| Author |
Message |
    
Cjburr
| | Posted on Tuesday, June 12, 2007 - 09:05 pm: | 
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Hello again you guys, long time no post for me, but my S1W is still running great with no problems of note.
However the same cannot be said of my Buell front ended Sportster and I feel the need to ask the knowledgeable folks here if they have heard of this problem or perhaps can help me with my troubleshooting plans.
After my front end install I converted my 883 to a Stage3 XB head 1250 with 11 to 1 compression, SE.575 cams, Bassani 2 into 1 exhaust, and Mikuni HSR 42 carb.
After break in I noticed excessive oil consumption (1/3 qt every 400 miles)and temps of 250 with any highway riding.
Upon inspection of the heads I found all the valve stem seals were not seated on the guides, and my valve to guide clearance was .0047 and .0053 on the intakes and .0025 on the exhausts.
This is where my excessive oil consumption was coming from and I believe the temps may have come from the air/fuel mixture being so contaminated with oil that it essentially lowered the octane rating of the air/fuel charge causing my timing to be too advanced for the conditions.
I have been told that all 04 and up conversions have a problem with oil consumption and high temps due to the motors wet sumping if ridden at 4000rpm or higher for any length of time and the only way to fix it is to somehow reduce the oil pressure at the higher revs yet keep the stock pressure at the lower revs so the lifters don't bleed down.
A pressure relief valve in the oil return plumbed to the pressure side is the only solution I could think of to do this.
Have any of you heard of this particular problem with the newer Sportsters or have any of the folks with conversions on their Buells suffered the same fate ??
The theory I am being told is that the wet sumping keeps the heads from draining thereby causing the seals to become submerged in oil and letting them then fail to keep the oil from entering the combustion chamber through the valve guides.
I'm having a hard time believing this as I tested my bike by running it at 5000rpm and higher for 25 miles and observed no oil coming from the breathers nor did I have any oil coming from the one exhaust valve that had a reseated seal on it.
I am currently having the guides and seals redone on my heads to hopefully solve the consumption issue and hope proper tuning will alleviate the temps, but I am being told that perhaps the problem will continue due to the wet sumping issue if I ride my bike hard....and I certainly do.
Any info or help in this matter would be greatly appreciated, however I cannot check anything on the bike right now for you guys as I am stuck in the high desert in California supporting the current Space Shuttle flight.
If something needs to be looked at to troubleshoot I will hopefully be back home in a couple of weeks, right now I'm just looking for info to chew on.
Thanks, Chris |
Blake
| | Posted on Wednesday, June 13, 2007 - 12:41 am: |
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Appropriate professionals have been notified. 
Oil will carbon up the combustion chamber which in turn will cause it to run hot, yes?
I'd think positive and hope that the new, properly installed valve seals will do the trick, but I'm no expert. Just lazy.
The wet sumping would show up on a dyno as it would rob a lot of power from the engine. You might have to do a full blown 1st thru 5th gear run though in order to catch it. Or run it on an eddy current brake dyno so you can keep it revving at WOT and high rpm. |
Cjburr
| | Posted on Wednesday, June 13, 2007 - 01:03 am: |
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Thanks, the more info I can get the better off I'll be. |
Pammy
| | Posted on Wednesday, June 13, 2007 - 09:10 am: |
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I can almost picture the face that would be spouting all that mis-information.
First off, the clearances are WAY too gi-normous! For bronze alloy(Cycle Rama guides), the clearances should be .001 for the intake and .0015 for the exhaust. Now the clearances for stock guides will be a tad more loose but not to the extreme you are seeing.
Secondly, the motor doesn't know if it's an 883 or 1200. If there was no carry over(wet sumping) before, there should be none now. That is, if nothing has gone wrong.
