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Discussion Starter #1
I'm about 13 feet above sea level.
Bike runs lean at higher rpms.
I was able to tell that I have a 42 pilot jet and both carbs have 180 main jets.

Looks like the factory mufflers were modified/gutted.
Bike is loud.
Stock airbox and filter

What are good starting points on jet sizes.
I read stage 1-3 and thier jet sizes but there is alot of conflicting info.
Excluding the dyno jet kits because the dyno jet 175 is not the same as other 175 jets.....they engineered thier own profiles.

Currently The bike runs well with minor popping on deceleration but in 4th gear max rpm is 4400 rpm
5th gear is 4000rpm with about 20% throttle to roll which makes no diffrence.
Netural I can get 6500 rpm
1st-2nd 5500ish.
But after 3500 rpm the bike stops pulling.
That problem is at interstate speeds.
Bike will max out at 76mph on a good day.

Like I said runs well.Adjusting the idle fuel screws help,before max rpm was 3600 at 2 turns out.
2.25 turns is my best result so far.

So I drilled out both main and pilot just barely and not its getting too much fuel.Drilled somespare jets I had so I can always put back the ones that run.I dont remember the main jet drill size I used but the pilot I have a pin vise and used a .025" bit which was barely larger than the original hole.
Perhaps I can run the original jets and shim the needle.....
What's a good starting point.
I'm also aware that the front and rear cylinder is supposed to have diffrent sizes cause of the cooling of the front cylinder vs the rear.
Shop is quoting me $500 just to clean and tune.
Not counting re jetting.
$90 per hour.
I'm not looking to put that kinda money into this bike.Its not in the best of shape.
I have time to try it myself first.
 

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VT 1100c 1994
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219 Posts
How's the compression, is the airfilter clean?
here you can compare jet sizes dj and K
Some say the rear jetting must be richer, some not... but I know that for the touring model they had that setup. There are different jet kits by dj for quite similar Shadows with different jet sizes, wich is confusing (engines, carbs are the same). I would say something around the DJ170-175 might be ok, but there are more experienced guys here.
But make sure the carb is cleaned, fuel filter is ok, air filter is ok (or get a K&N or BMC), oil is new and not some 15 year old crap.
When I got mine (94, californian 1100) she was a bit lame in the higher rpm, now after carb cleaning and rejetting ( I traveled the long road) I hit 100 mph with ease. It took me a while to understand that the K165 jet (factory) is just too little, so I got the Dynojet kit as it was on sale.

When she's lame at mid rpm you have to put shims to the needle, or with the DJ needle groove nr 4 or 5. When I tested the nr 5 instead the 4 the first time I was like "alright". Most of the times you are in the rpm range where the needle is position and shape (tapered makes sense) is relevant, still the main jets have to be the rigth ones. Otherwise you compensate a problem with the needle position instead of picking the right main jet.

Beside the 42 pilot try out a bigger pilot like 45, I had decel popping with standard exhaust (little modded), 45 helped a lot. I wouldn't drill the jets, get new ones, they are not expensive and you are on the safe side.

500 is not that cheap, but don't forget, with the 1100 getting carbs in and out take some time, my personal record is 15 mins. until the carb is on my work bench.
 

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Discussion Starter #3
Yea I had them out last night in about 20 minutes.
My beer did not have time to get warm.

Air filter is new and clean.
Runs excellent with the original jets besides the lack of higher rpm in higher gears.
I'll compression test tonite.
 

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Yea I had them out last night in about 20 minutes.
My beer did not have time to get warm.

Air filter is new and clean.
Runs excellent with the original jets besides the lack of higher rpm in higher gears.
I'll compression test tonite.
If your bike has a PAIR valve, locate the suction hose prior to the sub air cleaners and see which way the end is pointing. If it's pointing forward, locate it so it's down or back and see how the bike runs.
 

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Discussion Starter #5
Update.....a positive one.
Removed carbs and cleaned.Was not dirty but removed everything.
Blew carb cleaner through every port.

Installed new #42 pilots since I had them.
Took the 175 front and 180 rear main jets and use guitar strings that fit snugly and ran it through like floss until jets were polished.

Took the needles and mothers aluminum polish since there was very minor corrosion stains on them from the bike sitting for 5 years from the previous owner.

Chucked them upon a drill and polished with a cloth until smooth and shiny.
Added a .015" shim to the needles.
Both needles had diffrent numbers but both measured identical with dial calipers..
Set mixture screws at 2turns.
First start the idle was extremely low.
Raised idle let it warm.
Revving it up.....it was a completely diffrent animal.
Black smoke at there limiter.

Test drove and what a diffrence it made.
Top speed use to be 76mph tonite I topped at 96 mph and it gets there quick.
Probly more power to be had with a better jetting however I'm happy.
Thing I noticed is the mixture screws seem to tighten on thier own.
Yesterday I tuned them to 2.25 turns from closed on the ride home trying to go 70mph against wind.
Today they were at about 1 turn each.
Unless I forgot.....I'm old.
 

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Discussion Starter #6
Next is why the erratic idles
And carb sync.
Possibly a high flow air filter would eliminate the over fueling causing the black smoke.
 

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1983 Honda vt750 Shadow
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Never heard of the mixtures screws changing like that .Do they have the spring- then washer -then O ring on them?
 
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