Anyone know the CB125t pilot jet sizes? Manual would be good too

[motorbyclist]

Does anyone know the stock sizing of the pilot jets on a 1980 honda CB125t? I'm looking to buy new ones (in stock and larger sizes) or maybe redrill the current ones depending on prices...

An electronic or very cheap hard copy manual would be great also

My pilot jets are fairly clogged despite 24 hours soaking in carby cleaner followed by me with a very fine needle and 6-8bar of compressed air.... I can see daylight through them but it isn't round and the bike runs waaay lean on both cylinders. Once started it idles around 1500rpm but touch the throttle and the revs shoot up to 3k and sit there. right cylinder fires fine, left is intermittent/serious misfire. There are no air leaks that I can find....

The jets have been soldered and re-drilled in the past at a bike shop for a previous owner. The next previous owner let the bike sit full of fuel for 12 months. I'm sick of inhaling carby cleaner so looking to just buy new stock pilot jets plus the next size up if it isn't too costly (I suspect I need larger ones considering the gutted pipes and pod filters the bike is running)

[Yow Ling]

you can just buy a new set of carbs for $100 (guess) pm k14 and find out where he got his. jets are going to be maybe $15 each so you are better off starting new

[motorbyclist]

you can just buy a new set of carbs for $100 (guess) pm k14 and find out where he got his. jets are going to be maybe $15 each so you are better off starting new

but i've already buried a $20 can of carby cleaner in them!

I'll see if I can get the sizes and possibly re-re-drill it if it's going to be that pricey... and cb125t guys know their jetting out there?

[motorbyclist]

you can just buy a new set of carbs for $100 (guess) pm k14 and find out where he got his. jets are going to be maybe $15 each so you are better off starting new

I might add that that doesn't help with finding the correct size as a starting point for tuning... will PM known CB125t owners and see if they know what they've got - my jets have had the numbers filed off them as part of their rough history and a new carby won't help if the mods to the bike require a larger jet

[motorbyclist]

OK, I've had some luck:

From what we can tell after yet more hours on google, the stock pilot (slow/idle) jets are #38, and main is #88

It's a PD26A Keihin carby - pilot jet appears to be 21 series, and the cheapest supplier appears to be local.

So, once some PMs have been responded to and I've removed the old jet and assessed it for size, I'll go down to cycletreads and get two "N424-21 #38" for $10.90 each... if that's still too lean I'll go up to #40

so, $44 later i might have a bucket ready to race!

EDIT: later found the jets to be of a press0fit rather than threaded type, but size is correct at #38

[Pumba]

http://www.kiwibiker.co.nz/forums/member.php/8967-timg Timg was the previous owner before we let it sit. He had it on a dyno. Might be worth talking to him.

Otherwise John Conner would be the best person in Auckland to talk to. Pone number is on the AMCC website

[motorbyclist]

http://www.kiwibiker.co.nz/forums/member.php/8967-timg Timg was the previous owner before we let it sit. He had it on a dyno. Might be worth talking to him.

Otherwise John Conner would be the best person in Auckland to talk to. Pone number is on the AMCC website

haha yeah timg already got back to me on that and reckons they were re-redrilled to standard size

he also gave me john's email

[Buckets4Me]

haha yeah timg already got back to me on that and reckons they were re-redrilled to standard size

he also gave me john's email

John has built more cb125twins than anyone els i know
and he is more than willing to let you know about them. Just come down to a race day (say this sunday) and wave a few flags
then you can chew his ear off
thats if you are up around auckland

[Squiggles]

John has built more cb125twins than anyone els i know
and he is more than willing to let you know about them. Just come down to a race day (say this sunday) and wave a few flags
then you can chew his ear off
thats if you are up around auckland

That would require him to be up before 2pm

[motorbyclist]

That would require him to be up before 2pm

hurry up and finish that KLR will you?

[Buckets4Me]

That would require him to be up before 2pm

well that will teach him for living so far away

if he leaves saturday then he has plenty of time

[motorbyclist]

you can just buy a new set of carbs for $100 (guess) pm k14 and find out where he got his

shit that looks pretty attractive at the moment!

check this out - had to pull the jets out with pliers.... pretty sure this is meant to be a threaded arrangement but there was already plier marks and nothing to unscrew



story is a bike shop had to solder and redrill these as a past munter had drilled them out larger...

what do you guys reckon about the lack of thread? I've never seen them without it before.... the replacement looks like what i'm used to.... argh!

the good news is they are blocked by debris (explains lean mix, not surprising at all) and there was a number on one of them! #38 is correct

(and the bowls leak it turns out)

[aircooled]

pretty sure some early model honda carbs did not have threaded pilots & were pressed in,

wonder if you tap a thread & use threaded pilot jets?

[motorbyclist]

pretty sure some early model honda carbs did not have threaded pilots & were pressed in,

wonder if you tap a thread & use threaded pilot jets?

yes I've since found a few honda twins that had press-fit jets.

i might try cleaning these jets properly now they're out - if still no luck i might buy a pair of XR200 carbs (or any other 26mm slide carb) and fit those instead