SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> Cam chain jumping?
/cgi-bin/YaBB.pl?num=1315180155

Message started by drums1 on 09/04/11 at 16:49:15

Title: Cam chain jumping?
Post by drums1 on 09/04/11 at 16:49:15

At random times, usually at startup, but while riding too, my RPM's jump up about 500rpm's, and the exhaust gets quieter at the same time. The valves also sound different when this happens. Sometimes, if I rev it up, or when I decel from high speed, it will kick back down and exhaust gets louder again. I gotta keep messin' with the idle speed screw. Does this sound like a cam chain randomly jumping, and if so, how is that possible? I just put in the Verslavy about 800 miles ago. I'm also starting to hear a rapping noise up in the cylinder/head area.(Left side) Not to mention the whining gear-like noise, only when clutch is engaged, also on the left side of motor. I got a bad feeling that something is seriously out of whack from the large-rock-in-the-road incedent. Or, does this sound like another carb problem? I really don't want to rip it all apart again. I'm thinkin' of just riding it to death and call it a summer. Maybe I'll win the lottery and just buy a new one??

:-/ :-[ :o

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/04/11 at 17:33:39

Did you remove the little plastic piece when you put the verslavy in?

How many miles?

Title: Re: Cam chain jumping?
Post by drums1 on 09/04/11 at 17:37:53

Yes, got the plastic out.

20,800 miles on motor.
Verslavy installed at 20,000 miles.

700 miles since running over the rock. (Remember I punched a hole in the front right side of crankcase. Fixed with JB Weld)

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/04/11 at 18:05:47

It's not highly likely that the chain is jumping then jumping back. I would think if it were jumping it would continue jumping in the same direction.

Not much on the right side that would effect idle speed otherwise.

The only thing I can think of that might (and it's never been reported to happen) is the timing sensor coming loose and advancing or retarding the timing.

As far as the knock goes... I had a knock on my '88 when I got it. Turned out to be a burnt piston and a frozen wrist pin. And we thought the knock was coming from the bottom end. Which could've been piston slap.

explain a little more about the rpm's jumping up.
you say you're riding along and suddenly wants to 500 rpm more?

Title: Re: Cam chain jumping?
Post by Boofer on 09/04/11 at 18:23:38

Humor me and think if this could be the problem. 1994 Mazda 626 in good condition would whine and kick down auto trans, but lose nearly all power. Mass Airflow sensor just dirty. 1999 Dodge 1500 with 318 cu in. Nearly same problem...stopped up converter. 2- stroke engines do similar when air intake is impeded. Just wondering if you're getting enough air in/through/out? ihth jar your thought process. That's all I got. :)

Title: Re: Cam chain jumping?
Post by drums1 on 09/04/11 at 18:34:39

Air flow is good. New A/F. Exhaust not plugged.
Today when I 1st started it up, sitting there idling on SS, by itself, rpm's increase by about 500. A minute later it goes back down by itself. Out on the road at stop sign, rpm's jump up, 1/2 mile later it just goes back down. Sometimes takes longer. Seems to not do it after riding 20 miles or so. Went in store, came out and it was doing it again. The wierdest thing is how the exhaust gets quieter when it's racing, and louder when it goes back to normal. That's how I can tell right when it changes, randomly.
Verslagen, where is this timing sensor located?

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/04/11 at 20:08:43

before we get to that, check for an intake leak.
to simulate the leak take off the vac line.
if you have the stock petcock, turn it to prime.

What are we using to track down leaks now? used to be wd40

Title: Re: Cam chain jumping?
Post by drums1 on 09/04/11 at 20:10:31

my vac line is already off and plugged. I run stock petcock on prime. I will check my plug cap for leaks tomorrow am and report back.

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/04/11 at 20:21:52

check around the intake boot too.

Title: Re: Cam chain jumping?
Post by MotoBuddha on 09/05/11 at 04:56:01

A wild thought -- maybe your black box is going bad.

Title: Re: Cam chain jumping?
Post by Oldfeller on 09/05/11 at 05:03:16

If so, that would be about the first Savage one ever .... we are blessed with reliable electrics on the Savage anyway (not like a Yamaha !!).

Still, Yamaha folks arrange an alternate ground strap for both engine and frame to the main ECU unit to PREVENT a poor ground from causing their electronics to crap out early as their black box isn't available any more on most of their 10-15 year old bikes.

While you were in there last, did you check your cam journal bearing slop?

Sloppy journal clearance can make a knock sound on the left side, and worn out rockers can make a persistent loud tapping sound (I got that coming on on my hot rodded bike so I know what that sounds like).

Both can be fixed, but are expensive in time & effort (and replacement parts).

Your timing sensor is under your alternator cover -- if the screws were loose you could get some movement/variation. Ditto if your rotor was loose on the bolt/taper/keyway.
Neither are very likely and the same cover removal checks both.

