XR650R Smog Pump Question

8 replies to this topic
  • jaybert600

Posted June 04, 2002 - 05:04 AM


Is there a noticable power increase when removing the smog pump on the 650R? What other advantages are there other than a weight loss?

  • XRider

Posted June 04, 2002 - 05:43 AM


I don’t know if there is a power gain from removing the smog stuff alone. One of the benefits other than weight loss is that it really makes the bike run better. It stops the bike from popping on deceleration. Of course, I did re-jet.

  • billyj7175

Posted June 04, 2002 - 07:41 AM


I didn't notice any performance gain, other than the above noted absence of the popping on deceleration. Just to info you, if you plan on putting a Clarke tank on, or some radiator guards, you'll have to remove the smog valve.
I did mine myself:
Removed the valve, and plugged the two flex lines with 5/8 X 1 bolts and clamped them down tight.
The vacuum port on the intake can be removed and plugged with a phillips screw removed from the valve that you just took off.
I plugged the top of the airbox with a mt bike handlebar plug. It fit really snug, so I just pressed it down on the port real tight.
I left the crankcase breather hooked up to the airbox.

I did order a block off kit, that has the block off plate that mounts to the cylinder head, right between the exhaust ports, but I'm going to wait until I have a good reason to remove my radiators before tackling that job. I tried to get a allen wrench in there, but all of my wrenches are either too long, or too short, and I don't feel like cutting any of them off. Use caution when working around your radiators, those fins are very delicate and easily damaged.
By the way, get the block off kit from XR's Only, because it's about $15 cheaper than the one made by Applied Racing.

  • XRider

Posted June 04, 2002 - 08:13 AM


I got the kit from XR's Only and they supplied a custom length Allen wrench that worked perfect for the job. However, I did have to remove the left side exhaust head pipe and only remove the lower left radiator bolt. Like you said, be very careful of those radiators.

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  • loufish

Posted June 04, 2002 - 06:58 PM


I don't think there is any HP to be found by removing it, but....I got rid of it because I don't like any more junk on my bike then I have to.
My kit was $20 , and I had the head pipes already off, (the Pro-Circut pipe was going on at the same time)and had to cut down one of my allen wrenchs...that bolt was tight!

  • XRider

Posted June 05, 2002 - 04:25 AM


A guy sure could save himself a lot of time and work by saving up all the parts he buys like the tank, pipes smog block off, jetting, dual sport kit and install them all at the same time. Most of these mods either need to be done in relation with the other or you need to remove most of them anyway to install the other.

  • jaybert600

Posted June 05, 2002 - 04:28 AM


Thanks for all the input guys.

  • loufish

Posted June 05, 2002 - 07:07 PM


Thats just what I did, the bike had less then 1 mile on her, and I had purchased all the parts before hand, never rode it all, until all my parts where installed, all at once, even took off a day from work to get it all done...

  • BendThumper

Posted June 06, 2002 - 05:01 PM


I hated the popping but to get through the warranty, I just put a plastic plug in the hose opening for the smog pump thats in the air cleaner box. No more backfiring. simple until out of warranty fix.

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