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Discussion Starter · #1 ·
My oil pump went out in my sled. It started to run funny so I shut it down. It was really low on compression, so I checked it out and am going to have to rebuild the top end. I was looking for what would have caused the issue and the oil pump was froze up. I bought a new one, and I was told to adjust it for optimum performance, but how would you go about adjusting it? The sled has just over 5,000 miles on it, and its the oem pistons according to the dealer. Its gonna be bored, but I was thinking about using weisco pistons, but I heard that they are very finicky in sleds. I know they are forged where oem are cast, so you need to allow a good warm up before riding, but I always let them warm up. I can get some cheaper pistons, but are the weiscos worth the extra, or are the spi pistons the dealer is pushing a better fit? Is the break in cycle for a forged piston any different then a cast/oem? I apologize if this has been covered before. I appreciate any advice. :dunno:
 

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the adjustment for the oil pump is on the cable itself. the adjuster nut is mounted to the carb rack. the adjustment is based on the amount of freeplay in the cable when you pull it out of the adjuster. just need to know what the spec measure is.

i am a firm believer in oem pistons and rings so my opinion is probably biased. i have heard mixed reviews on the spi stuff, personally hate the wiseco stuff, and i can just about guarantee you wont see another 5000 miles out of either of those brands.
 

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the adjustment for the oil pump is on the cable itself. the adjuster nut is mounted to the carb rack. the adjustment is based on the amount of freeplay in the cable when you pull it out of the adjuster. just need to know what the spec measure is.

i am a firm believer in oem pistons and rings so my opinion is probably biased. i have heard mixed reviews on the spi stuff, personally hate the wiseco stuff, and i can just about guarantee you wont see another 5000 miles out of either of those brands.
Yamahadad- I'm shocked to hear your opinion on Wiseco product:dunno: :eek:
 

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Discussion Starter · #5 ·
I had the dealer look up some oem pistons that were .20 over and he said they were expensive, but they are on $88 a piece so thats really not too bad. I'm gonna go with the oems. I heard a lot of people say that weiscos should be called seizecos. I have ran them in bikes for years and never had an issue, but I never put 5000 miles on them either so I have to say the oems are pretty reliable. I'm hoping to have the cylinders back today, and then I can start putting it back together.
 

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oem all the way. also when ur breaking it in too add a little bit of mixing oil to ur gas it will run a little richer but helps better on the break in. bout 100 mil for a tank. do that for a couple tanks and the ol girl should be ready to haul ass
 

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Discussion Starter · #7 ·
Thanks guys. I feel a lot better now ordering the oems. I would be so angry if I put in new stuff to just see it mess up. I feel that if the oil pump wouldn't have went out that sled would of ran a lot longer, it was a strong runner. It seemed to be more reliable then some of my friends newer ones are. I was told I could have gotten away with just honing the cylinders, but I wanted to be safe.
 

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Discussion Starter · #9 ·
I got my cylinders and top end parts back today, so tomorrow I am gonna start and put it back together. The shop set up the cylinders for proper clearance for the pistons. They had to order the wrist pin bearings, but I get them tomorrow. The mechanic at the shop was pretty cool, he gave me some pages copied out of the service manual that dealt with breaking it in and the oil pump specs. He said oem pistons are used for a reason, but if you don't set up properly whether your using oem or aftermarket of any brand, it will fail. He said weisco piston are good piston if used properly, but he said most of the problem he has had with weiscos are cold seizures from not letting your engine warm up properly.
 

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wastedincome...I think piston choice is a lot like oil choices. Everyone has their reason for why they prefer a specific brand of oil or specific brand/type of piston. My thought is if you are happy with the performance you get from whatever, spark plugs, oil, pistons....hell even condoms, then stick with it, but if you've had bad luck then change to something else.
 

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wisecos are good, IF you let them warm up. Far too many people completely ignore any warmup. It doesn't have to sit and idle, but at least keep the throttle/torque low for 10 minutes of easy riding first.
 

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Discussion Starter · #12 ·
I have a friend that runs weisco pro lites in his zrt and they are great, but I know he lets his motor warm up. I run them in my dirt bike and have never had an issue. My dad runs spi pistons in his v max and they seem fine too. I only chose oem as they were actually a good deal and I could get them pretty easy and they are reliable pistons for my situation. I agree that some people are brand loyal. I'm not knocking any brand. If it works for you then use it as Phazer36 says.. One thing I am big on is proper sled maintenance and letting your sled warm up regardless of what pistons your running. I fire the sled up and then go in and get dressed, so it runs about 5 minutes, then I ride it a little bit before I open it up.
 

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wastedincome...I think piston choice is a lot like oil choices. Everyone has their reason for why they prefer a specific brand of oil or specific brand/type of piston. My thought is if you are happy with the performance you get from whatever, spark plugs, oil, pistons....hell even condoms, then stick with it, but if you've had bad luck then change to something else.
Great advice phazer'
 
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