| Author | Message | ||
     Scott_in_nh |
I haven't been riding much the last 2-3 years and my ear has "retuned" itself to all the odd noises that come from the Porsche 914 I'm driving so maybe it is nothing to worry about. I have an extra clatter coming from my 99 S3 that starts at about 3700 rpm. The bike runs great at all rpms and does not make any unusual noises at lower rpms. Normal or? Things to check? I adjusted the primary yesterday, but stupidly did it with a warm motor so I need to do it again. I thought maybe an exhaust leak, but loosening and retightening did not change anything. It is not getting worse, but I am going on about a 1000 mile ride next week so am worried a little. | ||
| Kalali |
I would readjust the chain at room temperature with total slack set at 1/2" at the tightest spot and see what happens. I can't think of anything else that is engine speed related, especially at med-high range, that would "clatter". Rattle yes but internal clatter no. | ||
| Malott442 |
Exhaust hangers? My front rattled at 3800 to 4400 | ||
| Reepicheep |
You know it's bad when the noises alarm 914 owners.  Do you have the flat 6 or the 4? Values for the 6's are getting stupid high. Matt's suggestion is good. Also, do you have the original primary chain tensioner? And if you have had the stator off, what did you torque the crank nut back too? The spec was revised (higher) after the manuals were published. | ||
| Scott_in_nh |
I have the 4 - too poor for the six! I have the upgraded (large) primary chain tensioner. I think it was the first upgrade I did back in 05/06 when I bought the bike! Stator has never been off. The 914 is a 74 - air-cooled, FI, pushrod, 2 valve, 5 speed with mass centralization and a redheaded stepchild to some - sound familiar? Thanks!  | ||
| Kc_zombie |
Gotta love the Karmann's! | ||
| Scott_in_nh |
I've owned a Ghia, Scirocco 16v and the 914 - all built in the Karmann Factory | ||
| Scott_in_nh |
So I went on my ride from the Seacoast of NH to Lake Placid NY with friends from work - including my boss. The bike was still making the noise but otherwise ran ok and we had a great time. five hundred and something miles into the ride and 54 miles from home, I lose power in one of the cylinders. I pulled the plugs and had no compression in the front cylinder. The plugs look fine. This was at about 5:15 pm on Friday. So began the 3 hour wait for AAA to find and get a bike equipped flatbed to me. Today I pulled the front head and I have a bent exhaust valve, but no other damage! So the questions: Was the noise a damaged valve that still let the bike run well or was the noise something else that lead to the bent valve? There are no signs of detonation on the plug, valve, head or piston. The plug is dark if anything, no sign of it running lean. If the sound was pinging I would think that you would see the signs of it in an engine that got hot enough to overheat a valve? My fear is that I put it back together and the noise is still there. Thoughts? Anybody else ever have this happen? | ||
| Stev0 |
Was there any signs of physical damage on the valve/seat ???? Has your throttle butterfly still got both bolts in it ??? | ||
| Scott_in_nh |
No damage to the seat. I didn't look for the butterfly bolts, but the throttle works normally. | ||
| Scott_in_nh |
Can I get a replacement valve at my local HD dealer? If so what is the PN? | ||
| Stev0 |
If you've bent the valve I'd be looking closely at the guide, as it's probably damaged. exhaust valve.. # 18636-98Y guide.......... # 18113-96Y Those numbers are "Y" numbers which from my experience means Buell and hard to get, so it may be easier to go aftermarket. Id' also be looking VERY closely over everything as it's unusual for a valve to bend especially with no obvious signs of overheating... Possible culprit is a seat that's popped out and been knocked back in. If that's the case then the valve seat pocket will have to be machined and an oversize seat fitted... This is a job for an engine reconditioning shop who, preferably, are familiar with HD's. Personally I would class this as a good time to get both heads freshened up, maybe a pineapple hone through the bores and new rings... | ||
| Scott_in_nh |
I put on a 1250 kit last summer and the heads were cleaned and polished at that time including new valve seals. The valve guide and seat also show no sign of damage and the valve still moves freely but not loosely in the guide. I know it is an odd thing, but there is no smoking gun.... | ||
| Stev0 |
Did the noise change with temperature ??? I've chased a noise in a engine before that turned out to be a loose valve seat... not common but I've seen it a few times on Evo Big Twins. | ||
| Scott_in_nh |
No it did not. Looking at the valve, it is clean for 3/16" around the edge and then has an "impact" line across it (really just where the carbon came off". This line corresponds with the bend. I now believe the edge of the valve was being hit relatively lightly but constantly by the piston. That is the noise I heard at 3700 rpm. Why it was hanging up is a mystery, but it eventually got hot enough to really stick and bend. The piston has a shiny spot where this contact was taking place, but no damage. Can a lifter fail in a pumped up mode where it does not let the valve seat? I'll check the pushrods for straightness too, but they appeared to be fine and Ill check for any evidence that the valve seat moved, but I think it unlikely. | ||
| Stev0 |
