rejet needed?
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Tourer
Joined: Sep 2008
Posts: 257
Likes: 2
From: Jersey Shore
rejet needed?
So I just picked up an HD stage 1 air cleaner for my 97 Softy and while at the dealership I asked the guy behind the service counter which jet sizes I should go with with after changing the air cleaner. His response was "none, you should be fine with the stock jets". This kind of goes against everything I've been reading here as well as the advice I've gotten from friends who owned carb'd bikes in the past. Does this sound like sound advice? I really wanted to tackle the rejet while in the process of installing the new air cleaner if it's even necessary.
Outstanding HDF Member
Joined: Oct 2007
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From: El Cajon Ca.
It all depends on what you have in there right now. You might be able to get away with just a mixture adjustment or you might need to change both your main and slow jet. After you do the install you will have a better idea of what you need to do. If you can adjust your carb to where it runs well without it having a lean popping you might be OK. If you end up needing to re-jet it's no big deal. Come back and let us know after you get it back together and let us know how it runs. Make sure to have your bike warmed up before trying to tune your carb.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
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From: Coromandel Peninsula New Zealand
If fitting a K&N or similar filter you should increase jet size by 15-20%, I would go up on the main from whatever is in there + 10, so 175-185 for example....I use a 200 and colder plugs in mine.
Lo-speed jet I would have put a #48 in there the day I bought the bike in any case.
Lo-speed jet I would have put a #48 in there the day I bought the bike in any case.
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Tourer
Joined: Sep 2008
Posts: 257
Likes: 2
From: Jersey Shore
thanks for the replies guys! I'm going to install the air cleaner this week and adjust from there.
spanner- the jets you mentioned were exactly what a couple of my buddies suggested as well so I'll be sure to keep those on hand if needed. I found lots of great info through the search on rejetting, doesn't look too intimidating.
BTW the service guy at the dealership said to stay away from rejet "kits" he said they were junk and will typically fail in time. Any opinions on that??
spanner- the jets you mentioned were exactly what a couple of my buddies suggested as well so I'll be sure to keep those on hand if needed. I found lots of great info through the search on rejetting, doesn't look too intimidating.
BTW the service guy at the dealership said to stay away from rejet "kits" he said they were junk and will typically fail in time. Any opinions on that??
Cruiser
Joined: Sep 2011
Posts: 236
Likes: 0
From: Ontario, Canada
A quick question, do the jets need to be changed if only changing the air intake?
I could see it if there were performance exhaust pipes on the bike as well. More air in, more air out - right.
But if the intake is changed only, would there be a need? Would there be a significant enough increase without the exhaust to warrant rejetting as well?
I could see it if there were performance exhaust pipes on the bike as well. More air in, more air out - right.
But if the intake is changed only, would there be a need? Would there be a significant enough increase without the exhaust to warrant rejetting as well?
Seasoned HDF Member
Joined: Dec 2010
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From: Coromandel Peninsula New Zealand
The intake will make a lot of difference, its a case of more air in requires bigger jets (more fuel)....pipes won't make a huge difference to jetting....unless you are going from stock mufflers...maybe add 5% for pipes.
Be aware that you may need to add a shim or two under the needle as well as the jets...the shims can be buggers to track down but many indies have a bag of them that they keep from jetting kits.
The kits are fine but require a bit more patience to get them set up....with the standard carby internals I find it easier to work out what sizes are needed.
Be aware that you may need to add a shim or two under the needle as well as the jets...the shims can be buggers to track down but many indies have a bag of them that they keep from jetting kits.
The kits are fine but require a bit more patience to get them set up....with the standard carby internals I find it easier to work out what sizes are needed.
Outstanding HDF Member
Joined: Oct 2007
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From: El Cajon Ca.
IMHO a 48 slow jet is way big. Try a 45 and find a 46 if that's not rich enough. I ran a 48 in my built up 95" twin cam and it was still a little rich. Bigger is not always better in this case. And all bikes are different. You can't always use what your buddy with the same build uses.
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Road Master
Joined: May 2005
Posts: 1,121
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From: Mass.
Leave the main jet alone. Change the low speed jet to a #45. Use a Dynojet, Thunderslide or my favorite, the Yost power tube kit. The Yost is the simplest and I think the most efficient. Drill out the idle adjustment plug (if it isn't already) and LIGHTLY seat it, then turn it out 2 1/2 to 3 turns. You really don't need to mess with the main jet until you do cams and or headwork.
Last edited by dc1450; Dec 11, 2011 at 02:40 PM.
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Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Leave the main jet alone. Change the low speed jet to a #45. Use a Dynojet, Thunderslide or my favorite, the Yost power tube kit. The Yost is the simplest and I think the most efficient. Drill out the idle adjustment plug (if it isn't already) and LIGHTLY seat it, then turn it out 2 1/2 to 3 turns. You really don't need to mess with the main jet until you do cams and or headwork.
One point though...in the USA you have way different gas so we tend to jet bigger in NZ...a 50 slow and a 200 main is not uncommon....
Extreme HDF Member
Joined: Sep 2010
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From: Phoenix '53, '88, '09 Big Twins
I would suggest staying away from the "tuner kits" mentioned above.
nightrider.com has a bike tech section, there are sections on tuning and modifying the CV carb.
And that's what i did for many, many happy evo miles
with modified slides, my fxr has 45 and 170 jets and the flhtc has 42 and 165 jets
mike
nightrider.com has a bike tech section, there are sections on tuning and modifying the CV carb.
And that's what i did for many, many happy evo miles
with modified slides, my fxr has 45 and 170 jets and the flhtc has 42 and 165 jets
mike
Last edited by mkguitar; Dec 11, 2011 at 03:40 PM.