jetting an evo

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jetting an evo

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Tarvis
4 years ago

Howdy all,
Yesterday I got my hands on a supermeg for my 92 evo dyna. Can't wait to install it over the weekend.

Haven't rejetted a carb before (but do know how to pull it apart and put it back together - no dramas there), so a little unsure with jets to start with.

I was thinking a 45 or 46 pilot with a 175 main. I've got a CV performance jet needle/emulsion tube coming to replace the stocker, plus a hand full of different jets.

Dont' want to run it lean to start with - so thought I would see if others on here have any experience jetting.

Mods are (will be) 2:1 pipe and K&N filter in stock airbox.

Cheers,
Tarvis

tussuck
4 years ago

46 and 175 are good starting points (i would also have a 180 and 185 handy and try them out as well). Plus the needle needs match and the CV perf ones are as good as any (have you looked at their website to see if they have any generic tuning suggestions?)

Wideglider
4 years ago

'96 Evo WG. Running a 48 pilot & main jet 185, Thunderslide kit. Mixture screw 3 turns opened.
Big sucker type Arlen Ness air filter, Bassini Road Rage 2 into 1 pipe, Screamin' Eagle SE3 cam.
Not too lean (or rich), performs real well.

Tarvis
4 years ago

Thanks Tussuck and Wideglider,

I'll go with the 46, pretty sure I have ordered both a 180-185.

The CV guys have a forum that has some info, I need to do some reading over the week while I wait for their parcel to arrive.

Cheers,
Trav

tussuck
4 years ago

Yell out if yah get stuck for jets as I have a few going right up to 230

Krash Kinkade
4 years ago

Travis your on the right track 46 is the right pj ( normal hard to find a 46 so most get 48 but is a bit on rich side ) if you need to go higher than 200 mj you need a different needle. good luck.

John.R
4 years ago

From memory im running a 45 and 175 with a Sporty needle (N65C, which I think some of the other companies rub)
Mine isn't spot on though and still needs tweaking. It's hard to directly compare main jets with diff needles. It seems like everyone running normal needles are about +10 on the mainjet compared tpto sporty needles which give more fuel 1/4 and 1/2 throttle.

I had a 48 in but it was wayyy to rich.

tussuck
4 years ago

I'll have a look tonight at home as I'm sure i have some good articles on this from when I turboed the FXR (it runs a Standard CV carb).

Tarvis
4 years ago

Thanks Tussuck, that would be great.

perthhog
4 years ago

Just for topic sakes What pipes are on it now ?
I would just put the pipe on first and try it and go from there
As the bike has been around for awhile so who knows what
Else has been done to it Has it got a cam,comp,already
Upped jets , ignition system upgrade ?

As I’ve found with one of my evos when I went from 2+2 to 2+1
I had to lean it a bit but that motor isn’t stock .

I like the cv carb better all round bit more forgiving to tune

And if you do have the carb off. May aswell. Swap the inlet fitting
Out for a all brass one whilst it’s off if it has the original
Plastic/ steel type . Can get them from harley

Tarvis
4 years ago

hey Perthhog,
The bike is basically stock right now, with stock 2:2 (with crossover) pipes.

I bought it last year and most of what I have done is replace old and worn parts so its reliable. This includes (for the engine):
- new base and head gaskets, rings, new rocker cover rubbers etc;
- new pushrods, new rocker arms, honed cylinders;
- carb rebuilt with new seals, float needle, brass fuel inlet (plastic was cracked), idle mixture screw that you can reach.
- Pretty certain the cam is stock, but it might be on the upgrade list for me later. Probably would want an ignition upgrade at the same time. (and at this point I should be asking myself how much more money to put into a 30 year old bike).

The bike was a daily ride for someone that used to live over in the west, he had put some bigger pipes on but they were buggered when I bought it hence splashing out on the Supermeg.

The bike seems to have very good cranking compression now (or I have a shit battery, one or the other), and pulls decently given its age.

On a final note, I've had a blast doing the work myself on it. I push paper all day so getting into the shed at night to rebuild the motor was a great mental break from the daily grind.

tussuck
4 years ago

Quoting Tarvis on 15 Aug 2019 01:02 AM
hey Perthhog,
The bike is basically stock right now, with stock 2:2 (with crossover) pipes.

I bought it last year and most of what I have done is replace old and worn parts so its reliable. This includes (for the engine):
- new base and head gaskets, rings, new rocker cover rubbers etc;
- new pushrods, new rocker arms, honed cylinders;
- carb rebuilt with new seals, float needle, brass fuel inlet (plastic was cracked), idle mixture screw that you can reach.
- Pretty certain the cam is stock, but it might be on the upgrade list for me later. Probably would want an ignition upgrade at the same time. (and at this point I should be asking myself how much more money to put into a 30 year old bike).

The bike was a daily ride for someone that used to live over in the west, he had put some bigger pipes on but they were buggered when I bought it hence splashing out on the Supermeg.

The bike seems to have very good cranking compression now (or I have a shit battery, one or the other), and pulls decently given its age.

