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General Category >> Rubber Side Down! >> Maybe pushing the S40 a little hard?
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Message started by Fry on 08/23/12 at 07:03:43

Title: Maybe pushing the S40 a little hard?
Post by Fry on 08/23/12 at 07:03:43

Hey all! I've been lurking the forums since I got my S40 back in May. Loving the bike so far, it's my first bike and this forum has helped me learn a ton!

I ran into a bit of an issue coming into work this morning. Generally I avoid the highway on my way into work, but was running late this morning. I rode about 30 miles on the highway, trying not to go over 75mpg and generally staying around 70. After about 30 miles of great traffic I got to an off ramp started to decel and the motor shutoff. Gave it a little gas let out the clutch and it kicked back on, but it had me concerned. I pulled off to the side of the road and sure enough the bike stalled out. I couldn't get it to start without giving it a little bit of throttle, and if I let off the throttle it would stall again. My S40 only has 2k miles on it and no performance mods/tweaks.

Did I just push the engine too hard? Is this normal for an engine that's overheated? Also after staying on the throttle and riding for a mile all was well again. Leading me again to hope that it was just over heated.

Any ideas? Thanks in advance!

Title: Re: Maybe pushing the S40 a little hard?
Post by ToesNose on 08/23/12 at 07:23:52

How full is the tank? How steep was the off ramp? Was it fine after you got off the ramp and were back on level roads?

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/23/12 at 07:28:58

Read this and do the test.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1

Seriously, don't mess around asking a lot of questions or chasing all the various comments from all the well wishing posters that you will get around here on the list. They can have you chasing your butt and tearing stuff apart before you have tested or analysed a single thing if you let them.

DO THE TEST, and post your results the very first thing right off the bat. Then the senior members will have something to work with and can actually help you trace down your problem.

And no, Toes, this wasn't aimed at you. Although you did sneak in some of the same stuff mentioned in the milliseconds before I hit my enter key, I didn't know you had done it.

And if you hadn't done it, four (4) other enthusiastic people would have. You guys need to learn how to help people, by leading them through the diagnostic tests in TECH SECTION, rather than just throwing out "what ifs".

Title: Re: Maybe pushing the S40 a little hard?
Post by ZAR on 08/23/12 at 07:30:05

Welcome Fry!!! I've never owned a brand new bike(a lot of basket cases and well-broken-in scoots though) so this is just my thoughts,take with a grain of salt. I'm thinking with only 2000 miles you may be pushing it a little. Your manual should give you break-in speeds for certain milage readings and I'd go by them.

I commute 45 miles each way to work(1996 Savage w/11,800+ miles) and I run 70-75mph for 20 miles on the interstate with no problem and have throttle to spare if needed. Back when we had the 105*F+ temps the scoot ran a little hotter than normal but I never had it die on me.

As an after thought......at 2000 miles it may be time for some adjustments and service. Have you changed your oil yet?

Good luck and keep us in the loop!

Zar

Title: Re: Maybe pushing the S40 a little hard?
Post by ZAR on 08/23/12 at 07:33:25

4F6C6466656C6C6572000 wrote:

OF since his scoot is brand new and only 2K miles......what are the odds the petcock is failing this soon? Not trying to argue....just curious.

Zar

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/23/12 at 07:48:51

A vac petcock on a Savage has one noted strange quirk, at full running speed the vac level in the engine decreases slightly which partially decreases the fuel feed from the stock vac petcock. This can lead to a listed & known symptom of stock vac petcock malfunction (fuel starvation) which is exactly what he described in his first post.

He can do the test set up, make a high speed run, report the results and then get more "help" from there.

And you do know that vac lines can fail at any time, right? Verslagen replaces his vac line yearly as a matter of rote. If he tests "vac petcock system deficient" then I am sure someone will suggest replacing his vac line.

Key thing when a new person posts with a situation is to FIND OUT WHAT HIS SITUATION REALLY IS. The standard tests in Tech Section are designed to do this.

If anyone posts with a fuel related issue, to remove over half the of "unknown" from the situation use the http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1 test. Do it first thing, right off the bat, make the poster reply that he did the test and get him to tell us what he found out.

This will tell you instantly what he understands about the bike and what he doesn't understand. It also cuts out over half the fail modes instantly (no matter which half, half are GONE). Then you focus on what is left.

