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Author Topic: The Tale of Two Jets...  (Read 492 times)

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Stogierob

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on: August 29, 2018, 05:23:28 pm
In a thread that was lost during the upgrade, I was waiting on jets from JRC Engineering to address why my bike was idling so fast.  I got the new jet kit and dropped the pilot jet from a 38 to a 25.  I also dropped the main jet from a 140 to a 132.   This is on a PWK 30mm Flatside carb on an 08 bike.

And now, the G-dd@nmed bike idles even FASTER!!!  Again, no idea what the actual rpm is (man I wish i had a tach, and a fuel gauge, and a ...  Oh, nevermind...) but the bike was going 20mph at idle in 1st gear.  I had the accelerator screw at 1 full turn from full close and the air screw at 1/2 turn.

What the hell!!!

Suggestions?

and just to continue to frustrate me, the right side toolbox/former air filter box popped open because one of the little tabs on the locking cylinder broke off. 

I am NOT having fun yet!!!

Stogierob...


Arizoni

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Reply #1 on: August 29, 2018, 05:35:35 pm
Are you sure you don't have an air leak between the carb and the cylinder head?

It doesn't take much of an air leak to make the engine idle fast.
Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary


tooseevee

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Reply #2 on: August 30, 2018, 07:14:50 am

 I had the accelerator screw at 1 full turn from full close and the air screw at 1/2 turn.

What the hell!!!

Suggestions?

Stogierob...

         Yes. I have a suggestion.

          Pay attention to what you've been told about the "Accelerator" screw which is actually the Idle Speed Screw.

            You DO NOT screw the Idle Speed Screw all the way IN and then turn it OUT. We have told you this before.

          I don't know what you have done (good OR bad)with this jet change because I have NO experience with THAT carburetor. BUT

         Here's what I would suggest you do and it's all I'm going to say:

          Go start the engine. Immediately turn the Idle Speed Screw OUT until the engine dies. Now turn it a half turn IN (CW) and start it again.

         Did it slow down? If not I don't know what to tell you next except that I don't think I can help you any more.

      And if the Pilot Jet is correct the engine should not be running correctly at all with the mixture screw 1/2 turn out. We've already told you that with the correct Pilot Jet (what that is I do not know) it should be aprox 1 1/2 turns out.


 
« Last Edit: August 30, 2018, 07:19:37 am by tooseevee »
2008 AVL Classic.Extensive head work by Ace.Ace canister/TM32/Ace manifold.Small open bottle/hot tube removed.Pertronix Coil.Bobber seat.Fed mandates removed.Battery in right side case.Decomp&all doodads removed.'30s Lucas taillight/7" headlight.


Mick Bailey

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Reply #3 on: August 30, 2018, 09:29:37 am
Agreed.

And if the idle screw will not stall the engine, then make sure the slide will fully close - ensure you're starting out with some slack in the cable to begin with, otherwise you won't be able to get a proper adjustment.

The main jet has no effect on the idling. Only change this if you've plug-chopped at full-throttle and decided which direction to go (richer or leaner). For me, this is the last adjustment once everything else is properly sized and adjusted correctly.


tooseevee

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Reply #4 on: August 30, 2018, 09:47:50 am
Agreed.

The main jet has no effect on the idling. Only change this if you've plug-chopped at full-throttle and decided which direction to go (richer or leaner). For me, this is the last adjustment once everything else is properly sized and adjusted correctly.

       Yes. That is THE last thing you do is change the Main Jet. IF necessary.

        To Stogierob:
        It is so much the last thing that I have yet to this day to change the Main Jet on the TM 32 that came stock in it many years ago. And that is because I have never done ANY WOT work to this carb yet. Have not found it necessary. I am literally never on the Main Jet and this is a VERY good running engine. I can go as fast as I ever want to go without being at WOT. I don't think I'm even at half throttle to maintain 65 (actual probably 60). I have run it up to 75 a couple times just to see how it feels and it gave me no indication that I should be worrying about fucking with the Main Jet.

       I never would have suggested that you change the Pilot and Main at the same time on this carb. In fact I think I said a long time ago that I thought the jets were probably OK.

       I hate to be harsh and I might get told about it, but you just aren't paying attention. You don't seem to be absorbing our suggestions so it is very hard to help you and just creates further confusion down the line. Your last post proves it: Mixture screw out 1/2 turn? Idle Speed Screw screwed all the way IN then a 1/2 turn out? Come on. Nobody EVER said to do that.
« Last Edit: August 30, 2018, 09:55:04 am by tooseevee »
2008 AVL Classic.Extensive head work by Ace.Ace canister/TM32/Ace manifold.Small open bottle/hot tube removed.Pertronix Coil.Bobber seat.Fed mandates removed.Battery in right side case.Decomp&all doodads removed.'30s Lucas taillight/7" headlight.


