Jump to content

Compression Just Isn't Right


mcaf29

Recommended Posts

  • Replies 42
  • Created
  • Last Reply

Top Posters In This Topic

I just dropped to a 40 pilot and here is what my plugs look like

 

faaaa3a2.jpg

 

 

It should be an obvious oh you are running really rich, but I just don't get it. BTW, I figured out i don't have an airleak, I think the reason it revved up before was because when I change my jet sizes the fuel drains out. When I started its in a sorta lean condition for a few seconds. I didn't get scared today and shut it down when it did this and I let it even out. The weird thing is there was the same throttle response as the 42 pilot, the air screw did nothing for the 42 or the 40, and the idle really doesn't do anything. I know you all may think I'm crazy but I'm leaning towards electical, I got a spark tester so I'm gonna pursue this next. Here is why and you can tell me why I may be right or wrong. I live at sea level, open airbox, proflow w/ K&N, +4 timing, and V-force reeds. I know the reeds will richen it up causing me to drop a size or two, but this is ridiculous. I cannot see how I would need to run a 38 pilot in my 33 mm carb at sea level at 50 degrees, the 35 pilot is the lowest available. So what do I do in the summer? or if I move to a higher elevation? It cannot be right for my shee to be running a 38 or 35 when it came with a 52 pilot. The main it came with was a 180 and I run a 178 and shee revs out clean. So I think that at low RPM's my stator which has been flooded with water a few times (resistance checks out though) does not put out enough power to get a clean burn. I think as the RPM's build the power increases enough to get a clean burn which is why I'm around normal on my mains. When I toss the stroker in I want this thing to run perfect for at elast the next year or so.

Link to comment
Share on other sites

im wondering how you had 17's on pump anywhere with out a raised exhaust port and not blowing it sky high.at sea level that should have detonated, is your pump fuel 100 octane?...and i might be mistaken but the plug burn is combustion, not spark, if the spark ignites the mixture you should still get an accurite plug chop?, what pipes are on this bike, notice the bottom rim of your plug is clean meaning a new plug, that looks rich to me but im just pissin in the wind like everyone else....post what you find....

Link to comment
Share on other sites

How are you sure you don't have an air leak? I had a leak once at the carb boot, and it wouldn't suck air untill the upper RPM range. A melted top end finally alleviated the situation. I hate air leaks. How did you test it? How long did it hold vacuum? On your theory about the carb not having enough fuel in them, I don't think that is a valid argumant. It takes less than 5 seconds for a properly fed carb to fill the bowls. As long as your fuel feed line(s) aren't pinched, it shouldn't be a problem. By the time you turn the fuel on, and hop on it, the bowl would be half full of fuel. You shouldn't be having to mess with the pilot jet as much as you are. I still believe you have an air leak. It seems like the only explanation for the wierdness you are experiencing. And the stator theory, A weak stator should put out enough zing at idle, and when the revs pick up, you are drawing more power, and it wouldn't be able to handle it. In theory, it sounds good. But, I have never seen a "weak stator" on a bike. I did have a loose wire on my coil a couple times and it would backfire and what not at higher revs. it would start and idle fine, but not run up top. Kind of the opposite thing that you are experiencing. I don't know alot about single carb jetting. never messed with one. But, jetting is jetting. SO, what kind of guage are you using for compression testing, and what setup do you have for leakdown tests? Being that you have a 2-1 intake, this could pose a slight problem for narrowing down a leak if one exists, but you should be able to tell either way. 7" of vacuum for 7 minutes is a decent rule of thumb. I personally like to see them hold it for longer, but at that length of time, it should be fine to run without a problem.....

Link to comment
Share on other sites

Chase73 was running 35 pilots in his. Same problem. Try it out, what do you have to lose?? He lives in MA.

I agree w/ Boony though. Better to be safe then sorry. Make sure you have NO air leaks. Something doesn't sound right. Your air screws should make noticeable changes, especially on Keihin carbs...

Link to comment
Share on other sites

Well, Here's an update. I went riding today and all hell seemed to break loose. My engine was making a clackety clack clack sound, shee started to sputter big time and I couldn't ride past quarter throttle wihout feeling like my motor was gonna blow. The weird thing is the left plug was brown and the right one was black. Now here was the problem, Was I jetted too rich so the right was black, and I had an air leak on the rleft which made it brown(so if I was actually jetted right I'd be way lean) Or was I jetted perfect on the left and had an oil leak on the right side(lost a little bit of oil)? Its really a rhetorical question now cause I split the cases tonight. I split the cases in 6 hours!!! That's big for me since it took a couple weeks when I did it before.

 

I came across several problems that may be the cause for the noise but luckily it wasn't what I thought it was. I thought maybe my crank bearing went therefore the vibration broke the oil seal and oil was getting in the crankcase. I'm glad to say that the crank looked like I bought it today. I spun the bearings and they sound perfect so its not that. I'm waiting on my stroker crank anyways so i was going to tear apart the motor. I was pissed cause I wanna sell the crank and thought that I couldn't if the bearings were shot.

 

The first thing I found was my stator looked smoked really bad, and it smelled like an electrical fire when I opened up the stator case. I really think this is coincedence cause it still ran with it looking beat. I also noticed my flywheel rivets were geting really loose, and there is a ton of play that could be causing the noise.

 

Another thing is there is a little play between my clutch basket and the gear so that could be helping to make some noise.

 

I'm gonna be so pissed if I put this thing back together w/ the stroker crank and have that same noise(I'm gonna get the Ricky stator setup and the Hinson basket to rule tose out).

