SuzukiSavage.com - Bucking / missing at 65 mph

49mack

YaBB Newbies

Offline

SuzukiSavage.com
Rocks!

Posts: 42

Bucking / missing at 65 mph
03/06/14 at 12:41:02

Help! I bought a decent 1996 Savage, 19,ooo miles. I had a problem when hitting about 60 mph. The bike bucks and snorts like it is running out of fuel. Here's what I've done: adjusted the valves, cleaned the tank and fuel lines, checked and gapped the plug (running a nice tan color), changed the air filter, removed the carb and installed a new float needle seat and float bowl gasket. It improved slightly - the bucking does not start until I hit 65 mph and also backfires when downshifting. I am at my wits end! One other question. . . there is a small line the same size as the line that connects under the gas tank. It seems to go nowhere. I don't believe it is a battery overflow. Any advice, please? I am retired and don't want to drop a wad at the nearest dealer, 45 miles distant. Any and all advice is gratefully appreciated. Thanks!

Back to top

IP Logged

LarryP YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 1	Re: Bucking / missing at 65 mph Reply #1 - 03/06/14 at 12:50:42 Mack, I noticed that you did not say anything about cleaning the carb, re jets , passages. Perhaps ? Hope some of the other guys will weigh in with valuable advice. Larry
Back to top	IP Logged

HondaLavis

Senior Member

Offline

It's nothing
personal; the other
one came first.

Posts: 451
Plano, TX

Re: Bucking / missing at 65 mph
Reply #2 - 03/06/14 at 13:27:04

Our petc0ck - the fuel valve under your gas tank - is vacuum operated. If you have a small vacuum leak it may be starving your engine and not providing enough fuel. Perform Serowbot's petcock test, found here: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1

You are not alone, it's a pretty common problem. If you determine that to be your problem, simply purchase a genuine YAMAHA Raptor 660 petcock. Do a little research, the part number can be found variously throughout this site Wink

Back to top

"You ride a single cylinder motorcycle??"

"When you're good, one is all you need." Wink

I guess that means I'm no good anymore; I've got 4 more cylinders! '08 Yamaha FJR1300 and still '01 Savage

IP Logged

verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: Bucking / missing at 65 mph Reply #3 - 03/06/14 at 13:34:03 This identifies the carb hookups... http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1098869040
Back to top	Versey's Place Tech Section Index IP Logged

old_rider

Serious Thumper

Offline

Backyard Bill
Productions

Posts: 3147
flordia panhandle
Gender: male

Re: Bucking / missing at 65 mph
Reply #4 - 03/07/14 at 05:13:06

Mack... I did the white washer needle valve mod and adjusted the air/fuel ratio on my wife's LS650 and the bucking has settled into a mild surging and the backfire on shutdown went away, still backfires a bit on hard downshift , wife never gets it past 60 so she doesn't feel it.
I'll be watching this thread to see if you solve it completely... oh and I also changed that vacuum petc0ck out.
Does that small line come off of your carb? or tank? sounds like an overflow.

Back to top

We are here to laugh at the odds and live our lives so well that Death will tremble to take us.

IP Logged

49mack YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 42	Re: Bucking / missing at 65 mph Reply #5 - 03/07/14 at 10:46:57 I did not rejet. I did let the carb soak / sprayed passages in carb cleaner for four days. This morning I tried the vacuum line bypass test with no success. I am thinking my next move should be a COMPLETE carb rebuild and the Rapptor fuel valve. Any additional comments are appreciated. Thanks!
Back to top	IP Logged

bobert_FSO

Senior Member

Online

SuzukiSavage.com
Rocks!

Posts: 421
Wichita KS
Gender: male

Re: Bucking / missing at 65 mph
Reply #6 - 03/07/14 at 11:25:41

Before tearing the carb apart, I would try a Raptor petcock, or at least run on PRIME. My stock petcock developed a stiff diaphram and would not open the petcock under low vacuum conditions. This manifested itself under high speed/high load conditions like attempting to drive 65mph into a 20mph headwind. My bike would act like it ran out of gas. It would stumble a few beats and then actually quit. Switching to PRIME while coasting down would allow the engine to start firing again.

