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2007 VT1100C2
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Discussion Starter #1
Just got my shadow back from the shop. Put it in for a rejet after I put cobra dragsters on, because I was afraid it was too lean.

It runs great now, has lots of power in the low end and sounds great accelerating. But it has MAD decel popping. And curiously the idle stop screw is screwed in a lot. Before the new pipes, after removing the air injection system, I had it pretty much unscrewed as far as you can and still had a strong idle and no popping.

I didn't touch the air fuel screws so I don't know what he's got them set at. But this is a high end, VERY reputable shop and he did the whole 9 yards as far as doing a thorough and professional job tuning and syncing and all that.

What am I to make of this? It can't be even more lean after installing a dyno jet kit, right? Especially when it has plenty of power? Is there a tuning scenario where everything is in balance but one can still have decel popping?
 

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2007 VT750DC Spirit “chopper”
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I kinda like the pop, I adjust my stuff accordingly to have just an occasional pop, just one or two slowing down is all I need... no machine gun craziness haha.
 
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I kinda like the pop, I adjust my stuff accordingly to have just an occasional pop, just one or two slowing down is all I need... no machine gun craziness haha.
I kind of like a pop sometimes but the crowd I have been hanging out with looks down at pops. Basically they are an older crowd with carbs bikes and in their opinion you haven't setup your carbs right if you are popping. I heard a guy talk about indexing his spark plugs. Ya, I'm doing that and he can't prove it did anything but take a bunch of time. That's what some of these guys are like.

Carbbed bikes are a dying breed along with guys who know how to work on them.
 

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2007 VT1100C2
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Discussion Starter #5
Well I was just looking in the dynojet kit box that he gave back to me, and it looks like he used a 165 for the front, and 170 rear. The instructions in the box say that that is for a stock exhaust setup. For aftermarket exhaust with high flow baffles it says to use 170 front and 175 rear.

He was saying something to me about our high elevation and lack of oxygen. Salt lake city is under 5,000 ft. Does this sound ok? I don't care about perfect tuning just don't want to be so lean as to cause engine damage. There's a lot of warning about that online. And I kind of like a low pop or two as well this was just doing way more than that.
 

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1991 VT600 VLX
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Did he change the needles? If yes, then stock jet sizes are not stock anymore.
 

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2007 VT1100C2
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Discussion Starter #7
I ended up taking it back in to have him redo it.
I took a ride on the freeway and it was hesitating/jerking at 80+ mph. Never had that before.

So he has a 165 and 170 jets in when the specs call for 170 and 175. He had the needle clip in slot 2 when it was supposed to be in slot 3.

His determination for why I had the hesitation at the top end was TOO MUCH fuel, and he lowered the clip to slot 1 with 1 washer shim.

I will try to post sound of the idle later. Sounds like it keeps dropping rpms for a moment, every 5 to 10 seconds or so. But I rode it home and it still has popping. I have to try it on the freeway still.

But do those carb settings sound legit for this bike, just because of my altitude? Guy kept saying those specs were for sea level. But I thought Honda didn't require any carb adjustment for altitude until like 7000 or 8000 ft?

I need help here it's difficult to ride with all the popping, it's just so excessive. I don't understand why it's popping MORE after a rejet.
 

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Discussion Starter #8
Just went on the freeway and it still jerks. Have to be open throttle close to 85-90mph, then l ease off throttle JUST A HAIR, and it cuts all power for a split second and jerks. Easy to reproduce. Decel popping seems completely unchanged but he said it was better. Ok, it might not sound like a shotgun, but it is a very loud cracking.

This guy then said he pulled the plugs (1 plug?) and they were dark indicating too rich. I just pulled 2 and they both look like this:

293418


Am I crazy or does that look lean and not rich like he says? It's white with a scorch mark.

He chastised me for taking the air fuel screws out a turn to lessen the popping, saying it'll just add more fuel. Ok, but if too much fuel is the problem, wouldn't taking them out make the popping worse? I nonetheless took them out 1 and a half turns from where he set them once again and it did ease the popping.

I am considering DEMANDING that he set the carbs to the dynojet specs (sea level schmee level) as I requested from the beginning, and then calling it even. If it is indeed too rich I alone will bear the responsibility.

when I first took it in I told him it was really lean and I thought it might need to go up a couple of jet sizes. When I took it back in there today I told him that I would put in the Jets and needle position that the kit specifies. Instead he leaned it out even more. I guess me saying what I wanted wasn't enough? I have to directly order him to put in bigger jets that he doesn't want to put in?
 

