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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Carb Manifold Leak? /cgi-bin/YaBB.pl?num=1531164110 Message started by JayColli on 07/09/18 at 12:21:50 |
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Title: Carb Manifold Leak? Post by JayColli on 07/09/18 at 12:21:50 Hey All, Got myself a 1986 early last year and with the help of this awesome forum I've slowly been edging my way towards a properly-working bike! I've had a few repairs/adjustments done based on my readings here but I can't seem to find any references to the symptoms of a manifold leak between the carb and the cylinder head, which is the latest explanation for why the bike misbehaves. A brief history of work so far: The bike had a new carb kit into it when it was cleaned and inspected by a competent mechanic. Raptor petcock was installed and the cam chain was replaced, also by the mech. At this point the bike was still not working properly so I decided to try a mechanic a bit closer to home. The new mech checked the coils and they all got the OK but he noticed that the manifold was a bit distorted and suspects an air leak. The bike idles and revs perfectly when in neutral but looses power, bogs down, sputters and pops at certain RPMs when riding, mostly in the top end. He was unable to test the TCI and the local Suzuki dealership has a less-than-stellar reputation so I decided to have the mech replace it. I'll find out in the next couple of days whether or not that finally fixes things. This post is mostly for reference, just in case anyone has a similar issue and can't find anything on this type of air leak, but I'd be interested to hear if anyone has anything to say on the matter. I'll post the results here regardless! |
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Title: Re: Carb Manifold Leak? Post by DragBikeMike on 07/09/18 at 15:32:04 You can test that rubber manifold for leaks by spraying carb cleaner around the manifold with the engine idling. If there is a leak, the engine will stumble when the carb cleaner hits the leak area. Be careful not to allow the carb cleaner to drift into the mouth of the carburetor as this would give you erroneous test results. Use the carb cleaner sparingly. It only take a little. |
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Title: Re: Carb Manifold Leak? Post by batman on 07/09/18 at 17:14:20 The carb pulls it's highest vacuum and supplies it's least fuel at idle .If the intake manifold is leaking air ,I would think the idle and low speed throttle setting would be affected much more than higher speeds. In that vein ,I would suspect a fuel delivery or ignition problem. Higher speeds require the voltage used by the spark plug to be higher ,(and the plug wire ages and may crack allowing the spark to jump to ground before reaching the plug) you might try wrapping the plug lead from the coil to the plug cap with electrical tape.(If the ignition module is working at idle and above there is no reason to thing it's not working at higher speeds) Some rebuild kits have been known to come with the wrong jets that are way to small ,stock size are 47.5 pilot 155 main for your 86 . The fact that you have the Raptor is good , but the person you had rebuild the carb may not have been aware that thereis another very fine screen filter that sets above the float valve seat in the carb body that the fuel passes through,that might be partly plugged (causing the float bowl level to drop at higher speeds(,higherflows),starving the carb). There is the advantage in not letting others work on your bike, Like you knowing what size jets your running ,and what procedures to follow that others may miss. |
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Title: Re: Carb Manifold Leak? Post by JayColli on 07/10/18 at 04:58:39 484B5E474B441E122A0 wrote:
Batman, you help is greatly appreciated! I took a look at the old jets that came out of the carb and they are indeed 47.5/155 so I'm going to ask my mech to take a look at what's in there now, since he has it off the bike already. The pilot air jet (70) was also replaced so that may be worth checking while he's in there, even if it's not a common problem. I'll also ask him to tape up the plug wire from the coil as the plug cap was replaced last year but the wire itself is original. I suspect the fine screen you're referring to is part #20 in the attached diagram? The original was taken out and hopefully replaced! I'll mention that to him as well but unless it got clogged up immediately after installation it should be good. |
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Title: Re: Carb Manifold Leak? Post by JayColli on 07/10/18 at 05:03:55 595F502C2E292D1D0 wrote:
So easy! Thank you for the reply! I hope my mech knew how to do that and didn't order a new manifold for nothing - not cheap at $100! |
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Title: Re: Carb Manifold Leak? Post by batman on 07/10/18 at 05:57:35 Yes the screen is part # 20 ,but I don't think it would be included in a rebuild kit . the float valve and seat would be I believe, but the screen may have stayed up inside the body and been over looked, and it's the last thing the fuel passes through before the float valve. If you installed an inline fuel filter between the Raptor petcock and the carb ,I'd remove it as these aren't needed and have been known to cause problems with fuel delivery (trapped air bubbles). A new piece of fuel line might also help ,as the old line may be going bad on the inside ,and be carried into the screen(#20). |
