The Yamaha Road Star Warrior Forum

I threw my LCV in the trash about 7 years ago, just need to add a bit of throttle for a few seconds on cold start up.

If the LCV is defective disconnecting the electrical connector will not prove out the system if the LCV valve is stuck in the open position.

Locate the large rubber hose that is connected to the center port of the LCV valve, this is the "air in" hose. Disconnect the other end of the hose that is either connected to the air box or a breather filter & plug the hose. This will stop the air flow through the LCV. See if it runs.

As suggested check the compression. You need a 12mm adaptor for a screw in gauge. A hand held gauge may work if you can get it in the recess. Don't know, never tried with one of those.

Procedure: Disconnect all spark plug wires.

Remove one spark plug from each cylinder.

Open throttle to wide open position.

Install tester & crank the engine for 5 compression strokes.

Repeat for the other cylinder.

Compare readings.

Back fire through the throttle bodies (normally refered to as "sneezing")  usually is caused by a lean condition.

Checking the compression will  verify good or bad intake valves.

Your bike is not out of time mechanically, the cams are gear driven.

The timing is not adjustable unless you machine the trigger wheel for the CPS.

Work on the items suggested & post results or shoot me a PM.

JPEastbayWarrior:

Gotta go to work. See you guys about nine hours from now.

- can only offer moral support...but you are winning and now chuchkey has joined the battle...your on ya way...your skills and patience are being admired

and a great education for the rest of us....your posting back results is what this forum is all about....good man

But you had the PC3 installed before when it was running right, correct?  What are your mods again?  I have to run, but IMO try reinstalling the PC3 just as it was back when the bike was running right.  Its possibly managing your idle air:fuel and higher rpm's to match your mods.

It seems like the symptoms you describe are backwards from what a bad LCV generally creates?  What I mean to say is that the LCV's default position is closed (no extra air) but I suppose it could fail in the open (allowing extra air) position.  This can be checked by first making sure the three hoses exist on the LCV and that the center larger hose has its air filter installed, and also making sure the two smaller hoses are connected to the base of each venturi.  If yes, then remove the filter from the larger LCV hose and plug it temporarily, then when the engine is completely cold, start it.  If it acts differently, you'll notice it.

BTW unless you have high compression pistons, 91 octane does nothing for you.  Google 'octane' to see what it really does as a gasoline additive (it doesn't give gas more power - it only allows higher compression temperatures without early combustion).

[see also comments below]

What do you think?

JPEastbayWarrior:

Only thing now is that once it starts getting between warm and hot it starts to drop off line. I have to sit there and keep bliping the throttle to keep it running. [so it starts when cold, and when it gets warmer the trouble starts]

I can adjust the throttle screw and it will run at about 1,300 RPM without killing itself. [could indicate the LCV is stuck open (allowing extra air) or could indicate a loose hose from the LCV to the base of the venturi]

As I adjust it closer to 1,000 RPM it starts to die and the hotter it gets the faster it starts happening.

This is all happening without my PC3 connected. I figure get the idle issue right and then bring in the PC3. [depending on your mods it might be necessary to install the PC3 to have it run properly once warm and the LCV closes]

JPEastbayWarrior:

OK, so I went and fired the bike up and it ran. I did something right because it went from running like crap, to not running, to running again. Only thing now is that once it starts getting between warm and hot it starts to drop off line. I have to sit there and keep bliping the throttle to keep it running. I can adjust the throttle screw and it will run at about 1,300 RPM without killing itself. As I adjust it closer to 1,000 RPM it starts to die and the hotter it gets the faster it starts happening. This is all happening without my PC3 connected. I figure get the idle issue right and then bring in the PC3.

 Its got to be the TPS. There is just something about 1,000 RPM that the bike does not like. But the TPS checked out good on the meter more times than I can count.

 LCV? I hope not because that damn thing is expensive. Who runs the bike with no LCV? How is it done? If I can run with no operational LCV then that might explain what is going on.

 Let it rip guys. What do you think?

No way bro, you bring tons of good info to these boards and you're okay in my book!

Sushi_Biker:

I'm definitely getting an education. I suspected that timing was fixed but I wasn't sure. Now I feel like a git for saying earlier that off-timing could be part of the problem.

 Im at work now but Im checking the post while on lunch.

 Im going to do a compression check on Friday when I get paid. Auto parts store has a gauge with the 12mm adapter for about $39.00. I know that is a cheaper tester but I might use this thing once maybe twice over the next few years. As long as its not being dropped the "cheap gauge" will serve me well a few times. As far as the calibration being off by 5psi or so thats fine. I just want to see if there is a HUGE difference between each cylinder.

