rolling roads/dynos

[bagzy]

Spence how the devil are ya, top site mate, bout time i had a butchers, hope to see you soon.

Just a quick one to see what experience/tips/recommendations members may have had with certain dynos/rolling roads.
I want to get my recently completed smallframe primmy et3 sprint set up for optimum power and efficiency. (Spec :136 malossi, full circle race crank,hp4 ,zirri 4th gear,25mm dellorto, reed vv,sip jl race pipe, 20bhp, 80mph)
Ive only had one experience with dynos in the past so any help will be appreciated.

Bagzy. armed forces sc

[Smallframe]

bagzy , just noticed your sprinter on readers rides, I know the lad who was selling this on ebay at the time (he now regrets the sale of course). This scoot has already been dynoed at PSN, who certainly know their stuff.

All things said and done though I am still of the opinion that dyno's are only of benefit for race/sprint engines on the basis that extra h.p is squeezed out for good dyno readings is done by setting carbs very lean.

for road going scoots i believe squeezing them extra h.p out on a dyno does heighten the chance of detonation.

finally, from your experience of riding that motor does the 2.34 upgear in the motor pull the zirri short 4th well or is it too revvy for the highways.

[bagzy]

Cheers mate, yes the lad i bought it off was in two minds about selling it.
I was aware it had been dynoed at PSN, at that time the motor had just been built and it was set up for sprinting and its "running in" period, (on the rich side etc, )this is fine higher up the rev range with peaky power but bogs down at tickover and low revs. Now its run in i want to get it set up for road use.

I agree with you ref squeezing every last drop of h.p out of it, this is not my intention, if anything theres quite a lot of scope left for further tuning, (bigger carb,different inlet and reeds etc) but im more than happy with the power as it is. Its very quick as it is, all i want to do is get it more road use friendly
With the zirri 4th you trade off a little top end but it closes the large ratio gap which you get between standard 3rd and 4th gear which obviously helps to keep the power on.
I cant see a noticeable difference in the revs at the top end.

Im ideally looking for a dyno thats local, otherwise id go back to PSN. Cheers again

[Smallframe]

If you want to lose the lowend bogging down, try a D29 needle in the carb or try your existing needle (which i assume is somewhere between D22 and D26 ) on the top clip, thus making the fuel air mix leaner at low throttle positions.

I found the only way to make my engine more road-use friendly was to hang up my exotic expansion chambers on the garage wall and and stick a humble leovinci pipe on for improved low end torque.

[bagzy]

Cheers for the advice, ill give it a try, im running a 25mm dellorto on it at the mo, regarding the pipe, i was already thinking of that one, do you think it will make a difference.

[Smallframe]

It did on my polini kit. The malossi is a lot revvier kit tho' so yuo would expect a revvy pipe like the jl to compliment it.

As the resonance chamber and lead pipe are so large on the JL, there is bugger all back pressure at low revs and this consequently affects the low down torque. I have a zirri & a somnini D & F both hanging up for the very same reasons. You will lose a degree of top end power tho' as the rev range will be reduced, but you can't have the best of both worlds can you .

JL3 on my lammy performs great low to mid and then just tails off as the pipe doesn't permit high revs ( a lot like the taffy).

Lend a bargain bucket Leo/ polini pipe and do some experimenting, you;ll deffo see some difference, but whether you find it a positive one is unknown for your engine setup.

As an afterthough, you could also try the 2.56 primary as 2.34 is really the territory of zirri and fabrizi cylinders as in very very tall gearing.

[bagzy]

cheers smallframe, (do u have a name mate?)youre a f***kin wealth of knowledge, you know this scoot better than i do ! Ive always owned just lammies until this past year, with vespas ive only ever liked Smallframes, and thats mainly due to their ride/roadholding. As you may have noticed i like fast scooters and im sure youll agree theyre the best handling scooter that vespa ever made. As a mechanic im like a sponge at the minute with all things smallframe so appreciate any advice given, im guessing by your handle your a bit of a smallframe nut ! Will be doin a bit of experimentin over the next few weeks, i"ll let you know how i get on. Thanks again, appreciate it.

[bagzy]

Just an update Smallframe, took the scoot into allstyles. Geoff stevens the tuner had a look for me, tinkered with the needle, leaned off the fuel at low revs and changed the plug from a cold 9 down to an 8, instant result, have now lost the low down bogging down and pulls cleaner from low revs. Not perfect but much much better. The leovinci is the next task, then geoff is gonna make the carb adjustments to suit if any. I was recommended to use 3% oil mix, whats your thoughts on this ?, am using rock oil synthesis fully synthetic, expensive but one of the best.

[Spence]

Bagzy, just as a quick aside, how much are you shelling out for Rock Oil fully synth? My regular dealer charges £8.75, although if I travel as far as Bootle I can get it for £6.50. Never seen it any cheaper than that, especially at rallies where you can't get it for less than £9.

[Smallframe]

I'm using sysnthesis 2 aswell and for £6.50 a bottle.

but if I buy 4 fourlitre bottles in a case it only works out about £5.50 which makes sense in the long run what with rising oil prices.

I thought this site had froze, till I noticed todays input mr spence

[Smallframe]

I run my smallframe on 2% and optimax with no problems at all. My Lammy is on 3%

[bagzy]

Fellas it looks like your prices for rock oil are reasonable, it costs me £9 a bottle, typical suvvern prices !! Have used it in my tuned scoots for years with no probs so the expense is worth it me thinks.

[Spence]

The amazing thing is, and I think Mike will agree, the place where we can get it for £6.50 is generally expensive for everything else. Shows it pays to shop around.

[bagzy]

Smallframe, cheers mate,took your advice with the leovinci and glad i did !
A massive difference, it pulls strongly now through all 4 gears right through the rev range.
The only downside is the exhaust tails off at about 70-75mph, but i can live with that, only 5-7mph down on the top end compared to the SIP. All that was required was a slight re-tweak of the carb. I now have an exotic sip evo exhaust decorating the garage wall !

[Smallframe]

I know the "leo" aint as mean lookin as the SIP curly ( resorting back to a 3.00 x 10 tyre too), but u can always keep that for the balls out sprinting can' t you. maybe spence should have a new section added to the gallery entitled "peoples garage/ shed walls" adorned with exotic pipes.