Tell us how you are measuring the valve to guide clearance. |
Pammy
| | Posted on Wednesday, June 13, 2007 - 09:18 am: |
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Oh, and oil in the combustion chamber will cause the motor to run hot. Sometimes to the point of detonation and destruction. |
Revperf
| | Posted on Wednesday, June 13, 2007 - 09:30 am: |
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I can't offer anything other than what Pam did because, as usual, she is right on target. Needs to be addressed asap though, because, as she said, you are setting yourself up for a potential detonation nightmare with all the oil contamination. As carbon deposits build they can form gas pockets in them that will then detonate like bombs in the combustion chamber. This will carry all the way to the rod bearings like hitting the top of the piston with a hammer. A word of caution. If the guides are being replace again I would assume that this now will be the third time that a guide has been in and out of the same guide boss. Please, please make sure that the bosses are properly measured and the appropriate crush is placed on the new guides so that you don't get oil leaking by the new ones and set yourself up for a whole new set of problems. |
Cjburr
| | Posted on Wednesday, June 13, 2007 - 08:13 pm: |
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Thanks for the input.
Pammy, I measured the guides by taking a mold of them and measuring the mold with an optical micrometer, the actual measurements were .00473 and .00531, the optical micrometer is certified to measure out to 5 places.
There was plenty of carbon in the combustion chamber when I tore it down to inspect. The bike had started to ping at take off when it was hot and no amount of retarding of the ignition would make it go away.
I am being told that the Sportster motor wasn't designed to run for any period of time at rpms above 4250....I find this statement ridiculous.
If this were true why on earth would anyone go with a big bore kit and cams that make power above that rpm ?? My S1W will run all day at higher rpms than that and have no problems.
More importantly why would all these companies show all these dyno sheets of their kits making all this power above 4250rpm if you can't ride the bike at those speeds.
Pammy, you guys are in Florida correct ?? I wish I had remembered you when it was time to fix my heads. The fellow who is fixing them was recommended to me by the tech rep from Ferrea, his name is Ron Hamp, he has built many XR750 flat track race bikes and comes well recommended. I believe he will do a thorough job for me, but you were closer.
The bike never exhibited any wet sumping as an 883 and didn't use any oil to speak of. I was very meticulous with the build of my bike and checked and doublechecked every measurement, squish, valve pocket, etc, etc.
I take it that you guys are not experiencing any problems with conversions on the 04 and up motors ??
I will reassemble the motor when the heads are done and we will see if the problem persists.
Thanks, Chris |
Pammy
| | Posted on Thursday, June 14, 2007 - 05:04 pm: |
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Cycle Rama is in Florida. Wes has heard of your new head guy, but he doesn't know anything about him.
Changing the guides should be a snap.
Were these new heads? |
Cjburr
| | Posted on Thursday, June 14, 2007 - 07:04 pm: |
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I got the heads on ebay and they were supposed to only have a few thousand miles on them. The carbon build up on them and the pistons that came with them supported that, but you never know.
Because of this I had them completely gone over and upgraded to stage3 along with new pistons to go with the chamber work about 2500 miles ago.
I also performed a leakdown test on the motor and got only 2% leakage on both cylinders if that helps with any diagnosis.
If I can get the bike to run down the highway without the high temps and oil usage I'll come and see you guys for some dyno tuning. I'm over in Edgewater, just south of Daytona.
Have you guys and gals seen this before on the newer bikes ??
Thanks, Chris |
Pammy
| | Posted on Thursday, June 14, 2007 - 07:59 pm: |
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Ron Hamp, reworked the heads? Were the guides/valves replaced?
Come on over anytime.
We have not seen/heard of this trouble in the newer Sportsters |
Cjburr
| | Posted on Thursday, June 14, 2007 - 09:36 pm: |
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No they were done by another shop, I am having him do them over to make sure they are correct this time.
I have been mulling over the oiling system to try to understand why it seems the older models with conversions don't seem to be having this issue.
This is my theory, if I am misunderstanding how the system works I would appreciate you correcting me. I'm not saying there is a problem with wet sumping as you haven't seen it.
I believe the 2 sections of the motor are separate from each other except for the oil passage from the sump. The heads are only connected to the cam side and the crank side is only connected to the cam side by the oil passage from the sump to the cam chest.