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Title: Re: Carb Manifold Leak? Post by verslagen1 on 07/10/18 at 07:01:11 All of the float valves I've looked at, the screen is attached to the valve body. |
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Title: Re: Carb Manifold Leak? Post by JayColli on 07/10/18 at 07:51:28 Thanks again Batman! I had removed the in-line filter and replaced the fuel line to the carb earlier in the year hoping that it might help but it didn't seem to make a difference. It was a pretty huge filter and I had a lot of fuel line on there to make it work. It caused a lot of headaches when riding on bumpy roads as it would sometimes catch the choke and pull it out just enough to kill the bike once it was warmed up. Verslagen, the one that came out (pictured below) is like you described. My mech is checking the fuel jets to make sure I have a 47.5/155 combo and the float valve to make sure it matches the original. I'm hoping the correct pilot air jet was used as it was replaced when the kit went into the carb. That'll likely be the next thing to check if everything else looks ok. |
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Title: Re: Carb Manifold Leak? Post by verslagen1 on 07/10/18 at 09:28:42 6A4159634F4C4C49200 wrote:
I have an '88, on that carb with stock intake and muffler I did not like the stock jets. Went down to 152.5 on the main. It was also very finicky on the white spacer. Any thing other than the stock white spacer didn't run right. Common issues with carb rebuilds is to swap the main jet with a large jet under the slide diaphragm. So... check your jets. |
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Title: Re: Carb Manifold Leak? Post by batman on 07/10/18 at 23:53:35 The filter is shown and listed as a separate part, from the float valve assembly , ( the screen's base is nylon, and is press fitted on the brass float valve seat and sits on the ledge shown ) removing it from the assembly allows back flushing it, making cleaning and inspection much easier. |
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Title: Re: Carb Manifold Leak? Post by LANCER on 07/11/18 at 06:50:32 4368704A66656560090 wrote:
So easy! Thank you for the reply! I hope my mech knew how to do that and didn't order a new manifold for nothing - not cheap at $100![/quote] He charged you $100 for the rubber flange ? Really ? They retail for $34.14 at Sudco, my supplier. That was not a fair price, even if that was all that was done and he added some labor. That should have taken him all of 5 minutes to make the swap. Did you get an itemized invoice after the work, listing parts and labor seperately ? |
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Title: Re: Carb Manifold Leak? Post by Panhead on 07/11/18 at 11:17:03 Just a suggestion (since I didn't see it mentioned), you might want to check the float level since it could possibly be just slightly too low and create the problem you described. If the bike idles fine you don't have a vacuum leak. If it pops occasionally when throttled hard it is probably running too lean which could be caused by float level being too low and not enough fuel in the bowl. That could be caused by any fuel restriction as those mentioned, but it's usually good to start with the basics and possibly save some money. |
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Title: Re: Carb Manifold Leak? Post by Panhead on 07/11/18 at 11:20:06 Oh! And congratulations! The 86 is my favorite Savage. |
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Title: Re: Carb Manifold Leak? Post by JayColli on 07/11/18 at 12:15:22 Hey Fellas, Thanks again for all the helpful advice! Verslagen, thanks for the very applicable advice, it's greatly appreciated and it looks like you nailed it - main jet is the incorrect size (135) but I didn't see a spacer in the bag of goodies that came out of the carb originally so hopefully the stock one is still in there. Lancer, I called my mech's supplier (Suzuki dealer) and the manifold with O-ring comes to $73 after tax. It's my first time dealing with this mech so I'll see how much it comes out to on the bill - I'll definitely be asking for one that is itemized. I think $100 was just an approximate price off the top of his head. Batman, your advice was spot-on! He took another look at the jets and there was a 135 main in there! He swapped the stock 155 back in and will be testing it with the new flange tomorrow. He didn't mention anything about the pilot but I did ask him to check both so I'm assuming it's ok. Panhead, great suggestion and thanks for the congrats! If replacing the main jet doesn't totally fix the issue I'll suggest he re-check the float level. I hate to keep going back to him with suggested fixes but the knowledge and experience you guys have to pass-on is too good not to mention it to him. |
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Title: Re: Carb Manifold Leak? Post by batman on 07/11/18 at 14:54:49 Glad we could help Jay, we've seen this a few times with rebuild kits sold on line,they are billed as being for the LS650 ,but with the jet sizes being much smaller I believe they were made for the Tempster 400cc ,a bike with a motor that is a smaller clone to ours and was never sold in the USA. |
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Title: Re: Carb Manifold Leak? Post by JayColli on 07/29/18 at 12:25:44 Hey Fellas, Just thought I’d check-in and let everyone know she’s working too notch! |
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Title: Re: Carb Manifold Leak? Post by batman on 07/29/18 at 13:36:40 Keep the rubber side down! |
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