JL chambers midrange

[triple1972]

Hi guys. This is not a new subject or uncommon issue but I just wanted any feedback from guys running JL chambers. I have a tuner and did not do the tuning myself. The pipes lack midrange (4-6K rpm). This is an RD 350 with stock cylinders. K&N,Y Boot, TDR reeds,crossover, Dyna ignition,Dave F. No porting. Is this what it is with JL chambers? 180 mains and not sure of clip position but has been moved accordingly. I did forget heads are DG that were machined by Scott C. to his 350 specs which I think are what are in the HVC heads but that should only be a plus?

[Barrie]

Lift the carb needles one increment

[Jspooner]

I only have experience with one bike and JL pipes and I can say I'm not impressed. It is a 350 with a fresh rebuild, Dave F mod and basically the same mods as you, only with Uni pods instead of the Y boot set up. I did the tune and all the other work as well. The bike runs great, really nice actually, just not impressive. My son has a 350 built basically the same way but with Spec II classics on it. If going by the butt dyno, I'd say the Spec II bike wins big time.

[Seizer]

Aren't the JL GP and Spec 2 F1 style pipes made for a higher rpm power curve? And pipes like Denco, Bassani etc made for a more "user friendly/around town" spread?

[pdxjim]

Can't comment on your condition specifically, but I bought JL pipes for my TDR250 in about 2007.

They sound fantastic and are much lighter than the stock pipes.

That said, in 2016 or so, I had Martin "Martin77" Johnson in the UK make a set of his hydroformed underslung pipes for me and ever since the JL's  have been hanging up in the garage. 

The JL's felt great until I had something else to compare them to.  Martin's pipes feel to make more power everywhere except at overrev.  Looking forward to getting them both on the dyno later this summer.

Apples to oranges, I know, but it's all I got.

[Hawaii-Mike]

I remember reading that JL pipes aren't great for RZ's either.
However JL pipes are considered to be one of the best for Kawasaki triples.

[teazer]

Hmm.  The one we ran on the dyno a few weeks ago had stage 3 porting, YZ85 reeds, Dave F carb mods and JL pipes and it went well up to about 5500 and then it went a touch flat to 6.000 and then a straight line from there to 9k.

Even stock an RD never had a lot of power in the 4-6 range which why the RZ had a powervalve exhaust - to make more low end power.

Just keep the revs above 6,000 and you will never notice it.

[triple1972]

I went for a good ride today and I wasn't as disappointed as first short ride. I think it's easy to think the midrange is awful because you have such a big increase in the higher rpm's. Not like they pulled like a train down low when new! Guess I will find out how tight my motor is because it pulls hard to 9K plus.

[triple1972]

A lot of guys put down the DG chambers but for a small improvement in hp, better sound, lighter weight, and minimal jetting changes I think they are a viable option that keeps your bike more streetable. On the pipe all the time can be  tiring. My 2 cents.

[teazer]

I agree.  DG pipes are hardly a new design or made of unobtainium, but they work fine on a mild motor. They are often overlooked by guys who don't need more pipe but want a more modern looking combination. 

Let's face it, most of us don't ride in the upper ranges of the rev range all the time.  We spend most time at relatively small throttle openings at modest revs - unless we are out at a track or having a wild moment.  DG are perfectly adequate for that sort of riding, but will never be the fastest or prettiest.

By comparison, JL pipes are sex on wheels.  They are exquisitly made and ideal for a Sunday blast as long as it's not downtown Chicago on a Saturday night or commuting to work. 

[pdxjim]

No JL or aircooled RD specific, but I found this thread (off Norbo's UK LC forum) about the development of midrange specific pipes to be quite interesting.

http://rdlccrazy.proboards.com/thread/40669/lc-exhaust-test-results

Not my favorite looking pipes, but I'm leaning towards these for the "4U0regon"  RD350LC I'm building now.

They sacrifice an hp or two up top, but make 10+ hp more than the nearest competitor in the midrange where it counts for 90% of the time.  Peak power is at 8200rpm instead of 10000rpm ... I mean, who rides around at 10,000rpm?

Look like they'll be almost $800 by the time they get here, but I've a feeling it'll be worth it.

[Nkreig]

Try reed block spacers in between the reed block and the cylinders.

[Hawaii-Mike]

Sounds like a good choice, PDX Jim.

[m in sc]

the reed spacers make a huge difference. remember, the issue here is reversion and double carburation. the spacers address this and unshroud the boost port. its a win-win.

[pdxjim]

the reed spacers make a huge difference. remember, the issue here is reversion and double carburation. the spacers address this and unshroud the boost port. its a win-win.

Yeah, all this research and work I'm doing on the LC has me thinking back about the TDR.

VForce reeds and reed spaces are on the agenda for this winter.