The only pressure the cam side sees is from the oil being pushed through the passage on the downstroke. That pressure is vented through the breathers.
The vent from the oil bag to the cam chest allows the pump to send the oil to the bag without pressurizing the bag and blowing the cap off. It is not there to vent the cam chest, the breathers do that.
The upstroke actually causes a vacuum to form in the crank side, the better the ring seal the better the vacuum. This vacuum is also pulled through the oil passage from the sump causing some vacuum in the cam side which in theory should actually help pull oil through the drains from the heads not hinder it.
The only oil it would pull back into the crank sump would be the amount in the passage at most.
With the better ring seal of the conversion you get a better vacuum in the crank side on the upstroke and more pressure on the oil being forced to the cam side on the downstroke. The oil squirters are introducing more oil into the crank side than the motors without them. If the passage wasn't changed to allow for the added volume of oil it might be possible that the system is not able to evacuate enough oil causing the wet sumping issue at the elevated rpms.
The pump doesn't have a pressure regulator so the squirters are going to be putting out more oil because the pressure is increasing with engine speed.
This may explain why the earlier bikes with no squirters don't seem to have this problem.
The more I look at this the more ingenious it is to me. It uses the forces in the motor to move the oil where you want it to go with no moving parts.
Is this essentially how the system works??
I'm not sure there really is a wet sumping issue with the newer bikes that have squirters but if there is perhaps this could be the cause ??
I wish I knew more about the older bikes without squirters, like how big the passage was from the sump. I was shown by someone smarter than me about these motors who posted the manual for the older ones and the newer ones and the only difference was that the heads drained into the crank area on the older ones and into the cam chest on the newer ones.
Crap!!!! that means there is less oil being introduced to the crank area on the new ones except for the squirters, I wonder if the volume of oil from the squirters is more or less than than what was draining from the heads on the older ones.
Oh well do I have the basics right ??
Thanks again, Chris |
Blake
| | Posted on Thursday, June 14, 2007 - 11:17 pm: |
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Dang! My head hurts! LOL!
Actually Chris you gave a darn good written description; I was able to reconstruct the applicable picture in my mind and follow along.
One data point I can add is that the older Buells like my '97 Cyclone do have some issue with wet sumping at prolonged high engine speeds. Henry Duga recommends swapping to the 1998 version oil pump in order to address that issue. In so doing there is also some slight modification required to the cam box side oil passages, either a hole drilled or plugged, I cannot recall. I still have my '98 oil pump in the box waiting to be installed.
You have email via BadWeB PM.
You also have a great attitude. Kudos to you for that. |
Cjburr
| | Posted on Friday, June 15, 2007 - 12:31 am: |
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I'm an idiot...can't seem to find out how to access my pm's. Do I need to set up a user account ?? thought I already had one.
Chris....the one wandering blindly in the BadWeb forest. |
Blake
| | Posted on Friday, June 15, 2007 - 06:02 am: |
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PM's are sent to your email, the one you used when you registered your account. |
Cjburr
| | Posted on Friday, June 15, 2007 - 07:15 am: |
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Thanks Blake. |
Blake
| | Posted on Saturday, June 16, 2007 - 12:41 am: |
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Chris,
Trust me, you are not alone in the PM quandry. That question pops up about once a week. I'm happy to help clear it up.
I sure am sorry for your trouble.
I just re-read your first post more carefully. I agree with you. Whoever tried to convince you that oil was gathering in the heads due to wet sumping is not someone I'd trust concerning my engine.
Sounds like you are well on your way to resolving the issue and I'm betting that the new seals, properly installed, will solve the problem and get you back to all smiles and miles of riding. |
Blake
| | Posted on Saturday, June 16, 2007 - 12:44 am: |
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Thanks Pammy and Brian for taking time to advise Chris on this issue. I sure do enjoy reading what the pros have to say on such issues. |
Cjburr
| | Posted on Saturday, June 16, 2007 - 01:42 am: |
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From further research by others also trying to find differences between the Buells and the Sportster motors, it seems there is a reed valve between the 2 sections of the motor in the Buells (XB's) is this correct and what purpose does it serve ??