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1999 Shadow 750 ACE VT750CD3 Modified
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Also IIRC the supplied washer (shim) should be on the E-clip not under to protect it from the hold down spring.
I'd rather be a little rich than too lean and that plug looks on the lean side to my eye too.
Tuning is always a little hit and miss, I found long ago you are better to do it yourself and then blame yourself.
 

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1983 Honda vt750 Shadow
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One thing about changing exhaust to aftermarket parts is if they don't have a cross over pipe between them it increases the popping. A cross over help soften the exhaust puses and lessens popping.
 

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Discussion Starter #11
Also IIRC the supplied washer (shim) should be on the E-clip not under to protect it from the hold down spring.
I'd rather be a little rich than too lean and that plug looks on the lean side to my eye too.
Tuning is always a little hit and miss, I found long ago you are better to do it yourself and then blame yourself.
I only wish someone with some experience could have helped me then I might have tried doing it myself. At this point I wish I had anyways. But on the other hand, if I messed it up I would've been wishing I took it to a shop.

Oh, also he said one of the diaphragms was torn and the gaskets looked flattened and discolored. He asked if I put any fuel cleaner in it and I said seafoam. He said it messed up the rubber. I paid almost $300 for all new carb parts. In total it was over $700. After paying that, I'm gonna keep going back until he gets it right, or at least puts in the jets I ask for. It should AT LEAST run as good as it did before I brought it in.
 

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Discussion Starter #12
One thing about changing exhaust to aftermarket parts is if they don't have a cross over pipe between them it increases the popping. A cross over help soften the exhaust puses and lessens popping.
I'm just comparing it to before he jetted. Same pipes, pre and post jet.

When all I had done was pull the stock pipes off and bolt on the Cobras, it introduced decel popping back to my ride but not this much. This is much worse than that. I can't really minimize it much with the air screws or by gently easing off the throttle. So I'm resorting to pulling in the clutch to brake to a stop. It's making me not want to ride it. In fact I'm just not going to all weekend until the shop opens. Weather in the 70s for the first time and the whole weekend is shot.
 

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I'm just comparing it to before he jetted. Same pipes, pre and post jet.

When all I had done was pull the stock pipes off and bolt on the Cobras, it introduced decel popping back to my ride but not this much. This is much worse than that. I can't really minimize it much with the air screws or by gently easing off the throttle. So I'm resorting to pulling in the clutch to brake to a stop. It's making me not want to ride it. In fact I'm just not going to all weekend until the shop opens. Weather in the 70s for the first time and the whole weekend is shot.
Sounds like you don't agree about the proper jetting for your bike with the guy who did the work.
He seems to be positive about the jetting as is, what does he think the is causing the drivability issues you are experiencing??
I don't think you will convince him to do the work over your way, even if that's what you asked for originally, and suggest you do it yourself.
Not on my shadow but other V-twin 2 carb bike I have been able to remove the float bowls AND change the main jets with a 1/4" hex ratchet and bits WITHOUT removing the carbs.
A mirror helped too, and might work for you.
I have not looked at a bike like yours and this might not work for you
Something like one of these:
Amazon.com : 1/4 hex ratchet
I have 3 ratchet heads(Craftsman?), 1 straight, 1 each offset +/-.
On another bike there was not enough room for the hex ratchet so I used a 1/4" ignition wrench instead.
.
 

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1991 VT600 VLX
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I bet 5$, that stock jets & needles with A/F mixture screws out stock + ~3/4 turn out, would solve most of popping.
 

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2007 VT1100C2
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Discussion Starter #15
Sounds like you don't agree about the proper jetting for your bike with the guy who did the work.
He seems to be positive about the jetting as is, what does he think the is causing the drivability issues you are experiencing??
I don't think you will convince him to do the work over your way, even if that's what you asked for originally, and suggest you do it yourself.
Not on my shadow but other V-twin 2 carb bike I have been able to remove the float bowls AND change the main jets with a 1/4" hex ratchet and bits WITHOUT removing the carbs.
A mirror helped too, and might work for you.
I have not looked at a bike like yours and this might not work for you
Something like one of these:
Amazon.com : 1/4 hex ratchet
I have 3 ratchet heads(Craftsman?), 1 straight, 1 each offset +/-.
On another bike there was not enough room for the hex ratchet so I used a 1/4" ignition wrench instead.
.
He thinks it's too rich.

I'm actually not sure if he overall richened or leaned it from stock.

Would the needle clip position even effect wot at high speeds or is that a jet issue?
 

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He thinks it's too rich.

I'm actually not sure if he overall richened or leaned it from stock.

