Scooterotica

The New Franspeed Avanti Exhausts are now in stock at Andy Francis & myself, straight fit!
The modification that JB's did is fine but I would have altered the main bracket on the exhaust to save machining the fins.

I altered a Franspeed race pipe last April, I will try and post some photos up during the week. For JL3's it is a fairly easy modification to carry out if you have access to a welder.

OK, quick update here, sorry for the delay i have been off ill but am back now!

Anyways, (recap) as you know we fitted the brand new Avanti kit and gave it a preliminary run up with Andys old PM pipe (see beginning of thread for graphs), however at that point we found his old/worn clutch had finally given up and needed replacing. The scooter was hitting circa 18bhp with a gentle run on that pipe and rich jetting, but we knew there was also power being lost due to clutch slip. So we have stripped the engine again and fitted a new clutch, we actually opted for overkill and went for 6 plates, the reason for this is that we intend to tune this cylinder after it has been run in, so with the BHP figures we are expecting we didn't want to have to go back in and up-rate it again at a later date. We also fitted a new gear selector spring too as Andys was jumping with his old kit anyway.

So with the new clutch in we hit just over 19bhp with the same jetting on the PM pipe, we then changed the pipes and release another 3bhp by using the Franspeed Race, see graph:



Nice to see peak power is at a relatively low revving 7000rpm.

So just under 22bhp with the Franspeed Race, with 4.6 gearing, 6 plate clutch and still on 'safety jetting' on the brand new kit.....and at only 7000rpm, not bad! 24bhp should be achievable with post run-in jetting. Also, as soon as i get back to the workshop this week i shall pick up the graphs that show torque also, sorry they are not on this post, and then we have 3 or 4 pipes to alternate and compare. I certainly cant see any other them beating the Franspeed Race on peak BHP, but some may prefer the look of Clubmans and such....so we will test and report!

More info to follow soon..............!

Picked up the graph with torque showing:



Bearing in mind, that this kit is straight out of the box, no porting/tuning to cylinder or casings, simply bolted on and run up on the dyno (on a rich setting) that 22bhp @ 6000rpm and 17ft-lbs torque @ 6400rpm is pretty impressive. There are not many kits that will do that straight out of the box, and if they do.....they are not piston port, are usually producing the power much higher up the rev range, and usually cost a lot more! lol

This kit also has great potential for tuning, out of the box it is just so low-revving that many touring types will just fit it, bolt on a Franspeed race or an ADS touring pipe....gear the hell out of it and pull low revs and good speeds everywhere, happy smiley faces! But also, i can see already that those who want a real kick in the pants and a bit of 'peak power' instead, can easily have this kit ported/tuned up to spec!

Exhaust comparisons will commence soon....... ;o)

thats a good result Dan
im guessing the jl4 will be pretty much the same and jl3 a similar or slightly lower peak but with improved delivery from the bottom end (although its a lower powered pipe its a closer tuned length to the port timings of the avanti)
what main jet you running at the moment?

Darrell Taylor wrote:thats a good result Dan
im guessing the jl4 will be pretty much the same and jl3 a similar or slightly lower peak but with improved delivery from the bottom end (although its a lower powered pipe its a closer tuned length to the port timings of the avanti)
what main jet you running at the moment?

Yes, i'd say so.....got an ADS touring pipe fitted tonight, gonna run it up in the morning and see whats what.

Then.......a clubman

The Avanti suggested gearing / exhaust combos read 4.8 with the Franspeed Race and 4.6 with the Franspeed road /tour.
How do you think the graph would look if it had been fitted with 4.8?

Graphs for Franspeed Race vs ADS Tour vs AF Clubman on Avanti TT3 kit:

Red: Franspeed Race
Blue: ADS Tour
Green: AF Clubman

BHP

Red: Franspeed Race @ 22bhp
Blue: ADS Tour @ 19 bhp
Green: AF Clubman @ 14bhp

Tourque

Red: Franspeed Race @ 17ft-lbs
Blue: ADS Tour @ 16ft-lbs
Green: AF Clubman @ 12ft-lbs

See this thread for full write up: http://scooterotica.org/forum/viewtopic ... 9&start=10

Hi Dan,

How far are you going with jetting on these early test.
is it just jetted to be safe or are you going right thru the range.

cheers

I was thinking along those lines myself. If for example the carb was fitted with a 140 main jet which is good for the race pipe, how would that reflect on the readings for the other pipes, with say, the clubman only needing a 130?

the main jet shoudnt influence the results too much as the air fuel ratio remains pretty constant between pipes although in this test the race pipe may have needed to be a touch leaner as the carb will enrichen with increasing operating rpm that the fran has over the ads3
the ignition timing can be more important when comparing pipes