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GTM Header System for MGX-21

GTM®

GTM®

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GT di Razza Pura
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We confirmed this week that our dyno-proven (built to order) GTM Header/connector/H-pipe with stock heat shields HERE, fits the MGX-21 with stock or aftermarket mufflers. Ago muffs shown below. The owner of this bike is wrapping his headers, so he purchased brushed. They are available in black per the purchase page.

gtmotocycles.com

GTM California 1400 Full Stainless Header System

GTM® Full Stainless Steel Headers for your California 1400 BUILT-TO-ORDER ONLY - ALLOW 4- 6 WEEKS+ BASED ON FINISH REQUEST. CONTACT US TO ORDER. 100% Made-in-SoCal-USA. Dealing with a cracked H-pipe connector or heat shield studs? Our full stainless performance stepped-header system mates to...
gtmotocycles.com gtmotocycles.com

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Great news! Does that mean you'll be producing more California exhaust systems? Noticed everything has been out of stock for a bit.
 
Nice! That GTM full system and fuel mapping kit are the first things I was considering upgrading with my bike. You guys were throwing down some power increase numbers hovering in the 30% range. What mostly contributes to that? Can you get similar numbers with stock pipes but change the tune? Or is there something about the airflow from the headers down that these aftermarket pipes change? I am new to all of this so sorry if it seems obvious.
 
eliasmckee said:
What mostly contributes to that?
Click to expand...
All outlined on the thread (with embedded purchase links) below. Our stepped headers are a big part of the gains over mufflers only.

GTM®

Thread 'GuzziTech GTM modded Cal 14 Dyno vs. Stock'

I finally got the GTM® modded Cal14 on the Cycle World dyno late yesterday, and the results are below. A completely stock 1400C shown as a blue trace below, then with my GTM® Slip-on mufflers and H-pipe with opened air box lid and GTM® Fueling kit, results in the green trace: ~6-8 hp constant gain, and 8 lb.ft where you'll live the most.
With the full GTM® Exhaust & Fueling Kit (install How-to HERE) along with the modded air-box lid & K&N filter (gold trace) = Long mufflers give ~20 hp & 20 lb.ft. gains over...
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