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Do I need to rejet the carb??

3K views 8 replies 3 participants last post by  JakerHsnaker 
#1 ·
I have seen this discussion a couple times pop up but I could not find a definite answer.

1987 Honda rebel 250. I removed the air box and installed an emgo pod filter. Still have the stock exhaust tho and do not plan on modifying that.

This is kind of a specific question that im hoping someone has dealt with and tinkered with before. Soo what I am asking is should I rejet my carb to compensate for the pod air filter? Anddd if so do all the jets need to go up a size.. or multiple sizes.

I read that the 85-87 models run richer and can have straight pipes without needing to rejet as long as the airbox isnt messed with. Does this mean that a pod filter is fine as long as the exhaust isnt messed with??

The bike is running fine, I think. I cant really tell if its runnning how it should or if it's running too rich/lean. one thing I have noticed is that the exhaust pipes may be getting excessively hot. I wrapped my exhausts and the fiberglass material wraps were nearly burnt all the way through after one 30 minute ride. Not sure if thats normal or not.

Uhh also in case its important, I have my breather running directly into the pod air filter through a small mesh inline filter. picture of that is attached as well.


Hopefully this is my last question for you guys lol. seriously considering naming my first born kryton or flitecontrol or shadowshack. krycontrolshack?? Attached is a before and after of my bike, this forum helped out a ton.
 

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#3 · (Edited)
The first generation Rebels were jetted for optimum performance. The second gen jets were downsized for better fuel economy, and run a little leaner as a result. Getting the jetting right with a pod filter is a matter of trial and error because of the differences in different brand/sizes of filters. You'll need to pull the carb, install the new jets and then do a spark plug inspection.

To do this, ride the bike far enough at highway speeds that the engine is completely warm. Five miles or more ahould do it. Then when it is safe to do so, hit the kill switch and coast to a stop in a safe location off the road. Remove both spark plugs and see what they look like. If too lean, go up another main jet, repeat, and so on. Of course you will need to carry a spark plug wrench. Here's a chart showing various plug colors/conditions: Spark Plugs

Here's a link to a jet size calculator that shoulld get you close: Jet Kit Calculator Techincal - Jet kits for Carburetors

You'll still need to do a spark plug check to know if it's right or not.

If your firstborn is a son, don't name him Sue!
 
#5 ·
Other than putting first generation size jets in my second generation bike carb, I have no experience with carb mods. Several members have used the calculator and said it is spot on. I would still want to check the plugs after going with their recommendations.
 
#9 ·
Hey guys just following up. new jets and shimms are installed. The jet kit calculator was spot on. My rebel is running way better now. spark plugs are within the appropriate range of color, starts easier, idles better, and sounds better. Runs perfect and on hot days I dont even need to use the choke while warming up.

10/10 would recommend the jet kit to anyone who removed the air box and installed a pod air filter but still has stock exhaust.
 
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