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Bike run ALOT better when it's cold outside???????

14K views 18 replies 7 participants last post by  bladecutter  
#1 ·
Oh, yeah. I've only that it for a couple months. I think it first started missing when the temp started getting warmer. Maybe it always had the miss, it was just not warm enough for me to notice. Doe sthat make sense?
 
#2 ·
Is your bike jetted? The outside temp shouldn't make that much of a difference unless it is really hot with a lot of humidity. I have a '97 as well and the temp doesn't bother it that much.

How did your graph look on the dyno? 90 hp is way down! I've seen our years at 100+ hp, even some at 106. Stock they put down more than 90. I would say there is something wrong with your carbs. You may want to check your plugs too. Make sure they are all getting a spark and they are in good condition. When was the last time you tuned it?

Other than that I don't know what to say. A mechanic would know more than me.

What color is it? I have a red one with a D&D slip-on. You don't see too many of these bikes anymore, it's nice to see someone else with an older bike.

Good luck!

'97 ZX6R
D&D slip-on, geared, custom fender kit
 
#3 ·
My bike is still missing at high RPM's. But the past couple of days the temp has dropped down to like 55-65 degrees. I had my bike out when it was cold like this and the miss was gone and it was running GREAT! Does anybody have a clue to why it would do this? It has a full Muzzy exhaust and no other mods. I put it on a dyno at a bike rally the other day and it made a whopping 90 HP [:I]at the wheel. It is a 97 ZX6R. Thanks Gents.(Ladies?)
 
#5 ·
Wild question for ZX6RinNC...

When you had that Muzzy installed, did you have the carbs rejetted? If not, then chances are you might be running a bit on the lean side, and your engine isn't getting enough fuel to power you at higher rpms.

But if you did have it rejetted, what size jets were stock, and what size jets were installed? By the sounds of it running better in cooler weather, it sounds like it might be way too rich.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?
 
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#6 ·
Regarding the hight rpm misfire, When was the bike last serviced and the valve clearances checked ?, Check the plug gaps with a feeler gauge.
As the others have said, all engines run better in colder air as the charge is denser, but the carburation may be wrong and the bike may be running a bit rich.

Ash


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#7 ·
Red97 do you mean 100hp + at the crank?
becuase I think ZX6RinNC means at the wheel in which case 90 is pretty good. The 97 ZX6R has a claimed HP rating of 105 and probly around 85 @ the wheel.
As for the cold weather yea it will help it in terms of power I dont know exactly why but I remember when I was riding my air cooled 2 stroke it was way better when it was cold. Something to do with the optimal engine temperature and the components expanding and contracting i guess.

"Speed kills, but atleast you get there faster."
 
#8 ·
Thanks guys.

Red97, yeah mine is the Red one, too. That is the only reason I went to look at it. It has the muzzy pipe and a neon red windscreen. It still has the factory checkers. I really like it, because I have yet to see another one.

I put (and gapped) plugs in about 3 weeks ago.

The lady I bought the bike from said that the exhaust was the only modification.

Do ya'll think a Stage 1 jet kit will do the trick? The guy that dynoed my bike said that it would probably give me about a 5hp boost.
 
#9 ·
Cold air is denser than warm air, which means there is more oxygen per square inch of air. Oxygen is needed for the fuel to combust, so when it is cold, more oxygen into your engine = better combustion which = more power.

Turbo's & supercharger's work on the same principals (more air = more power);)
 
#10 ·
If the bike only had a pipe slapped onto it, and wasn't properly rejetted, then yes, a jet kit will probably solve all your bike's ills.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?
 
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#11 ·
Originally posted by bladecutter

If the bike only had a pipe slapped onto it, and wasn't properly rejetted, then yes, a jet kit will probably solve all your bike's ills.
Slip on cans rarely make a difference to fuelling, but K&N type filters do, There are many bike on the road with a jet kit fitted which are running worse than stock as they haven't been set up properly.

When was the last time the air filter was cleaned? it sounds like air starvation to me if it runs ok when cold BTW

Ash


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#12 ·
I cleaned the air cleaner when I put the plugs in. It was pretty clean except for a few bugs.

Are K&N filters worth the money? That's a lot of money if it doesn't do much. I was thinking about getting one, but I don't see how it could possible be any better. Flowing that is, I realize I won't ever have to buy another one.
 
#13 ·
Originally posted by ZX6RinNC

I cleaned the air cleaner when I put the plugs in. It was pretty clean except for a few bugs.

Are K&N filters worth the money? That's a lot of money if it doesn't do much. I was thinking about getting one, but I don't see how it could possible be any better. Flowing that is, I realize I won't ever have to buy another one.
Its not the cost of the K&N which is the expense, its the Dyno time to set the bike up properly. All of the Dyno shops in the UK charge on average ÂŁ250GBP to buy and install a Dynojet kit and K&N filter and set it up on the Rollers which is about 3-4 hours work.

Ash


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#14 ·
He said in the very first post that it was a FULL Muzzy exhaust system. That means that all the flow characteristics were changed. He needs to have the bike properly rejetted if it wasn't done already.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?
 
Save
#15 ·
Originally posted by bladecutter

He said in the very first post that it was a FULL Muzzy exhaust system. That means that all the flow characteristics were changed. He needs to have the bike properly rejetted if it wasn't done already.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?
[:I]I thought he was using a can only. The only way for sure is to get a printout from the dyno run (which they should have given),Why else go on there, The top end numbers are academic unless you are racing.

Ash


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#16 ·
My dyno sheet starts at about 33hp and is just a steady climb to 90hp. The guy (same guy that dynoed it at the show)I took my bike to for a rear tire said he would put the kit in, dyno it and adjust everything on the dyno. My wants $200 and said the kit itself runs about $120. I'm going to compare the sheets and see want a difference it really makes. I'll be happy with 5hp. I'll let you guys know.
 
#17 ·
The Idea of a kit is to re-adjust the mixture to remove any flatspots. If you have a linear power curve, then the bike is already set up well, and you may not see an improvement on what you have. The popular misconception is that they are like a NOS kit which is just not the case. They are designed to just allow an extra bit of fuel in to match the increase in flow a K&N or similar gives. Its still down to how well the tech does his job.

Ash


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#18 ·
My 100+hp estimate was due to information that I had read on the net. A couple guys had 6R's (95-97) that were dynoed in the 100+ range and on Ivan's performance site, he has dyno results from a 2000 6R with a full muzzy and his kit that was dynoed at 106. To my knowledge, the 6R's motor hasn't changed much (until now), so I figured the numbers would be comparible.
D&D's web site has dyno #'s that have an '00 6R with a slip-on making 101 hp.

I've never dynoed mine so I have no idea what it is making, I just figured it was close to that.

'97 ZX6R
D&D slip-on, geared, custom fender kit
 
#19 ·
He should try going up 1 size main in all 4 carbs and have another dyno run, and see which way the power level goes. Since he already has a nice flat curve, switching 1 jet size up hopefully won't throw that off too badly.

Usually its one needle clip position for every other change in jet size. Lets say you have 150's and you are in the third needle position. You go up to a 155 main, you need to deecrease the needles by 1 position, so you would switch it to the 2nd position (from the top) to lean out the mid range a bit since more fuel is being admitted past the larger mains. If you had 150 mains, and went down to 145's, then you would switch to the 4th needle position.

BC.


I didn't do it, I swear.
And even if I did, what makes you think I would admit it to you?
 
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