My 350 has a strange problem with fuel delivery, I suspect something with the carb is not quite right, but after cleaning it and such I cant seem to resolve the issue.

The machine idles a bit on the high side, even with the idle screw completely out. I have checked the play in the throttle and the slide in the carb does close completely. when you increase the throttle, there is a delay in the Engine actually reving of about half a second, the fuel/air delivery does not seem to be instant, but is quick. Then the Engine runs at the higher RPM for a few seconds after you release the throttle, gradually idling back down over about 3-5 seconds. Sometimes the Engine will then start to increase its rpms, until it is almost at full throttle. When this occurs, the Engine kill switch will not shut down the motor (( Internal Combustion Engine ? )). It seems to diesel and continued to run, one time even after I removed the spark plug cap. I have to pull the choke and then shut off the fuel line in order to make it shut off.

Any ideas? I am wondering if something with the jetting in the carb is out of wack, but I am still very new to these machines so I am not sure what to do next.

It sounds to me like you have a air leak and the extra air is making the Engine run lean, when it revs up if you open the choke does the idle drop?

You cleaned the carb? If so did you adjust the air screw per the service manual?

The air screw is the one simple thing that I have not fooled with yet, I was hoping to do that today, but when the Engine reved uncontrollably I just put it back in the garage. I have not tried the choke when the Engine is idling normally or cold. The only two times I have used it has been when the kill switch would not shut of the Engine, in an attempt to shut it off and it works as expected, making the Engine sputter and big down some until it runs out of gas in the carb. I'll give it a try tomorrow and see what I can make happen.

Before you start it, carefully turn the air screw in and count how many turns until it stops, stop turning when you feel it bottom you don't have to seat it, max turns you want to go out is 2 full turns, if you need more you either have a problem and or need a bigger jet, how does the intake manifold look they are known to crack on top.

Is the pulse tube that goes from the Engine to the fuel pump tight and no cracks or leaks?

The air screw was out about 3.5 turns. I backed it out to 1.5 and then .5. The throttle response seemed quicker, but the machine still took about 5 secs or so to slowly idle back down from a slight rev.

The pulse tube appears to be original, it is pretty ratty looking and I already tried to change it but could not manage to remove it from the case easily. I only checked it by disconnecting it and checking for pressure with my thumb, while turning over the Engine. it appears to be working, but I would not be surprised if there was a leak in the line. I will have to work more on swapping it out, do you think using new fuel line hose will be ok for that? I bought lots of it, but The current line appears to be braided.

The intake manifold is probably original also, but it does not look as bad. It was pretty greasy and I cleaned it with some Engine degreaser, I can see about half of its surface now, but it does not appear to have any cracking at all. I will give it some more cleaning and see what I can discover. I guess now would be a good time to check the reeds now anyway.

One more note about my setup, I do not think it will matter but the gas tank is so rusty that I have made an improvised tank using a small 2 gallon gas can and sticking the fuel line in its spout. If the machine is worth rebuilding I will likely just get an after market tank. The testing setup I have created is not using the T connector or overflow line and is using a replacement fuel pump with a new fuel filter. I can see gas moving through the filter so fuel supply does not seem to be an issue.

Welcome!

Sounds like a small air leak to me also. I would spray WD40 or carb cleaner around the intake/carb/seals/head and base gaskets while idling to see if it changes rpms. If it does, you have a leak for sure. They are getting old(1985), like me.

If you are going to rebuild her top to bottom anyway, wait until you are done with a rebuild then do a leakdown test to check the gaskets/seals. You can give the manifold/intake boot a good look then. I have had several stock boots crack(generally right under the clamps).

Any board members close enough to give a hand?

If you have a cracked boot, let me know, I have several stockers and I will send you a good one.

Gary

Yeah, I think you are right. This oddy does appear to be in restorable condition so I think I will just start the rebuild. I am not skilled enough to change the case bearings, but I can have the top end redone and clean/inspect everything else. Just popped off the cylinder head, I think this is long overdue.

Good choice on rebuild. Sure lookes like it could use some TLC. Have fun. We ( the board) do like pics.

Looks like someone before you has been running a very thick(20:1) mix, oil to gas. It also looks like you have gotten very rich recently(fuel to air) and washed a lot of deposits off the dome. Looks kinda bronze colored too???? Lean(air leak) very recently or past? Looks to be a very large squish band(piston to dome), easy fix also.

Do you have a micrometer to check bore size? Defiantly has some fairly deep scoring/scratching(loss of compression) possibly causing the rich condition. Did you do a compression test? We can talk you through the bearing/seal replacement, will save you alot of $$$$ over dealer or machine shops $90 an hour BS. New bearings, gaskets and seals may cost about $100, next bore job $50-60, and a piston kit is around $100. Hoser might bore the cylinder for you for free if you ask nicely(he has a machine). Ya, I put him on the spot but I know he will take care of board members. He's a great guy.

Any "how to" questions, just ask or use the search Engine. Also, be wary of some "helpful" people on Ebay trying to sell you stuff. Ask about anything here first, and save yourself alot of pain and anguish! LOL

Lots of great 350 knowledge here, more than anywhere...period! I don't know everything , by far, but some one here will post up.

Gary

Looks like some rust on the cylinder bore?

Now is a good time to at least go through the top end...

You have a service manual it will show you step by step on measuring and checking parts, any questions just ask were here to help.

Nukem your not putting me on the spot the FREE bore is an open offer to any PilotOdyssey.com member http://pilotodyssey.com/PO/viewtopic.php?t=892

You might check out the CSI pages to give you an idea what your looking for once you get inside.

Post all the pics you can of your Engine and parts the more the better

Thanks for your help everyone, I have found these forums to be the most useful tool in rebuilding so far. I think I read various stuff for six hours on here last night. I pulled the compression cold and it was around 110. I have not let it idle more than 2-3 min so I have not tested the compression after warming it up. I am not sure of its current bore as I do not have a micrometer but I would guess it has not been bored as the entire machine seems to have been neglected by a prior owner. The guy I bought it from knew very little about it, only he had been storing it for two years with the intention of restoring it but had not gotten around to it. He had 6 other bikes including a atc 250r so I can understand that. I cleaned tons of dirt out of the master cylinder, and the piston in the rear caliper had completely rusted to the caliper housing where someone left the barking brake on for who knows how long. I am amazed that it was still running. I will have to post pics of the brake piston, I have managed to clean it but I am unsure if it will be usable with all of the surface pitting it has.

hoser has been very helpful so far indeed. I am very glad I found these forums, as the other sources of information I had located so far were as you suggested, more people pushing a sell than anything. Helping with a bore would be great and I may take you up on that intake manifold.

Yes, I have gotten to know the shop manual very well, even if some of the pictures in it are a bit dark. I will get some more pics posted soon. Thanks for the bore offer, I will probably take you up on it.