I am assuming it allows air from the gearcase to go to the crankcase on the upstroke of the pistons to eliminate the vacuum caused by this in the crankcase of the Sportsters. If it allowed the pressure of the downstroke to vent to the gearcase that pressure wouldn't push the oil out of the crank sump to the gearcase to be scavenged.
Or does it give the engine the opportunity to transfer more of the vacuum into the gearcase to help the heads drain ?? Without it you only have the one passage from the sump to transfer the vacuum, or am I reading the oil schematic wrong and there is more than one passage.
I kind of envision it like the difference between someone taking a breath through a straw and then blowing through the straw and someone taking a regular deep breath and blowing through a straw. More volume and pressure the second way.
Do the Buells have the scavenge port at the front of the crankcase like the Sportster or at the rear like the 03 and older models ??
I'm basically trying to see what the differences are between the bikes that don't seem to exhibit problems and mine. I may very likely not have any problems once the heads are squared away but I still enjoy learning along the way as it may help in the future.
Do the XB's have the scallops on the flywheels for a crank position sensor ??
The fact that my scavenge point is in the front of the crankcase makes me wonder if upon acceleration the oil would tend to pool at the back of the crankcase and then have to pass by my scalloped flywheels where it would be whipped into a froth on it's way to the sump.
sorry if these are rudimentary questions but I am still a novice with these engines and a curious ba$tard too
Thanks again, I'm glad my Buell brought me here to give me another source of good info. Never really thought it might help the old Sportster too.
Chris...currently roasting in the desert. |
Revperf
| | Posted on Sunday, June 17, 2007 - 10:24 am: |
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Chris,
Ron Hamp is a personal friend of mine. You are better than fine with having him work on your stuff. Very smart, capable guy. Either way, I would really encourage you to not worry about the overall mechanics of the oiling system of your Sportster. That ain't the root of your oil consumption problem. I personally know one of the guys that rode one of the rubber mounts during development at Talledega close to the redline for hours. 883's and 1200's, btw, not that it matters.
Brian |
Cjburr
| | Posted on Sunday, June 17, 2007 - 12:02 pm: |
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Thanks Brian, that was my take on Mr. Hamp from my conversations with him also but really good to hear from someone else too.
I'm not really worried about the oiling system, I'm just curious about the differences between the Buells and the Sportsters. I can't see Buell making these changes to the basic system for no reason and have to wonder why they were done.
The Buells seem to have always been ahead of the curve with respect to these engines and if they make a change to a system one can't help but wonder why.
I don't plan on splitting my cases and doing all sorts of mods to them, just curious about the differences.
The reed valve between the 2 sections if it is there really piqued my curiosity.
Chris |
Cjburr
| | Posted on Monday, June 18, 2007 - 12:26 am: |
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Closer inspection of the oiling diagram someone was kind enough to post for me has revealed I'm an idiot and the return for the sump is at the back of the crankcase not the front.
I'm relieved as being in the front made no sense to me.
still curious about the reed valve in the Buells though.
Chris...my brain is becoming jerky in the desert |
Cjburr
| | Posted on Wednesday, June 20, 2007 - 07:45 pm: |
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anyone find out about these reed valves ???
are they at the crank sump? or between the gearcase and crankcase?, do they exist???
Am I losing my mind ????
Thanks, Chris |
Pammy
| | Posted on Wednesday, June 20, 2007 - 09:45 pm: |
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There are none...That doesn't mean you aren't losing your mind though...  |
Cjburr
| | Posted on Wednesday, June 20, 2007 - 11:20 pm: |
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Thank you...a definitive answer for both questions from someone who knows and has actually taken the time to personally listen to my rambling questions. 