On a final note, I've had a blast doing the work myself on it. I push paper all day so getting into the shed at night to rebuild the motor was a great mental break from the daily grind.

Same here.... I do all my own work except where the tooling needed is out of my cost bracket (like honing jugs etc)
- Next time you have the cam cover off have a gander at the cam to see the markings as its pretty easy to figure out what you have. Also check the breather cam thingy as well as they wear (S&S make a sweet reed valve unit that just sits in the hole)
- The factory ignition is fine for most uses (its just a bloody spark after all!), however its the RPM limiter changes that an aftermarket one provides that draws the crowd.
- The carb is REALLY forgiving for jetting, so once your close to the mark riding the bike will let you know (i was tuning a turbo so ended up installed a Wideband O2 sensor and data logger as the fueling at WOT had to be spot on or you just fry pistons)
- Watch the round rubber seal between the manifold and inlet port on the jug as they perish and you get all sorts of odd issues as a result.

Wideglider
4 years ago

Quoting Tarvis on 15 Aug 2019 01:02 AM
hey Perthhog,
The bike is basically stock right now, with stock 2:2 (with crossover) pipes.

I bought it last year and most of what I have done is replace old and worn parts so its reliable. This includes (for the engine):
- new base and head gaskets, rings, new rocker cover rubbers etc;
- new pushrods, new rocker arms, honed cylinders;
- carb rebuilt with new seals, float needle, brass fuel inlet (plastic was cracked), idle mixture screw that you can reach.
- Pretty certain the cam is stock, but it might be on the upgrade list for me later. Probably would want an ignition upgrade at the same time. (and at this point I should be asking myself how much more money to put into a 30 year old bike).

The bike was a daily ride for someone that used to live over in the west, he had put some bigger pipes on but they were buggered when I bought it hence splashing out on the Supermeg.

The bike seems to have very good cranking compression now (or I have a shit battery, one or the other), and pulls decently given its age.

On a final note, I've had a blast doing the work myself on it. I push paper all day so getting into the shed at night to rebuild the motor was a great mental break from the daily grind.

Quoting tussuck on 15 Aug 2019 02:29 AM
Same here.... I do all my own work except where the tooling needed is out of my cost bracket (like honing jugs etc)
- Next time you have the cam cover off have a gander at the cam to see the markings as its pretty easy to figure out what you have. Also check the breather cam thingy as well as they wear (S&S make a sweet reed valve unit that just sits in the hole)
- The factory ignition is fine for most uses (its just a bloody spark after all!), however its the RPM limiter changes that an aftermarket one provides that draws the crowd.
- The carb is REALLY forgiving for jetting, so once your close to the mark riding the bike will let you know (i was tuning a turbo so ended up installed a Wideband O2 sensor and data logger as the fueling at WOT had to be spot on or you just fry pistons)
- Watch the round rubber seal between the manifold and inlet port on the jug as they perish and you get all sorts of odd issues as a result.

- The factory ignition is fine for most uses (its just a bloody spark after all!), however its the RPM limiter changes that an aftermarket one provides that draws the crowd.

An aftermarket ignition also gives you many more options for timing advance at different revs which improves performance.

perthhog
4 years ago

Quoting Tarvis on 15 Aug 2019 01:02 AM
hey Perthhog,
The bike is basically stock right now, with stock 2:2 (with crossover) pipes.

I bought it last year and most of what I have done is replace old and worn parts so its reliable. This includes (for the engine):
- new base and head gaskets, rings, new rocker cover rubbers etc;
- new pushrods, new rocker arms, honed cylinders;
- carb rebuilt with new seals, float needle, brass fuel inlet (plastic was cracked), idle mixture screw that you can reach.
- Pretty certain the cam is stock, but it might be on the upgrade list for me later. Probably would want an ignition upgrade at the same time. (and at this point I should be asking myself how much more money to put into a 30 year old bike).

The bike was a daily ride for someone that used to live over in the west, he had put some bigger pipes on but they were buggered when I bought it hence splashing out on the Supermeg.

The bike seems to have very good cranking compression now (or I have a shit battery, one or the other), and pulls decently given its age.

On a final note, I've had a blast doing the work myself on it. I push paper all day so getting into the shed at night to rebuild the motor was a great mental break from the daily grind.

Sounds like you’re on a roll and loving it Forget the cash
Think of it as a investment to relaxation lol You could
Always be down the pub every night pissing it
On the wall or spending it on horses .
And yes if you do go cam more comp
Later on ignition system is worth upgrading
It’s a lot more than just a rev Limiter

perthhog
4 years ago

Quoting Tarvis on 15 Aug 2019 01:02 AM
hey Perthhog,
The bike is basically stock right now, with stock 2:2 (with crossover) pipes.

I bought it last year and most of what I have done is replace old and worn parts so its reliable. This includes (for the engine):
- new base and head gaskets, rings, new rocker cover rubbers etc;
- new pushrods, new rocker arms, honed cylinders;
- carb rebuilt with new seals, float needle, brass fuel inlet (plastic was cracked), idle mixture screw that you can reach.
- Pretty certain the cam is stock, but it might be on the upgrade list for me later. Probably would want an ignition upgrade at the same time. (and at this point I should be asking myself how much more money to put into a 30 year old bike).

