1988 Elite SA50 carburetor

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bonesv
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Re: 1988 Elite SA50 carburetor

Post by bonesv »

That's a great response Bob! :thumbwink:
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Ok that makes sense. Being a novice with carbs I actually thought the oil hose had a steel interior. The bad news for me is that steel piece broke off my carb I think. Is that repairable or do I have to buy a new carburetor? I’m afraid the answer is that my original carb is toast.
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Re: 1988 Elite SA50 carburetor

Post by bonesv »

A good question! There's some things that can not be repaired. Your carb probably can be tho. Getting it to the right person is the trick.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

The good news is that the broken valve was only for the bottom carb drain tube. So this morning I got the carb all hooked up and put on the important t half of the air box (not the cover) and it fired twice and ran super high rpm so I had to shut it off. Was hoping to made some mixture and air screw adjustments per manual but now it won’t start. Any thoughts? No gas leaks so that’s good.
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Re: 1988 Elite SA50 carburetor

Post by hondafan »

Sounds like the initial problem was the float and needle, causing it not to shut and letting too much gas in . It probably wasn’t set right or had debris by the needle , causing gas to flow out of the overflow tube and into the air box. The high rpm now sounds like a lean condition, vacuum line or gasket or you put your throttle cable in wrong causing it to stay opened. Go over everything. If it is to lean it will not start.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

I gave it a break and tried again a few hours later and started right up but idle maxed out and could not get it to calm idle down. I looked at throttle valve and it seemed ok but when I roll the throttle on handle bar no change just high idle. Should I take it to driveway and take it off center stand then try to adjust?

The air screw goes out 1 and 3/8 but where roughy should the other throttle screw be? Mostly screwed in or out? Thanks for the advice and response.
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Re: 1988 Elite SA50 carburetor

Post by btosi »

My guess is you have the throttle plunger (not sure of the correct name) rotated 180 deg. There is a slot in the plunger and that needs to line up with the pin in the carb throat. Remove the cap on the carb, slide the plunger out and when you install it make sure the groove in the plunger is lined up with the pin in the throat.
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Re: 1988 Elite SA50 carburetor

Post by Wheelman-111 »

Greetings:

As BTosi wrote, you must be exceedingly careful when you slide that close-fitting slide into its tunnel. Fingertip-pressure handling and no more. If it resists, withdraw and rotate a few degrees until you find the sweet spot. It should not take more force than picking up a pencil once it's aligned, UNLESS you or someone else previously tried to force it in. Examine the slide and its bore carefully for gouging or chunks of metal representing the little nub that has been sheared off by man-handling.

Set the throttle-stop screw so that it raises the slide just a mm or 2, once smooth slide action has been achieved. Fire up, warm to operating temperature and adjust idle to 1800 before playing with the air mixture screw to highest idle.
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Re: 1988 Elite SA50 carburetor

Post by Meatball »

Its best to have the airbox removed and LOOK into the carb venturi to get a visual on the slide. It should be able to slide smoothly up n down when twisting the throttle grip and coming to rest all the way down while leaving a very small opening for an idle condition. Set the mixture screw the proper “turns out” from fully seated per the service manual. Turn the idle screw IN until it begins to raise the slide just a tiny bit. Install airbox WITH foam filter AND lid fully secured. It wont run properly at factory settings without a complete airbox assembly installed.

Once running and fully warmed up, set idle screw in/out to achieve good idle rpm’s. 1800 is ideal but if you dont have a device to read rpm’s you can set it by ear and get close enough.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Almost see the light at the end of the tunnel! Ok so thank you Btosi. You were exactly right. I had the throttle valve exactly 180 degrees wrong. I have my throttle back on the grips. So I adjusted the air screw 1 and 3/8 but did about a quarter turn more closed. The mixture screw is so hard to adjust but not having tach tool it sounded about right and rear wheel was not spinning g. Took it down the road and when I get up to speed the only way to stop “unwanted cruise control is to apply brakes. It’s not backing off when I release throttle till I hit the brakes. I think I’m down to the two screws being adjusted . Any thoughts now? And thanks to all who replied today.....you guys are all awesome!
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Almost see the light at the end of the tunnel! Ok so thank you Btosi. You were exactly right. I had the throttle valve exactly 180 degrees wrong. I have my throttle back on the grips. So I adjusted the air screw 1 and 3/8 but did about a quarter turn more closed. The mixture screw is so hard to adjust but not having tach tool it sounded about right and rear wheel was not spinning g. Took it down the road and when I get up to speed the only way to stop “unwanted cruise control is to apply brakes. It’s not backing off when I release throttle till I hit the brakes. I think I’m down to the two screws being adjusted . Any thoughts now? And thanks to all who replied today.....you guys are all awesome!
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Re: 1988 Elite SA50 carburetor

Post by Meatball »

If you have cruise control, theres something not letting the throttle slide return to the bottom when you let off. Maybe something binding in your grip? Maybe a dry/sticky or kinked throttle cable? Maybe the slide spring is tired? Just gotta get that thing sliding up n down like butter when you blip the wrist. Do some digging.

IF..the slide is super smooth and slams shut nicely when you let off..you may have an air leak and are super lean. Check crank seals both sides. They have been known to pop out and allow in unregulated air. Also check for leaks around the base gasket, intake and carb connections. An air leak would cause a massive heat spike and turn your motor into a very nice door stop, paper weight or boat anchor.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Meatball,

I did notice the spring in the throttle slide (attaching to carb) is not exactly straight, it’s ki fat got a bend in it and maybe should be replaced. Based on the websites I have looked at any parts for that seem really tough to find. Any suggestions where to buy that spring? Thanks for the tips. I suspect it might be that spring.
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Re: 1988 Elite SA50 carburetor

Post by Wheelman-111 »

Greetings:

I'd bet money that the spring isn't the problem. Check the slide bore and the slide itself for gouges and high-spots causing the hang-up. Then work the throttle cable from the carb end and see how much drag it has. Lube or better replace the cable if you can't get it to move with light finger-tip pressure.
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Re: 1988 Elite SA50 carburetor

Post by NiftySA50 »

Thanks Wheelman,

After doing some more research today I think the problem is right where you are pointing me to check. Being a novice I also think when I was trying to adjust the gas mixture screw I unscrewed it all the way and possibly that allowed the throttle valve to drop below the screw which could cause the sticking throttle at high speeds? Not sure if that is right.

Unless you suggest otherwise I think my plan is to take off the air box, pull out the throttle valve, screw in the fuel screw, inspect and reset the throttle valve back in place, look through the air side of the carburetor and watch to see the slide moving okay with the handle throttle and then if all is well reconnect air box and then keep the air screw at 1 3/8 turn out, the fuel mixture screw maybe one full turn out from seated and then hook up my new tach meter I ordered and arriving today to the spark plug. If I'm not mistaking then I would set the fuel mixture screw to 1800 RPM, then find the highest idle on the air mixture screw (no more than a quarter turn either way) then re-adjust the fuel mixture screw to 1800 RPM's again. Feel free to let me know if I'm off base with that plan. I would never be this close to having a good working SA50 without the advice from the experts in this group. Thank you so much.
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