Hardcore Sledder banner
1 - 15 of 15 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hello, I have a 1984 Yamaha Phazer 480 that will start right up and idile fine. The problem is when at WOT it only goes about 50MPH and won’t rev over 5,000 RPM. However when stopped then going straight to WOT it will hit about 6,500 RPM then quickly bog back down to 5,000. I have the fuel air screw set at 1.5 turns out as it calls for in the manual. It has a new top end new belt and the carbs have been cleaned. Does anyone have any suggestions?
 

·
Registered
Joined
·
313 Posts
How old are the clutch parts? Clutch springs, arms, buttons, helix may all be worn out. The track may be too tight. How does it run if you lift the back of the sled, i.e. with the track off the ground?
 

·
Premium Member
Joined
·
39,238 Posts
Need more info, one is when were both clutches completely rebuilt? 37 year old sled should have had them done several times by now.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #4 ·
Need more info, one is when were both clutches completely rebuilt? 37 year old sled should have had them done several times by now.
Runs about the same when you lift the back end off the ground. I would assume all the clutch components are the original parts. I just got the sled and the previous owner didn’t mention that he ever did anything with the clutch. How much would I be looking at spending to get new parts for it?
 

·
Premium Member
Joined
·
39,238 Posts
Runs about the same when you lift the back end off the ground. I would assume all the clutch components are the original parts. I just got the sled and the previous owner didn’t mention that he ever did anything with the clutch. How much would I be looking at spending to get new parts for it?
It would vary according to what it may need, sometimes cheaper to buy new or aftermarket.
 

·
Registered
Joined
·
313 Posts
Is the track at the correct tension? We used to run pretty loose track tensions on our Yamaha's. Mostly to get the hyfax to last longer. What about the chain, make sure it's not too tight. The bolt that applies the chain tension should only be hand tight maybe a quarter turn more. The clutch belt should be at or just above the edge of the secondary clutch. If it were me I would buy all new clutch parts, springs for both, rollers for the primary, if the arms in the primary are notched at all where they run on the rollers I would get new arms. Plastic buttons on the primary spider. Helix in the secondary is probably fine, not sure those wear mutch unless the plastic sliders are really bad. You'll also need tools, a puller to get the primary off and a tool for the secondary to squeeze it while you remove the "C" clip. And you have to pay attention to how far the secondary clutch halves spin when it's being taken apart so it can go back together with the same. Buy and use a black marker to mark things before you take them apart. You can adjust back shifting by changing the position of the secondary spring and the rotation of the clutch halves. Google will be your friend to locate parts, prices, and how-to videos. Get a new clutch belt.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #7 ·
Is the track at the correct tension? We used to run pretty loose track tensions on our Yamaha's. Mostly to get the hyfax to last longer. What about the chain, make sure it's not too tight. The bolt that applies the chain tension should only be hand tight maybe a quarter turn more. The clutch belt should be at or just above the edge of the secondary clutch. If it were me I would buy all new clutch parts, springs for both, rollers for the primary, if the arms in the primary are notched at all where they run on the rollers I would get new arms. Plastic buttons on the primary spider. Helix in the secondary is probably fine, not sure those wear mutch unless the plastic sliders are really bad. You'll also need tools, a puller to get the primary off and a tool for the secondary to squeeze it while you remove the "C" clip. And you have to pay attention to how far the secondary clutch halves spin when it's being taken apart so it can go back together with the same. Buy and use a black marker to mark things before you take them apart. You can adjust back shifting by changing the position of the secondary spring and the rotation of the clutch halves. Google will be your friend to locate parts, prices, and how-to videos. Get a new clutch belt.
I did just install a new belt and it sits foot in the drive clutch but when I ride it I can start to smell it burning. I guess I need to go through the clutch.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
I was trying to say that I just put a brand new belt and it sits good in the drive clutch but after a little while of riding I can start to smell my belt burning. Is this normal with a brand new belt with only one ride on it or is this a sign the clutch is bad?
 

·
Premium Member
Joined
·
39,238 Posts
I was trying to say that I just put a brand new belt and it sits good in the drive clutch but after a little while of riding I can start to smell my belt burning. Is this normal with a brand new belt with only one ride on it or is this a sign the clutch is bad?
Could be a sign of several things including a wrong belt, track has a hard time rotating, bad clutches, wrong deflection, bad shaft bearing(s), etc.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #11 ·
I just loosened the track a little and now with no load it will get to 7,000 RPM very slowly but under load it still won’t go above 5,000.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #13 ·
Okay so I found out that only one of my cylinders is running. I’m thinking this may be the reason it’s not reving out all the way. I cleaned the carbs twice and cleaned out the fuel tank but with no luck. I then swapped my coil with an extra one and now I am getting better spark from both plugs but it still is only running on one cylinder. If I take the pto wire off while it’s running it shuts off but when I take the wire off the other cylinder it has no effect so that’s where my dead cylinder is. Both cylinders have good compression too. What else can I try to get the both cylinders to fire?
 

·
Premium Member
Joined
·
39,238 Posts
What was the compression when you checked it?

Have you ohm'd out both resister caps?

Have you checked crank phase?
 
1 - 15 of 15 Posts
Top