Hard running when cold or even after 20 minutes cool down.

Okay, So i recently redid the carbs, plugs, oil.

The bike has no problem cold starting with the choke (enrichment system) however, when trying to drive the bike while cold, or anything less the optimal running temperature it sputters, and lags horribly.

After running the bike and getting it hot its fine. I can turn off the engine and let it sit for up to 10 maybe 15 minutes and get right back on without have to choke or anything. But anything longer then that and i have to give it choke or throttle to start it and it will sputter and kick back a bit until warmed back up. Its fine once you get up to about 5000RPM under light load, but heavy throttle or low rpms and its popping a lot.

Any ideas?

I cant say this was a problem prior to the plugs being changed as there were other issues, but i think it got worse when i changed the plugs. Bad gapping maybe? I just dont see how that could be so temperature related.

 

Re: Hard running when cold or even after 20 minutes cool dow

well, i do not think that this necessarily has anything to do with how your plugs are gapped, however you should check them to make sure they are the correct heat range and gapped correctly.

The lag and popping that you describe, to me sound like your air fuel lixtures may be off. When you celaned your carbs, did you adjust the air-feul mix, to make sure they correctly placed ~ 2.5 to 3 turns out. And when you pull those plugs to make sure that they are gapped good, what do they look like. i would suspect that they look brand new ( indicating a lean condition ). If this is the case, you may need to back out the aire fuel screws a little to get that wonderful tan color, that we all love! If they are dry (sooty) black, then you may need to dial the screws in a bit. Also if they are wet (oily) black, then there is some valve work in your future.

Just a few thoughts from no where near an expert. I am sure that someone with much more smarts than me will weigh in soon. Good luck.

Kevin

 

Well, i did the carbs before i came here. And as such, didn't bother to touch the enrichment system. So i never moved the pilot screws.

Oh, and the new plugs were purchased directly from Yamaha. I would hope they gave me the correct ones. The part# is BPR7ES

And i put Yamalube 20W-50 in it with a new filter as well.

 

grab a timing light and check your timing. i had the exact same symptons at a diffrerent rpm range. the ignitor box was running in advanced timing.

check your timing at idle. and different rpm ranges.

 

Thanks snowwy66,

I'm inclined to lean away from it being a timing issue. It was running pretty good after the carb work. Then i did the plugs and oil and now its acting like a retard. That and i don't have a timing light

Should i check the plugs after letting it sputter a bit or when its hot and running good?

 

So im going to my friends house tomorrow to check the plugs and gapping and what not and he has a timing light. Where do i point it on this bike <-- that sounds like a dumb question to me and im sure it is

 

You can't alter the timing, if the TCI is bad, it has to be replaced, it doesn't sound like that, though, I would say you are lean, set the pilot mixture screws at 2 3/4 turns out from lightly bottomed.

 

sorry i forgot to mention something. I mentioned it on an earlier thread but forgot to here.

When i took apart the carbs it was before i came here and found the carb walk through. I never touched the enrichment system or the pilot's. So since none of those have been touched since it was working correctly i don't think it could be the pilot screws.

Its not blowing smoke or anything. But its definitely idling rough when cold. Almost seems like one of the cylinders is mis-firing. I will check the gap and the color of the plugs tomorrow. Hopefully that will shed some light on this.

I would prefer not tearing apart the carbs for a 3rd time if possible. But if it comes to that i will.

 

have you synced the carbs this will help alout after cleaning everything . mine were so far off had a 1cyl misfiring at idle actually would drop that cyl off and would run rough not enough fuel butterfly wasnt open the same as the rest

 

I need the yics tool for that right? It didn't start doing this until long after i did the carbs though. Is this something that could have presented all of a sudden like this?

 

Proper carb cleaning can't be done if you don't remove all the carb parts. Idle mixture screws and jets need to be removed to be cleaned proprely. Hard starting when warm is a indication of a slightly lean idle mixture. Try opening the idle mixture 1/8 turn and see if that helps. Just because it worked before does not mean it was right. A color tune setup will help get the mixture right.

 

You should clean out your enrichment circuit, remove and clean pilot jets. Also, you have to bench sync before throwing them back on the bike. That can be done without the YICS tool.

Search around. You'll be getting other suggestions too!

 

One of the guys around my area here has a yics tool. I met with him last week for a Vancouver ride. He said if its needed he has it, so im not concerned about finding the proper tool

 

Lucky!

 

Don't i know it!!

 

Okay, so i just checked the plugs and they look really clean, maybe a very slight tan color.

And i regapped to .76*. No change in running condition.

So from what i understand the newish looking plugs mean that i am running lean and will need to adjust my pilots? and if possible sync the carbs? (They all look identical so i think they are still sync'd okay.)

And how could this just happen so randomly. It was running fine, i don't understand it one bit. It started once i put those new plugs in. Damn i wish i had not thrown out the old plugs. I'm just not understanding how this is only happening when its hot or cold. I would expect that from a temperature controlled choke system but not from a manual choke.

Could someone confirm if these spark plugs are okay. I just check NGK website and they didn't list them as compatible.

 

Re: Hard running when cold or even after 20 minutes cool dow

Okay i just checked XJ4Ever listing.

I have been given BPR7ES
But he lists the correct plugs as BP7ES. I called the local parts store and they said that they are different temperature ratings. I will see if i can find them. If i recall correctly the old plugs were BP6ES... cant say for sure though as those are listed for the XJ1100.

 

BP7ES and BPR7ES are the same temp range plugs, the "R" version is a resistor plug. Your bike originally uses the BP7ES version, the non-resistor plug.

However, if you do away with your resistive spark plug caps, then the use of the BPR7ES would be the proper choice.

 

deleted

 

AHHH HAHAHA.... the smart ass i am.

At one point i took a picture of the old plugs with my camera. They were B7ES

So they werent 6's... Pfft.

So i called the shop again, the B7ES were discontinued a long time ago from what he recalls. And their replacement is the BR7ES without the P. He is going to exchange them for me for free

So the catalog says i should use BP7ES and the shop is now saying i should use BR7ES

 

Sorry bro but you really need to your carbs right before you
drive yourself nuts trying to get her running good.
Yes a tweek of the pilots may help for now but if the carbs
haven't been completely pulled apart and cleaned, trouble
is only a few miles away.
"No short cuts" has always been the mantra of the experts on this
site and they're right.
Just looking at the venturi and declaring them ok won't cut it either.
after a throrough cleaning you need a proper bench sync Then a
meter sync (gauge,bottle,manometer whatever).
Then you can worry about the pilot mix.
Dont forget the valves need to be adj.
Whatever step you choose to skip will be the prob later on.
We don't say this because we want to see you elbow deep in
carb cleaner or to sound Knowledgable.
It's because we tried it with short cuts first and had to star all over
again.

 

thanks parts,

I understand that when something needs to be done, then it needs to be done and not patched up.

But i had a feeling it was something else, and i was correct.

I switched the spark plugs for BR7ES and its running fine now. It was either a dud plug, or just the wrong one for the engine. Although the parts catalog does call for the P (projected, i think that's the definition.), my bike never had those plugs and probably didn't like them for some reason.

I left the bike all night, jumped on it this morning, ran it for about 2 minutes while i got my helmet on and it was fine pulling out of the driveway.

Thanks for everyone's help though. Its nice being here and knowing that there is someone always here who will be able to help point out those really odd problems.