Title: Re: Maybe pushing the S40 a little hard?
Post by ZAR on 08/23/12 at 08:00:29

Thanks for the clarification OF. You make perfect sense in getting someone to do the testing work-through to help them learn their scooter and to give the gurus here a feel for someones understanding of mechanics!
That's why you're the 8-) dude!

Title: Re: Maybe pushing the S40 a little hard?
Post by groupus on 08/23/12 at 08:24:55

At high rpm for 30 miles with lower vacuum and a fresh, stiff diaphragm spring, you probably just emptied the carb bowl. Perform the test, but it might be difficult to duplicate the symptoms. If it does it again, you can always try switching to reserve to see it that fixes it.

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/23/12 at 08:34:16

:) reserve?

Title: Re: Maybe pushing the S40 a little hard?
Post by justin_o_guy2 on 08/23/12 at 08:46:29

When I raised my idle speed mine stopped doin that.

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/23/12 at 09:11:40

Yup, and there are LOTS of good reasons why we tell all the newbies to make sure their idle speed is 1,000 rpm or slightly better.

Keeping enough oil pressure to supply the cam bearings is the main one, but keeping enough vac suction to keep the vac sucker sucking is another.

Can you say this 5 times fast?

"...... how much vac could a vac sucker suck if a vac sucker could suck vac?"

Title: Re: Maybe pushing the S40 a little hard?
Post by LouSiana on 08/23/12 at 09:14:56

The vac system should (or may I say it must) work even if one's emptying his fuel bowl at top speed.

OK, right, the vacuum decreases the more throttle you give.
But it should at least be enough even if you go on max speed all the way.

I found out (and some others here around) that not only the vac tube sometimes plays tricks on you, also the rubber flange between carb and head (exactly the two screws which loosened), one should have a close look if that four little screws holding the diaphragm case on the petcock are tightened well.
On a newer bike they should, elder ones may need some little service there. Cause may be the paper sealing and the diaphragm shrinking with time.

Title: Re: Maybe pushing the S40 a little hard?
Post by verslagen1 on 08/23/12 at 09:42:11

The problem noted may be more incidious than we have thought.
This is a common problem... run at high speed and sudden decel to a stop... and silence.
What's happening here?
High speed... low vacuum
decel to stop... high vacuum? no! we have a CV carb. The butterfly is downstream of the carb and the vac pick up. So it's possible we're seeing a low vac to low vac issue causing the bowl to empty and the engine to run lean and cut out.

Title: Re: Maybe pushing the S40 a little hard?
Post by Pine on 08/23/12 at 09:42:35

hehe

so last night... ran 60 - 70 for about 20 miles.. engine began to cut out... swiched to prime (I can do that blind.. I forget reserve) ... bike only got down to 50 before comming back to life....

Its all good.. my new Raptor petcock is on the dresser awaiting install this weekend. It just got here 3 days ago.

PS: dern it.. jut realized I refilled the tank this morning to get to work.. now I have a bunch of gas to drain, saturday! :P

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/23/12 at 09:57:21

352631302F2224262D72430 wrote:

Interesting, isn't it?

"So it's possible we're seeing a low vac to low vac issue causing the bowl to empty and the engine to run lean and cut out."

Do this ongoing for a few years, lean out the engine at full speed multiple multiple multiple multiple times and then what sort of piston symptoms will you see when you pull your engine down later?

Title: Re: Maybe pushing the S40 a little hard?
Post by Fry on 08/23/12 at 10:21:01

I'll do that test tonight and report back what I find out. To answer some other questions the tank was 3/4 full so plenty of gas. Thanks everyone!

Title: Re: Maybe pushing the S40 a little hard?
Post by groupus on 08/24/12 at 07:04:46

Oldfeller, pine, sorry I meant to say put it in prime, not reserve. When low vac is not filling the carbs as fast as they are emptied, it doesn't matter how much gas is in the tank.

I also noticed that when I am running low on gas, it will chug along fine until I come to a stop light. Then I'll have to blip the throttle and switch to reserve/prime bedside it starts to die. I'm supprised that this has not been brought up as an issue before.

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/24/12 at 07:18:57

Groupus,

You have a known issue Groupus, you are posting in a thread where we are discussing your known issue as we help a newbie through his discovery process of what he's got (which is your issue, btw).

"I'm supprised that this has not been brought up as an issue before."

What do you suppose your issue might be, now that you stop and think about it.

