Post by 90GTVert on Sept 4, 2009 9:56:53 GMT -5
I was noticing a lack of performance, particularly not gettting much over 50MPH unless I partially tucked and almost free revving sometimes. I pulled the CVT apart this morning to do some checks and tuning. As I removed the cover I noticed lots of dust, which is pretty much normal for this thing and the amount of miles it gets. The unusual part was that the dust had brass spcs in it. "Oh boy." As I started taking things apart, I discovered that two of the rollers were being destroyed.
You can see that one roller has no brass in it, and the brass that was in it is worn. The other roller was in the process of being chewed up as well. There is a dammaged section in my aftermarket vari that I think caused the problem. One of the guide's for the rollers is a little chewed up. I think it may be from me running with no sliders on the vari plate. They just disappeared a few weeks ago. No trace of them, of course my CVT case is open in many spots. I've been 65MPH without them with no other issues, so I figured I'd just run with it until it caused a problem. I woulda replaced the sliders, but I don;t have a clue where to get 'em for the aftermarket unit. Now I'll need to replace the whole thing anyway.
With that figured out, I thought I might as well try some tuning... even thouh my vari will prob ruin whatever is in it at the moment. Bob's supposed to be up today so we can take the scoots out tonight and I don't wanna be stuck at 50MPH and acting funny. I had moved to a 105 main with the UNI clone filter, but it was sluggish so I started out by going to a 98 main that I was using with the K&N. I hooked up a tach and started making some passes down the same road, the same distance (intersection to driveway & back) in a short time period so conditions remained constant. All runs were made sitting up in the same position, etc... Here's what I did and where I got...
..98 Main...1,500 Contra...5.5g Rollers...54MPH...8,800RPM
..98 Main...1,500 Contra...6.5g Rollers...55MPH...8,600RPM
..98 Main...1,000 Contra...6.5g Rollers...55MPH...8,300RPM
..98 Main...1,000 Contra...5.5g Rollers...55MPH...8,600RPM
..98 Main...1,000 Contra...6.0g Rollers...56MPH...8,400RPM
102 Main...1,000 Contra...6.0g Rollers...55MPH...8,300RPM
100 Main...1,000 Contra...6.0g Rollers...57MPH...8,600RPM
On most tries it seemed like I was pretty much topped out unless I wanted to tuck or go a much greater distance or something. On the last run it woulda kept going past 57MPH but I was at the braking point for my driveway. Doing 8,600RPM at 57MPH and knowing I can get to around 65MPH tells me that I got a lot closer to my RPM goal than I thought with the little bit of port work I did a couple of weeks ago. Even at 65MPH I don't think it would tach 9,500 where the pipe says it's peak power is. It's still a nice improvement from 7,800RPM at 54MPH where I was before porting and tuning.
I shared this stuff to give anyone who hasn't tuned their scooter, or even those that have done mild tuning, and idea of just how specific you have to be to get the best performance from your scoot. Roller weights need to be correct to 0.5g and jetting from even 98 to 100 or 100 to 102 makes a difference. Once again illustrating why I won't try to tell someone what jet they need. Most of the folks here reading this already understand, but I find the information gathered to be interesting and possibly useful to others.
You can see that one roller has no brass in it, and the brass that was in it is worn. The other roller was in the process of being chewed up as well. There is a dammaged section in my aftermarket vari that I think caused the problem. One of the guide's for the rollers is a little chewed up. I think it may be from me running with no sliders on the vari plate. They just disappeared a few weeks ago. No trace of them, of course my CVT case is open in many spots. I've been 65MPH without them with no other issues, so I figured I'd just run with it until it caused a problem. I woulda replaced the sliders, but I don;t have a clue where to get 'em for the aftermarket unit. Now I'll need to replace the whole thing anyway.
With that figured out, I thought I might as well try some tuning... even thouh my vari will prob ruin whatever is in it at the moment. Bob's supposed to be up today so we can take the scoots out tonight and I don't wanna be stuck at 50MPH and acting funny. I had moved to a 105 main with the UNI clone filter, but it was sluggish so I started out by going to a 98 main that I was using with the K&N. I hooked up a tach and started making some passes down the same road, the same distance (intersection to driveway & back) in a short time period so conditions remained constant. All runs were made sitting up in the same position, etc... Here's what I did and where I got...
..98 Main...1,500 Contra...5.5g Rollers...54MPH...8,800RPM
..98 Main...1,500 Contra...6.5g Rollers...55MPH...8,600RPM
..98 Main...1,000 Contra...6.5g Rollers...55MPH...8,300RPM
..98 Main...1,000 Contra...5.5g Rollers...55MPH...8,600RPM
..98 Main...1,000 Contra...6.0g Rollers...56MPH...8,400RPM
102 Main...1,000 Contra...6.0g Rollers...55MPH...8,300RPM
100 Main...1,000 Contra...6.0g Rollers...57MPH...8,600RPM
On most tries it seemed like I was pretty much topped out unless I wanted to tuck or go a much greater distance or something. On the last run it woulda kept going past 57MPH but I was at the braking point for my driveway. Doing 8,600RPM at 57MPH and knowing I can get to around 65MPH tells me that I got a lot closer to my RPM goal than I thought with the little bit of port work I did a couple of weeks ago. Even at 65MPH I don't think it would tach 9,500 where the pipe says it's peak power is. It's still a nice improvement from 7,800RPM at 54MPH where I was before porting and tuning.
I shared this stuff to give anyone who hasn't tuned their scooter, or even those that have done mild tuning, and idea of just how specific you have to be to get the best performance from your scoot. Roller weights need to be correct to 0.5g and jetting from even 98 to 100 or 100 to 102 makes a difference. Once again illustrating why I won't try to tell someone what jet they need. Most of the folks here reading this already understand, but I find the information gathered to be interesting and possibly useful to others.