than most of what we own. Yet they seem to do it ok.
I think it's a bit of a myth as I've heard of 4 strokes go bang too.

[sickpup]

[mchaggis]

They rag the engines before they let them out of the factory anyway though, to make sure there aren't any duff ones. Have heard a story from a lecturer about a diesel engine piston exiting the crankcase at very high speed during this testing.
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I must not be a troll...
Mmmm, Guinness
Discovering the delights of Hammerite and a 3/4" brush.

[Fortuna]

I had no choice with the amount of tuning my R1 had. Plus it had to be re jetted.
I would rather get it dyno'd and running right or the very low chance it goes bang.
Ironically if I didn't have a dyno run it would have blown up eventually through not running correctly.