Help save the life of a GS. Carb-related?

[TheCafeKid]

HEY! I might take those off your hands. Are they the kinda triangular shapped lights? Like on an ES? I might be interested in the lot, boddies and all. Let me know!

[hikermikem]

Anyone have an extra vm carb float bowl screw sitting around they don't want?

Might want to consider these - all allen heads...

http://cgi.ebay.com/ebaymotors/GS550-GS750-GS850-GS1000-NON-CV-Stainless-carb-screws_W0QQitemZ260442935514QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item3ca39bd0da&_trksid=p4506.c0.m245&_trkparms=65%3A10%7C39%3A1

[wkmpt]

Might want to consider these - all allen heads...

http://cgi.ebay.com/ebaymotors/GS550...%3A10%7C39%3A1

Ordered a set today. The Philips heads on mine were getting a bit sketchy.

[wkmpt]

Update on valves. It's my understanding that the appropriate tolerances for my 77 750 are between 0.03mm-0.08mm, so that's the standard I attempted to measure to.

My smallest feeler gauge is a 0.051mm/0.002in. I think I'm going to order this set http://www.sourcingmap.com/steel-metric-thickness-feeler-gage-gauge-002100mm-p-21339.html, so I can have some thinner sizes as well.

But at any rate, that 0.051 feeler is too thick to pass on all of my valves. At this point, I should see if I could get my hands on a very thin shim, to get a clearance I can pass, so I can figure out which shims I'll need to get to match spec, right?

I pulled all of my shims (one at a time) so I'd know what's currently on the bike.

#1 in-2.80 ex-2.75
#2 in-2.85 ex-2.75
#3 in-2.85 ex-2.80
#4 in-2.70 ex-2.85

I've thought about grabbing one of the 2.70's and dropping it in place of one of the 2.85's or 2.80's, to try and get a ballpark of how much thinner I might need to go. Would that be a good use or a waste of my time?

[TheCafeKid]

Update on valves. It's my understanding that the appropriate tolerances for my 77 750 are between 0.03mm-0.08mm, so that's the standard I attempted to measure to.

My smallest feeler gauge is a 0.051mm/0.002in. I think I'm going to order this set http://www.sourcingmap.com/steel-metric-thickness-feeler-gage-gauge-002100mm-p-21339.html, so I can have some thinner sizes as well.

But at any rate, that 0.051 feeler is too thick to pass on all of my valves. At this point, I should see if I could get my hands on a very thin shim, to get a clearance I can pass, so I can figure out which shims I'll need to get to match spec, right?

I pulled all of my shims (one at a time) so I'd know what's currently on the bike.

#1 in-2.80 ex-2.75
#2 in-2.85 ex-2.75
#3 in-2.85 ex-2.80
#4 in-2.70 ex-2.85

I've thought about grabbing one of the 2.70's and dropping it in place of one of the 2.85's or 2.80's, to try and get a ballpark of how much thinner I might need to go. Would that be a good use or a waste of my time?

Good use, but if you're .05mm is too large to fit, I would simply change to the next smaller shim. The shims range in thickness by .05mm, so even IF your .05 passed, jumping to the next shim would make it .10..acceptable. Loose, but acceptable.

[Don-lo]

Can you rotate the buckets with your finger when the lobe is away? This is a good way to feel if any shims are really tight. If the bucket turns freely, then going down 1 shim size should suffice. If it is actually bound tight, then try 3 sizes (and compression in that cylinder should be very low with shims that tight).

[wkmpt]

Can you rotate the buckets with your finger when the lobe is away? This is a good way to feel if any shims are really tight. If the bucket turns freely, then going down 1 shim size should suffice. If it is actually bound tight, then try 3 sizes (and compression in that cylinder should be very low with shims that tight).

All the buckets rotate freely, so I'm going to try going down one size first, then measure and go from there.

[wkmpt]

Valve adjustment clearance-related question.

I have all my intake and exhaust valve clearances to 0.07mm EXCEPT for #3 intake (0.09mm) and #3 exhaust (0.1mm). Following the Zook manual, checked clearances, rotated the engine a full two revolutions by hand, checked clearances again, then rotated and checked one more time to make double sure. Came up with the same clearances on all counts, so I believe the measurements to be solid.

I'm still waiting on my valve cover and breather cover gaskets to show up, should I go about getting some shims to reign in some of the slack or wait for the everything to settle before I grab some different shims?

I know that I'm going to need to re-check clearances after a few miles down the road, but I wanted to get some second opinions as to whether I should tighten those two clearances up now or see how the shims settle.

Thanks all!

[first timer]

it's always better to have your valves a little loose then tight, run it for a few miles then recheck some of the bigger gapped stuff to see if it tightened up.

Did you replace your intake boots or check them for leaks? Or replace the orings behind them?

I find that surging and idle troubles tend to be air leaks, dirty carbs or funky ignition and it sounds like you took care of most of that. Valve adjust does effects the engine but not as bad as the items stated above.

Another thing I have run into is if the bike is old and been sitting sometime the tank will rust and the particals will get into a fresh cleaned set of carbs and clog the little filter caps over the float needle and the needle jet. Double check your petcock filter and carbs if you still have idle issues after you have done everthing elese.

[wkmpt]

it's always better to have your valves a little loose then tight, run it for a few miles then recheck some of the bigger gapped stuff to see if it tightened up.

Cool. I'll start there and see where they go.

Did you replace your intake boots or check them for leaks? Or replace the orings behind them?

The intake boots were still very pliable. I replaced the associated o-rings with new.

I find that surging and idle troubles tend to be air leaks, dirty carbs or funky ignition and it sounds like you took care of most of that. Valve adjust does effects the engine but not as bad as the items stated above.

Yeah, I'm starting with the valves to eliminate the associated variables, so I can move on to diagnose other problems. Gonna get it running, check compression, check float height with the drain screw tool I just made, then hopefully all I'll need is to get the carbs right on the manometer so I'll have a week left in the riding season...

...sometimes the tank will rust...

Actually, I'm a lucky sod on that account. My tank looks like factory new on the inside. Actually, I should probably treat it to keep in looking that way...

[first timer]

the boots might still be pliable but the rubber does seperate from the metal plate they are bonded to which allows air infiltration. Is the rubber around the mounting plate on the boots still intacted or is it dried and cracked?

You can test for boot leaks by setting the idle at the point where the bike will still idle but any less and it won't. Take some carb cleaner and spray around the boots, basically the cleaner will get sucked in, burn and the idle will increase. Make note if using carb cleaner or something flamable like that do not go over board, zap it a little then wait for the vapor to clear out then zap it again otherwise you might have a little fire on your hands.