willz

Hello all.
I did some searching but couldn't find a good answer in an existing thread. Here's the deal:

I got a dynojet jetkit (and K&N air filter) put into the SH by a local honda shop (already had Jardine's on it). I got it back last week and tried to take it out yesterday. The (cold) start was really rough and the rear cylinder (at least thats the area I think it was) sounded a little weird. I got it out of the neighborhood but it was doing a lot of crackling and backfiring when I closed the throttle. Also there is now a significant flat spot at about 4k rpm when accelerating. Then it died at every light I stopped at. So I got it home and turned the idle up a little. Still a lot of backfiring and the flat spot but not dying at lights anymore.
This morning on another cold start the noise from the rear cylinder area sounded worse, like something wasn't spinning in sync with everything else (this is my main concern) and it was slightly harder to get fired than it used to be (which means it will be a royal PITA once it turns cold in winter).
Any ideas? Thanks!

Edit: One other thing, when idling at a stand-still, if you rev the engine it doesn't drop right to idle speed when you close the throttle. it slows to 2k, then slowly drops down to idle.

Also, if anyone knows a good tuner in the nothern VA area that can get me squared away, please let me know.

Syclone

If you paid the local honda shop to install it, I'd take it back to them and make them tune it.

Dave in NY

I agree with Syclone - only I'd bring a baseball bat with me. Whoever installed the kit was an idiot. Scream at them until they have an experienced mechanic work on it rather than the new kid.

I paid a hefty amount to the local Ducati/Triumph dealer to have my kit done (I have this phobia about carbs and electrics) and it was money well-spent: crisper throttle response, it feels a little peppier all around, and it'll idle at 1K RPM even. No back fires, either through the exhaust or hiccups back through the carbs.

It's inexcusable for a dealer to return the bike to you in that condition. Once they straighten things out for you, find someone else to do all your work moving forward. One of the things that's nice about Ducati mechanics is they understand the carb quirks of V-twins (different size jets front and rear due to cooling differences, for example).

Good luck - once the carbs are fixed it should run beautifully!

trinc

the idle hanging then dropping indicates a lean condition but since it's backfiring it may be an air leak. is the PAIR valve disabled ?

+1 to taking it back and making them correct it. it sounds like they installed it, probably to the standard setting but didn't do the hard work of fine tuning it.

if your looking for another shop i'd suggest finding one with a good dyno w/ a sniffer. that way you'll get a printout of the a/f throughout the RPM range.

tim

johnclopp85

I agree with what all these guys say. TAKE IT BACK. I also put a dyno kit on my SH about a month ago, and like you I have a K&N on it. Although, my pipes are D&D not Jardines. I put the kit on my self, and used the jets recommended by dynojet. The bike runs great. The only problem I have is the back firing issue, but tomorrow I'm going to disable the pair system.

supermatt996

some of those guys just install the kit. but only when you ask them to sync. the carbs do they do it i had the same problem. they said you didnt tell us you wanted the carbs sync. i thought it was a common sense thing that came with the carb work.

Hawkrider

It's quite possible they didn't drill the hole in the slides. The hole is designed to work in conjunction with the new DJ springs to raise the slide faster. This would make the bike run lean at part throttle.

The idle problem is due to either clogged idle jets or improperly adjusted mixture screws.

Bring it back. Have them fix it. Tell them they suck. In that order, of course.

willz

Thanks all. I'll bring it back to them (pain in the ***) and see what they can do. They better not try and charge me anything...

willz

One other quick question...
I'm not going to do this, but what kind of harm can come to the engine (or other parts) if it runs lean for an extended period of time?
Thanks everyone again for the responses...

mikstr

Running lean for an extended period of time can result in burned valves and damaged seats, especially on the exhaust side

willz

Update:
I got the bike back from them and I'm undecided on the results. They put in a 50 pilot jet and I guess fattened it up a little to make it richer. They gave me the stock pilot jet back but I haven't looked at it to see if I think its clogged or anything.

While it runs acceptibly, I'm not sure its running as well as it could. The flat spot is gone but there is still a tiny little dip that I notice in the same range. The other reason I say I'm not sure its running as well as it could is because I was emailing with a Dynojet guy and describing how the bike was running (before this fix) and he said that replacing the pilot jet was masking the other problem of the mid-range flat spot, not solving the real problem (tuning it correctly).
Anyway, lessons learned.
Firstly, I should have never installed a jet kit. It was running fine without and the extra power isn't all that much more. Plus its mostly in the top range and I'm not up there enough for it to really matter.
Second, when doing performance mods that I can't do myself, take it to a performance shop to get them done. Don't take it to the local dealer no matter how good they are at scheduled maintenence. Performance is not their specialty.
Finally, I've never been good at knowing when to fold a losing hand and I basically had the mentality of I was going to get this done no matter what. It's cost me a fortune and has totally not been worth it. I would suggest to anyone considering a jet kit NOT to get one. That being said, I still may take it to a highly regarded performance shop in my area and see if they can tune it to perfection with their dyno, which is what I should have done in the first place.
I'm going to be even more disappointed if my gas mileage goes to **** because of this bigger pilot jet.
anyway, thanks for the comments all...

Circuit_Burner

A competent shop with mechanics who care about tuning it to its apogee is required for quality in jetting.
Getting rare these days, unfortunately.
The welfare state mentality among many mechanics, and their target desire of just getting it done as fast as possible for the paycheck, leaves many shortchanged.

Even if they are jetting yoda-gurus, a thourough jetting session involves the carbs comming off the bike several times to nail the settings. Even if they dyno, theres always properties to be had outside the cold logic of a dyno readout.
You can get lucky and get a dyno-jet kit using thier chart and hit the neighborhood generally with one single carb install session. Most times its a good enough setting thats all they do. I reached for a dyno-jet kit for bikes comming into our shop to hit the general area, but we would always make sure we would experiment up and down with the needles and mains. Once we liked one of three general settings, we would assess the idle situation and play with pilot jets only then. A set of jet drills are handy, and you can raise jet sizes one size at a time until you come into range.
You just cant go back, lol.

All in all, jetting is pretty much a bitch, and is supposed to be...in the scheme of things.

divingindaytona

With a properly installed jet kit you will notice a gain thoughout the RPM range, not just up top.

The problem you had was with the competence of the techs in the shop. As others have stated tuning takes time. Additionally after they were done with tuning, they should have synced the carbs.


With a set up jet kit the superhawk is more fun to ride, sense there is more torque.


Please tell me that you did not have you to pay them for them tuning there incorrect set up.


Answering your queston about running lean, in severe cases it may lead to buring a hole though the crown of a piston. Disclamer: This is after years of running way lean.