SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> not sure where to look
/cgi-bin/YaBB.pl?num=1219800124

Message started by oksavage on 08/26/08 at 18:22:04

Title: not sure where to look
Post by oksavage on 08/26/08 at 18:22:04

I had been having intermittent problems with backfiring and choppy acceleration while driving. Also bike tries to die at stop signs when warmed up. I have cleaned the carb and petcork, checked the vac line for gas etc. Still getting the weird lurches. It is an 86 with a 155 main and a 47.5 pilot and a jardine slip on. Could this be sticky valves?? Also, I'm new to bike riding so I know I occasionally over rev before shifting and it is hard to know what gear to be in around town. Last night I got it home and cranked down on the throttle it it revved up and then started to backfire repeatedly. It sounded almost as if I was twisting the throttle repeatedly but I was not. Where do I keep looking??

Title: Re: not sure where to look
Post by serowbot on 08/26/08 at 18:29:26

I know you said you checked it,...but it sounds very much like the vac line is leaking gas.
If not that, I'd check the slide in the carb...could be sticking...

Title: Re: not sure where to look
Post by oksavage on 08/26/08 at 18:35:30

I don't mean to be dumb but where is the slide???

Title: Re: not sure where to look
Post by Sandy Koocanusa on 08/26/08 at 18:37:29

On my '87, I had to go up to a #50 pilot in order to get in range for tuning. The 47.5 just wouldn't do the trick after I started screwing with the exhaust. It would backfire every time I changed the throttle position. Others will disagree, but I say make sure you get the non-bleed type jet if you rejet the carb. I didn't do that the first time, and lost about 10 mpg over night with the bleed type jet.

Title: Re: not sure where to look
Post by serowbot on 08/26/08 at 18:39:48

It's in the carb, you access it from the top...4 screws hold the top on, they can be boogers to remove, gotta' pull the gas tank to get to them...

Double check that vac line first, ...even give it a little suck,..make sure there is no gas coming down to the carb,..could save you a lot of work...

good luck,

Title: Re: not sure where to look
Post by oksavage on 08/30/08 at 20:35:16

ok. definitely not the petcork. I seem to only have a problem from 3/4 to full throttle. It just won't run smooth when you get on it hard. I checked the plug (only about a month old) and it was very black. Obviously to rich but how to lean it out. When I adjust the air'fuel screw on the carb it starts to backfire like a howitzer at shutdown. right now it just woofs. Would a hotter plug work? Right now I'm using a plain champion.

Title: Re: not sure where to look
Post by Sandy Koocanusa on 08/30/08 at 20:39:11

What kind of shape is your air filter in?

Title: Re: not sure where to look
Post by oksavage on 08/30/08 at 20:52:37

ok I guess it's a whitish gray

Title: Re: not sure where to look
Post by Sandy Koocanusa on 08/30/08 at 21:31:38

Is the plug black and wet, or black and fluffy/dry?

To answer your question of how to lean it out at WOT, you could try a smaller main jet size.

I'm still not clear on one thing. Is the bike freaking out at wide open throttle, or at high RPMs? We need an expert in here, but none has shown up yet. If the problem is at high RPMs regardless of throttle position, I wonder if it could be a timing issue? It being an '86, if it has a bunch of miles on it, the cam chain is likely to be growing. That affects timing, although to what degree I'm unsure.

I'm speculating on that one. Don't put too much stock in it.

Title: Re: not sure where to look
Post by dasch on 08/31/08 at 01:28:09

ain't an expert, but air fuel mixture screw ONLY affects idle and little above idle. Leave it alone for full throttle problems. You have a 155 main? That's kinda large. Lets a lot of fuel in. If your air filter gets dirty at some point... You'll have a flood at high throttle openings.

But... you say you have backifres at high rpm? With throttle opened or closed at that very moment? That's unusual for a rich mix. Dunno.

Title: Re: not sure where to look
Post by oksavage on 08/31/08 at 06:31:50

I replaced the cam chain in May. the tip of the plug was dry and black. How do you get high rpm's and not open throttle?

Title: Re: not sure where to look
Post by Charon on 08/31/08 at 06:56:24

If the engine is operating under a light load, say in traffic in a low gear, you can have quite high rpm with an almost closed throttle. Even at highway speed, 55-60 mph, the throttle is barely halfway open.

To eliminate the air filter as a problem, remove it and ride the bike. If the problem clears up, the filter is clogged. Try to avoid any especially dusty roads while doing this. Riding for a short time without the filter is unlikely to cause any damage. Make sure you don't leave anything loose in the airbox for the engine to inhale.

Title: Re: not sure where to look
Post by dasch on 09/03/08 at 01:41:28

Misunderstanding. I never said "opened" throttle. I said "wide opened" ;) . Pedal to the metal. Floored. You can easily have very high rpm with only half a throttle, or less, as Charon said. In low gears, per se, or the extreme case - in neutral.