| Author | Message | ||
     Sportyeric |
Funjimmy's S1 has lunched its engine, reasons unknown. The rear rod is stiff to move on the crank pin and the rear of the rear piston is heavily gouged. The oil pump and drive gear are fine. It had been rattling a little when cold since a previous rebuild that we thought was a slightly loose-fitted piston (forged piston). It has had a windage tray in it for several years. Our best theory is that the windage tray is preventing adequate oiling to the rear cylinder and crank. The front head isn't off yet. The windage tray will be removed. Any other ideas? What can cause both the lower con rod and the piston to seize? The cam cavity looks fine. | ||
| Firemanjim |
Real cylinders are prone to overheating and seizing ,could have been bad intake seal,also.No way was oil scraper at fault. | ||
| 1313 |
I have nearly 105,000 miles on my S2. When I T'stormed the engine (36,000 miles) I put in a Zipper's windage tray in. Nearly 70,000 miles with no problems due to the windage tray. 1313 | ||
| Jackbequick |
I don't understand the need for a windage tray in a dry sump engine, what's that about. Jack | ||
| Sportyeric |
The con-rod bearing seizing is part of the mystery. Would a "rear cylinder seizing" from, say, an intake leak, cause the bearing to seize also? Maybe flecks of piston getting into the "fork" area? Intake leak might be revealed through whitened plugs? Would have to create whitened plugs? | ||
| Firemanjim |
Jack,under higher rpm's there is enough oil in sump for crank to run through.Scraper is a cheap addition while building motor so why not. Eric,seizing piston will put a hurt on that rod bearing. | ||
| Sportyeric |
Hmmmm. I'll pass that along. Different question now. This one relates to my engine build. I'm thinking that I will try not to use adjustable pushrods after decking the heads 20 thou. If the range of the plunger in the lifter is 200 thou, adjustables would be set to the halfway point, right? Why is that? Why not down to the bottom 1/5 of travel. The cylinder will grow as it heats but won't shrink. If I test with a spare adjustable pushrod and find that at the halfway point its within 60thou of the length of the stocker, I could just use the stocker and let the lifter operate at the 'almost fully compressed' level. I'd stilll have 40 thou at the bottom and all that travel at the top to take up cylinder growth. And if the answer is "pumping up", what does that mean. Or, specifically, how does that happen? What's the mechanism? | ||
| Funjimmy |
A little more info. The engine is now sitting on the bench and the front head and cylinder have been removed. What's quite surprising is that the front rod bearing appears to be fine. As always the front cylinder and piston are both in excellent condition too. Over the years I have had a continuous problem with scuffing the rear cylinder. I originally thought that the engine was running to hot due to other performance mods like Branch heads, domed forged pistons, Red Shift 567 cams....the list goes on. Or maybe the timing was to advanced (dual plug heads), or possibly the fuel mixture was to lean. To address these issues I have built a 3 quart aluminum oil tank with temp gauge. I have had the bike dyno tuned with a gas analyzer to optimize the fuel mixture. I have also added a computer programmable ignition module and set the maximum advance to 28 degrees as advised by Jerry Branch of Branch Flowmetrics. The oil in the tank usually heats up to approx 160 deg F. and rarely to 190 F in hot traffic. But still I have big problems. This is why I have considered the windage tray/flywheel scraper as the last straw. Oil to the cylinder walls is provided by oil whipping off the flywheels and onto the cylinders. The windage tray is at the back of the motor scraping oil off the wheels right under the rear cylinder. Perhaps by the time the oil flies off the wheels it only gets the front cylinder. Can any one shed some oil on this topic. Thanks FunJimmy | ||
| Funjimmy |
I recently read the "How do I adjust my lifter with your HL2T kit installed?" on the S&S web page. They suggest that the proper adjustment for lifters with their travel limiter kit installed is to bottom out the plunger then back out the adjuster approx 1/2 turn. This is considered to be a zero lash setting but would still have some negative travel for wear in the valve train. Remember that new valve seats can be pounded deeper into new and rebuilt heads as well as the need for future valve grinds tolerances. Quote - Some engine builders prefer to adjust pushrods another one- half turn looser. This provides additional travel for the valve in the hydraulic piston assembly. Additional travel can improve the ability of the hydraulic unit to pump up and maintain zero valve lash. | ||
| Rocketman |
Without looking at your engine it's not easy to offer a diagnosis. You haven't posted much info to go on either so consider this. The piston could be scuffed on one side because the crank pin bearing has failed in some way restricting the operation of the rear rod thus placing strain on the piston side - leading to overheating of course. Looking for a possible cause of failure might be leading you up the garden path considering your modifications and how you claim the motor is well set-up. There may well be nothing wrong with your set-up at all, mechanically or otherwise. I'd look closely at the crank pin assembly for fatigue or similar and I'd be especially careful to make sure the crank pin was receiving proper lubrication. When you rebuild if I were you I'd purchase the S&S crank pin and rods for around $400. Rocket | ||
