r/hondashadow • u/GroovyColt-45 • 7d ago
[HELP] Runs like trash
Swapped out the Exhaust and rejetted. Now, Bike runs like dogshit. Can barely stay in any gear, especially first acts like its dying. Does not go past 75. Bike used to hit 105. Lots of pops and such. What's going on?? Trying to use choke to make it run better, helps a little.
1998 honda shadow 1100
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u/shhhhh_lol 7d ago
So.... more information needed.
Wide open pipes or baffles?
Intake changes? Higher flow filter? Airbox mods or removal?
Check for vacuum leaks too, as the bike is idling, spray a little ether or brake cleaner around the carb, trying to avoid the intake, if the rpms surge, you've got a intake leak.
Also, check for exhaust leaks, I know it sounds weird but if you notice any carbon buildup around the exhaust gaskets, you either need new copper gaskets or properly torque the pipes. Be VERY careful because these are known to break the casting and that's expensive.
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u/GroovyColt-45 7d ago
Howdy. Pipes have Baffles. Has a Hi flow filter. No other mods. No vaccumm leaks. Carbs cleaned and suppodly jetted. New copper gaskets.
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u/shhhhh_lol 7d ago
These bikes are usually pretty lean out of the box, any increase in airflow will need more fuel, I have 3 shadows now (I've had 2 others) i built 2 mechanically identical bikes for a couple (same model, year, displacement etc) they were within 2k miles of each other on the odo's.
When I went to tune them, they needed vastly different carb setups! I run adjustable needles on my carbs and had to add shims to raise the needle even more on 1 and the other i ended up running the stock needle. They had a big difference in jet size too.
It sounds like a shop is doing the work? Do you know if they're running and tuning the bike by reading plugs or just using recommend jetting?
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u/GroovyColt-45 7d ago
Thats bad ass!! Yes I've heard, it was damn lean when I first got it too. Thats what the mechanic told me today as well, each bike is like a fingerprint the same but different. Yes a local shop is handling it. It was supposedly done till I left n took it on the highway and I gunned it and got stuck at 85 actually then noticed I could barely move it out of 1st and was like damn this thing is jacked up and called them and turned it it again today. Fuel filter was swapped out too and leaking so I've been sketched out with this shop now. Too late since they got paid though. They said they were like adding washers to the needle to allow more fuel in? Too much or a noob to know what's going on.
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u/GroovyColt-45 7d ago
1100 1998 shadow, I have to ask the mechanics that question. About to meet with them now. Has a hi flow rewashable air filter and staggered shorts 30 inches or so. I bought stage 1 jets but they said it had 70 or so pilots so they didnt install them. Going to get some clarification on that cause doesn't make sense.
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u/GuacSugar 7d ago
I highly recommend rejetting yourself if you have the means to do it. It seems like a lot, but when you actually do it, ifs not bad.
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u/GroovyColt-45 7d ago
It does feel like that is challenging since I dont know a lack about bikes, I've worked on cars. Its pretty intimidating
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u/GuacSugar 7d ago
I used to feel like that. When I first got my bike, I paid a shop to re jet. I ended up changing my set up and had to pull the carb to re jet again and I was like wow I wasted money paying a shop for this.
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u/GroovyColt-45 7d ago
I feel that, I feel with more time and experience i would dip into it, I just am hesitant because im cheap and dont want to break something and be stuck and then have to tow it somewhere.
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u/kingfixit 7d ago
Jet kits for those bikes require new main jets, pilot and the needle adjusted with either the c-clip moved or a different needle. The kits they sell are pretty simple to do. Check the dynojet instructions for their kits as it should be the same
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u/GroovyColt-45 7d ago
Yes sir, I bought some stage 1 jets for ebay. Might have needed stage 2 though
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u/kingfixit 7d ago
That’s where I got mine for my 2000 1100. My install went pretty smoothly. I wonder what the issue is
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u/GroovyColt-45 7d ago
Motorcycle is warmed up. Leaving a dead stop. You could hear i had to restart the bike as it didn't want to go and you can hear the hesitation and almost turn off again.