Arizoni

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Reply #5 on: August 30, 2018, 01:19:13 pm
Noting that the PWK 30mm Flatside carb uses a single throttle cable in an adjustable fitting at the top of the carb., is it possible the throttle cable is not letting the slide move all the way to the bottom of its travel?

The throttle cable should have a small amount of slack or looseness when the throttle grip is released or it will hold the throttle slide up higher than it should be, making the engine run fast.
Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary


Stogierob

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Reply #6 on: September 01, 2018, 05:39:35 pm
well the upgrade is preventing me from posting what I want, so i'll just post that i've finally got it working (both the post and the bike).  it has been a combination of your suggestions and what JRC Engineering has suggested, which at times was contrary to each other.

it finally sounds like an RE.

thanks


Mick Bailey

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Reply #7 on: September 02, 2018, 07:23:47 am
Would you detail what you did to sort it out?



Stogierob

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Reply #8 on: September 02, 2018, 09:30:30 am
Would you detail what you did to sort it out?

Well i would, but i keep getting that damned Database Error whenever i post something longer than a few lines.

Short explanation:  took carb apart.  Saw how air screw worked.  Changed pilot to 30.  Put carb back on bike.  Backed air screw out an obscene amount.  Now idles nice and slow and only pulls the bike at 4mph in 1st at idle.

Stogierob


tooseevee

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Reply #9 on: September 02, 2018, 12:00:10 pm

Short explanation:  took carb apart.  Saw how air screw worked.  Changed pilot to 30.  Put carb back on bike.  Backed air screw out an obscene amount. 
Stogierob

       How many turns out (exactly) is obscene?

        There is an exact method and process for adjusting that air screw after the engine is up to operating temperature. And that's "run it down the road" temperature.

         When the Mixture Screw is out the proper number of turns (counted in 1/4 turns) that make the engine idle properly, it is also an indication of whether or not the correct Pilot Jet is in the carb.

         Your Mixture Screw adjustment can't be done with the engine not running.
2008 AVL Classic.Extensive head work by Ace.Ace canister/TM32/Ace manifold.Small open bottle/hot tube removed.Pertronix Coil.Bobber seat.Fed mandates removed.Battery in right side case.Decomp&all doodads removed.'30s Lucas taillight/7" headlight.


Arizoni

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Reply #10 on: September 02, 2018, 06:07:02 pm
Stogierob

The forum software does not like symbols so if your using them, that could explain why it doesn't want to enter your posts.

Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary


Stogierob

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Reply #11 on: September 02, 2018, 06:16:27 pm
Or iPads or MacBooks or chrome or safari.  Im going to get my PC laptop and try posting more detail from there.

Obscene is relative.  Out is not closed.  In is closed.  That my logic.  This carb is challenging my default reference set.

More later.

Thanks all!
Rob


tooseevee

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Reply #12 on: September 03, 2018, 07:12:36 am

Obscene is relative.  Out is not closed.  In is closed.  That my logic.  This carb is challenging my default reference set.

Rob

       "Out is not closed. In is closed"?

         What the hell is that? ??? ??? Don't you think I know what closed is ? Is that all you got from my Reply 10?

         I've tried to be clear and concise and help you and you don't seem to get it.

         Your carburetor is NOT that complicated and I and others have tried to explain clearly how to dial it in and you don't seem to pay attention.

           You went ahead and  changed jets and you didn't even determine whether that was necessary or not.

           I'm finding it more and more difficult to keep trying to help you. 

          I just looked up the PWK carb user manual online (took a few seconds to find it) and read through it. It's very clear and pretty much exactly says what we've been saying since your first post here.

           I don't know how to help you any more.     
2008 AVL Classic.Extensive head work by Ace.Ace canister/TM32/Ace manifold.Small open bottle/hot tube removed.Pertronix Coil.Bobber seat.Fed mandates removed.Battery in right side case.Decomp&all doodads removed.'30s Lucas taillight/7" headlight.


Stogierob

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Reply #13 on: September 03, 2018, 10:11:58 pm
tooseevee - that wasn't an explanation to you.  if you can't control your stress, i'd suggest not replying to this thread any longer.  Someone else asked what I did to get to a lower idle.  considering i haven't been able to post more than three sentences without receiving a database error, i answered that individual in very short phrases.  I actually haven't been responding to you at all since anyone who posts the phrase 'i don't know how to help you anymore' isn't worth my time.  that's the reply of a child who is petulant that they aren't being properly listened to. 

to everyone else who has offered help.  I am finally starting to understand how the adjustments work on the carb.  That I now having it idling somewhere close to how other REs sound on various youtube videos, i'm giving the carb tuning a break.  when I feel like i have more time and mental energy, and possibly a way to measure actual RPMs, i'll finish the job.  For now, it's on to the cosmetic work of making it look like a 1942 WDCO.

Thanks!
Rob