 Thank you Churchkey. I completely forgot that the cams (speed star 2nd edition) are gear driven. My mind is being so wrapped around the finer thinking details that I am forgetting the big basic's. So if compression is bad dry then I will add a teaspoon of oil. If that makes the psi go up then I have a piston/ring problem. If adding the oil does not change anything then the valves need to be check. How often do the hydraulic lifters fail?

Arizona, I ran 87 and 89 octane before and my bike would not run that well and would have a knock or two when rolling on hard in the summer with 100+deg outside. I started running the 91 and that never happended again so I just stayed with it. I have the HC Patrick Racing pistons.

 I checked the LCV hoses very well a few times now. Tonight Im going to pull the filter off the middle hose (Barons BAK) and twist a bolt into the hose and see what that brings. Thank you for reminding me that the LCV being unplugged will not suffice.

When I first started digging into this problem I noticed that on the laptop the throttle position was a 4. When I rest the Tposition the bike would die. This souldn't happen. I assume

 Lunch over, gotta go, stay tuned. Will reply tonight with more.

 Here is a list of mods: BAK, springs, cams (speed star), port and polish, HC pistons (10.5 PR),  VH Propipe, 31tooth, 240, PC3 with advanced map on both cylinders by way of welded in O2 bung for dyno testing, 3deg valve job, balanced crank.

 Well I said I was going to do the compression test on friday but I did it today. Bought the gauge at the auto store for $39.00. Came home and pulled the spark plugs. Since I had them out I checked the gap. The owners manual says the gap should be 0.03-0.04. The service manual says the the gap should be 0.031-0.035. Mine were sitting at 0.04 (a little wide) so I adjusted them to the service manual. They are sitting at 0.033 which is in the middle of what the service manual says.

 Anyways, I put one spark plug in each cylinder and installed the compression gauge on #2 (forward) and cranked it for about 6 revolutions (thats when the gauge stabilized). The result was 190PSI thank the Lord. Disconnected it and installed it on cylinder #1 and cranked it for about 5-6 revs (stable gauge) and got 190PSI right on the dot. Thank the Lord again.

 So both High Compression pistons are right at 190PSI. I was tripp'n about it all day at work. Now, this means I don't have to mess with the valves and/or piston rings. Guess I can sleep good tonight.

 Im going back out to put humpty back together and plugg the LCV to see what change that might make.

 I'll also put the PC3 back on and set the position to 4 just like it was on the laptop.

  Stay tuned guys.

 Well I put her all back together. All filters, covers, plugged everything in, double check and tripple checked everything.

 First combo start I did was with no PC3. That was not working at all. Really had to crank the throttle back to keep her going. Then I plugged off the main hose to the LCV. That had about the same result. Then I did the PC3 with the LCV "open" and that kind of made it better. Last I did the PC3 with the LCV "plugged" that had about the same result. Finally got the bike running with the throttle position on the laptop at 4 but the RPMs were at about 1,300. So at this point Im kind back were it all started. I even loaded a zero map and the map from dynojet that had the closest mods compared to mine. Needless to say that was a waste of time. A time or two during all this "combo" testing the exhaust went BOOM. I had the garage door open and that made the neighbors jump. One old lady was doing her evening walk and she was about 20yds up the sidewalk when it happend. When she got to my drive way she looked so scared. Poor thing probably thought a gun went off. Once she saw what was going on she was still scared. I could only imagine being her and seeing some "punk" with his motorcycle, music, and tattos.

 So anyways, I got mad again but kept my composure. I said "Thats it". I took all the vaccum lines and the throttle body out. I check the vaccum hoses by sucking really hard on them and of course they were good. Then I started cleaning the throttle bodies by blowing compressed air into all the little holes. Nothing came flying out and nothing was clogged. BE CARFUL IF YOU DO THAT. There are little tinny o-rings and springs that go on the adjustment screws.

 While I was down there with all that open space I ohm'd the fuel injectors and got 15.1 on both. I couldn't find the reference in the manual on "checking the injectors" other than the 5 click diag. from the dash but what ever, they both had the same ohms. I did the little wire that plugs onto the injectors as well. There was 0.1 resistance so that was good too. So I put that all back together and along the way I cleaned and lubricated as well.

 I'm an engineer in the US Coast Guard and alot of the "broken" things I find are from cleaning the part and the surrounding area really well. It keeps your eyes focused on every nick and cranny and has saved the day more times than once.