Under run-around-town conditions I never experienced a problem.

Back to top

IP Logged

49mack YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 42	Re: Bucking / missing at 65 mph Reply #7 - 03/07/14 at 11:35:49 Gents, many thanks for replies. I just ordered a Raptor petcock even though the bypass was not successful. The stock petcock seeps a tiny bit anyway. A new one will be good. But cannot find a source for a complete rebuild kit for the Mikuni BS40SS. Any advice?
Back to top	IP Logged

49mack YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 42	Re: Bucking / missing at 65 mph Reply #8 - 03/07/14 at 11:37:01 Old Rider, what is the white washer repair or mod? Thanks!
Back to top	IP Logged

Arnold Serious Thumper Offline The dude abides... Posts: 896 Westchester, NY Gender:	Re: Bucking / missing at 65 mph Reply #9 - 03/07/14 at 12:29:11 Also make sure the gas tank cap is properly vented.
Back to top	IP Logged

old_rider Serious Thumper Offline Backyard Bill Productions Posts: 3147 flordia panhandle Gender:	Re: Bucking / missing at 65 mph Reply #10 - 03/07/14 at 12:31:06 Here ya go... follow this post to do the mod... http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1104205157
Back to top	We are here to laugh at the odds and live our lives so well that Death will tremble to take us. IP Logged

49mack

YaBB Newbies

Offline

SuzukiSavage.com
Rocks!

Posts: 42

Carb woes and fixes
Reply #11 - 07/19/14 at 14:26:21

I'd posted about my Savage spitting and coughing at 60 mph and got some advice. Seems the main fix was to upgrade main jet size from 145 to 155. In being highly frustrated getting the float bowl off, I determined to make it easier. Replace your float bowl screws with socket head (Allen) screws from Home Depot. 5mmx12mm, SKU # 387480032789. The best tool is a flex shaft reversible screwdriver. Mine is made by Allied. The flex shaft allows you to get the bit into position and install / remove them. Getting the cheap tin can screws out was a headache. Putting in the new Allen heads was a breeze. I can change jets in 10-15 minutes. Oh, by the way, thanks to the rider who advised cutting one full circle of spring off the reversionary valve assembly. Magic! No more backfiring.

Back to top

IP Logged

engineer Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 872 Gender:	Re: Carb woes and fixes Reply #12 - 07/19/14 at 18:27:21 I remember your thread, did you ever get around to doing the white spacer mod? Yep, stainless steel Allen head screws make a whole lot of jobs easier. They should sell them that way.
Back to top	2005 S40, Intruder shocks, Dyna, 52.5/150, 3 washers, 2 turns, modified seat, Raptor IP Logged

Todd James Full Member Offline SuzukiSavage.com Rocks! Posts: 238 Mansfield, Ohio Gender:	Re: Carb woes and fixes Reply #13 - 07/19/14 at 22:08:55 I replaced all of the external screws on my carburetor with Allen head screws. Here's a picture that shows the location, sizes, and quantities of the screws.
Back to top	Carb_Screws_Web.jpg 2007 S40, Dyna, 52.5/150, .073 Spacer, 2 Turns 2007 Sportster 1200, V&H Pipes IP Logged

49mack

YaBB Newbies

Offline

SuzukiSavage.com
Rocks!

Posts: 42

Still coughs and stumbles like running out of gas
Reply #14 - 07/20/14 at 10:47:23

Engineer: Please tell me again about the white spacer fix. I can't find it. Last night I installed a 155 main jet (up from 145) and it still coughs and sputters like it's running dry at about 61 mph, level ground. I've adjusted valves, gapped the plug, new air cleaner, Raptor petcock. . .
I like this bike but it's getting close to becoming a trade-in!
Thanks, Engineer!
49mack

Back to top

IP Logged