Lost power up hills

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Jaycee604

Jaycee604

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Jan 31, 2022
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One of my bikes has great acceleration (very snappy) and will rev up to 8700rpm. The top speed is good and slight hills are no problem, but the steep hills i used to ride up with ease are now almost impossible without using the peddles or dying. Also, once pulling the clutch in after achieving half or full speed, i ll pull the clutch in, coast or come to a stop, it takes 3 or 4 seconds to calm down to a proper idle. Then it will idle steady for a min then just die. I can get why everyone will say air leaks but i dont think thats what it is. Please help lol
 
Chad_Broski

Chad_Broski

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Hmm... I remember this thread from somewhere .
Ahh, Yes! here is something that might answer your question!

Lost pull and speed up hills

So i recently took off the nt carb and installed pz20s on both of my bikes. I got them to have great acceleration and top speed but now one of them isnt that great up hills anymore. Could the temp change the last few months do anything? Both have the same setup. Also i am 200 pounds and my bikes...
motorbicycling.com motorbicycling.com
 
Jaycee604

Jaycee604

Member
Jan 31, 2022
39
9
8
Chad_Broski said:
Hmm... I remember this thread from somewhere .
Ahh, Yes! here is something that might answer your question!

Lost pull and speed up hills

So i recently took off the nt carb and installed pz20s on both of my bikes. I got them to have great acceleration and top speed but now one of them isnt that great up hills anymore. Could the temp change the last few months do anything? Both have the same setup. Also i am 200 pounds and my bikes...
motorbicycling.com motorbicycling.com
Click to expand...
i literally posted both. They are slightly different. Didnt help my problem so i made one more specific.
 
Chad_Broski

Chad_Broski

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Feb 2, 2022
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Jaycee604 said:
i literally posted both. They are slightly different. Didnt help my problem so i made one more specific.
Click to expand...
I know, I was just picking. This sounds really though if you haven't fixed it yet and no ones been able to pinpoint the issue. I say go over the seals and gaskets one last time head gasket, base gasket, intake manifold seals; the whole shebang. You could of possibly blew one out partially. Open up the carb and clean it out thoroughly, there may be bits of dirt clogging the jet (not likely to happen bcuz the needle usually catches it first, but it happen to me one where the engine would just bog, I cut it off and shook the he** out of the bike to dislodge the particles, no more problems). make sure all the head bolts are tightened tight, but not too tight, and do the same with the spark plug; but before you do that, try to turn over the engine while resting the spark plug (in it's boot) on the engine to make sure you have a fairly strong spark. Also make sure everything else is bolted on properly, maybe your expansion chamber came lose, causing you to loose torque, or carb maybe came loose, causing air leak. If all else fails, report back for further instructions.
 
Jaycee604

Jaycee604

Member
Jan 31, 2022
39
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Chad_Broski said:
I know, I was just picking. This sounds really though if you haven't fixed it yet and no ones been able to pinpoint the issue. I say go over the seals and gaskets one last time head gasket, base gasket, intake manifold seals; the whole shebang. You could of possibly blew one out partially. Open up the carb and clean it out thoroughly, there may be bits of dirt clogging the jet (not likely to happen bcuz the needle usually catches it first, but it happen to me one where the engine would just bog, I cut it off and shook the he** out of the bike to dislodge the particles, no more problems). make sure all the head bolts are tightened tight, but not too tight, and do the same with the spark plug; but before you do that, try to turn over the engine while resting the spark plug (in it's boot) on the engine to make sure you have a fairly strong spark. Also make sure everything else is bolted on properly, maybe your expansion chamber came lose, causing you to loose torque, or carb maybe came loose, causing air leak. If all else fails, report back for further instructions.
Click to expand...
head, muffler, and carb are all tight. Just cleaned the carb today. Changed nothing. New oil seals. Its weird because i have great torque, just not up steep hills
 
Chad_Broski

Chad_Broski

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Jaycee604 said:
head, muffler, and carb are all tight. Just cleaned the carb today. Changed nothing. New oil seals.
Click to expand...
okay, then make sure the head gasket, base gasket, and intake manifold seals are not cracked in any way. If you have an Engine Compression Gauge I would utilize it to make sure compression is where it should be.
 
Jaycee604

Jaycee604

Member
Jan 31, 2022
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Chad_Broski said:
okay, then make sure the head gasket, base gasket, and intake manifold seals are not cracked in any way. If you have an Engine Compression Gauge I would utilize it to make sure compression is where it should be.
Click to expand...
those gaskets have been replaced. I dont have an engine comp gauge. If i was lacking compression dont you think my engine wouldnt have the rpms or torque it has ?
 
Chad_Broski

Chad_Broski

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true, the only other thing that i could tell you to do is get a multimeter and make sure all the terminals on the cdi and ignition coil give the right readings, and attempt to do a plug chop to see if u r running to rich/lean. If you said this has happened on both of your bikes that's bound to be it, or what sidewinder jerry (i think?) basically said, 'it's just the wind'.
 
Jaycee604

Jaycee604

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Jan 31, 2022
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Chad_Broski said:
true, the only other thing that i could tell you to do is get a multimeter and make sure all the terminals on the cdi and ignition coil give the right readings, and attempt to do a plug chop to see if u r running to rich/lean. If you said this has happened on both of your bikes that's bound to be it, or what sidewinder jerry (i think?) basically said, 'it's just the wind'.
Click to expand...
looks like another dead end. The wind has been stronger before and that never affcected it. I ll try getting a new cdi and plug.
 
Chad_Broski

Chad_Broski

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Feb 2, 2022
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Jaycee604 said:
The wind has been stronger before and that never affcected it. I ll try getting a new cdi and plug.
Click to expand...
okay, so just askin', did you notice this after you bolted on anything in particular, or was it just random. I f it was after you bolted on a certain piece of equipment, the issue might lie therein. If it was just random, then it might have something to do with the weather affecting the jetting, so two words: plug chop.
 
Jaycee604

Jaycee604

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Jan 31, 2022
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Chad_Broski said:
okay, so just askin', did you notice this after you bolted on anything in particular, or was it just random. I f it was after you bolted on a certain piece of equipment, the issue might lie therein. If it was just random, then it might have something to do with the weather affecting the jetting, so two words: plug chop.
Click to expand...
Yeah i get what you mean. I cant remember
 
Chad_Broski

Chad_Broski

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lemme pull out the textbooks.
Edit: according to Yamaha:

How Carbs Work (very basic)
  • Pilot Jet – controls idle till about 1/8 throttle opening
  • Needle Jet and Jet Needle – controls largely 1/4 to 3/4 throttle opening (with some overlap)
  • Main Jet – controls only 3/4 to full throttle opening
 
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Jaycee604

Jaycee604

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Jan 31, 2022
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Chad_Broski said:
you would be correct
Click to expand...
Yes im aware of those specs. But if i was to open the throttle all the way up and hill and open it all the way on a straight road the engine would rev higher and go faster on the flat. So my question is, is the jet being used going up a hill? The engine barely sounds like its running yet the throttle is all the way open
 
Sidewinder Jerry

Sidewinder Jerry

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Chad_Broski said:
lol. At this point it seems to be only that, or the carburetor is improperly jetted (for the winter). Cuz, what else is their if this is happening on both of ur bikes?
Click to expand...
Yes, jetting and lowering the oil mixture can certainly help in extremely cold climate conditions. One would be surprised by gaining as little as 20 lbs how it can affect the performance of your engine.
 
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