| Author | Message | ||
     Versatileman |
Hi all, I have been reading the posts in this forum for the past few months, but I think this is my first post, and it is a question that I would really rather not have to post. I bought a 1997 S3T back in May and I love the bike. I bought it with 23,000 miles on it and I just rolled over 26,000 today. Here is my problem, it has developed what sounds like a rod knock (or maybe wrist pin noise) over the past 200 miles. I read tons of posts on primary chain noise and compensator nuts coming loose, and I have checked these things, but the noise is still there, especially warm, and it is getting worse, . It has had the oil changed with Mobil one 20W-50 every 1,500 miles and the dealer said that this is the same blend that has been used in the bike for the past 15,000 miles. I hate to do it because it runs soooo good, doesn't burn any oil, and has almost no valve train noise, but it looks like I am going to have to pull the motor and tear it down, but I am having a real hard time finding part info on the internals of this motor (I ordered a factory service manual yesterday). I guess my questions are: Has anyone else had the same problem? and what is the internal differences between this 1200 and a sportster 1200 of the same year? Are the rods, pistons and gaskets interchangeable? Sorry for the long post and all the Q's, but this is my first V twin and I do not possess the knowledge that I would like to on this engine. - p.s. I am a GM master and ASE master tech as well as a certified Polaris tech and I used to be a Cat Master tech so I am comfortable in my abilities, I just lack experience with this motor so I am asking the experts. Thanks Guys, can anyone help a newb out? | ||
| Blake |
Doug, The factory provides a parts manual as well; it's worth the investment. I know the pistons are different. I woudln't think the rods or gaskets are different but I'm not at all sure. Any Buell dealership should be able to tell you though.  | ||
| Versatileman |
Thanks for the reply, I hate going to the dealer because it is over 2 hours away, but I guess I may have to. | ||
| Pammy |
Are you sure a lifter isn't going? | ||
| Pammy |
I know you said it didn't have any valve train noise. But a lifter that has collapsed can make some god-awful racket. | ||
| Pammy |
Also, if the lifter turns and takes out the cam... | ||
| Blake |
Doug, Give one of our dealer-sponsors a call; they'll put a manual in the mail to you and give you the information you need right now over the telephone. | ||
| Versatileman |
Blake, I will do that. I am almost positive that the noise is at crankshaft speed. I can hear some valve train noise, but nothing major. (nothing outside of normal) The knock is most prominent at deceleration and at that "float" right between shifts at no load. I can sometimes duplicate it by holding the engine at a constant 2,000 rpm's. I wouldn't expect a lifter to be that sensitive to load and come and go like that. Also, even though it is a twin cam, I assume that the cams move at half crank speed, so the noise would be at a different frequency. However, I am not at all comfortable diagnosing a motor that I have little experience with, so please, if I am wrong, please correct me, I really appreciate all of your guys input. | ||
| Jlnance |
Give one of our dealer-sponsors a call Welcome to Badweb Doug, it's good to have you here. Since your new, I thought I'd mention that Pammy is one of those sponsors that Blake is taking about. She and her husband run Cyclerama. | ||
| Pammy |
Dude the Sportster/Buell engine would be a 4 cam set up. Technically I guess that would be a twin-twin cam. All joking aside...the discription you give above could be:at the least...a loose alternator. Or it could be piston slap or wristpin noise. | ||
| Versatileman |
I am going to bring my mechanics stethlescope home tonight and try to pin-point the noise location. My crude -prybar to the ear- method showed te most likely source to be either in the right side engine cover or the crankcase. If the problem was only when the motor was cold I would say that it sounds alot like excessive piston slap (it has that kind of resonance). My fear is that it is not worn bad enough to see when I tear it down. Thanks for the ideas, | ||
| Pammy |
Keep us posted on what you find. | ||
| Court |
If you need a 1997 S3-T Service Manual, just let me know. | ||
| Versatileman |
Well, I had an extra few hours tonight after work so I striped the top end and pulled the cams to check for excessive wear. Here is what I found. Someone has been in here before, the cam gears were marked w/ red paint stick, kind of redundant since they are stamped, but who knows (guess I need my manual to arrive before I can re-time them) The cam lobes and lifter rollers looked like only light wear. The piston tops are carboned, but looks like normal wash. The cylinders are clean and the rear jug is only very slightly scratched in one small spot, the piston has the same scuff on the forward facing side (someone beat on it before the motor was warm and the piston expanded before the jug) I was suprised to find bushings instead of bearings on the rod ends and cams, but they look ok, minimal scoring. The bottom rod bearings feel tight but I can't see much of them unless I pull the