I just got done installing a new belt, black spring, and the Naber module on the 650 this weekend and now I have a few questions. According to the speedo I have lost about out 6 mph at the top end. I did install the 360 belt and reshimmed it to NYROC's specs (Great site!) I heard that you may loose 1 mph but 6 ouch. I removed one 6mm shim and the deflection seemed to be in range at 1" and the belt had a little bit of a chirp in gear just sitting but that has quit. This thing used to go 64 to 65 and now I can hit 58 to 59 on the flats. The Module seems to be a big help on the lauch I have to be careful not to pull the front up from a stand still but I would like to find out why my top speed has dropped. Any help would be greatly appreciated.

 

Try pulling the black spring out and test it again. We found no change, but I am curious what will happen in your case with the P360 belt.

The 360 belt is a bit wider I recall. Maybe it can't get far enough down in the secondary and that is dropping your top end.

 

I'm on the road right now but when I get home tuesday I will take out the black spring. If that doesn't work I will put everything back to stock and start adding one at a time. That was my original plan but I couldn't resist not putting it all on at once and the fact that I had a mud drag I was leaving for the next morning.

 

Thats the best bet, go through it all, one thing at a time. I am the same way you are,...I get 3 new toys I want to play with them all at once LOL. I have heard of speed gains in the 2-4mph range with the P360 belt.

 

This is getting frustrating I went and started over tonight! First I took the 650 out and went for a test drive without changing anything and to my disapointment I had more problems when I first hit 35 mph it backfired two quick times. I didn't really think much about it because these are cold blooded machines. Then at 45 it started to surge and I couldn't get it past 52. I turned around and went home to tear it apart put my old belt on that was in good shape but alittle off in the deflection after that I could only hit 49. Back to the shop to take out black spring and put 360 belt back on. On the road it had more snap and seemed to be going good untill 45 then it felt like I would get some power then it would retard and then power and then retard I did manage to hit 52 but thats not even close to the top speed I used to get. It felt like it was surgeing on and off. The only thing I didn't try was to remove the naber module. Has anyone had a problem like this I love the machine but am getting frustrated with the lowered top speed and surgeing.

 

Sounds like something is wrong with the speed sensor/module system. Check all the wiring; make sure the ground to the module is good and all other connections are good. The symptoms you describe (surging, very low top speed) are precisely what happens if the CDI isn't getting a signal from either a module or the speed sensor.

 

I agree that it doesn't sound clutch or belt related at this point...WAM

 

Cisco, are you 100% sure you are measureing the belt deflection the correct way? Reason I ask this is because the first time I adjusted my belt deflection I was getting wrong measurements because after I replaced the belt on the pulleys I didnt turn the pulleys to let the belt ride back on top of them.

I went back and read your first post. If it was running fine before and now you made some adjustments and added things 99.9% of the time its something related to what you did. The other .1% is just coincidense that something else happend. If I had to bet money on your problem from what you discribe I would bet its a loose belt. If you are 100% sure the belt deflection is within specs then my money would go on the Nabor module.

 

Doesn't sound clutch related. My guess is electrical, module, or connections,

Was the back fire though the carbs or out the exchaust?

Things to check besides taking the Nabor off and trying it without it. Choke, flap in front of snorkel, and
air cleaner.

 

First of all thanks for all the help this is by far the best Atv site that I have found. To answer a few questions when I checked the belt deflection I rotated the pulley to get the belt to sit in the highest spot that it would sit which was actually sticking out about a 1/8 of an inch. The only thing that I questioned was to measure from the peak or the valley of the top of the belt I used the peak so I think I'm all right there. On the other questions I replaced the choke springs about a month ago the snorkle has a clear passage and the back fire's came through the exhaust. I am going to take the naber off and check all the wireing today and see what happens. Thanks again for the help!