 So I don't know what to do at this point guys. Im running out of steam. NOT!!

 Im going to do what Warpig said as far as the LCV being blocked off on the brass pipes comming from the throttle bodies. The more I think about it I find it to be a really good idea. If that LCV is not closing all the way and you only have the main tube blocked than one piston could be sucking from the other through all that hose and the valve. So what I am saying is its like having another vaccum system that is causing the pistons to compete for air.

 Well thats it, finished my dinner and post. Going to block of those LCV tubes and see what I get. If that doesn't work Im going to go after the one thing that I haven't checked yet. The CPS. Im also thinking short in the harness. That will be time consuming but if you have a clear bench and a meter its all about testing Ohm's on one wire at a time from start to finish. There are other little pig tail wires that plug into the main harness but that sould go fairly quick.

 As always, stay tuned and sorry for all the typos.

Dang, your persistant. hang in the man. If you want, I can come over and hold a light for you or hand you some tools or something.

 Well I'll be DAMN that made a huge difference! You guys won't believe this (well maybe you will). Check it out.

 So after my last post and dinner I went out to the garage and started back at it. I tripple checked everything to make sure nothing was unhooked or loose that would give me a false reading while I wen't on to the next few checks.

 So as Warpig did with his LCV, I did the same with mine. I removed some hoses and blocked them off with some bolts that are just the perfect size. Turned on the key and noticed no codes were on the dash (I probably have about 20 that I need to clear later). I then cranked it over with patience. Finally after the third time she started to idle at around 700. I gave her a blip and started screwing in the idle fast to keep her up high so I could listen down low and all around the intake. Surprizingly she sat at 1,300RPM but this time it sounded smooth and tight. Then she started falling off and died. I thought I was back to the drawing board. I did it one more time however and she stayed at 1,300 smoothly for about three minutes. I thought "Thats an improvement, I didn't even blip the throttle once". It hit me at that point that the blocked off LCV was working but only if it was blocked off on both tubes (remember I tried it with just the main tube the first time). Warpig was right about both tubes and so was my logic on the two pistons fighting each other through the partially seated LCV (glory is still all yours Warpig you put it in motion).

 So there I am with a smooth idle at 1,300 with just the TPS hooked up to the ECM (factory style). Started turning the screw back and got to 1,200 no problem then 1,100 and finally got to 1,000 which is right where I like it. She stayed there for another 4-5min but then started to chugg and sputter. I gave it a blip and she settled at 1,100 and then went back to where I had it. As the seconds went by I had to blip more and more. She started sneezing through the intake and I heard a mild pop in the exhaust. Needless to say I killed it so I could think. Got to far along now to have something go south.

 Sat there for a minute and once again I skipped the obvious. I remember Arizonawarrior hounding me to plug in the PC3 and set my throttle position back to 4 from the laptop. She was getting to hot for the ECU map so I got the PC3 all hooked up and gave her a start with the PC3 positon at zero. Started her up and she would try to idle at 700 or so and then dies (much richer now). Twisted the idle screw some more and another push of the old start button and she went to 800 or so. At this point I blip and screw at the same time (that sounds hot). Finally after a few seconds she was sitting at 1,000 with a throttle positon of 2. Could not believe that I was finally getting ahead. I let it run for about 5 minutes and it stayed right there. I couldn't believe it. So guess what I did??

 I grabbed my helmet almost excited as a school kid going on summer break. I put on my boots and threw a leg over. Kick stand up and in on the clutch and away I went SLOWLY. (don't get too excited guys).

 I was going down the street at a cool 2,000 RPM listening for everything. Hell, I went for a quarter of a mile or so and everything checked OK so I put it in 3rd and hit 2,000 again. Still, everything was alright so I went to 4th and back to 2,000 but she started to make little pops about every 300 feet or so. At that point there was no real threats so I ran it up to 2,500 in 4th. This rpm range was where the bike wanted to act like it was running out of fuel when I went on that 200 mile trip. Naturally we all would think CPS from vibration or TPS for a constant cruzing position of the throttle (pending mods of course, all our bikes have a different TPS positon while cruzing and vibrations).

 So where was I? Oh yea, cruzing at 2,500RPM no problem but then I heard a sneeze a few times within a three block run so I slow down to 2,000 again and cruzzzz some more. Then I got some balls and I opened it up all the way and man did she run. It was SMOOTHER on this roll on since the last 100 that I've done up to this point. I was in disbelief but when I was comming down as soon as I hit the 2,500 to 3,000 RPM range man o man did she start poping out the exhaust like it was the 4th O' July but thats O.K. I can live with that for now besides I was home by then.