 

Could the noise be from my tranny? The gears look really good, and I don't know how to check them anyways. I guess I could bring them to the stealership and have them look at em.

 

One last thing. How do you apply yamabond correctly? It took me 3 times longer to physically separate the cases this time because I got some on the threads. The crank was stuck to top case by the yamabond, it took forever (Although using anti-seize on eveyrthing else last time made the rest of the teardown silky smoooth). Do you Yamabond around the outside of the bearings? Or do you just yamabond the case mating surfaces? Thanks for the help.

Link to comment
Share on other sites

Damn,,,, I'd say the problem lies in the stator....Can't have a loose stator..the smell would tell me something definately isn't right there. The basket will have play. As for the jetting, I think you have an air leak somewhere....You should have a black plug on normal riding. It should only be brown when your wot..

Link to comment
Share on other sites

Thanks. Yeah the play on the flywheel isn't the normal play, its like its about to let go kind of play. I ordered the Ricky Stator flywheel and stator set. About the airleak, that's the most likely cause lucky I didn't cook my motor. Well, its one giant airleak now so I'm starting from scratch when my stroker gets here. Its funny now attached you can feel to inanimate objects. My hot rod crank looks so good that I feel bad pulling it out, I'm definately sticking w/ Castor 927.

Link to comment
Share on other sites

Thanks.  Yeah the play on the flywheel isn't the normal play,  its like its about to let go kind of play.  I ordered the Ricky Stator flywheel and stator set.  About the airleak,  that's the most likely cause lucky I didn't cook my motor.  Well,  its one giant airleak now so I'm starting from scratch when my stroker gets here.  Its funny now attached you can feel to inanimate objects.  My hot rod crank looks so good that I feel bad pulling it out,  I'm definately sticking w/ Castor 927.

The flywheel sounds shot. If there is any play, that is not good, as the timing will be out of whack. Your plugs fire off of the the flywheel, and the pickup coil. If the timing bumps on the flywheel aren't locked with the rotating crank, your timing is now fluttering so bad that the engine and CDI has no idea WTF is happening. I am betting that you had an air leak in the left side. You could have smoked a crank seal on that side causing it to suck air as well. but, now that you have it ripped apart, we will never know the cause of it. I would definitely do a leakdown on it this time around. If you don't have the tools for it, then go to the stealership, and have them do it, I would suggest asking them to let you watch it, and if they don't want to let you, then go to someplace that does, or setup your own tester. There are pics on here somewhere... Air leaks are a VERY BAD thing. My stator smelled like crap when I pulled it out and it was all rusty too. It was fine though. I just needed more lighting power. So I got a ricky stator unit. Good luck on the install of the stroker. And on the yamabond, everone has their own way to do it, but the way I do it, is I yama bond everything. Bearing surfaces and all.

Link to comment
Share on other sites

Thanks Boonman. I did a leakdown test but it seemed inconclusive. I pumped it up to 7 lbs and it kinda held. It dropped about 1/2 to 1 psi but somtimes it dropped none over the many tries, and from what I read here its acceptable. The leak down tester in the images forum is the one I used. I'm sorry to put you guys through this but I think I have an idea what it was (I've said this a thousand times right). The crank seal looked o.k. so I think it may not be that. You guys are gonna kill me for not remembering this the other night. When I took the cylinders off, the left side (lean side) inside cylinder nut came off really easily. Not so much hand tight but I'm talking far less torque to remove it than the others, very close to handtight. At the time I was just tearing it down and kinda blew it off and didn't really analyze it. So tell me if this follows suit. O.K. I do the leak down test cold, and the cylinder gasket holds the vacuum so it looks good to go. Well I rode it for quite some time before it started acting up, the heat cycling (hitting water thus cooling) and the vibration may open it up enough to let air in. I come home wash it let it cool and leakdown test it and it appears fine. I'm gonna have to say its way too much of a coincidence that the loose nut was on the side that was lean. I'm gonna call it 11:45 a.m. Monday November 10th, 2003 beeeeeeeepppppppppppppppp. Unless anyone else revives it.

 

I will however update you all how the rebuild goes and how the stroker works out. I think the flywheel is beat and the clutch basket has play cause the guy who owned it before was running 17 cc domes at sea level so it just stressed the hell out of the stock motor.

Link to comment
Share on other sites

YOu might be on to something there. Anything is possible...WHY DIDN'T YOU TELL US!!!!!!! :lol::lol::lol: At least you have something, was there any oil around the cylinder?? I'm sure you will, but I'll say it anyway. Just take your time and check EVERYTHING while its apart...The nut could have been the problem, but could also be coincidental, so I'd give it a 100 point inspection when it goes together...keep us updated.. and good luck!! B)

Link to comment
Share on other sites

Thanks again for sticking this out. I'm gonna go over EVERYTHING. I mean anything that doesn't look close to perfect its gone. Thats exactly why I've gone w/ the ricky stator setup and new hinson hub, I'm not taking chances when I've got so much invested already. I'm thinking about taking the gears over to the yamha dealer and have them look at them cause I really don't know what to look for. I mean the gears all look good to me.

Link to comment
Share on other sites

I sent my '89 motor out to Pt racing and had them go through it for inspection. I was going to build a 403 stroker until they called me one day and said I was looking at $3000 before the stroker kit!!!!! Said I need a whole new clutch basket and clutch, new 6th gear, new cases (upper and lower), new stator, crank, etc.....They sent the motor back to me at no charge for the inspection. Just shipping. I thought that was pretty cool. They sent it back totally disassembled though...I mean completely disassembled...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...