98 vmax 700 what is wrong? compesssion? carbs? with vids..

hereismylife

hereismylife

Active member
Joined
Dec 27, 2005
Messages
1,174
Location
Pa
Website
www.hereismylife.com
I finally got the sled running running. I am having some problems with it. It seems to have a miss. I changed all 3 plugs and same problem. Also it seems to miss at idle but once you start reving slowly to seems fine.

I am not sure but I think one of the cilinders is to low compaired to the rest.

One more thing. You have to give it a little throttle to get it running. It did this all last year but idle was ok. The carbs were also cleaned last year

What do you think?

Thanks for any help on this

Here is the vids

http://s689.photobucket.com/albums/vv254/j_k_auto/98 YAMAHA VMAX 700 ISSUE/









 
Last edited:
Is that one reading Zero if so thats not good. If you have access to a bore scope you could go in and look around and see how things look before pulling apart. You have spark on all three cylinders? And are the carbs clean?
 
Doesn't sound like it is running on all 3 cylinders even when you rev it. See if one of the plugs does not warm up. It should also be wet. If one is cool and not wet, then put a 1/2 teaspoon of gas down it and see if it runs different.

Like mtnmaxman600 says check for spark on all three plugs. You may want to start testing your electric ignition parts.
 
mtnmaxman600 said:
You have spark on all three cylinders? And are the carbs clean?
Click to expand...

1. YES
2. SHOULD BE CLEAN I CLEANED THEM LAST YEAR AND ALL WAS GOOD.

The only thing I found on all 5 sleds I have is the pilot sometimes clogs but every thing else looks good in the carbs.

Yes there is around 130 to 150 in the engine just not all the same from what I was seeing. Maybe I am wrong
 
Ding said:
Doesn't sound like it is running on all 3 cylinders even when you rev it. See if one of the plugs does not warm up. It should also be wet. If one is cool and not wet, then put a 1/2 teaspoon of gas down it and see if it runs different.

Like mtnmaxman600 says check for spark on all three plugs. You may want to start testing your electric ignition parts.
Click to expand...

Well all 3 plugs are wet since I did not get any snow yet to ride. I did pull all 3 plugs and cranked it. All 3 had the same spark.
 
Your compression is okay. My 700 made 135 psi and was told that that is normal for that motor.
It is most-likely going to be back in the carbs.... You're probably going to have to go back and re-check/re-clean the jets and make sure that you blow out the the pilot circuit. It sounds as if there is possibly a fuel issue, it may be getting fuel but possibly not enough to run on. check for cracks and deterioration of the intake manifold as this will cause a cylinder to not want to fire because of a lean condition. I'm only saying this because there is spark and compression. If all checks out I'm wondering if it could be a bad base gasket... Or could be the one of the plug wires. Is it the same plug that doesn't warm up all of the time? Did you put 3 brand new plugs in to test?
 
Last edited:
Are you just starting it for the first time this season? how did you store it this summer? Did it run fine last year after you cleaned the carbs? I'm with Sxr700Bandit, A bad plug will cause some simular problems. If it was me, I would change to new plugs and try it, are they still wet? If That's not it, I would pull the carbs to make sure all is right including screw settings. Those pilots are very easily gunked up by bad gas. Check your carb boots also. Soc
 
Sxr700Bandit said:
Your compression is okay. My 700 made 135 psi and was told that that is normal for that motor.
It is most-likely going to be back in the carbs.... You're probably going to have to go back and re-check/re-clean the jets and make sure that you blow out the the pilot circuit. It sounds as if there is possibly a fuel issue, it may be getting fuel but possibly not enough to run on. check for cracks and deterioration of the intake manifold as this will cause a cylinder to not want to fire because of a lean condition. I'm only saying this because there is spark and compression. If all checks out I'm wondering if it could be a bad base gasket... Or could be the one of the plug wires. Is it the same plug that doesn't warm up all of the time? Did you put 3 brand new plugs in to test?
Click to expand...

I will check for cold plugs today. I went with 3 that where in the engine than 3 used I had for spares then 3 new ones. They were all wet.
 
sockeyerun said:
Are you just starting it for the first time this season? how did you store it this summer? Did it run fine last year after you cleaned the carbs? I'm with Sxr700Bandit, A bad plug will cause some simular problems. If it was me, I would change to new plugs and try it, are they still wet? If That's not it, I would pull the carbs to make sure all is right including screw settings. Those pilots are very easily gunked up by bad gas. Check your carb boots also. Soc
Click to expand...

Yes for the first time. I always run it out of gas and than fog the engine.

It ran ok but you would have to give it a tad of gas to get it running. But would sit there and idle with no problem. It did sound different then my 00 & 01 sxr 700.
 
Update Update Update

Well here is what I found so far. I somehow put on the exhaust manifold gasket on backwards. Also I pulled the carbs and found 1 pilot clogged. I understand this would cause problems :o|

I reinstalled the gasket right and it ran better but still bogged.
I took vids to show you today after the gasket was fixed.
Also there is some extra oil on the ground during this run.
It does smoke more at idle then my 01 & viper why????

I am just trying to figure out the bogging and oil on the ground.

It seems to be burning to much oil and yes the oil cable is at 22mm

Here is the vids & pics

http://s689.photobucket.com/albums/vv254/j_k_auto/98 YAMAHA VMAX 700 ISSUE UPDATE/
 
j_k_auto said:
Well here is what I found so far. I somehow put on the exhaust manifold gasket on backwards. Also I pulled the carbs and found 1 pilot clogged. I understand this would cause problems :o|

I reinstalled the gasket right and it ran better but still bogged.
I took vids to show you today after the gasket was fixed.
Also there is some extra oil on the ground during this run.
It does smoke more at idle then my 01 & viper why????

I am just trying to figure out the bogging and oil on the ground.

It seems to be burning to much oil and yes the oil cable is at 22mm

Here is the vids & pics

http://s689.photobucket.com/albums/vv254/j_k_auto/98 YAMAHA VMAX 700 ISSUE UPDATE/
Click to expand...
The bog may be because the motor is still cold, I noticed you set the choke to half and the motor perked right up. The smoke may be because of excess oil in the exhaust, my sled leaves puddles like this the first time I fire it up for the year. Have you played with the needles? If so you may have them set to lean.
 
Giving the sled a tiny bit of gas, even when it is warm is just the nature of the motor. We always seem to do that, and I believe many others will tell you the same.
 
Sxr700Bandit said:
The bog may be because the motor is still cold, I noticed you set the choke to half and the motor perked right up. The smoke may be because of excess oil in the exhaust, my sled leaves puddles like this the first time I fire it up for the year. Have you played with the needles? If so you may have them set to lean.
Click to expand...

The carbs are all stock. I started another post on the needle seetings to see what people say.
 
SXlover said:
Giving the sled a tiny bit of gas, even when it is warm is just the nature of the motor. We always seem to do that, and I believe many others will tell you the same.
Click to expand...

You lost me one this? What are you trying to say?
 
Well I am going through the carbs tommorrow. I am going to set the fuel screw to 1 1/2 or maybe 1 3/4 and see how it goes from there. Not sure which will be better. I will probably take another vid once I get it running again.

I just hate to take the carbs off to turn another 1/4 turn to see if this fixes the smoke/bog problem :o| 5 sleds are alot of work and working on them for 3 weeks I am getting tired. :o|
 
On the bog, make sure your cables are not set to tight. Because of the TORS system they need to be set fairly loose. If not you will get a bog. This has tagged me a couple of times. Soc
 
You must log in or register to reply here.


Back
Top