| Author | Message | ||
     Kyrocket |
I'm at wits end! For those that have been around you know about the blow up and subsequent rebuild with the 1250. Well, after putting 100 miles on it I was losing valves. I'm beginning to think it's the actual rocker box itself. I replaced mine with those off of a XB9 and while they should have been the same it measured a few hundredths shorter so I put the originals back on last night along with the head and two new valves. When I turned the rear wheel nothing in the front box moves. The piston is moving up and down in the cylinder but that's it. So I'll tear everything back down, AGAIN, and hope and pray it's the lifters. It has to either be that or the two front cams which if my cams went south you'd think you could hear them grind when the tire was rolled. This is really becoming a headache. I bragged on this bike for 24K basically trouble free miles and now this. Are there any other ideas that I'm missing? | ||
| Oldog |
the key way in the cam box sheared its on the driving gear I am so sorry to hear of the troubles you are having, but you are learning a great deal about the finer points of the engines construction ( not sarcasam ) | ||
| Preybird1 |
This is why i did not do my 1250 kit myself. I didn't trust myself enough to get it right. How are you losing valves? Sticking still Or breaking off? Are the valves breaking at the head or the stem at the locks? If nothing is moving i would say lifters. Did you take them out for the rebuild? When my motor grenaded i had the lifters checked and tested to be sure before it went back together. I have to much money and time into my bike to not make sure everything was ok before re-assembly. | ||
| Brinnutz |
No...but enjoy it. =) lol Going on my 1 year anniversary of the last ride on my Buell on the 19th. But that is because I keep adding projects that delay any other progress. | ||
| Fast1075 |
If it sheared the key...that explains the bad valves... | ||
| Dpg |
Not sure about the key way shearing, never have had that problem. I did my 1250 assembly myself and it was a really easy modification. In fact I did the SE cams and springs and an S&S E carb on the bike (Sportster) at the same time. Everything was pretty simple and done with just the FM and parts manual. Only issue I had was that my motor was and early Evo and the pushrod cover bases are an o-ring seal that you have to push in and then do a 1/4 turn. The lower semi-fins on the Millenium cylinders kept me from removing them due to the increased width of the cylinders at the bases. I ended up grinding the side of the cylinders to make the clearance. I'd do another 1250 anytime. This was the first time I had gotten into that motor. Safe ride, Gary in Oaktown | ||
| Rick_a |
Mine nearly sheared that key when it was stock. The pinion nut needs to be over-torqued to 70 ft-lbs to insure it doesn't back out with more aggressive cams and valve springs. | ||
| Brinnutz |
Uh-Oh. I sure hope I torqued mine to that!?!?!? What's the stock torque on it? I put red loctite on mine.... | ||
| 14d |
35-45 Ft-lbs w/ red loctite is what FSM calls for. | ||
| Kyrocket |
I haven't looked at my manual but if the keyway sheared wouldn't it effect all the cams and not just #1&2? I've only put 100 miles on it since the rebuild and those have all been below 3500 rpms. If ya'll remember this wasn't just a 1250 but a full blown split the cases and replace a chewed up crankpin. It looked like an old Coke bottle when I got it out of the flywheels. The valves are bending just above the head of the valve. First was the intake on the rear cylinder then the exhaust on the front. I went ahead and replaced both valves on the front with a valve spring compressor I bought online for $50 to the door. It's already paid for itself. Soooo, I will research this keyway because in reality that is probably the easiest fix baring any other damage it may have caused. Right now I'm taking a daughter downtown to the car show, this bike can wait. Oh yeah, Brinnitz, Sept. 5 was my blow up date so I feel where you're coming from. I think I have an automotive project coming my way so I'm taking pics at the car show, I'll let yous know later about that. Thanks for the ideas | ||
| 14d |
A sheared key would affect all cams I'd think, not just the front two. How are the pushrods looking? Sounds like you need to open up the gear case to get to the bottom of this. Between a burnt out clutch, broken muffler mounts, being injured, work and other BS I've only put 1,200 miles on in the past 10 months. Everything's coming together now, just have to be patient a little longer... | ||
| Rick_a |
That spec is marginal (if not totally inadequate) for heavy valve springs required for more aggressive cams. From NRHS's tech tips on cam installation:
 Something to consider. It's your engine...build it as you will. As I've said, I had mine a c-hair from breaking...it had elongated the slot on the cam drive gear and the nut had lost it's tension. | ||
| Buellistic |
The BLAST FSM says 19-21 ft.lbs. plus and additional 15 to 17 degrees roation ... These are the same parts as in the TWINS ... FSM's are something else from FSM to FSM !!! | ||
| Kyrocket |
Hmmm...left a message early this morning from home but didn't show up here. Maybe I forgot to post but it went something like...if the keyway did shear off wouldn't it affect all the drive gears and not just the front two? I'll agree that both front lifters going south at the same time seems fishy also. The rear is fine, getting good compression and everything. I guess I'll just have to open it back up this weekend. | ||
| Oldog |
you have failures on both cylinders i sadly expect that you will find a mess in there, | ||
| Kyrocket |
HALF A KEYWAY AND WOODRUFF KEY IS ALL THAT RUNS THE TIMING? I put the motor together but never really gave it a thought. The nut backed off just enough to let the gear separate from the woodruff key, just have to tighten it back up. Thanks for the updated info on the torque specs. Glad to be part of a community that knows what they're talking about (politics excluded  ) and is willing to share. | ||
| Oldog |
Good you found it! I hope that there was no other damage. the torque spec should be TTFOI tighten the "Fire" out of it. | ||
| Brinnutz |
So I only tightened mine to fsm spec. Should I redo? | ||
| Kyrocket |
What else do you have to do  ? If you didn't put loc-tite on it definitely pull it back off. Even if you did you may want to think about it. It only took mine 100 miles to back off. | ||
| Brinnutz |
Red loctite and I think I went 40-45 ft/lbs | ||
| Fast1075 |
Don't forget to use a good solvent like BrakeKleen to remove all traces of oil from the threads on the crank and the nut prior to adding the locktite and doing the final torque...the locktite will adhere much better on a clean surface than an oily surface. | ||
| Brinnutz |
Well I didn't do that either. Jim, do you mind if I redo?? LOL | ||
| Oldog |
Non Issue on that tool Brin I know that you are still in progress, I may need your amazing ability to sourse tuber parts, say.... can you find me a pegasus timer cover?  | ||
| Brinnutz |
I'll keep an eye out man! I only have one, but if I had another, it'd be yours! | ||
| 14d |
I just stood on the rear brake while I torqued it to 45, this is making me reconsider... |