 When I pulled into the garage I got off and let her idle. She was right there at 1,000RPM and steady. As soon as I realized that the bike was running fair at this point the new Black Eyed Peas song started running through my head. I turned her off right when my wife and kid walked out with smiles and I started singing that song "Tonights going to be a good night". We were all craking up and they were so happy for me.

 As the excitment settled and they went into the house I quickly started making notes and putting all the new data toghter and this is what I got:

 1. The LCV was going bad on me. It effected the 2,500 RPM range by allowing the two pistons to compete for air. The TPS position was at 4 when all this started because every now and then I would have to adjust the throttle because the LCV was seating less and less as time goes on and TPS 4 was just where I ended up at.

 2. Even though I am poping and sneezing right now its not that bad. Remember I took out those two screws on the throttle bodies two times during all of this. Once because I adjusted the wrong side and the second time because I pulled the bodies out to blow compressed air in all the holes. Luckly I was able to put them back close enough from memory to make it around the hood for a successful test ride.

 3. Because of the success on the LCV blocking, my TPS is now at 2 on the laptop. The only reason I can't get it to zero is because the bodies are not in sync. Once I get the bodies in sync there is a strong chance that the TPS will finally get back to zero. The proof is showin.

 So needless to say Im rounding third base and Im in the home stretch. Im going to let it sit over the weekend because of Holloween and I have spent every night in the garage this week away from my family who I would like to aknowledge at this point. Valerie (wife) thank you so much for being this patient and having a wondeful dinner for me and allowing me to get back to work instantly. You once again have my back and I will remember this for a long time. Jordan (9yr old son) Thank you for being patient as well and helping your mom in the house and for doing all your home work and chores without being told ten times. Also thank you for letting me borrow the $40.00 so I could get the compression tester at the auto store. Once again you had my back as well and were bright eyed and bushy tailed when I needed your help. I owe both of you a fun and exciting Holloween weekend.

 So as I close out I would like to remind all that there is still work to do but the light is at the end of the tunnel now.

 Church. thank you for your wisdom. AZwarrior, I am proud you stuck to your guns about the PC3 and you were a big help. Warpig, thanks for the LCV blocking and sticking to your guns as well. Antitech1, its about time you chined in because I'm the one that sold you the last PC3 I had and helped you do the perfect install at my house in Newman CA. I changed my screen name after I moved to the SanFrancisco area (I was formerly JPMontereyWarrior).

 And thank all of you out there who followed this thread so far. Keep this to your favorites because it is a good example of how a few things on these bikes can act together to create a problem that 1.) We might think is the TPS or CPS as the culprit or 2.) The dealerships will charge you an arm and leg to replace one component at a time costing hundreds maybe even a thousand of $ untill the problem is solved.

 I want all of you to know that the reason why I am so O.C.D. with this thread is because I owe it to you and the site. Many people here have helped me in the past when I first got my warrior. My obsession on not quitting is also because of everyones tax dollars. I am paid by you to do a job of search and rescue in the US Coast Guard and that is one reason I do not quit because of my trainning to find you and get you home to your family. I'll never give up.

 I will fill everyone in on the final adjustments over the next few weeks. Again, sorry for the typos

 Justin

Good job Justin.

You can balance the throttle blades with 2 lengths of solid wire like 035 mig welding wire, mechanics or bailing wire.

Open the throttle & install the wires between both of the throttle blades & housings, close the throttle.

Pull both wires up & assess the amount of drag on each wire.

Adjust the balance screw located between the throttle bodies to equalize the drag.

After the throttle blades are set suggest syncing the throttle bodies, I use a Motion Pro mercury gauge however you can make a sync gauge. There are how to instructions on this forum.

For the vacuum tap to the gauge: Install vacuum tees in the hoses for the manifold air pressure sensors.

Found the home made sync gauge how to.

 http://www.powerchutes.com/manometer.asp

 Justin.....wish I would have read this earlier.  I am in Milpitas and would have been happy to lend you my compression tester.

Either way, great read and good on ya for getting it handled.  I recently relocated my LCV and was wondering if I could just remove it.  Thanks for the input warpig.....that baby will be coming off soon.

Thanks for being in the Coast Guard for us and please be safe.  If we are lucky, a ride is in the not too distant future and we can hook up.

Scott

Fantastic!