Recurring Problem!!!!!

[85vmax]

Every now and then my Max has a mind of its own, I would ride to work 8 miles, and the bike runs like a bat out of hell, idlin at 1k rpm.
I'll get ready to go home, start her up and she spits a little, has a lumpy idle as if running on 3 cylinders, yet the rpm is now about 1300 rpm, and rides fine but doesn't pull as strong until after 4-5k rpm.

This happens often enough that its irritating me now. It may not happen for a coup-le rides and just appears.....

I need a little help in pinpointing the prob.
Would it be ignition or carbs.

Running Dyna 3000...carbs should be fine, just had them off cleaned out and adjusted flouts. They just have the DJ Stage 1 needle and springs.
K&N with the Y off, and Kerker full.

This also happened before I pulled the original carbs. and this is also not the same carbs I put on....these are a nice clean set from a 2002.

Sometimes I could be sitting in traffic on a really hot day.and it would just change to the crappy running.

Any ideas welcome,
Chris

 

[SpecOps13]

My 89 still acts this way. It will run perfect and then feel like it's idling on 3 cylinders. If I blast off it will clear up,
then sometimes right back to the same and other times run perfect again. This is my second set of carbs too. I
have a modified stock set up on the carbs and needles. No air box mods and Kerker 4-1.

I'm about to pour in some Start Your Engine Additive and give that a shot.... In other words I'm in a very similar
boat to yours. Our electronics are different. Mine being Analog and yours being Digital...

I'll let you know in a few days if the additive helps.... Good Luck, let me know what you try too....

 

[85vmax]

Dave...ive had this prob for as long as I can remember, once I started messing with mods. I've already tried sea foam, b12, and start your engine , sometimes it makes a difference, sometimes not. But it always comes back.
Rode to work this morn ran like crap....started up to come home ran great.

And yes your symptoms are exactly the same it sounds like...I guess we can eliminate ignition since that's different.
But like you said would run great, crisp trottle response , then a little rough, crappy response until u open it up.

I've put everything back to stock, except the exhaust..still happens...must be the kerker:ummm:
I've changed the air box boots, this newer carbs still there.
I'll keep u up to date as this happens often enough.
Thanks,
Chris

 

[Rhoy Carter]

You can try it with the sidestand relay unplugged, I have seen this relay do some really weird things.

 

[sdt354]

My 89 still acts this way. It will run perfect and then feel like it's idling on 3 cylinders. If I blast off it will clear up,
then sometimes right back to the same and other times run perfect again. This is my second set of carbs too. I
have a modified stock set up on the carbs and needles. No air box mods and Kerker 4-1.

I'm about to pour in some Start Your Engine Additive and give that a shot.... In other words I'm in a very similar
boat to yours. Our electronics are different. Mine being Analog and yours being Digital...

I'll let you know in a few days if the additive helps.... Good Luck, let me know what you try too....

Dave, are you running a stock TCI?
Steve

 

[SpecOps13]

Yes, stock TCI.... Got any thoughts on that??????:ummm:

I was gonna run my Start Your Engine through the bike but I have a full tank and
it says 2 oz per gallon minimum. So, I'll have to run out 1/2 a tank first...:bang head:

 

[85vmax]

You can try it with the sidestand relay unplugged, I have seen this relay do some really weird things.

will unplug today if i get a chance...looking up in the clymers now....have a honey do list to get to if i want to go out on my 200 miler tomarrow.

thanks,
chris

 

[SpecOps13]

I went to Barney's Yamaha today for a test ride. My 89 ran perfect. It didn't get any attention though. Guy pulled in right after me with a 75, RD 350.
People were slobbering over it all day....


I let the bike warm up good and did get their attention when I left. 25 mph, 2nd Gear Rolling Smoker.....:rofl_200::rofl_200::rofl_200: Next time out, I think the gas
is low enough to add the Start Your Engine Stuff....

