"shop-teacher" (shop-teacher)
09/14/2018 at 11:01 • Filed to: Two wheels broken
3
19|
"shop-teacher" (shop-teacher)
09/14/2018 at 11:01 • Filed to: Two wheels broken | 3
| 19 |
Bump for the daytime crowd.
I visited my buddy Tall Bill (he has no idea why they call him that) yesterday to work on our Gambler scoots. We each bought janky Honda Helixes to run in the Gambler 500-Illinois, which is a scant 2- weeks away. While we bought them months ago, last night was our first proper digging into them ... For ... Reasons .... Shut up.
Anyways, mine was pouring fuel out of the carb and wouldn’t start, so to cover the bases I purchased both a rebuild kit and a new Chinesium carb. Tall Bill knows his stuff about carbs, so I helped ... Passed him tools, read the manual, and fetched beers. The carb was disassembled, cleaned, the float and needle/seat were replaced, and then we put it all back together.
It started, idled, and we took it for a short test ride. It sounds like a go-kart, but it ran. So we then decided to see if it would achieve highway speeds. Nope. After about a minute stuck at 45 mph, it coughed, died, and wouldn’t refire.
Slick Willy went to fetch his truck and trailer (on his scooter), whilst I waited and pondered if we could really make this happen.
Of course upon trailering it back to his house it refired.
We dug in and found a pretty good looking spark plug, with a bit too big of a gap, and we found a fuel line that was improperly run. We fixed those issues. We also found that the fuel pump is aftermarket, and poorly mounted with a couple zip-ties. We performed a flow test, expecting to find it was starving for fuel. Well, it flows WAY more fuel than the stock pump, probably too much.
It now fired up easier, and had more power, so we took it on test ride number three. This time Billy-boy followed in the truck.
It pulled decent up to 45-49, but then after a minute or so started surging and bucking and slowing down. I pulled to a stop, and it didn’t die this time, so I took back off towards the house again. Again it pulled pretty good up to 45 or so, then after a minute or less, started surging and bucking and slowing down. Again it didn’t die this time.
So, we either have a fuel delivery problem, an ignition problem, or both.
We need to decide a plan of action. I’m tempted to throw a $13 coil on it to see if that will help, but I really felt like the surging and bucking was fuel related. Could too much pressure to the carb be causing this? Should I put a fuel pressure regulator on it? Should I replace the fuel pump? It will have to be another aftermarket one, because OE pumps are $150, and I am not sinking that kind of money into this silly project.
What are Oppo’s thoughts?
gmporschenut also a fan of hondas
> shop-teacher
09/13/2018 at 21:28 |
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Have you checked the valves? I got a free mower that wouldn’t run, replaced the carb, coil and spark plug, still would run like crap at WOT. then did a valve adjust me nt. They were a crazy amount off , ran it a bit, and checked the valves again and now it starts up every time.
Highlander-Datsuns are Forever
> shop-teacher
09/13/2018 at 21:30 |
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A pressure regulator is pretty easy to plumb into the fuel line. I’d start there.
Future Heap Owner
> shop-teacher
09/13/2018 at 21:35 |
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Man I have no idea, but I love this sort of post. Keep us in the loop!
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shop-teacher
> gmporschenut also a fan of hondas
09/13/2018 at 21:48 |
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Oh yeah, I forgot about the valves. We had thought about that. Probably a good idea.
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gmporschenut also a fan of hondas
> shop-teacher
09/13/2018 at 22:29 |
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Maybe try recalibrating the carb. I have crappy luck adjusting them correctly.
Takuro Spirit
> shop-teacher
09/14/2018 at 11:05 |
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Sorry I can’t help, too busy laughing at the work bench.
razorbeamteam
> shop-teacher
09/14/2018 at 11:22 |
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I’d get a regulator, I bet those cheepo carbs are finicky with fuel pressure.
So Shiney. So Chrome! So Frunky
> shop-teacher
09/14/2018 at 11:23 |
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I’m betting valves too but easiest thing first: Is a shitty old air filter or something else inhibiting airflow?
Pickup_man
> shop-teacher
09/14/2018 at 11:26 |
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If you can perform a leak down test, or a compression test at a minimum I’d start there and make sure everything checks out ok.
My main guess though is fuel, especially if you put a Chinese carb on it. Putting on an aftermarket carb, regardless of where its from, is a total crap shoot because the jetting is a total guess, on top of that the Chinese jets tend not to be very precise so even though it might say it’s the same size, it still might not be. If you have the time/money I’d buy a rebuild kit for your stock carb, and unless the stock jets are complete trash, clean them and reuse them instead of what comes in the rebuild kit.
A pressure regulator also seems like a likely culprit, if the pressure is too high then the float cant do it’s job of shutting off the fuel and the pump will ess entially force excess fuel into the engine. There’s two easy ways to check that, do a high speed run, where you’re having issues, and kill the bike, pull the plug and if it’s super black, then it’s pretty obvious you’re getting too much fuel. To determine if it’s a fuel pump or a carb issue try rigging up a tank and try gravity feeding the carb and see how it runs.
Future next gen S2000 owner
> shop-teacher
09/14/2018 at 11:34 |
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Vacuum leak at the carb? Float adjust incorrectly? Just thoughts. I don’t really know.
Mercedes Streeter
> shop-teacher
09/14/2018 at 11:46 |
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How does the gas tank look? It could be that the engine is pulling in garbage from the tank at higher speeds. That’s what I believe happened to my GS until I could clear the engine and tank of whatever crap got in there.
Also, an I join ya both on this fun? I need to get mine running, too. lol
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shop-teacher
> Takuro Spirit
09/14/2018 at 12:22 |
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I figured y’all would enjoy that :)
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shop-teacher
> Pickup_man
09/14/2018 at 12:25 |
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We didn’t install the Chinese carb. I bought that to have a backup on-hand (it was only $30, seemed like a good idea to have a backup). Bill pulled the stock carb apart and cleaned it, and replaced the float and the needle/seat.
Those are good ideas to check for fuel pump issues! Thanks!
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Pickup_man
> shop-teacher
09/14/2018 at 12:32 |
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Ah yes, I see you mentioned that, must have forgot.
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shop-teacher
> Mercedes Streeter
09/14/2018 at 12:39 |
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The tank looks fine. We pumped out the old nasty gas, and put fresh stuff into it. There are also two filters on it. One factory, and one that clearly came with the aftermarket fuel pump.
I’ll let you know when we set up our next work night. The Helixes are both at Bill’s house.
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shop-teacher
> So Shiney. So Chrome! So Frunky
09/14/2018 at 12:40 |
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That’s a really good question!
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shop-teacher
> razorbeamteam
09/14/2018 at 12:43 |
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We still have the stock carb, we just cleaned it, and replaced the float and needle/seat.
The cheapo carb was purchased for an insurance policy, if you will. It was only $30.
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shop-teacher
> Future next gen S2000 owner
09/14/2018 at 12:44 |
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Both definite possibilities.
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shop-teacher
> Pickup_man
09/14/2018 at 12:59 |
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No worries, it was a long and rambling post! Thanks again for the advice :)