Title: Re: Cam chain jumping?
Post by Routy on 09/05/11 at 05:55:57

Sounds like an intermittent vacuum leak ? Could even be leaking intake valve. Remember that while slightly leaking valves will affect hi sp performance thu lower compression, it will be much more noticable at idle, (bad idle) and if valve guides are bad enough, could not only cause an inconsistent bad idle, but also the valve...and/or other noises you talk about. Maybe do a leakdown test ?

Title: Re: Cam chain jumping?
Post by drums1 on 09/05/11 at 08:47:44

I think that may be where I'm headed. This morning I went out to fire it up after changing the oil. Did the same thing. Jumped to high idle by itself. No vacuum or intake leaks that I could see or hear. I did however, tightly cover the exhaust with some old rags--Idle dropped down and stayed there until I removed the rags and revved it up some. Then it went back up. After warmup it quit doing that, but still was running high. I then revved it up and it came down. I didn't ride out at all, but yesterday, while on the road, it would be doing it intermittantly. Up down up down.
And still, when idling high, exhaust is quieter than when idling slow. Noticeably. Strange. Almost sounds OE, and it's a HD torpedo with baffle out. (Virtually a straight pipe)

OF--I wasn't personally in there. I had the head gasket rechecked and fixed at the dealer. (There was a broken head bolt, dating back to the "blown head because of no oil" incedent)

Title: Re: Cam chain jumping?
Post by Serowbot on 09/05/11 at 09:25:03

With your bikes history,.. it could very likely be something more serious, but,.... how about a sticky needle slide?...

Title: Re: Cam chain jumping?
Post by drums1 on 09/05/11 at 09:53:12

I was thinking that too, but not sure how that would so drastically change the sound of the exhaust.

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/05/11 at 10:48:04

392F28302E6C5D0 wrote:

I did however, tightly cover the exhaust with some old rags

You covered the outlet or the joints or the whole thing?

Title: Re: Cam chain jumping?
Post by BurnPgh on 09/05/11 at 11:39:10

10333B393A33333A2D5F0 wrote:

My black box went bad last year. It does happen but it didnt make anything happen like you're describing.

Title: Re: Cam chain jumping?
Post by drums1 on 09/05/11 at 13:12:57

Verslagen--I had a wad of rags, and covered the back end tightly--still have minor leaks at front of muffler. The idle would drop down, and probably would have stalled, but I pulled rags off just before that. The idle would then stay low until I revved it up a bit, then it would be high again. But initially plugging the exhaust would cause it to drop down. Once the engine warmed all the way up, it would just keep running fast even while plugged.

Needless to say, I'm afraid to go anywhere on it at the moment. I'm thinkin' something's gettin' ready to blow.....

Title: Re: Cam chain jumping?
Post by verslagen1 on 09/05/11 at 13:22:28

I would do a compression test.

I don't think backpressure will ease an issue with intake leak.

Title: Re: Cam chain jumping?
Post by drums1 on 09/05/11 at 13:24:39

I don't have a guage at home, but I can run over to where I used to work and borrow theirs tomorrow.

Title: Re: Cam chain jumping?
Post by drums1 on 09/07/11 at 05:52:37

Dammit, my buddy with the compression guage kit doesn't work there anymore--and of course his phone is unlisted. I will have to wait and buy one when it starts raining money. Until then I guess I'll rough it and hope it don't blow up far from home.

Title: Re: Cam chain jumping?
Post by Markusublime on 09/07/11 at 23:01:13

The only things I've known to cause engine rpms to jump higher on a carb engine is a vacuum leak,ignition timing changes,or loose/sticking throttle plates.I'd be spraying around the carb and intake with brake clean spray (non chlorinated). If you hit a vacuum leak you'll hear the rpm drop down,and it evaporates quickly so you won't be left with a mess.

Title: Re: Cam chain jumping?
Post by Oldfeller on 09/08/11 at 05:36:23

;D

I like the vac slide in the carb sticking slightly due to oil getting on it, personally. Test is to apply a jigger full of Bill's magic elixir to two tanks of gas, run them both out in turn and call my nurse in the morning .....

Wouldn't happen to have recently oiled your cone air or flat filter, would you?

Title: Re: Cam chain jumping?
Post by drums1 on 09/08/11 at 07:25:03

Nope, I have a regular OE air filter. No oil involved. I am starting to lean towards the sticky slide. Although the carb was supposedly cleaned and rebuilt a few months ago at the dealer, when I had the 2 new tires installed. I think I will try the Seafoam before tearing the carb apart, yet again.

Title: Re: Cam chain jumping?
Post by justin_o_guy2 on 09/08/11 at 09:07:30

Although the carb was supposedly cleaned and rebuilt a few months ago at the dealer

All the more reason to suspect it. Stuff thats been worked on & CAN contribute to a problem youre having needs to be looked at.