propuckstopper
New member
Hi everyone. I am hoping someone here can give me some guidance, or at least a very good guess. I have a 2001 SRX 700 which has left me pulling my hair out the last few weeks. Let me explain.
This sled has an intermittent 7000 RPM problem. One minute, it will pull the bars out of your hands and rev to 8400 RPM and just fly. The next minute, I can only pull 7000 RPM. I just never know what the next throttle squeeze is going to produce. When this 7000 RPM problem happens, you can hear the engine making a different tone. It just doesn't sound right.
So, the first thing I went for was the Powervalves. They were minty clean and in perfect adjustment with no pullthroughs. I cleaned them again anyway and readjusted them. The problem persisted.
Did a compression check and found great numbers (136, 135, 134). Cleaned the carburetors. Changed the spark plugs, and the plug caps. Still the problem persisted.
Very fortunately, I have a friend with an identical 2001 SRX 700. So we have been taking parts off his sled and experimenting.
So, when I can get the sled to do its 7000 RPM thing, I have noticed that the spark plug in the center cylinder (#2) is wet. Not soaked, but certainly not burning like the other plugs. You can tell that the cylinder is colder to the touch as well.
We started by borrowing a coil from my friend's sled and put it in my center cylinder. No change.
We then took the entire servo motor, cables, and valves off his sled and put them on mine. No change. Used his CDI box. No change.
There is only one other thing I can think of, and I thought I would ask here before tearing any more stuff apart. I noticed that the center cylinder is where the fuel pump pulse (vacuum) line is. I am wondering if maybe the diaphragm has gone bad and is sucking fuel through the pulse line and killing off the center cylinder?
As an aside, I notice that our sleds exhibit far different cold starting characteristics. When started in my warm garage, his SRX fires up and idles right down to 1800 RPM or so. Mine wants to run at 2400 RPM and hangs for a long time. I can get it down to 1800 RPM but usually I need the choke to do so. My pilot jets are clean. We checked the entire pilot circuit twice.
Again, compression is great, spark plugs and caps have been changed, coil has been changed, CDI has been swapped, complete servo and cables swapped, and still no change.
Also checked the under engine wiring harness for rub through. I did fix this a few years ago, and it is still in excellent condition.
So, could it be the fuel pump wetting out the center cylinder? I also thought maybe clutch issues, but that wouldn't explain a wet spark plug.
Please advise. Thanks for your help!
This sled has an intermittent 7000 RPM problem. One minute, it will pull the bars out of your hands and rev to 8400 RPM and just fly. The next minute, I can only pull 7000 RPM. I just never know what the next throttle squeeze is going to produce. When this 7000 RPM problem happens, you can hear the engine making a different tone. It just doesn't sound right.
So, the first thing I went for was the Powervalves. They were minty clean and in perfect adjustment with no pullthroughs. I cleaned them again anyway and readjusted them. The problem persisted.
Did a compression check and found great numbers (136, 135, 134). Cleaned the carburetors. Changed the spark plugs, and the plug caps. Still the problem persisted.
Very fortunately, I have a friend with an identical 2001 SRX 700. So we have been taking parts off his sled and experimenting.
So, when I can get the sled to do its 7000 RPM thing, I have noticed that the spark plug in the center cylinder (#2) is wet. Not soaked, but certainly not burning like the other plugs. You can tell that the cylinder is colder to the touch as well.
We started by borrowing a coil from my friend's sled and put it in my center cylinder. No change.
We then took the entire servo motor, cables, and valves off his sled and put them on mine. No change. Used his CDI box. No change.
There is only one other thing I can think of, and I thought I would ask here before tearing any more stuff apart. I noticed that the center cylinder is where the fuel pump pulse (vacuum) line is. I am wondering if maybe the diaphragm has gone bad and is sucking fuel through the pulse line and killing off the center cylinder?
As an aside, I notice that our sleds exhibit far different cold starting characteristics. When started in my warm garage, his SRX fires up and idles right down to 1800 RPM or so. Mine wants to run at 2400 RPM and hangs for a long time. I can get it down to 1800 RPM but usually I need the choke to do so. My pilot jets are clean. We checked the entire pilot circuit twice.
Again, compression is great, spark plugs and caps have been changed, coil has been changed, CDI has been swapped, complete servo and cables swapped, and still no change.
Also checked the under engine wiring harness for rub through. I did fix this a few years ago, and it is still in excellent condition.
So, could it be the fuel pump wetting out the center cylinder? I also thought maybe clutch issues, but that wouldn't explain a wet spark plug.
Please advise. Thanks for your help!
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How about the stator ?
crazykid
New member
Thats what i was thinking also, Mine had the same symtoms as described before the stator crapped out on me. One day it would tottaly rip another not so good, then it just gradually got slower and slower, i just couldnt understand until it just wouldnt start one day, replaced the stator and it was a whole new animal. Good luck.
propuckstopper
New member
needaSRX said:
Well, I haven't tried that. But could a bad stator cause only one spark plug to be wet? Would a bad stator not cause problems in all cylinders?
