Same old story: Jet size

B

bikerbill2021

New Member
oh hai

so i know this has been asked time and time again, but sifting through the archives for a specific bike and setup for said bike is a PITA

anywho, jet size. ive got my 75 CB500T project bike sitting here, im going to be running pods and basically the stock exhaust (CB450 pipes/muffs to eliminate that stupid crossover thing the 500Ts come with). now, will the stock jets suffice with this setup? or am i going to need to upgrade, and if so what size and where can i get the proper jets?

thanks guys, just want to make sure i get everything squared away on my project now while i got it apart so i can spend more time riding it then fixing it this season 8)
 
stock carbs are fine. might want to go up a size in jetting. i say ride it and then see how it runs/check the plugs. ;)
 
It might be what you like to hear, unfortunately, it's wrong
Your going to need bigger main jets and spend some time playing ith float levels as the needles ae non-adjustable.
Fitting pods to Honda 3 jet carbs is loads of fun ::)
You will be far better off with stock airbox and exhaust change.
PJ
 
I have very little experience with this (or anything else for that matter), but I went back to my stock airbox from pods on my 750 and am very happy with it. No more guessing. Plus I find that PJ's always right... ;D
 
+1^ PJ is really knowledgeable and especially when it comes to the motor... His advice has always yielded results, for me at least.

My experience is that pods might look cool, but many times they can be more of a headache... I like to ride my bike, not spend the entire summer riding season tuning and fiddling
 
these are some good tips guys, i was debating on running my stock filters or not, the problem is, i have no idea what the PO did, (if he did) to the carbs, he could have had them jetted for all i know, so thats the next place to start i guess ugghh :-\
 
I like to ride my bike, not spend the entire summer riding season tuning and fiddling
Click to expand...

What?! Geez, then you miss out on that wonderful pleasure of getting it spot-on! Man its a good feeling! 8)

Bikerbill2021, it can be a right pain in the ass to rejet a bike perfectly to suit pods and free-flowing exhaust setups. First stop is your mainjets. You'll want about 1 or 2 sizes over stock, so find out what 'stock' is and go from there. It may be easier to order several sizes to suit; for example, with my GS850 I ordered 2 sizes (125 & 130, stock 115) and found I still need to go richer by perhaps a size. Keep in mind I'm running both pods and a 4-1 exhaust there.

As has been said before in this thread, once you get your mainjet right (confirmed by a plug-chop @ max load w/WOT) you then go either to your needle or to your float height. Needle should be adjusted to give you best pull up the midrange without spluttering or staggering anywhere. Float height should be adjusted so the bike will accept full throttle anywhere without spluttering or bogging down, specifically when cruising at around 3,000rpm.

Once you've got all that sorted you can make fine adjustments to things like pilot jets etc. Remember to only change one thing at a time or you won't know what worked and what didn't. May help to keep a 'modification log' as you go so you can remember what's worked and what hasn't.

Sound like a lot of effort? Yeah, it is. Its totally worth it though once you get the bike running well, but if you don't want to go through that process then just fit the stock setup and treat it to a new set of rubber boots if they look perished. Performance will be good and you may not (may not) even have to touch a thing to have it running like a champ.

Cheers - boingk
 
Bill, it sounds like you don't like carbs?
If that's the case, it would be stupid to fit pods.
Make carbs stock, go up one size on main jets
It will probably be slightly lean but you wont have same headache as jetting with pods.
Without adjustable needles its going to be a lot of trouble.
I have (limited) access to a dyno with gas analyser, I haven't got jetting on my 360 right (yet)

PJ
 
haha whoa guys i never said i didnt like carbs :p

haha this is my first project/bike more or less, so i have no problem doing test runs in order to get her running top notch

so i guess the next question would be, does anyone know the stock jet size on a 75 CB500T? (or a guide to find the jet size) and also, where i could purchase the different sized jets needed?

thanks guys 8)
 
CB450, MJ 125, pilot 38
CB500, MJ 130, Pilot 38
I think 450 needles are adjustable, that will make life a lot easier

PJ
 
They all look to be Kei-Hin 14 series (single float)
There are adjustable needle that fit but I forget what they are out of, probably Kei-Hin oval bore carb off XL 250~350 from early 70's
Problem is, I haven't worked on 450~500t since 1979~80, 30yrs is to far back to remember details (Its kinda scary when I say that, might be getting 'old' :D)

PJ
 
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