I saw a very strange thing while looking at pictures from the 06 manual. They show a couple of pictures of the inside of the crankcase and in one there is clearly a slot in the case right above the cam bushings that is open to the gearcase, yet in the next picture the slot is no longer there.
Is the crankcase vented to the gearcase on the Buell's ?? It would seem that they should be, otherwise when the pistons go up you would create a vacuum in the crankcase.
Chris...the one with the slipping cogs upstairs 
Thanks again Pammy, you rock  |
Blake
| | Posted on Thursday, June 21, 2007 - 04:04 am: |
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Vaccum in crankcase maybe good. Pretty sure good. Pressure bad. |
Pammy
| | Posted on Thursday, June 21, 2007 - 06:07 am: |
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Pro Stockers run vacuum pumps even to create negative pressure in the crankcase. Vacuum is our friend...
Keep in mind that when one piston is going up, there is another piston coming down. |
Cjburr
| | Posted on Thursday, June 21, 2007 - 08:02 am: |
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Very true on a V8 or V6 engine but I believe on these common crankpin VTwin engines the pistons follow each other so closely that they are going up and down almost together except for a few degrees of crankshaft rotation.
This is why they are a variable volume crankcase engine unlike a V8 where when one piston is going up one is going down and the volume of the crankcase remains constant.
The two halves (gearcase and crankcase) are vented through cast in passages in the older models but it seems the passages might be gone in the newer models.
Vacuum is a good thing in the V8's, it helps with ring seal and blow-by. On these engines it would seem having vacuum in the crankcase on the upstroke might facilitate carry over through the sump passage to the oil pump and through the crankpin roller bearings. That could only happen if the two halves of the engine were separate from each other except for the passage from the sump to the oil pump.
Having the crankcase separated from the gearcase on the downstroke would pressurize the case and facilitate pushing the oil from the sump through the passage to the oil pump. This would make some sense unless the the route from the sump to the oil pump is sealed and the pump is able to scavenge at all times and doesn't really need the assist of the downstroke to pull oil from the sump.
I would really like to understand this system. Let me know if I've really bungled something here.
Thanks, Chris |
Al_lighton
| | Posted on Thursday, June 21, 2007 - 10:06 am: |
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The XB engines do have a reed valve that is in the wall between the main flywheel cavity and the cam chest. The tube frame and older XL engines don't have the reed valve. I have no idea about the newer sportster engines. But it wouldn't really make sense for them to have it. The XB engines have an additional path up to the rocker boxes for blowby gasses through the pushrod "tubes" via a third hole between the two lifters. But since sportsters still use true pushrod tubes, they don't have that third hole.
My understanding is that the reed valve opens as the pistons come down and push blowby gasses through the reed valve into the cam chest and up to the rockerboxes. It must still be a parallel path for blowby gasses to the oil drain back tubes in the cylinders. But on the piston upstroke, the reed valve closes and prevents flow reversal through that third hole in the pushrod tubes. I may be wrong, but I think that's it's purpose.
Al |
Pammy
| | Posted on Thursday, June 21, 2007 - 01:03 pm: |
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You are correct about the pistons following one another so closely. They are only 45 degrees apart. |
Cjburr
| | Posted on Thursday, June 21, 2007 - 08:23 pm: |
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Thanks Al and Pammy. Al from the way the reed valve stop is shaped I would say you are correct. The stop is bent towards the gearcase so the reed valve will open that way and the vacuum created by the pistons going up will pull it closed.
This venting of the crankcase on the downstroke means one of two things to me.
1. The oil pump doesn't need much of an assist from the downstroke to scavenge the sump, perhaps the passage to the pump from the sump is sealed to such an extent that the pump acts like it has 2 scavenge sections(would be nice)
2. The pressure vented from the reed valve isn't so much that the pressure created by the downstroke can still force the oil from the sump to the pump.
Could the third hole between the lifters be the drain from the pushrod side of the heads ?? Is this hole's exit in the gearcase ??
hope you guys an gals don't mind all my questions...don't wish to be a pest, just trying to learn.
Chris |
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