.... I can't really believe all the people telling us they are running around on bikes that die out on them at high speed and stop them cold on the roadside, and all the OTHER people who have bikes that have to be revved up and coaxed to keep running when they get caught by a stop light .....

AND THEY HAVEN'T FIGURED OUT WHAT'S WRONG YET.

(shakes his head and sighs)

:-/

Bill, get my rocker out and get it set up on the porch, I think I'm gonna go sit in it a while ....

Title: Re: Maybe pushing the S40 a little hard?
Post by Fry on 08/24/12 at 08:32:39

Okay so blocked off the lines and ran on prime with no real difference. The bike ran fine on the way home that same day. I've thought about switching to a manual petcock but I know me, and I'd probably leave it on the first time I parked :-[

Title: Re: Maybe pushing the S40 a little hard?
Post by rfw2003 on 08/24/12 at 08:35:42

[quote author=222A312630302C430 link=1345730623/15#18 date=1345822359]Okay so blocked off the lines and ran on prime with no real difference. The bike ran fine on the way home that same day. I've thought about switching to a manual petcock but I know me, and I'd probably leave it on the first time I parked :-[/quote]
As long as you don't have a problem with your float in your carb, leaving it on won't hurt it. I've left mine on for several days at a time with no issues.

Your Float system in the carb keeps it from just draining from the tank when the carbs bowl is full.

R.F.

Title: Re: Maybe pushing the S40 a little hard?
Post by EJID on 08/24/12 at 08:42:22

[quote author=7F776C7B6D6D711E0 link=1345730623/15#18 date=1345822359]Okay so blocked off the lines and ran on prime with no real difference. The bike ran fine on the way home that same day. I've thought about switching to a manual petcock but I know me, and I'd probably leave it on the first time I parked :-[/quote]

I switched to the raptor at the beginning of this year and think I've only turned it off 2 times, both maintenance issues. I always forget that I "should" turn it off, but it was a habit of riding it for the past 2 years with the stock petcock that re-trained me :-[

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/24/12 at 15:26:00

Let Fry make his decisions at his own pace -- he knows where to look when it reoccurs, and he also knows what the other error mode faces the vac sucker can show can be.

Men can acknowledge something without it causing a need for them to do anything about it right now .... ask any woman, she'll tell you all about it.

Groupus's request for somebody to say "the vac petcock is a piece of shite" is all handled now and Charon is kinda sorta standing up for the vacsucker (or at least he is insisting on factual data, which is always a good thing). He should have a good time doing so.

I am interested in the poll results, do they change overall any compared to the past or do they stay around 1/3, 1/3, 1/3 as they have in years past.

Folks saying they habitually hand maintain their idle speeds at stop lights is a new one for me -- we have folks attacking that issue by playing with their little side diaphragms on their carbs when they may be having yet another face to the long known petcock strangeness instead.

Title: Re: Maybe pushing the S40 a little hard?
Post by Oldfeller on 08/24/12 at 16:23:15

After all, his spider only did one (1) single push up over his main jet .....

:)

Title: Re: Maybe pushing the S40 a little hard?
Post by Fry on 09/19/12 at 06:44:56

Alright well I wanted to post a quick update. I've taken the highway a number of times since that day and have not been able to reproduce the problem. Not sure if maybe I tightened up a leak when I pulled the vacum to test out the petcock. Either way for now it's working so I'm going to leave it be.

Hopefully the problem with either never come back, or come back in a way that I can reliably reproduce it. Thanks for the help everyone.

Title: Re: Maybe pushing the S40 a little hard?
Post by Fry on 04/26/13 at 13:17:21

Well it's been a while and I wanted to updated everyone on this. Looks like it was the petcock. I've swapped out the OEM with a raptor petcock and have no had the problem the last couple weeks I've been riding.

Thanks to everyone for the advice.

Title: Re: Maybe pushing the S40 a little hard?
Post by ToesNose on 04/26/13 at 13:19:20

Ahh spring has sprung and Fry is back riding!! Enjoy ;)

Title: Re: Maybe pushing the S40 a little hard?
Post by Dane Allen on 04/26/13 at 13:45:27

525A415640405C330 wrote:

It was worth it just to read Oldfeller's replies!!! ;D

I am all about taking advice from knowledgeable people without arrogant second guessing on my part. I switched to the Raptor last week at just under 1k miles and will be getting the Versy next month.