Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[smiley1049]

A friend has a 84 FXRS he says it has a EV2 cam couldn't find any info on it,Bored 40 over no other real info on it but when you crack throttle wide open it falls on its face he has replaced module,Coil,and plugs no change any of you guys have any ideas what direction I should go with this bike. It also has a Screamin Eagle Carb.

[hrdtail78]

Since the Gods didn't reply....

I'd look at some simple things first.  Is the slide seal good?  Air/ idle set correct?

[Thermodyne]

If it runs well at part throttle, then I would look to the fuel system.  Blocked tank screen, rotten fuel hose, crap in the carb.

Check the supply first then the carb.  Pay particular attention to the high speed jet and the slide.

[cvoDoug]

Petcock, fuel filter then get into the carb.  Could be starved from the source.

[JoeSDE]

My EVO would bog down a little at WOT, I believe it was the main jet. Bike would pick right up when you backed off the throttle slightly. Long time ago, my mind is mush....bigger jet.           JoeS

[Thermodyne]

My EVO would bog down a little at WOT, I believe it was the main jet. Bike would pick right up when you backed off the throttle slightly. Long time ago, my mind is mush....bigger jet.           JoeS

Lean causes that problem.  Just swapping out the needle and adjusting the idle mixture usually fixes it.

[smiley1049]

Thanks that gives me a direction to go.

[North Georgia Hawg]

I have some experience with Evos. I am not familiar with the EV2 cam... but the Andrews EV3 cam is a fairly high-duration cam commonly used in lighter bikes like the FXRs.

Regarding the carb, the main jet and the idle jet have almost nothing to do with one another, and the main jet really doesn't come into play until about 3/4 throttle. If your main jet is too big, it can cause the bike to not have as much power at near WOT or full WOT than it does at lesser openings. Many people think that making the WOT throttle mixture way rich helps - but it really doesn't. Of course, the stock main jet is almost certainly going to be too lean, which will also yield reduced power at WOT.

I played with many idle and main jets on my '95 FLHTP, and eventually settled on a 185 main, and probably could have done as well with a 180. I settled on a 45 idle jet, which is not something the MoCo ever offered to my knowledge. I used aftermarket jets.

One of the best ways to get max performance from a CV carb is to use a Sportster needle from around 1988, set one ring up. There are better aftermarket slides, too, that perform better than the stock slide.

Is does sound as if the entire fuel system needs to be thoroughly cleaned and the carb cleaned out, if not totally rebuilt, and the jets looked as well. Lost of gook builds up in CV carbs over the years.

The site http://www.harley-performance.com has a wealth of information that would be useful to you.

I installed their Stage 1 carb upgrade kit, and it worked wonders: http://www.harley-performance.com/stage-1-carb-kit.html It replaces the diaphragm, main spring, jets, bleeder tube, etc. It's well worth the money.

Good Luck!

Ken

[JoeSDE]

Used a Yost power tube in mine and left everything else stock. Stage 1 kit looks like a nice piece, however.     JoeS

[Thermodyne]

I have some experience with Evos. I am not familiar with the EV2 cam... but the Andrews EV3 cam is a fairly high-duration cam commonly used in lighter bikes like the FXRs.

Regarding the carb, the main jet and the idle jet have almost nothing to do with one another, and the main jet really doesn't come into play until about 3/4 throttle. If your main jet is too big, it can cause the bike to not have as much power at near WOT or full WOT than it does at lesser openings. Many people think that making the WOT throttle mixture way rich helps - but it really doesn't. Of course, the stock main jet is almost certainly going to be too lean, which will also yield reduced power at WOT.

I played with many idle and main jets on my '95 FLHTP, and eventually settled on a 185 main, and probably could have done as well with a 180. I settled on a 45 idle jet, which is not something the MoCo ever offered to my knowledge. I used aftermarket jets.

One of the best ways to get max performance from a CV carb is to use a Sportster needle from around 1988, set one ring up. There are better aftermarket slides, too, that perform better than the stock slide.

Is does sound as if the entire fuel system needs to be thoroughly cleaned and the carb cleaned out, if not totally rebuilt, and the jets looked as well. Lost of gook builds up in CV carbs over the years.

The site http://www.harley-performance.com has a wealth of information that would be useful to you.

I installed their Stage 1 carb upgrade kit, and it worked wonders: http://www.harley-performance.com/stage-1-carb-kit.html It replaces the diaphragm, main spring, jets, bleeder tube, etc. It's well worth the money.

Good Luck!

Ken

Not sure where you got you carb info from, but it's just not set up the way you describe it.  Any fuel added at idle, is also added to the high speed circuit.  And any fuel added with the slow speed circuit is also added to the high speed circuit.  As the throttle uncovers each addition fuel port, it adds fuel.  The early ports never drop out as the throttle is opened.  So the slow jet directly effects the high speed jet, but not the other way around.

The reason for a scooter gaining power if you ease off the throttle is that you reduced the air without altering the fuel.  The high speed fuel circuit is unaffected by slightly closing the throttle from the wide open position.  Reducing the amount of air, helps to correct the overly lean condition that was causing the scooter to fall off.  It's a classic problem that lean jetted Keihin Slide carbs have.  In the days before dyno's and exaust sniffers, the wide open roll out was one of the main tuning indicators.  Roll out about an 1/8 turn on the throttle and if the motor pulls, it's lean.  If it just falls off it's correct, unless the pipes are black, in which case it's fat.  In practice, we started a little lean and went up till the fall off disappeared.

I'm not sure what and EV-2 cam is either, but it doesn't really mater, the symptom he listed indicates a lean condition at wide open throttle.

[cahdbiker]

Chuck R, If your screamin' eagle carb is a CV type carb I would check the diaphragm for any possible leaks. If it similar to an S&S carb try adjusting the accelerator pump.CAHDBIKER

[smiley1049]

Yes it does have the adjustment on the accell pump that helped a bunch

[blueglide88]

I'll bet he has the old style SE carb since it's a 1984. Back then the SE carb was a butterfly setup, and it had 3 fuel jets and 1 air jet. I don't have my notes from back then, but I had that carb. He needs to find out what the stock jetting is and use that as a starting point. Replace only 1 jet at a time, and only 1 size at a time. Lengthy process but it's the only way I know of to jet it properly.

I suggest he dump that carb and put on an S&S or a CV. I've had both on my EVO, and they both have strong and weak points. The S&S will be far easier to jet correctly.

[ltank]

A rejetted CV will perform as well as a S&S on a 80" motor with good gas mileage. CV carbs work well in high altitude with no problems. Its the design. Even with a good mid to upper rpm cam the Carb is fine.
Buy a used one. You might find someone to give you one even. I have used both the DynoJet and CVP. CVO is better and cheaper. You will be HAPPY HAPPY HAPPY!

[North Georgia Hawg]

A rejetted CV will perform as well as a S&S on a 80" motor with good gas mileage. CV carbs work well in high altitude with no problems. Its the design. Even with a good mid to upper rpm cam the Carb is fine.
Buy a used one. You might find someone to give you one even. I have used both the DynoJet and CVP. CVO is better and cheaper. You will be HAPPY HAPPY HAPPY!

Yep! I was thinking he had a CV carb like my FLHTP had... but back in '84 they were using the old Keihin butterfly carbs. The CV carb is much better, and when properly jetted is nearly bulletproof. They may be hard to find these days tho. Got rid of the Evo when I bought the Honey Badger, and don't think about this old stuff much anymore!

Ken