Involute

Stock filter
Bafflectomy
4500 feet at home
Around 7500 feet in the mountains
Stock jetting before I started messing around with it (low power and didn’t want to idle until the engine temp was up to 170 or more)

I put in a Factory Pro Kit last weekend. 178 front, 182 Rear. Needle clip on third slot from the top. Screws 2 turns out.

After re-jetting the bike seemed to be running fine until I got up in the mountains yesterday. At higher elevation (7000 feet or so) the bike falls on it’s face when trying to accelerate hard. I’m assuming I’m too rich but before I tear in to the carbs and swap mains again I’m hoping for one of the more experienced than me to offer advice. Depending on how I was riding I got as low as 28MPG (not flogging it) and as high as 35MPG, but when I got 35 I was following a cop for 50 miles and riding it at scooter speeds.

Do my settings seem out of whack? I’m under the impression that if I use the Honda recommended jet sizes for 5000 feet I’ll be running way too lean. Aside from the issue at higher elevations I was pretty sure I was close. I do plan on getting it dyno’d sometime in the near future to see what the A/F ratio looks like but I’m hoping to get everything close before I take it in to avoid numerous runs and carb removals. I’m also trying to avoid riding 50 miles to get to higher elevation and then remove the air filter to see if it helps.

I have searched and read all the high altitude jetting threads I could find and it appears other people have had good luck with similar carb setups. I know I can spend hours and days changing things until I get it right but that’s no damn fun, and I’m lazy by nature. I’m assuming that the Bafflectomy produces somewhat similar results as Slip-Ons do. Is that my mistake?

Thoughts……………suggestions?

A buddy of mine has 98 SH with Two Brothers Slip-Ons and stock filter. His settings are identical to mine except he still has the stock spacer under the needle clips. Based upon his Dyno runs (and memory) he is just a little bit rich. I rode his bike at our normal 4500 feet and it seemed to run great. I’ve never done any hard acceleration on his bike at higher altitudes though. I’m assuming he has, and as he’s pretty damn sharp in regards to bikes, he’s a Dipshit in all other aspects (I had to add that in case he reads this), I assume he has no problems at all with his bike at higher altitude.

trinc

did the factory jet kit instructions tell you to remove the lower .020" washer thats on the stock needle ?

tim

8541Hawk

You really don't want to run without that (or at least some washer) under the "c" clip to keep the points of the clip from wearing into the slide.

Involute

If I recall the instructions said nothing about the washer. I'll go back and read them again. I do know that what I received had no info on elevation changes.

It sounds like I need to tear in to them again and put the washers back in and go from there

I wonder how fast I can do it the second time around

So is it safe to assume the jet sizes seem OK and that the punched out stock exhaust is pretty close to the same flow as a slip-on? While I'm in there I'd like to tweak anything that seems out of whack to you guys.

Now I just need to find time to do it all again.

Oh..........and thanks for the replies. I really appreciate the knowledge on this site.

superbling

I know it's an apples to oranges thing but I just installed a factory kit in my VFR. It did call for using the stock washers. BTW, mine is running great but won't have a chance to try it at altitude (6-7k ft) till the end of the month.

RK1

I don't have any experience with the Factory Pro kit but have some ideas.

Were your pilot screws 2 turns out when you had the bad idle 'till fully warmed up problem?

I ask 'cause both Honda and DynoJet spec 2 and 1/2 turns out. When I was experimenting with my bike I tried 2 turns out and had the same idle problem you described until I turned them back out again.

I don't think the bafflectomy affects exhaust flow that much, and not all slip-ons are the same. "street baffle" slip-ons usually run fine with stock jetting, maybe a little better with raised/shimmed needles. Race-straight through-loud slip-ons are the ones that usually benefit from larger main jets.

Honda recommends going down a jet size for operation over 6500 ft. Sounds like you went up a size or so. What percentage of your riding is done over 6500 feet?

I'm guessing, but I'd think you'd be better off with the equivalent of stock size mains and open up the pilot screws a bit.

Involute

Makes sense to me. Thanks for the info.

I do need to confess that I didn't pay any attention at all to where the screws were set before I got involved. I was sure that setting up the carbs the same way my buddy had his would be the ticket.

I looked at the Kit instructions more closely and it does say to use the stock spacers if the bike has them.

When I got the bike the PO told me he'd never jetted it and I tend to believe him as I pulled out the stock main jet sizes. Since the tweaking I did to it the bike idles great. On cold starts (60 degrees outside) I put the choke on for about 15 seconds, turn it off and blip the throttle a little for about 5 seconds and she idles nicely. When warmed up no change in idle speed or behavior. If it wasn't for the way it acted while trying to accelerate at altitude I'd have not known of any problem until I had the bike dyno'd.

At 4500 feet on the highway the bike seems to pull very well from at about 1/2 throttle but I'm thinking it starts to flatten out a little when the mains kick in.

To answer your question:

The bike will spend a fair amount of it's life at around 6000-6500, but It'll be ridden the hardest on the track at 4500 feet. The high altitude riding will be pretty much aggressive Sport Touring.

Hawkrider

It sounds to me like you're rich. Try putting the stock washers back in and also lower the needles by one notch (c-clip up). If you're idling fine and the roll-on at the higher elevation clears up then I wouldn't mess with it anymore. You want to adjust the mains for max power at your track elevation. That's where you will spend most of your time at WOT at higher revs.

Oh, one other thing is that you can use your choke as a troubleshooting tool. Next time you're at high elevation pull the choke **** a little and see how it runs. Better means you're lean. Worse means you're rich.

Involute

If I can motivate my lazy *** I'll take care of things tonight. Keep your fingers crossed for me.

Involute

Just when I thought my game plan was firm I get a response to an e-mail I sent a few days ago to Factory Pro.