I also had the symtoms that you had and crazykid and it was my stator also, don't hurt to try
My buddy with his FIII 600 is doing the same thing as you mentioned it would hang up at 7500 then let off and hit it again 8500 he had some one go over it, I will let you know what he finds out he was told that it might be his stator also
My buddy with his FIII 600 is doing the same thing as you mentioned it would hang up at 7500 then let off and hit it again 8500 he had some one go over it, I will let you know what he finds out he was told that it might be his stator also
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propuckstopper
New member
needaSRX said:
Thanks fellas. I am going to ohm out my stator tomorrow. The stator is something I never thought of because all my lights and gauges work well. But this sled certainly can be a hard starter at times and is so inconsistent at speed that it has to be electrical.
I'll give it a shot. Thanks.
let us know how it goes, hope this helps you out
staggs65
Moderator
also check out the rest of your harness. there are other potential rub through points besides under the engine. good luck, let us know what u find
crazykid
New member
The one wet sparkplug could be from a totally different problem or nothing at all, I wouldnt base your diagnosing to that one symptom, I forgot to mention that when my stator was on its way out, I beleive it wasnt giving out enought juice to run the servo motor, therefore only letting me get around 7500 rpm. Also ohming out the stator doesnt always work out right, it may spec out and still be bad, Been there done that, People were telling me stator, i just didnt beleive it till it failed.
sifton
Member
Had a friend that had similar problem- found it to be plug gaps!
i had the same pr jet aoblem. it turned out the brass spacer that goes between the main jet and the flow tube was in upside down allowing the flow tube to move up and down dumping gas into the carb without using the jet.
Devilin AblueDress!
New member
Like crazy kid said ohmimg out the stator may not tell the whole story. Most of the time testing ohms will only indicate a short. Where as if its putting out 15 volts= runs great or 11 volts may run but not right. I would recomend rigging your gauge on your sled to monitor output while riding.
propuckstopper
New member
Still running poorly...
We are now at our wits end. We just changed the stator tonight and still the same problem. We have changed pretty much everything on this sled now and it still runs poorly. I really don't know where else to turn.
Devilin AblueDress! said:
We are now at our wits end. We just changed the stator tonight and still the same problem. We have changed pretty much everything on this sled now and it still runs poorly. I really don't know where else to turn.
super1c
Super Moderator
How about the carb screens under float. A partial plug that moves around a bit? Just brainstorming. Chris
I had a somewhat similar issue with my '01 at the end of February. I replaced the stator/flywheel, CDI, coils, and voltage regulator before I found a couple rubbed through wires. The were located in the big bundled of wires that run down the frame tube just above the left footwell. The rub through spot was just above where the big bundle splits into 3 (or 4?) smaller ones.
A friend had the exact same problem, checked everything. He says it was an damaged oring that made it pull fuel through the choke circuit. Also try to run it without the load relay(the white one) to see if it´s a rub through.
propuckstopper
New member
I Think We Found It!
Hi guys. Just wanted to pass along some information. After messing with the sled all day again, we decided to check the fuel pump, which I originally thought was responsible for wetting out the center cylinder. It turns out the vacuum line was free of fuel so the pump is likely okay.
And then...
We decided to pull the reeds out of the center cylinder. When we did, we discovered a huge chip or break in the petals. We then pulled out the mag and PTO reeds and although they weren't as badly broken they were certainly chipped all up.
We are next-day airing in all new Yamaha reeds and will install them on Thursday. I will be back here to let you know how it went.
Check your reeds!
Thanks for everyone's help thus far.
Hi guys. Just wanted to pass along some information. After messing with the sled all day again, we decided to check the fuel pump, which I originally thought was responsible for wetting out the center cylinder. It turns out the vacuum line was free of fuel so the pump is likely okay.
And then...
We decided to pull the reeds out of the center cylinder. When we did, we discovered a huge chip or break in the petals. We then pulled out the mag and PTO reeds and although they weren't as badly broken they were certainly chipped all up.
We are next-day airing in all new Yamaha reeds and will install them on Thursday. I will be back here to let you know how it went.
Check your reeds!
Thanks for everyone's help thus far.
TopGunnSrx
New member
Interested to hear what you come up with.
propuckstopper said:
Can you send pics of the broken reeds (all 3 of them)?
propuckstopper
New member
Today Is The Day!
Today is the day to get this problem solved. The reeds will be here early this afternoon. I will definitely post results as well as pictures of the old broken reeds when I get them out.
We have enough snow here yet to test, so I will have a chance to put the sled under load.
Today is the day to get this problem solved. The reeds will be here early this afternoon. I will definitely post results as well as pictures of the old broken reeds when I get them out.
We have enough snow here yet to test, so I will have a chance to put the sled under load.