crank, and even then I am not sure I will see much. The Heads look ok, I will probably pull the valves tomorrow at work and clean them up and check the seats. This is what I was afraid of, no real noticeable problem except for a little piston scuff. I will pull the primary and flywheel tomorrow. I hate to have to split the cases because I'll have to pull the motor, but maybe that is next. -Does anyone know if the manual gives specs for bushing ID for the cams and the rod ends? -If I replace the rod end bushings does anyone know if they come pre-sized, or if they need to be sized at installation? -If I replace the pistons, should I just go w/ Buell parts, or is there another piston brand you would recommend? -Anyone got any other ideas to check besides striping the crank out of it? Thanks, sorry for the HUGE post Thanks, | ||
| Court |
>>>-Does anyone know if the manual gives specs for bushing ID for the cams and the rod ends? It does. | ||
| Pammy |
The red paint is usually to indicate the cam gear size. I would have taken the primary off first. Can you send me pics of the pistons and cylinders? Do not mess with the rod end bushings. | ||
| Versatileman |
I am going to pull everything and separate the flywheels to inspect the rod pin. I had a harley tech look at the pistons and he said that the minor scoring on the rear piston looks like it was caused by hardened material, not just a little cold seize / scratch. He said that he has seen several of these motors have the crank pin start to flake and cause the symptoms that I am describing. If I have it this far apart, I might as well replace the crank bearings, pistons and pins. Does his advice sound right? | ||
| Reepicheep |
You checked the oil pump pinion gear, that's tucked inside the cam cover, right? It's the one on the crank, not the one on the oil pump. Look for missing teeth, it is usually assymetrical wear. Regardless of it's condition, I would seriously consider putting in the new upgraded race part from the factory when I re-assembled. (note, don't confuse me with someone who knows a lot, defer to Pammy for that. I just know what broke on my bikes and look for that). | ||
| Versatileman |
Thanks for the input, it is not missing teeth, but the teeth do look a little worn, actually it looks like the hardened coating is starting to chip, or wear through. I'll replace that too. Hey Pammy, what is your guys ship time to MI, I may be putting in an order | ||
| Pammy |
MI is about 3 days via UPS | ||
| Versatileman |
Well, here is the deal. I separated the flywheels and dismantled the rod, pin and bearing assembly. The center of the rod pin (the bearing surface for the knife rod) is badly marred. I brought all the parts to the dealer that I bought the bike from (1,700 miles ago) and asked if there was anything they could do. The salesman that I bought the bike from literally disappeared once I told him what happened. I guess it was easier to run away than deal with the possibility of me asking for a break on parts or labor (which I really did not plan on doing) The service manager was a great guy who took the time to explain what they could do to rebuild the crank and I opted for them to replace the pin with an oversized one and cut the bearing surfaces to match the new rod bearings. p.s. The rod big end bearing sleeves are made of unobtanium from HD, It is not that they are on backorder or anything, they are obsolete - nice. Anyway, he is going to replace the small end bushings and cut the big end to match the new pin and hopefully I will be reassembling the motor Friday. I am going to replace the pistons with Weisco and I will cut the cylinders and valves here at the shop this week. It sucks that I have to completely rebuild this motor at 26,000 miles, but I sure don't see putting it back together with old parts (pistons, pins, crank timkin bearings) now that I have it this far apart. Just can't let my wife find out | ||
| Blake |
Shhhhhhh. You sure did dig right into it. You must be very comfortable working on engines. | ||
| Versatileman |
eh, an engine is an engine, its just a machine. Compared to a GSXR1100, or any inline motor, this thing is a cake walk. And yes, I have had some pretty good training in small engines too. I just have a hard time letting other people fix my stuff. | ||
| Versatileman |
Well, she is all back together. The rods were machined .020 over and a larger pin and bearing assembly was used. I re-assembled the crank and put new small end rod bushings in and honed them to size. The cylinders were machined, the pistons were replaced with Wiseco and the valves and seats were cut (I was amazed at the pitting on the exhaust valve seat). Add a james gasket set and she is good as new, maybe better. I am not real happy with the guy that sold me the bike (a local dealer) and told me that the bike was babied its whole life. The machinist that cut the rods told me that this type of failure is typical for bikes that get beat on real hard, seems the rod big end gets out of round and the slop allows the rod bearings to beat the pins surface, causing my failure. Good thing I love the bike or I would be real p.o.ed. Thanks to all for the advice and words of wisdom, hopefully I can repay the favor someday. | ||
| Blake |
Your attitude it admirable. Way to "giterdone".  |