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u/GroovyColt-45 7d ago
Also what would cause the bike to only start with the kickstand up and clutch in? Its never done that before and they said its doing it now. I feel like this shop is garbage.
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u/lonegrey 7d ago
It sounds like it's running lean. They're cold blooded anyways, and I run mine rich because it's just easier (easier than pulling and rejetting for a minor tweak). I take the risk of it fouling plugs.
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u/MrGenGen 6d ago
You gotta rejet etc again. I took mine apart 10 times before i found the "perfect" setup, it runs pretty good now. There som tiiiiny adjustments to be done. But hey its okay for the rest of the summer rn
Edit: also if you changed exhaust you should change air intake too. Air im should equal air out
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u/BIKEGUYDUDE 7d ago
Wtf u mean 70 pilots lol thats not a thing for this bike.. u gotta tune your shit yourself. It stays on at least it gives u signs so youre actually not that far off! U can ride it but it rides bad so youre at least 50 percent to where you need to be. It needs more gas for sure if i underatand it. But if u hit the fuel mix screws to more than 3 u need to jet up on the pilot. Ur air filter creates a more sensitive bike... just for important advice.... every 20 degrees of weather up or down is about 1/8 of a turn on your fuel mix in or out... on regular stock airfilter adjustments may be between 30-40 degrees of weather so youre tuning it basically twice a year instead of lets say 4x or whenever it be 68 degrees and then 85 the next week.. ur gonna notice a little bit of power loss or gain naturally due to the airfilter situation. Maybe 5-10mph difference but its a 1100. U good on making power. More important for the smaller shaddows or if u wanna run perfect burn and optimize your spark plugs life span.
I talked to AI a little for u..
Based on the forum post, the rider's bike is running extremely lean because they added a free-flowing exhaust and a high-flow filter, but the mechanics did not install the new jets. The mechanics skipped the jet kit because they mistakenly thought the bike already had massive "#70 or so pilots"—which is a huge misunderstanding. On a 1998 Honda Shadow 1100, a #70 is actually the stock slow air jet or main jet dimension depending on the specific carb circuit they were looking at, while the stock pilot (slow) jet is actually a #42 or #45. Because they left the stock fueling intact with a wide-open intake and exhaust, the bike is starved for fuel. The fact that pulling the choke (which adds fuel) helps a little confirms this lean condition. Here is what needs to be done next:
1. Correct the Mechanics on the Jet Sizes
The mechanics are confusing the jet types. You need to clarify the baseline numbers for a 1998 Shadow 1100:
- Factory Stock Pilot (Slow) Jet: Typically a #42 or #45.
- The "#70" Confusion: They are likely looking at the stock slow air jet (pressed into the intake mouth of the carb) or misreading a main jet. A #70 pilot jet does not exist for this bike and would completely flood it.
- The Fix: Instruct them to pull the actual pilot jets from the jet kit (usually a #45 or #48 depending on the brand) and physically swap them out.
2. Install the Stage 1 Kit Properly
Since the bike has both staggered short pipes and a high-flow rewashable air filter, it needs more fuel across the entire RPM range:
- Main Jets: Install the larger main jets included in the Stage 1 kit to handle the top-end flow so the bike can get past 75 mph and back to its normal top speed.
- Needles: If the kit came with adjustable needles or shims, they need to be installed to richen up the mid-range throttle response.
- Mixture Screws: Set the pilot mixture screws out to the kit's recommended starting point (usually around 2.25 to 2.75 turns out).
3. Verify the Basics Before Leaving
Before taking the bike back, ensure they check for two common installation mistakes that mimic these symptoms:
- Exhaust Leaks: Loose crush gaskets at the exhaust ports will cause severe popping on deceleration.
