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Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 1:06 am
by mawso
Can anyone help with comparing the performance of a JL2 & JL4 on non reed kit. Does anyone have any back to back info?

Looking for bottom end results and what torque can be produced...I know they both rev rev rev at top end.

Thanks.

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 7:18 am
by CPH Lambretta
Scootering did an exhaust shoot out a few years ago on both TS1 and a Honda 205.
The JL4 and JL2 where dynoed back to back, as I remember it the JL4 was far better and had better low down power. The JL2 had nothing low down then suddenly took off.

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 3:53 pm
by mawso
Thanks very much. That sounds like what I'm looking for...don't suppose you know approx what year it was? It'd save me some digging around.

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 6:43 pm
by fairspares
i use the jl4 franspeed ( which has the better spread of power over the standard jl4) on my street class sprinter with rapido barrel , excellent pipe will be getting a dyno run done very soon

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 7:37 pm
by mawso
Yeah a friend runs Franspeed race pipe, his bike goes v.well. I'm not looking to buy though, as I've already got both pipes and ran a JL2 before with good results on an iron kit. Have never ran a JL4 before though.

Really was just interested to see how they compared. JL2 is listed as fast road and the JL4 as full race. Although opinion is JL2 is a top end screamer and JL4 can perform well all round.

Anyway, was planning using a Mikeck but that needs altering to fit, so wanted get something ready sooner.

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 7:47 pm
by fairspares
the jl4 is the race pipe with power rev range at top end. also if its one of the older jl4s it splits around the down pipe as made from thinner steel. sounds like you got info from the old sip catalogue which is muddled up.

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 7:51 pm
by yam-lam
CPH Lambretta wrote:Scootering did an exhaust shoot out a few years ago on both TS1 and a Honda 205.
The JL4 and JL2 where dynoed back to back, as I remember it the JL4 was far better and had better low down power. The JL2 had nothing low down then suddenly took off.

in this months scootering mag ..... they have tested 15 exhaust old and new ..... based on ts1 .... :D

Re: Looking for info on JL2 v JL4

Posted: Wed Feb 23, 2011 8:19 pm
by mawso
I think I was going by Sticky's manual for specs, haven't got it to hand but I'm sure that's where I read it. Been on a JL website before, but can't find that anymore.

I'd bought the JL2 from Kegra thinking they were still selling the KRP2 not knowing they were remade by JL at the time...few years back now. I'd never heard of JL's then.

This JL4 has had a flat brace plate welded in near the stub and another piece of flat plate welded on top of one of the thicker cones...maybe it split here before.

Re: Looking for info on JL2 v JL4

Posted: Thu Feb 24, 2011 2:07 am
by corrado
Download the scooter centre catalog, http://data.scooter-center.com/download ... 2007_E.pdf

There's dyno plots on lots of exhausts inc the JL2 and JL4 with readings for 205 Honda and TS1 kits.

Re: Looking for info on JL2 v JL4

Posted: Thu Feb 24, 2011 11:27 pm
by fred
i'm using jl2 on a stage 4ish cast barrel,works really well. Whats port timings on barrel you're using
?fred