| Funjimmy |
While wrenching around in the garage and tipping a few wobbly pops with Eric last night I remembered a rather important little detail. The last time the bike was running really well was summer 2003 when I rode the SPLASH ride and then up into the interior of the province for holidays. While on route from the interior to Whistler to meet up with everyone for Border Raid, the rear head bolt right above the rear exhaust valve, although torqued, backed off causing the head gasket to fail. I had no options other than ride the last 100 miles home with a blown rear head gasket. In a panic to continue the balance of the season on the Buell, I just popped the head, swapped gaskets and bolted it all back together conveniently forgetting about the potential damage. The following year the bike was down for other reasons and when I finally got out on it this year the bottom end failed. Now I know what took the piston out and I’m quite comfortable with the consequences, but is that the reason for the rod bearing failure? FunJimmy | ||
| Rocketman |
A failed head gasket is unlikely to cause any mechanical damage - period. You know what took the piston out? Did I miss something? Rocket | ||
| Fullpower |
just after assembling an S&S stroker sportster motor, i had a weekend ride planned. worked all week, and tried to get the break-in and a couple oil changes done in the evenings. had some detonation problems, checked the cranking pressure: 240 PSI cold, both cylinders..... consultation with S&S..... i was running flat tops with 4.3125 stroke into S1 Lightning heads. 3.625 bore. somewhere north of 13 to one compression. so saturday morning comes , i've been talking up this ride to hope for 3 weeks, pestering every rider i know. so i fill the sportster up with half methanol, and half 100Low Lead aviation gas. running GOOOOD! i am riding 2 up, 12 year old son on back, wife leading FAAAAST. packing a gallon of methanol and an octane boost in saddlebag, for return trip. we get to Hope, settle in to cabins, etc. start enjoying the "small town atmosphere" before long we are making some extremely hard launches out on the paved road. painting the road black, and sure enough, I blow rear head gasket.... blaaat blaaat. gasket is WAY blown, part of it sticks out. rode home (150 miles) with son on back, it was able to keep up with one cylinder, each jug is 729 cc, so it was still a bigger motor than most motorcycles in the world. pulled heads off, got the grinder out and removed 7 cc of aluminum dust from each head. got the cranking compression down to 205 PSI cold. still has an appetite for OCTANE, but has been reliable for 25,000 miles. | ||
| Funjimmy |
Rocket Blown head gasket should cause a lean condition on the rear cylinder. That will drive the heat up and stick a piston. | ||
| Rocketman |
Jim, the gasket would have to be in a pretty weird condition to suck air in. It's more likely a failed head gasket will allow compression gas to be pushed out of the cylinder under compression on an air cooled engine. Hence the sometimes heard squeak?? But I'd enjoy the benefit of your knowledge otherwise. That's a trick looking S1 you got their Jim  Rocket | ||
| Funjimmy |
Rocket Thanks for the complement on the scooter. I am by no means a full source of info regarding air cooled engine failures, but I recently faxed off a copy of the dyno chart as well as a list of components in this engine and was told that the state of tune is certainly suspect. Seems that the plugs that I had installed where way to hot for an air cooled Buell engine and that the dyno chart shows combustion issues occurring around 5700 RPM. This probably manifested in detonation that subsequently blew out the head gasket. The underlying problem would have created considerable heat in the piston and head that would have stuck the piston, and the detonation could have pounded out the rod bearings. Maybe your are right about the head gasket not being the cause but rather a symptom. All that matters is that we cure the cause and not just treat the symptoms. Hopefully we all avoid a similar situation in the future. I'll post some pictures as I get the engine further apart. | ||
| Blake |
Pammy and Captain Pete might be able to provide some insight into your problem. | ||
| Captpete |
Sure, I'd be happy to share my insights on that one. If it were me, I wouldn't bother pulling the aft jug. I'd just throw the whole thing away and start all over again. It has a terminal illness. Uncommon in Buells, but there are documented cases. Ron Dicky can tell you about one, and maybe two. I can tell you all about one. Don't waste your money on surgery. | ||
| Funjimmy |
Pete What do you mean? When you say just toss it and start over. That's a little drastic. How can I cure the problem and what was (is) the cause. FunJimmy | ||
| Pammy |
What Petey is saying is when you have continuous problems like that sometimes it is best to start from scratch. Capt Pedro, had an S1 rebuilt(from new it was problematic)several different times by 3 reputable shops. He was recommended to bring it to Cycle-Rama because we have an excellent reputation for doing things that supposedly can't be done. Well, let me tell you there are some things that CANNOT be done. Through all my years on this earth, this was the first time that the meaning of the word CAN'T was ever so clear in my mind. If I could type faster/better I would give you the whole rundown...But I don't. If you want to call me about it or maybe Capt Pedro the Shark Shanker can fill you in. He is much more intertaining than I anyway. |
