Yamaha Starbike Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
626 Posts
Discussion Starter #1
I have a motion pro syncpro gauge. I had the screws for the fluid chambers backed out all the way and when I fired the bike up the fluid was just shooting all the way to the top and some out the hose. YES the idle was normal. Now if i blow back threw hoses to push fluid back down, when I stop blowing it comes right back up on the gauge. Any ideas? Bad gauge or something going wrong to increase the vacuum.
POD mod ..jets... full exhaust and air filter box removed with PVC filter installed.
 

·
Registered
Joined
·
3,650 Posts
Aide, how's the bike running? When you installed your gauges, was the engine already warmed up? The kb says to do the sync with the engine warm. I would make a two bottle gauge as in the kb, and see how it handles. If it does the same then you've just confirmed that your gauges are operating correctly. Did you look for a vacuum leak somewhere inthe system? Just some thoughts.
 

·
Registered
Joined
·
626 Posts
Discussion Starter #4
The bike is starting to run a slight bit ruff and pops a little more on hard decel. In the past a simple carb sync keeps her running well. The bike was rode for 30 km before I tried to sync.
The bike idles smooth and starts well...but if that pcv vale plugged up on breather tube wounder if that would increase vacuum? If I even let a little air leak in on sync ports (carb boots) the idle drops and runs like crap.
 

·
Registered
Joined
·
626 Posts
Discussion Starter #5
I have changed fluid in my gauge to 20W50 and even lowered idle to low and still fluid sucks up and out of gauge. I still am going to make my own gauge..but in the mean time could there be something that would cause to much vacuum? AIS is removed.
 

·
Registered
Joined
·
424 Posts
Maybe the problem isn't too much vacuum on one cylinder, but too little on the other. Carb sync, vacuum leak, crack in the intake manifold, loose bolt on the intake manifold, bad valve clearance, even something wrong in the exhaust system. Have you done a compression test yet?
 

·
Registered
Joined
·
626 Posts
Discussion Starter #7
I cam across my vacumm gauages, and so took the rubber hoses off carb sync tool because they have restrictors in line. When I hooked them up, sync looked to be way out. I didn't want to play with it to much because I need the bike for Port Dover on Friday. I ended up turning the sync screw a good full turn I bet and had to turn up idle 3 times. I figured on a test drive the bike would back fire spit and sputter but nope she pulled hard threw the range of speed.
When I cleaned the K&N filter which were not that dirty, this is when the bike started to act different this past weekend with backfiring, harder starting and surging while at a buck 20 on the 401.
 

·
Registered
Joined
·
1,090 Posts
So just for kicks after you did this did you check it again with your syncpro and see if it was working better?
 

·
Registered
Joined
·
626 Posts
Discussion Starter #9
So just for kicks after you did this did you check it again with your syncpro and see if it was working better?
I was just thinking this today while at work. It's on the list for the weekend. I am thinking on checking valve clearance again, was spot on I say about 10,000km ago and still sounds alright, but peace of mind :)
 

·
Registered
Joined
·
424 Posts
The thing about listening for valves is that you can't hear one that is too tight. Loose valve clearances, within reason, cause no damage and do nothing but make noise. Tight clearances can keep a valve from seating, thus losing compression and/or leaking fire back into the intake manifold.

From at least one other forum, cleaning KN filters can be tricky. Apparently they use some sort of magic oil, and if you use too much of it the filter becomes restrictive and messes up mixtures especially at high throttle settings.
 
1 - 10 of 10 Posts
Top