Hi guys,
i replaced broken intake valves and bolted the head on, only to find that i can't install any of the buckets. They go in just a few millimeters before becoming too tight and if i apply any pressure at all it becomes very hard to remove them.
A shop took the valves out for me so I don't know which bucket came from which valve, but I've tried them all and couldn't fit even a single one. I also measured their diameter with a calliper and as far as i can tell they are exactly the same size.
I tried freezing the buckets but that didn't help. I also sanded them with 1000 grit as well as applying plenty of motor oil but it's not even close to going in.
are they supposed to be this tight and how can i possibly get them in? would be ok to sand them down a bit, or have a machine shop thin them out?
would really appreciate your help.
They are just like putting brake pistons back into a caliper bore only a little worse. :icon_lol: They want to chicken and bind as you start them into the bore so it takes a little finesse to get them in to where they will slide freely. Make sure there is a little oil on them as you try, it's worse if they are dry. I never try to put the brake pistons back in without lubing them with brake fluid so I lubed the buckets with engine oil.
LOL, when I type c-o-c-k it gets changed to chicken by the spell checker!
thanks gsJack, I was wondering why the word chicken came up on this topic so often:)
I think I may be lacking the necessary finesse to get the bucket perfectly aligned.
i'm still hopeful i can do it w/o removing the head so i don't have to get a new head gasket and washers. Maybe a level or incline indicator could tell me how far off i am, otherwise i'll have to remove the head. Once removed, do you think it's a good idea to heat up the head in an oven and what's a safe max temperature?
i wonder if mechanics have special tricks or tools for this...
Don't think a special tool would help but you can usually tell which way they are cocked and tap them back towards straight to get them advanced a bit more, maybe a time or two to get them slowly in to where they'll quit cocking. Tapping them straight with the plastic handle of a screwdriver or something like that would be better than something steel. I use the screwdriver handle I'm tapping them in with. When tapping in alternate sides to help keep them straight.
Tapping seemed to wedge them in and made it very difficult to get them out. There's a discussion on this forum where a guy got a bucket all the way in but it wouldn't rotate and he had a hell of a time pulling it out.
I see you're saying to tap a few times and then hopefully they will straighten out and go down easily. I'll give it a try, maybe an inclination meter phone app will help out.
well I finally got them in. Just took some more aggressive tapping on the higher side than i was applying initially. I'm a bit concerned that 2 of them don't turn by finger. They do turn with light tapping against a screwdriver in the shim groove and one of them was about that tight when I took them out.
do the buckets generally wear themselves into place or is there danger of a broken valve like happened to another gstwinner on here?
I had a tight bucket that resulted in a broken exhaust valve. Bought my 02 GS in the fall of 03 with about 4k miles on it and checked the valves the next spring with 10k on it. Discovered that tight bucket then, it was very tight and hitting a screwdriver in the bucket notch quite hard it wouldn't budge. It was so tight the valve never closed completely when engine was cold, it stopped at .008"+ clearance as noted on my valve log but even on a cold day start up the bike would run a bit rough for a minute at most until the head started to warm and the bucket freed and the engine smoothed out.
I decided to leave it go until the next check in hopes it would wear in but it never did wear and the valve broke the following March on a very cold below freezing day while cranking to start. It struck the intake valve while stuck wide open while cranking. There have been a lot of tight buckets reported here discovered while checking valves but I don't recall any others resulting in broken valves. I suspect there are a lot more out there that remain undiscovered. Most sane riders aren't starting in sub freezing weather. :icon_lol:
http://www.gs500.net/gallery/data/500/GSvalvelogs.jpg
By the way, after the repair job that exhaust valve had a normal clearance with the same shim so I'd hesitate to change to a bigger shim on a valve with a tight bucket. Checking cold compression after shim changes should probably indicate it was OK though.