rs34's

OK, I changed the plugs and checked the spark and it seems to be running well. I want to synchronize these but have a quick question.

Should I leave the air filters on or off while adjusting?

make sure they are clean and leave them on. adjust it like your going to ride it.

OK thanks. I synched them with the air filters on and then took them off and saw no difference anyway.

I can't believe how sensitive the adjusters are on the RS34's. It was pretty hard to get them even, but what a difference it made. The bike would hardly idle until I got them dialed in. Much better! I really want to try them out but more snow is on the way

By the way, I was able to see (hear) that only the #1 carb is "clacking". What could be causing that? Getting everything synched really helped, but it is still rattling and I can actually see it moving around with the carb tops removed. The other 3 cylinder are nice and steady. Any ideas anyone?

Thanks

id check the compression on that cylinder and for a bent valve, also a loose valve guide.

I hope to do a compression test this weekend. Will it matter much that the engine isn't broken in yet? I'd guess that overall compression might be lower but all the cylinders should be the same?

Anything else that could cause only 1 cylinder to "clack" like that?

It snowed the night I synched the carbs, so I haven't been able to ride it since. Much more snow expected tonight...

It wont matter that it is not broken in yet. we are just trying to find something that is dif in that cyl. take out all plugs. do it with the throttle wide open ,and do it dry then add a 1/2 teaspoon of oil and repeat on each cyl.

OK, here's the numbers from the compression check:
#1 - 185.0
#2 - 187.5
#3 - 177.0
#4 - 191.0

Now, what does that mean, if anything? :huh:

It means you have very good compression.

You might want to take the carb rack off and look at the amount of space between the bottom of the throttle slide and carb throat on each carb while the slides are closed. Look into the front of the carbs and make sure the space on the number one carb is the same as the others. They should all be about equal.

Then give it a test drive an see what happens...

I take it that those # are from a dry test.
Nothing outstanding there.There just a little low ,due to the rings not being seated yet.
Did u do a wet test?(with oil)Wet u should be around 225psi.The wet test can identify a valve issue. But your #'s look fairly even now.

OK, added some oil and tried again - the results are very confusing :huh:

With Oil:
#1 - 190.0 (+5)
#2 - 198.0 (+10.5)
#3 - 172.0 (-5) what??
#4 - 182.0 (-9) huh?

The only difference this time was that the engine was really cold (around 30F outside). This really confuses me since 2 got higher but 2 got lower. Anyone make any sense of this??

I guess my main concern is whether or not I have valve damage?? Can we determine if the engine is sound as is? There are only 42 miles on the rebuild, so I'm sure the rings have a lot of seating left to do, and maybe the valves too??

i wouldn't worry about numbers like that those,they are quite good if they were more than a ten percent differance between lowest to highest i might be concerned even then i would do a leak down test to make sure i had a problem and to isolate it. the compression test is not nearly as accurate as a leakdown test.i've seen my self get two different sets of numbers just by how hard i was kicking a bike over.i normally use the compression gauge just to check to see if there is compression if it has some than i automaticlly grab the leakdown tester and use that for hard numbers a compression test can be thrown off by how dry the cylinders are,by tempurature by valve clearance.by all kinds of little variables. do your self a favor and get a leak down test done or better yet pick one up your self once you get the procedure down you will never relie on a compression gauge again.they are quite reasonable about the same price as a good compression gauge and if you have a small air compressor you can run it.follow the instructions and your good to go.

mark1122 wrote:

I take it that those # are from a dry test.
Nothing outstanding there.There just a little low ,due to the rings not being seated yet.
Did u do a wet test?(with oil)Wet u should be around 225psi.The wet test can identify a valve issue. But your #'s look fairly even now.

Is that 225 for 10:5 - 1 compression ratio? Do you think the compression will rise much as the engine breaks in?