They advise mains at 172/175 with the Clip on the third notch

That sounds way to lean to me. I miss the days when I really didn't give a crap if a bike was jetted properly

I'm thinking I'll go with Greg's advice and see what happens. He seems pretty smart.

Involute

Partial success!

I did exactly as Greg said EXCEPT, I went down one size on the back so now I'm 178/180, 2 turns out and second slot from the top with the stock washer. My elevation issue is much better and the bike seems to pull nice and hard at 4500 feet.

My only issue now is a pretty good Lean Stumble at about 1/8 throttle. It's most noticeable from 3000-4000 rpm in 1st thru 3rd gear. I know it was lean because when I pulled the choke out it got better and with the choke in it was worse at 4500 feet than at 8000. It was about 55 degrees coming home and in town a kept seeing the temp rising. It got as high as 218 at stop lights.

Is the fix for this simply going out a little on the mixture screw? Maybe another 1/2 turn?

Once again.............thanks for the help. I'm a jetting newbie.

Hawkrider

Smart ***, maybe.

Involute

Nobody appreciates a Smartass like me.


Oh.................and..................


Ahem! You forgot something.

"Is the fix for this simply going out a little on the mixture screw? Maybe another 1/2 turn?"

Hawkrider

Um, well if you don't try it then you'll never learn, right?

Give a man a fish, feed him for a day. Teach and man to fish and feed him for life!!!




Yes.


I'm a sucker.

Thumper

What pilot jet do you have, Stock 45? or something else.

The Factory Pro kits originally came with 48's and for some reason they went to 50's, which are too big a jet for most SuperHawk's.

The 48 Pilot is a sweet combonation. oh and changing the emulsion tube

Involute

Thanks.

I'll refer to you as "Plecostomus" from now on.



Thumper,

It's still the stock pilot. I don't believe my kit came with any pilots. I'm pretty sure it was returned to the dealer I bought it from by an unscrupulous customer that used what he needed and took it back. It had no bit to adjust the mixture screw either.

Involute

At least I Post ***** in my own Thread (for now).

I went out 1/2 turn and the surging is almost gone but the idle hangs up a little when letting go of the throttle.

I'm going to go another 1/4 turn to make it 2 3/4 turns total. That is unless some algae eating fish suggests something else

RK1

Involute;

Not to sound like a smart *** or an algae eating fish or anything, but I think you're still a bit rich on the mains and the Factory Pro guy's advice was sound. Because;

1) "bafflectomy" stock exhaust w/stock filter flows little if any more than stock/stock.

and

2) Running 4500'-6500' plus would at least cancel out whatever little extra flow you got.

stock jetting is 175f/178r. Fractory Pro guy suggests you go down a size based (I assume) on your altitude.

If the bike runs as good or better at 6500 than at 4500, forget it, but if it gets worse as you go up, you're still too rich. You're probably fine with 2 and 1/2 turns on the pilots.

Involute

Don't worry about sounding like anything. I appreciate and welcome your input.

At higher elevations the lean surge at 1/8 throttle gets better. I noticed that yesterday. Today I didn't go up in elevation, I just went a few miles to get the bike warmed up and to see what happened at 2.5 turns. It seemed that the surge at 3500-4000 rpm with the throttle barely opened got worse as the bike warmed up but was not nearly as noticeable as it was yesterday at 2 turns. That has to means it's still lean off idle right? (no sarcasm there........serious question).

I'm certainly not going to rule out that the mains could be too rich. My concern right now is to make sure the bike is not too lean and jetted OK. I plan on getting it on a dyno once I think it's OK in order to fine tune it.

It would make sense to me to go another 1/4 or 1/2 turn on the screws to richen it up at idle but this is the first time I've ever really tried to optimize jetting so I may just end up screwing myself.

Seriously, you guys have been riding tweaking the SH for quite a while and I value your input. I have given some serious thought to doing exactly as the FP people suggest but I can't help but think I'm pretty close right now based upon the way the bike is running everywhere except off idle. It is running a lot better than it was when I bought it but I have no idea where the screws were set at the factory and I also don't know how the FP Needles have affected things. I'm afraid I'll get myself in to the situation where I'm chasing my tail because I'm so new to this carb tweaking stuff. The problem is the older I get the more **** retentive I'm becoming about my bikes .

nuhawk

I read this entire thread and not in one spot does anybody talk about syncing the carbs. EVERY time the carbs come off the block they need to be synced. Just my .02 The Superhawk is a very carefully tuned machine. Small changes make big differences.

Randman

I have never had my carbs synced...is it fun?

Hawkrider

KC, go sync the carb on your DR.

Hawkrider

Well, firstly (is that a word?) I am a bottom feeder for all things except motorcycles, cars, and women (not necessarily in that order).

Secondly, like any valve, the mixture screw will have less effect the more you open it. The screws are like a fine adjustment. Pilot jets are like a coarse adjustment. Ever have a REALLLY old stereo with fine and coarse tuning *****? After you run out of adjustment with the mixture screws you need to make the step up on the pilots. If you truly are getting a lean surge then you should probably get 48s. This sounds a little contrary to logic based on your elevation but this is what your symptoms suggest. I'm going to assume that your air filter is good since you've taken the carbs off several times and you must've noticed its condition. If this doesn't solve the problem then all I can think of is a rats nest in your intake snorkle.

Randman

No, No...I am getting an 08' KLR 650....not a DR...come on now...Dual Sport...so next year at the rally, I will be offroading it a bit...LOL...Too much fun

Involute

Well, it looks like I'll be shoving my daughters cat in to the airbox. If there is a rat in the snorkel the cat should take care of things. At least I don't have to pull the carbs again. See, I'm getting the jist of things