 

[sdt354]

Yes, stock TCI.... Got any thoughts on that??????:ummm:
Dave & Chris, if nothing improves with the fuel additive, I'd try a known good TCI unit or a while, if you can borrow one. Possible coil issue also. I had a COP doing that to me a while ago.Possible intermittent electrical issue. Imho.
Steve

 

[bazwell]

Just throwing an idea into the mix.

I've also noticed mine is prone to similar symptoms sometimes.
To me, it's like a plug fouls if I warm it up at idle with a bit of choke. Sometimes it clears up, but usually it just stays for most of the ride. It also does it if I start it, don't get it completely warm, and then shut it down.

I'm not a big fan of warming up powerful engines at idle anyway. So, I will start it and ride immediately. Basically, as gentle as I can, nice and slow, so I'm still warming it up. But not at idle. I've noticed it's less likely to happen if I warm it up on the road.

If you run Iridiums, then maybe it is a common factor. I mean, you changed the carbs, and the problem is still there. Can't be the carbs then. Could it be plugs? I run Iridiums.
I've got a feeling it's a common problem on maxs.

 

[SpecOps13]

Thanx for any and all feedback. It's the only thing keeping me from saying my 89 runs absolutely perfect...
Like my 94 does... I wouldn't hesitate taking it on a really long trip if my FOG Body were willing....:confused2:

 

[sdt354]

Just throwing an idea into the mix.

I've also noticed mine is prone to similar symptoms sometimes.
To me, it's like a plug fouls if I warm it up at idle with a bit of choke. Sometimes it clears up, but usually it just stays for most of the ride. It also does it if I start it, don't get it completely warm, and then shut it down.

I'm not a big fan of warming up powerful engines at idle anyway. So, I will start it and ride immediately. Basically, as gentle as I can, nice and slow, so I'm still warming it up. But not at idle. I've noticed it's less likely to happen if I warm it up on the road.

If you run Iridiums, then maybe it is a common factor. I mean, you changed the carbs, and the problem is still there. Can't be the carbs then. Could it be plugs? I run Iridiums.
I've got a feeling it's a common problem on maxs.

It might be worth noting that my bike has ALWAYS run bad when cold. It needs choke to start cold, and doesn't really warm up for about 8-10+ miles.I usually let it sit running for a few minutes while I do a quick check. if I do ride it cold, Like you, I take it easy.
Carbs. can suck in a piece of dirt anytime and make you run crappy.And, the same goes for the ignition circuit ect. I do a pea shoot cleaning on a regular schedule and a shotgun at the first sign of running bad. I've always used NGK plugs, so I can't comment on other types. My 2 cents:hippy biker:
Steve-o

 

[85vmax]

will unplug today if i get a chance...looking up in the clymers now....have a honey do list to get to if i want to go out on my 200 miler tomarrow.

thanks,
chris

Ok....I was up late last night, but finally pulled the side stand relay. Only did 80 miles, I wanted to see the Tim Tebow show at 1.
The bike really ran well, no problems, and had 5 starts with it. Actually really ran well....my buddy had it up to 150 speedo, and I couldt catch him on his max.
This usually happens every couple starts, and already had 5 so I'll see how it goes by next weekend......I'll get it out once this coming week hopefully, but rain is the forecast for the next 8 days.

Dave if this occurs often I would try this also..nothing to lose. Thanks Carter....hope this is the culprit.

 

[bazwell]

Wow! Cool! I must also check that out. :clapping:

 

[Rhoy Carter]

You can always plug the relay back in after & if it runs good for a couple of weeks to prove that was the problem. I dont think that relay is that expensive if you need to buy another one.

 

[jfeagins]

The symtoms described here are the same as I experienced years back when my CDI box first started getting the dreaded low voltage syndrome. It progressively got worse until the point where I could definitely tell it crapped out each and every time the fan kicked on. Probably never did crap out unless the fan was running, but didn't necessarily crap out every time my fan was on. Started dropping two cylinders every once in a while at idle and would kill the bike at a light.