Derestricting a standard Mk2 exhaust.

Post by **moose011070** » 15 Mar 2009, 19:22

Dep sport pipes and the like are so expensive!

Has anyone ever tried to take the restrictor out of a standard front pipe and re-weld it? I have done this before with a KTM 125 (DTR 125 engine) trail bike. The bike in standard trim could acheive 62 mph. After the cat was removed from the standard pipe, rejetting and air box flow mods the KTM acheived 88 mph.

Does anyone know if there is a flow restrictor in a standard mk2 front pipe, there does seem to be a few spot welds around the thickest section of the pipe?

Also is there a cr 250 standard pipe that may be suitable for modification for the mk2 as they fetch around £25 to £35 on ebay, cheaper than the £160 - £199 i've been quoted.

Thanks for your time.
Moose

Post by **knackeredMk1** » 15 Mar 2009, 19:30

There is no restriction in any CRM250 pipe. Aftermarket alternatives give a little more power & torque but weigh a whole heap less and give a better sound.

Some people have modified CR pipes (~1989-93) and apparantly get a more dramatic power increase, but I'm not so sure

. Main problem is either changing the barrel to accept springs (like CR) or the pipe to be bolted on (like CRM).

Post by **moose011070** » 15 Mar 2009, 19:33

Bugger!

Apologies to all site users as I have managed to post this article in the wrong section, should be in technical section.

Post by **moose011070** » 15 Mar 2009, 19:36

Thanks Knackered, will take that onboard

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Derestricting a standard Mk2 exhaust.

Derestricting a standard Mk2 exhaust.

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