No Top End Over 90mph

YAMAHIZAL700

YAMAHIZAL700

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Joined
Feb 12, 2005
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863
Age
44
Location
durham, ME
HEY GUYS THIS IS THE SECOND POST ON THIS. MESSED UP AND POSTED IN THE NON POWERVALVED AREA. WAS RIDING THIS WEEKEND AND NOTICED A SLIGHT BOG OR LOSS OF POWER WHEN I GOT INTO THE THROTTLE. IT ACTUALLY DIED DOWN ONCE GOING ACROSS A FIELD BUT THEN CAME RIGHT OUT OF IT. I DONE 110MPH ON THIS SLED AND KNOW THAT IM NOT GETTING IT ALL RIGHT NOW. IM MISSING A LEAD GASKET FOR THE SILENCER END OF THE EXHAUST BUT SEEM TO MADE A PRETTY GOOD SEAL WITH RUBBER GASKET MAKER. I CLEANED THE POWER VAlVES AT THE BEGINNING OF THE YEAR. AM GOING TO DO THAT AGAIN OTHER THAN THAT THE SLED RUNS EXCELLENT. IT STARTS EASY IDLES GREAT. THE ONLY THING I DID WAS CHANGE THE PLUGS BEFORE I LEFT. ANY SUGESTIONS? THANKS
 

are you sure you did not foul a plug. power coming and going sure sounds like a fouled plug to me. the srx's are tempermental.

also. i cleaned power valves beginning of season too and just checked them this weekend. although they were pretty clean, i had another cable that pulled through.

I'd start with new br9es plugs again........
 
that exhaust needs the right seal cause at high speed the underhood pressurizes and will affect the pipe...also...nothing beats fresh plugs and fresh fuel...and i always run isopropyl when below like 25 degrees...
 
srx's are tempermental? since when? Throw in a new set of plugs, clean the carbs, clean the powervalves, make SURE that exhaust gasket is sealing, and you should be good to go.
 
well got the sled into the garage. checked plugs and like i thought it didnt foul any but did notice that the center plug wire was loose and when i pulled off the wire it fell out of the cap. i screwed it back together and it was nice and tight. the mag side cylinder was also a little loose but not nearly as bad. i know it was making a connection cause the plug was golden brown. i bet when i hit a bump that is what was making the loss of power or slight die down. cleaned clutches with brillo pad and soap and water. Holy shhhhh works awsome my clutches never looked so good. question i took my powervalves out and cleaned them with a razor blade. there was a lot of black buildup but not really a lot of resin or goop. when they were out i pulled the throttle and they didnt really do much. shouldn't they slide back and forth or do they only work right when they are fastened into the cylinder? they didnt really move much in my hand. last but not least my gearbox. i bought this sled last fall and when i went through it the chain was so loose that it was flopping around and making metal shavings. I shot it out with brake cleaner the best i could and retightened the chain. now when i checked again the chain was loose again. the tentioner bolt doesnt seem like it sits flat against the piece that rides against the chain. is this normal or can i make it so my chain doesnt loosen up cause that probably added to my loss of top end. the scary thing is that i cant feel the chain being loose enless i take the chain case cover off and that tends to get old after a while. thanks for the info guys!0 .
1
 
regarding power valves, they open by the electric servo at high rpm. so pulling the throttle won''t see any movement.

you should tug each one to make sure the cable has not pulled through the end of the valve. this happens ALOT. I have replaced two in 1000 miles of riding. it is a bad design and needs to be watched.

adjsuting the valves is pretty easy. take the cover off the servo motor. you will see a spool with three cables wrapped around. put the valves back to gether but then loosen the outer plates at the valves (where the cabled goes in).
Create a gap about 3/16" by loosening the little socket cap bolts. start the engine and by pulling the choke, get the engine to idle below 900 rpm. at this point the electronics pulls the servo to the open valve position. turn the engine off. and mark across the spool and housing. this alows you to manually rotate it the next time you need to adust, or as you will find out, when you pull a cable too much, the servo rotates. this way you can manually rotate it back to "open" position, without having to restart the engine.
now.... the proper gap for the powervalve cables is 1/8" when pulled open. you can take a 1/8" drill bit and slide it in the gap you created by the loosening of the outer plate. you then rotate the threaded cable ends at the servo (like adjsuting a bike cable) until you get slip/no slop on the drill bit. then tighten everything up and put the cover back on the servo.

also, you can cut 1/4" off the sparkplug cables and then re thread them back onto the cap. as the ends get corroded over time.

hope this helps.

Ramb
 
picture perfect! I know exactly what you mean. thanks for that and i def. need to trim a bit cause it did look a little messy in the plug cables. see this is the kind knowledge that you would never in a million years get out of a dealer. I so glad i fell apon this site while i was doing a google search for yamaha parts. thanks for the help guys!
 
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