Would the needle clip position even effect wot at high speeds or is that a jet issue?
I think that pic of your plug is the answer to that rich/lean question.
I have never dealt with after market jets but have read their numbers don't corollate with oem jet numbers/sizes, and cannot be considered to be sequential.

As far as needle clip position goes, my standard mod is to put a washer (or 2) under the oem needle that has a fixed clip with no adjustability.
I put 2 if it does not coil bind the spring of the retainer.
I did this to my Shadow (a single carb 750), without removing the plugs over the air/fuel screw and that alone greatly reduced the decel popping and increased acceleration.
Mileage did suffer but, to me, running richer equates to running cooler.
good luck on your quest,
jmo,
.
 

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Discussion Starter #17
I think that pic of your plug is the answer to that rich/lean question.
I have never dealt with after market jets but have read their numbers don't corollate with oem jet numbers/sizes, and cannot be considered to be sequential.

As far as needle clip position goes, my standard mod is to put a washer (or 2) under the oem needle that has a fixed clip with no adjustability.
I put 2 if it does not coil bind the spring of the retainer.
I did this to my Shadow, without removing the plugs over the air/fuel plugs and that alone greatly reduced the decel popping and increased acceleration.
Mileage did suffer but, to me, running richer equates to running cooler.
good luck on your quest,
jmo,
.
Just so I'm totally clear, because he's got me feeling crazy, you think the plug looks lean??
 

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I do too.
Not a bad idea to have a tan color. And as i mentioned the exhaust with no cross over will increase popping.
Mine pops like crazy even after i richened up the pilot jets too much and lost 10 MPG. Still pops !
I have come to love it as in " loud pops save lives"
 

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Pictures never do justice, but it does look a little on the lean side. For everything you’re doing, I wouldn’t be too concerned with the engine being ‘ruined’. You’re just playing to either side of stoichiometric (balance). Leaner gives a bit more power. Richer is a bit easier on parts. Carbs are analog devices, so ideally you would fine tune the jets and screws as you rose in elevation. The manufacturer is just saying it’s not THAT important until you hit XXXX ft.

The problem is, many mechanics get a little ‘Righteous’. “Who does this jerk think he is, reading something on the Internet and telling ME how to do MY job? Hey buddy! Oh, look! Your carb rubbers are ruined! Take THAT for a ‘Jerk Tax’...” Only they’re usually right. Most customers have no idea, and when things go wrong, they blame the mechanic for following their instructions. This guy might have it in his head now that he’s right and you’re wrong, and will just punish you for any further ‘annoyance’ you cause him.

Is there another mechanic around with a good reputation? Unfortunately, even the older ‘Shadetree’ retirees are outgrowing carburetion. Otherwise, have a discussion with this guy. Tell him you’re sure the dry, whitish plugs and popping are the sign of a lean condition, and ask if it would hurt anything to adjust the jets to the richer side. Appeal a bit to his ego, in that a mechanic of his talents could make that change so fast you’d barely even notice it was apart. Judge the reaction you get. If he’s set in his ways, you may not get anything other than more bills out of him.
 

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Just so I'm totally clear, because he's got me feeling crazy, you think the plug looks lean??
Yep, looks lean to me.
We need to know what @swifty2014 thinks though, he's the plug guru around here.

I bought a new Honda soon after the EPA mandated the non-adjustable carbs ( capped air/fuel screws, fixed needle clips, etc.) and it would surge at highway speeds, so much so, the pipes turned blue.
I put a washer on the needles, polished out the bluing, surging stopped, and called it fixed.

Soon after I did that I got a recall notice to fix the surging, it entailed changing the needles and polishing the pipes.
My friend managed my Honda dealership at the time so I got the replacement needles from him, pen stroked the recall for him to satisfy Honda, and never installed them.

For me, we ride 90% of the time in the carb range that is needle/main jet controlled, not just the main jet.
Raising the needle actually enrichens the mixture throughout the operating range, even at idle.

I'm not in the change/modify the pipes, chase the "best" carb jetting and giving up at "good enough" camp.
Although I will admit to doing some subtle/undetectable pipe mod's so the pipes drowned out the final drive whine.
Instead of the hole-saw mod a better way is to just drill thru the end cap on the baffle that is removed doing the hole-saw butchery.
That alone will change the sound/exhaust note to a deeper/tolerable level, with no fuzzy/whistling/annoying sound, and will drowned out the final drive and typical Honda whine/whirring.
That still costs nothing except buying a 3/4"+/- jobber (long) drill bit or proper hole saw, and only requires raising the needles most times.

jmo,
sorry for the bloviation right there.
.
 
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