You said the heads were done up not long ago ??? I've seen a lot of Shovel heads and Ironhead Sporties with that issue if the guide cleaarance is too tight. Can't recall seeing it on a evo/sporty.. Is there any chance the guide has moved in the head ?? I've seen that a couple of times in Evo/Sporties. Haven't come across a lifter issue that's caused that yet but there's always a first time .. 3700 is also a strange rpm as far as harmonics go as it's so low... but check your spring hasn't broken, I've seen that on V8 race engines but never on a HD. | ||
| Scott_in_nh |
Thanks Stevo, parts are ordered and I will give everything a close up inspection before reassembly. All I did to the heads was a visual inspection, carbon removal, hand lapping and new valve seals. (Message edited by Scott_in_nh on August 04, 2014) | ||
| Preybird1 |
Just thought i would chime in here. I had this happen to my bike and your lucky the valve bent and tucked up into the valve guide. I had this happen on the front and then the rear cylinder and i lucked out like you did the first time and i rebuilt it. Then rear went and it sounded like a blender full of nickels. Part of the rear intake valve stem shot through the intake into the front cylinder intake and it all exploded! Total top end rebuild......Heads,juggs,pistons,rods.    second time!   The 1st and 2nd time were caused by HD •••••• Quality control.....The exhaust valve grinds at the keeper were done improperly. This is well known on the tubers of a certain years. They had bad exhaust valves on the bikes. I not sure if i remember anything about the front as well. | ||
| Preybird1 |
I would want to find all the pieces and see what happened. And check the play in the connecting rod(s). I would have a shop you trust check this part. Once i got the hd parts out of the top end this bike it is much better and 10 time more reliable and i don't worry about revving this bike up on the interstate or the track! I would be really interested in the base of the valve stem.....See how my valve is missing the very end where the lock is supposed to be. Mine broke off and the valve dropped and piston came up and presto game over. | ||
| Scott_in_nh |
Hi Russ, thanks for chiming in. What seems to be unique in my case is that I did not have a valve stem failure and there are no pieces. I have a complete valve that is bent, along with springs, keepers, pushrod and rocker arm that are visually undamaged. | ||
| Buellistic |
"i" had this happen to my 2000 BLAST on the EXHAUST VALVE ... In 1999 FACTORY got is a bunch of bad exhaust valves ... The problem was the valve keeper notch was not cut properly and they would break at the notch ... Have no idea how many BUELL engine went south because of this, "BUT" my BLAST was one of them !!! | ||
| Scott_in_nh |
Considering that I cannot find the cause of the bent valve I think I need to take the cam cover off and check the pinion shaft key. I did replace the oil pump drive gear years ago, but don't recall what procedure I used for tightening and thread lock. Any other thoughts? | ||
| Buellistic |
Take your VALVE PARTS to a MACHINIST and have him look at the VALVE KEEPER area ... He might just tell you the VALVE KEEPER notch was cut wrong ... | ||
| Scott_in_nh |
I'm going to pull the cam cover. I think the pinion nut is loose and/or the key is buggered or broke. There has to be a reason the valve was contacting the piston and this is the most likely scenario... | ||
| Scott_in_nh |
So the root cause was a failed lifter pin. No other damage noted at this time. I'm not sure where I'm going to go from here.  | ||
| Reepicheep |
Sorry for a potentially dumb question, but what do you mean by lifter pin? I just pulled apart the lifters on my Uly, and I can't picture what part the "lifter pin" would be, or how it would damage a cam. And hard to tell from the picture, but is that cam worn down at the lobe by like 1/8th inch? Dang. Could that have been a siezed roller? Or just poor hardening on the cam? My M2 had a cam with a chunk that came out of it creating a pit, even with no other problems with bent valves or collapsed lifters or anything. No symptoms either, I stumbled across it replacing the oil pump gear. | ||
| Stev0 |
I think he's reffering to the anti rotation pin that stops the lifters from rotating and keeps the roller on the cam... | ||
| Scott_in_nh |
StevO is correct, the anti-rotation pin is broken and the lifter rotated causing the lobe to wear about 1/8th". I would imagine that the heat caused the lifer to hang in turn causing the piston to hit the valve. | ||
| Scott_in_nh |
So the questions are: 1) how do I get the pin and lifter out? right now there is a piece of the pin still in that is preventing me from removing the lifter. 2)What lifters should I use? Preferably something bullet proof but not too expensive. 3) What should I do to check and clean the rest of the motor? it is not a lot of metal and most of it was below the cam. 4) Should I look for a stock cam with the same size gear (it is marked with a green dab of paint)? Or am I really looking at a complete cam set? 5) If I get a cam set should I step up to an Andrews N6 or stay with the N4? It has a 1250 kit with stock heads and the squish set to <0.040" (no machining, but I measured it and assembled the motor without a base gasket to get it as close to 0.030" as I could). | ||
| Reepicheep |
Thanks for the explanation! That would do it... worse than a stuck roller. |
