I apologize in advance for the length of this post and my general long windedness…Being overly wordy is in my nature.

First, I wanted to thank everyone on this board for their tips, tricks and insight into the world of our beloved LS650. I’ve been lurking on this board for some time and finally decided to start participating. Hopefully I can share what I know and help out some folks just like you guys have helped me out. Now onto my current issues...

I have an ’87 Savage, Jardine exhaust, K+N replacement filter, 155 MainJet. Over the weekend I replaced a faulty pet c_ock with one I picked up off ebay. With the old pet c_ock the bike cruised around fine, but when I went to remove the carb for cleaning at the beginning of the season I realized that when in the “on/off” position, fuel actually flowed through it as if the pet c_ock was in the prime position. Imagine my surprise when I removed the hose from the carb and gas started spurting out and wouldn’t stop. Anyway, I replaced the whole assembly, put some gas in the tank – and it was fine from that stand point. In the “on/off” position, fuel did not flow through, and in the prime position it flowed freely. I’m a gear head in training, so excuse my ignorance, but I assume my initial problem had to do with vacuum, or lack there of.

Anyway, while I was at it, I took out the carb to check the jet size, shave down the white spacer and clean the carb. As I mentioned above, 155 jet size so I let it be, I believe the previous owner removed the white spacer (he was a tinkering kind of guy), and with my can of spray carb cleaner in hand, I removed a whole lot of gunk from the carb. I also checked the inline fuel filter – which has sediment in it, but I didn’t have one to replace it with at the time so I put it back in. Feeling proud of myself, I put everything back together, and after a number of tries, she fired up. Now that you know how I got here, I’ll cut out a bunch of stuff and get to what’s wrong with her. I’ve read about a number of folks on this board who are having a similar problems, and I believe I know what I need to do to fix it, but in case I’m missing something, I’d appreciate second opinions and comments.

The problems
When the petc_ock is set in the on position the bike spitters and sputs, poots and backfires through all gears, the throttle lags and surges in first and second gear. If I bring the bike up to 3rd or 4th gear, then slow down for a stop and start down shifting, the bike completely dies out. Basically, it feels as though its not getting enough gas. When I put the bike in prime, a lot of the problems still persist (sputtering, backfires) but they are reduced a little, the bike also does not cut out on its own when in prime. I’m assuming that this is a vacuum issue and that’s why the fuel is not flowing when in the “on” position.

Also, adjust the idle mixture screw does not seem to do anything. I’ve had it all the way in and all the way out, and the difference in idle sound was minor. The only time I noticed a difference is when I had it turned all the way in, so turning it out 2 turns. I had the screw almost hanging out of the carb and there was no difference in idle speed.  Also, the bike backfires EVERYTIME I turn it off – usually very loudly.

What I plan to do
Remove the carb and clean it again, paying particular attention to the slide. Removing and thoroughly clean all the jets. Double checking to make sure there are no holes in the diaphragm.
Using compressed air, blow out all the carb passages, including all the hoses to make sure there are no blockages.
Replace the inline fuel filter
Possibly replace the main jet with a 157.5 or a 160 (should I replace the pilot jet as well?)

My question is… am I forgetting anything? Is there something else I should be doing, could there be some other issue? Also… what’s the deal with my idle screw? Why can’t I notice any significant change in idle speed when I turn it?

Lastly, and this question is kind of for Lancer or anyone else who is running on of the Amal Mark 2 Carbs he is selling… I’ve been looking at replacing my carb with one of these performance carbs for a while, I know it might be a cop out to have this be the reason why I finally sink the $$ into it, but if I did do so, do you think it would solve my problems? i.e. do all the problems I have sound as if they are originating with the carb? Or could it be something else?


Anyway, thanks in advance, and once again, sorry for the length of this post.

Grail
p.s: any riders in MA on this board? I’m in good ole Witch City, Salem, MA

I have an 87' also and had about the same problems with mine when I got it. My bike had not been ridden for 14 or 15 years. The one thing that made a major difference was cleaning the needle jet and the pilot air jet. The needle jet has 8 tiny holes at its base and they were completely clogged with a grayish-white hard coating. I soaked this overnight with kroil and used a carburator cleaner on it the next day to remove it completely. This old bike only had 2170 miles on it when I bought it. I was assured when I bought it that everything was working well. The truth is that I am now enjoying having learned to work on the cycle. I have gone over and adjusted literally everything on the bike! First I bought myself a Clymer manuel and went from there. Be sure all of the passages are clear. I think I would stay with the 155 main jet and get everything else right before I started fooling with performance. Have a good one,....Ray

No white spacer is WRONG. Make it 1.2- 1.5 mm thickness with washers. If the pilot screw doesn't do anything and the bike is still running I'd check the pilot jet- it is supposed to be 52.5. If not- replace with the correct one. There is a small O-ring around the brass body of the fuel valve. Replace it with a new one - this is very very common problem - and make sure the new fits nice and tight. Check the float level / 27-29mm or1.1+ or - 0.04 in/.
Put it together and check for vacuum leaks in the intake manufold.
The bike should run just fine.

Hey guys.... thanks for all the replies.

Rob: Didn't clean the air filter as it's pretty new (under 1000 miles on it), but thats a good idea. I'm gonna put that on the to do list. Also, it is a stock needle.

I agree about the white spacer which is why I ordered another one from Ron Ayers as soon as I figured out it was missing. Should be here next week hopefully. Not in time for this weekends carb cleaning, but oh well. I'll either find a temporary solution or just pull out the carb again once it arrives. I hate pulling out that darn carb out...what a pain – could it fit any tighter in there?. Also, I think agree that a 155 main jet should be fine, which is why I didn’t change it. I have a 160 sitting around, but at this point I don’t want to mess around with bigger jetts. As suggested, I’ll be removing all the jets and soaking them in carb cleaner and making sure they are throroughly degunked. I’ve never done this when I’ve cleaned the carb, so it’s likely that this could be a problem. I didn’t know about the o-ring issue, so I’m going to replace that as well, and double check the float level. I’m still thinking this is a vacuum issue, but I definitely want to make sure I cover all my bases. Since the carb is such a pain to get in and out, might as well get it in the best condition I can while its out.

Thanks for all the tips guys, I truly appreciate it. Would still love to hear from folks who have experience with the Amal Carbs… I’m still thinking I might just replace it (even after tinkering with it this weekend).