The Self-Reving Problem

duluthmuffler · Posted: April 26, 2007, 11:44 pm Post subject: The Self-Reving Problem

You know the problem where the engine decides to not reduce its RPM without power braking it. Or where it somehow advances its own timing so it takes off!!! Yikes...I've replaced the springs on the ATU and lubed it up good. I've cleaned/polished the rod going through the cam, tried that clean and lubed. I feel like the real hang up is at the "cam" at the points side. These are new points too. Is there a way to relieve some of the tension from the feelers. Are there roller points? Help!

xsjohn · Posted: April 27, 2007, 11:40 am Post subject: Re: The Self-Reving Problem

I battled with my friends 77 and it turned out that he had the idol to high expecting it to idol when it had not warmed up. Try setting the idol when it is fully warmed up like 2 or 3 miles of riding at least.

John Underwood

duluthmuffler · Posted: April 27, 2007, 3:14 pm Post subject: Re: The Self-Reving Problem

Well mine is a 77 too! I also was just trying to get my fuel mixture right recently aswell. Although mine I think the idle is a little to low..warmed up I'm at 1200. Could it have something to do with the closed throttle position adjustment. (with the choke on @ cold start it goes imediatlely to 2700)

I also did a test where I wired shut the ATU's weights, to keep it from advancing, and besides running poorly at higher RPM..it didn't advance its own timing, and came down in RPM.. not fast..but down.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

1200 is the factory idle spec. These bikes like it, too. Much lower and the bike will up and stall for no reason at lights. Much faster and it will start into the advance curve and cause the very problem you're trying to eliminate. Sounds like you have some air leaks somewhere or maybe your float levels are on the verge of being too low. Sometimes the bowls may have enough fuel but at other times, they're too low and create a lean condition. Then the motor starts racing.

duluthmuffler · Posted: April 27, 2007, 8:15 pm Post subject: Re: The Self-Reving Problem

Well I might have that problem too. I've not tackled carbs yet.
Just so I know..how free is that rod supposed to be. It moves a little bit, but never all the way back. is that normal? This bike has always kind of had this problem.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

The rod should turn quite freely. It doesn't rotate much, maybe a quarter turn, but it should do so freely with no binding or hanging up. The springs should pretty much fully return it to retard. You should be able to turn it to full advance by hand and when you release it, it should snap back sharpy to retard. The rod bushings need to be lubed. The shop manual recommends a grease with moly in it. The bushings have grooves cut in their I.D.s. Clean and fill them with grease.

duluthmuffler · Posted: May 1, 2007, 10:09 am Post subject: Re: The Self-Reving Problem

So I did put grease in the bushing groves. But what I also did, may get a little frowned upon.. The replacement springs I got were still not strong enough to make anything snap back sharply.. So I took one of the old springs and cut it down to make a shorter/tighter spring. ATU snaps back great. Advance Curve is gone and I can work on my fuel mixture without worrying about another problem having an effect. The spring's durability is maybe the only problem. After this one I've got another old one... then maybe a pointless system?!

xsjohn · Posted: May 1, 2007, 10:49 am Post subject: Re: The Self-Reving Problem

Good going> I willl try that on my friends 2 point xs's...They both look just like you described....

John Underwood

brasco18 · Posted: May 29, 2007, 11:56 am Post subject: Re: The Self-Reving Problem

I had this problem with my 75/77 xs. The motor is 75 but the carbs are 77. From my experience it is one of two things, possibly both; the timing and/or the carbs. I would start with the timing. This requires the least amount of disassembly. My timing was far too advanced, causing the bike to not come down from high RPMs. You need to make sure your timing is spot on. Clymer's Guide explains how to do it pretty well. Next are the carbs. If you haven't yet, and feel it necessary, you should rebuild them. Clean them with carb dip, a chemical purchased at most bike/car part stores. Doing these two things should clear up your revving problem.

Gmaan · Posted: June 2, 2007, 11:29 pm Post subject: Re: The Self-Reving Problem

Check the intake tubes for leaks. a vacuum leak will cause an unstable idle. Lean pilot jets, and idle jets will do the same.

tudawgs · Posted: June 3, 2007, 8:37 am Post subject: Re: The Self-Reving Problem

Sounds to me like the throttle cable is binding.

wally · Posted: June 20, 2007, 3:39 pm Post subject: Re: The Self-Reving Problem

Again
I still seem to have my reving problem I have Boyer Ignition system just fitted new Carby Manifpolds have not had time yet to tune carby low idle screw at present set at two & one half turns

But after fitting manifolds it still was reving high
only stops when you adjust butterfly idle screw down a little then it settles down

wally · Posted: June 22, 2007, 2:03 am Post subject: Re: The Self-Reving Problem

& now it still reving up to 3000 rpm no matter what I do to the low idle screw it seems now the only way to drop the revs is to pull the choke out

Iam about to take up smoking again & mabe throw a match on it

wally · Posted: June 22, 2007, 2:20 am Post subject: Re: The Self-Reving Problem

Can some one Please tell me & Im sure its obvious
which mark is the Full Advance Mark

jayel · Posted: June 22, 2007, 4:48 am Post subject: Re: The Self-Reving Problem

here you go

wally · Posted: June 22, 2007, 5:50 am Post subject: Re: The Self-Reving Problem

Thanks Thats were I thought it was so my Boyer Ignition is set up right so I have red many posts about this reving problem I cant seem to beat it

Any Help out there

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

It sounds like you have carb problems. If the RPM's go down with the choke out, it is in the carbs. Did you richen them any when you did the conversion? I know I read somewhere that you need to richen the carbs, and can gap the plugs more with the Boyer ignition.

wally · Posted: June 22, 2007, 8:26 am Post subject: Re: The Self-Reving Problem

When it high revs & you pull the choke out & then push it back in the revs come down
What could that be?

xsjohn · Posted: June 22, 2007, 9:39 am Post subject: Re: The Self-Reving Problem

The choke adds air and fuel ....If it isn't shutting off it can be what you call a self reving problem.....Might be junk in it.......

John

wally · Posted: June 22, 2007, 4:17 pm Post subject: Re: The Self-Reving Problem

If the choke adds air & fuel & when I have the bike reving up 3000 rpm at a standstill & I pull the choke out & then in very quickly to stop it from reving

How & why does this stop it from reving if I am adding more air & fuel

Im LOST

xsjohn · Posted: June 22, 2007, 5:58 pm Post subject: Re: The Self-Reving Problem

Boyer Brandsden advancing or something.........Not retarding.....? Don't know about Boyer Brandsden....Does it use your advance mechanism....?

John

wally · Last edited by wally on June 22, 2007, 6:33 pm; edited 1 time in total

I dismantled the choke mec the plunger the rubber on on is damaged this MUST be my problem
What doe you think guys

wally · Posted: June 22, 2007, 6:31 pm Post subject: Re: The Self-Reving Problem

New Pic of Choke Plunger
To Large I know

wally · Posted: June 22, 2007, 8:53 pm Post subject: Re: The Self-Reving Problem

Boyer Set Up

What Happened to 650rider.com?

Yamaha xs650