| Author | Message | ||
     Jrad012x |
First post on this forum b/c I just bought a salvaged non-running 2004 XB12R as a project bike to keep me busy during my free time. The bike has over 7000 miles on it. After thorough trial and error, I determined the cause of the bike not to start due to intake valves being stuck. Today, I disassembled the bike all the way down to the heads and gear case cover off. The valves did not open because the bike was sitting for a very long time and carbon built up causing them to stick. After trying to start it before, this caused the exhaust push rods to bend. I checked the cams and the cylinder walls and they both are good. My only problem as of right now is one intake and one exhaust valve is not seating properly. I am hoping the cause is due to carbon build because there is a ton of it on the intake valves and valve walls. My first question is how hard is it to remove, inspect, and install valves? If I remove them, should I port and polish the intakes? How hard is it to port and polish the intake valves yourself? Should I or is it worth doing any other performance mods to the engine (i.e. bigger displacement, different valves/cams/rockers...etc) since I have the bike apart, the bike has over 7000 miles, and I do not know the history of the bike (I came from riding a '06 Yamaha R1 and still enjoy the speed, but still want a reliable bike)? How big of a engine mod can I do while still having a reliable bike? Basically, I need help with the valve problem, but am in need of advise on whether or not to do a engine performance upgrade. I've searched many hours on engine mods but never found a straight answer b/c every engine mod is different for everyone. I would like more mid to high performance since it has a good low end already. If this was your situation, would you do any mods to the bike at this moment? My budget is relatively reasonable since I got the bike real cheap. Thanks, Jason | ||
| Smoke |
what are your previous mechanical skills and current tool selection? have you ever rebuilt any motor? easy fix- buy 2 pushrods, take head to local shop for cleanup and reinstall. go ride and feel for what you think you might want. find another local xb guy and get familiar with ecm spy. exhaust options are in your future. post some pics of your current exhaust. tim | ||
| Aeroe |
I'm helping Jason work on his bike. As far as we can tell, everything on the bike is stock, including the exhaust. With the whole top-end of the motor disassembled, would any of you do any modifications before putting it back together? We're trying to take advantage of an unfortunate situation. | ||
| U4euh |
Look for Mike Miller at Ray Price HD/Buell and ask him for his advice, he recently did some upgrades along the same line. | ||
| Akbuell |
Engine mods are strictly limited by your wallet, actually. Porting/polishing the intake and exhaust ports is a time-honored way of getting more power. Compliment that with opening the air box, and possibly a different muffler. My big concern is the stuck valves. While carbon build-up MAY be the cause, normal valve action generally keeps the valve stem clean. Possibly the fact that it sat for some time is the reason for sticking. In any case, be sure to do a careful inspection of the guides, as they may be scored. If so, they don't get better, and will lead to more stuck valves, with possible/probable valve-piston contact in the future. A very careful inspection of the top of the pistons is in order. It may have sat for so long, and have bent pushrods, because a shift was missed and the valves hit the pistons, bending the valve stems. | ||
| Azxb9r |
If a vehicle sits for a long period of time, and the fuel goes bad, it will cause the valves to stick when you try to start it . I have seen this several times on cars that people have parked for extended periods. | ||
| New12r |
I leave all my bikes stock other than a muffler, and I am pushing 60k between two motors, and U4euh has the first one still ticking in his ride! Modifications IMO dont give enough return for the money. You get maybe 10 hp for $500 worth of head work then you get the headache of tuning to go along with it. Build it to stock, ride it and love it! Just my 02 after 5 years of happy XBing! | ||
| Jrad012x |
I took the heads into a local shop to have the valves professionally checked and replaced if necessary. I will more than likely keep the engine stock and just add an exhaust and ECM to the bike for now. I appreciate the advise and keep it coming if have more. I will keep everyone updated on the status of the bike. I cannot wait to get the bike up and running. Thanks, Jason. | ||
| Akbuell |
And before I forget, be sure to replace the cyl base gaskets when you put it back together. Pretty much a given to have a leak there if you don't. And you do have a service manual, correct? The procedure for bolting the heads back down is different from what you may be used to. |