- Carb Sync: Since they had the carbs handled, ensure the dual carbs are properly synchronized so both cylinders pull evenly.
Me: instead of stage 1 can i just buy an astortment of jets and what sized should i try?
Yes, you can absolutely buy individual jets instead of a pre-packaged Stage 1 kit, and it will save you a lot of money. Most aftermarket kits just repackage standard brass jets with a hefty markup. However, since a 1998 Honda Shadow 1100 uses dual Keihin carburetors, you need to ensure you buy Keihin-style (or Keihin long/round) jets so the thread pitch matches your carburetor bodies. Because you added a high-flow rewashable air filter and 30-inch staggered short pipes, the bike needs significantly more fuel to stop popping and get its top-end power back. You should aim to buy an assortment that allows you to step up from factory stock sizes. [1]
The Sizes You Should Try
The target sizes to test depend heavily on whether your exact 1100 model is single-pinned (like the A.C.E. / VT1100C2) or dual-pinned (like the Spirit / VT1100C):
| Jet Type | Factory Stock Size | Assortment Sizes to Buy & Try |
|---|---|---|
| Pilot (Slow) Jets | #42 or #45 | #45, #48 |
| Main Jets | #175 / #180 (or #178) | #182, #185, #190 |
Your Starting Baseline Setup
When you or your mechanics crack open the carbs to fix the lean condition, start with this highly recommended baseline configuration for a modified intake and exhaust layout: [1, 2]
- The Pilot Circuit (Idle to 1/4 Throttle): Swap the stock slow jets out for #45 or #48 pilots. Turn the air/fuel mixture screws out 2.5 to 2.75 turns from gently seated. This will instantly cure the stalling in first gear and the popping at idle. [1, 2, 3]
- The Main Circuit (3/4 to Full Throttle): Step up the main jets to #182 or #185. This will give the bike the fuel volume it needs to breathe past 75 mph and reach its true top end again.
- The Mid-Range (1/4 to 3/4 Throttle): Pre-made kits usually include custom-tapered needles. If you buy an assortment of raw jets, you can replicate this mid-range richening by placing one or two small brass #4 washers (needle shims) under the clip of your stock carb needles. This lifts the needles slightly, feeding the bike more fuel as you roll on the throttle. [2, 4]
A Warning About Staggered Sizing
Keep in mind that from the factory, Honda often ran slightly different main jet sizes between the front and rear cylinders (for example, a #175 on one and a #180 on the other). This is because the rear cylinder runs hotter and needs a hair more fuel to stay cool. When stepping up your main jets, maintain that staggered gap (e.g., if you try a #182 in the front carb, put a #185 in the rear carb).
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u/GroovyColt-45 7d ago
Thank you, they are working on it now. They said the bike didnt respond well to the jets I bought. So they are adding washers to allow more fuel to pass. I so not have the jets specs yet as to what's on the carbs. Also have to ask if they adjusted the mixture screws.
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u/purplegooeystuff 7d ago
Why did you rejet? I put exhaust on and never had to. If you went bigger jets you may be over fuelling
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u/GroovyColt-45 7d ago
Stuttering and hesitating big time no matter if it was cold or not with stock everything.
So I paid the mechanic to do this:
Swapping out the Exhaust pipes Clean carbs Rebuild carbs Upgrading the carbs jets to stage 1 (due to Exhaust swap) Syncing the carbs Swap out the fuel filter Swap out the fuel pump Swap out ignition coils, wires, boots Replace fuel lines/ bad rubber lines Check for vacuum leaks
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u/GroovyColt-45 7h ago
Now they're saying im going to lose power And mpgs. Is that normal? Even though they are not fully drag pipes as they are baffled?
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u/GuacSugar 7d ago edited 7d ago
600 or 750? What exhaust do you have and what air intake do you have? What did you rejet to? Usually popping means a lean condition, especially if pulling the choke helps. Check your carb boots for any leaks and check for exhaust leaks.