The bike was a daily ride for someone that used to live over in the west, he had put some bigger pipes on but they were buggered when I bought it hence splashing out on the Supermeg.

The bike seems to have very good cranking compression now (or I have a shit battery, one or the other), and pulls decently given its age.

On a final note, I've had a blast doing the work myself on it. I push paper all day so getting into the shed at night to rebuild the motor was a great mental break from the daily grind.

Quoting tussuck on 15 Aug 2019 02:29 AM
Same here.... I do all my own work except where the tooling needed is out of my cost bracket (like honing jugs etc)
- Next time you have the cam cover off have a gander at the cam to see the markings as its pretty easy to figure out what you have. Also check the breather cam thingy as well as they wear (S&S make a sweet reed valve unit that just sits in the hole)
- The factory ignition is fine for most uses (its just a bloody spark after all!), however its the RPM limiter changes that an aftermarket one provides that draws the crowd.
- The carb is REALLY forgiving for jetting, so once your close to the mark riding the bike will let you know (i was tuning a turbo so ended up installed a Wideband O2 sensor and data logger as the fueling at WOT had to be spot on or you just fry pistons)
- Watch the round rubber seal between the manifold and inlet port on the jug as they perish and you get all sorts of odd issues as a result.

Quoting Wideglider on 15 Aug 2019 03:38 AMedited: 15 Aug 2019 03:39 AM
- The factory ignition is fine for most uses (its just a bloody spark after all!), however its the RPM limiter changes that an aftermarket one provides that draws the crowd.

An aftermarket ignition also gives you many more options for timing advance at different revs which improves performance.

It sure does Helps Tailor the tune for performance, comp,cam starting , pinging etc
oh and you get a rev limiter too lol

Tarvis
4 years ago

Resurrecting my slightly old thread here fellas.

First of all, happy new year to everyone and stay the hell away from bush fires if you can help it!

Second, I'm still struggling to get the jetting 100% right on my bike and thought I'd get some follow up thoughts from folks before pulling the carb off again.

I currently have a 45 pilot 180 main in the carb with a CV performance emulsion tube and needle. Bike is a '92 EVO with a supertrapp 2:1 and K&N filter in the stock housing.

Plus look as follows:
Front:
Rear:

Rear is obviously richer than front.

I'm thinking of taking the pilot down to a 42. But it seems odd to me that a stock pilot jet would be right for a bike with a 2:1. I don't think the 180 is an issue because riding around the south east suburbs, its not getting enough time at 3/4 to WOT.

I have also noticed that when using a bit of choke to get it going, when I push the choke in the last 1/3 to 1/4 of choke does not impact the idle. Which makes me further think it is overfuelled at idle/slightly off idle.

I've had a bit of advice that even going back to stock jets should be fine with a 2:1, and while I respect the guy who gave me the advice I'm nervous about running lean.

Would appreciate any ideas on next steps? step down to a 42 and road test/plug chop?

Cheers,
Trav

tussuck
4 years ago

How did you go? Personally I would ditch the emulsion tube and revert to stock. What needle are you running as well?

Tarvis
4 years ago

Hey Tussuck,
Last night I put a 44 pilot jet into it (forgot that I had one). I'll fire it up over the weekend and see how it goes after a bit of a ride.

The needle is the CV performance needle which is supposed to be like the early Evo sportster needles (N65 i think).

I may end up taking out the emulsion tube for the stock one, but will see how I get on over the weekend first.

Happy new year to you.

Cheers,
Trav

tussuck
4 years ago

In all honesty the mix of needes, Emulsion tubes, pilot/main jets and drilling the slide tend to make a f'ed up carb.
BEst bet would be to baseline the unit by returning to stock. I have wasted many hours over the years messing around with these and only to find that the wizzbang widget i added caused it to run like crap

Krash Kinkade
4 years ago

leave the CV stock & just work with pj & mj, never drill out the the hole in slide , don't use any of the so called performance kits. & they work fine. if you are planing on riding the bike every day & economy important. a Bobby Wood k1 needle ( if you can get one ) will work well & give out standing economy. ( but the economy is more noticeable if you will be sitting on 100kph regularly ) as the Bobby Wood needles are stepped & not tapered. I have a k2 needle in the CV on my bike, I've also got a different to stock carb air bleed, so the pj on my carb goes further up rev range b4 the mj comes in, so I run larger size pj , also have a spacer to increase float bowl capacity & an imultion tube that uses Holley mj's as they go up in 1 thou increasements. it works well & no flat spots

Topics

1/2

jetting an evo

jetting an evo

Tarvis

tussuck

Wideglider

Tarvis

tussuck

Krash Kinkade

John.R

tussuck

Tarvis

perthhog

Tarvis

tussuck

Wideglider

perthhog

perthhog

Tarvis

tussuck

Tarvis

tussuck

Krash Kinkade