RH50 unexplained lag on top end

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Skeeter64_LV
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RH50 unexplained lag on top end

Post by Skeeter64_LV »

Hi, I recently bought a used 2013 RH50 out of California. It had 3500 miles on it. It was a trade in at a Honda cycle dealer. When I test drove it, I noticed an exceptional amount of smoke from the exhaust (too much for a normal 2T). The dealer said, "oh that is what 2 strokes do". After inspecting the oil resevoir, i saw it had cheap 2T oil in it. So first things first when I got it home was to replace with high end full sythetic oil. Boom, smoke problem gone. Next issue came about after about the 4th ride. All was good, hit 45mph+ on flat road, and since I live on the side of a mountain in Las Vegas, my hill climb top speed is about 20mph. The issue was on my return trip home, the scoot would not go over 30mph on straight flat road where normally it would do 45+ and the exhaust had a bogging sound.
Need some help trying to figure out what the problem might be. I have emptied and changed the fuel, added a little SeaFoam, this did make a bit of an improvement, with some sudden increased power surges going up the hill but not long lasting. My next step is going to be changing the spark plug. I love this scooter and love riding it. Just want to make sure it is running to it's potential. Thanks for anyones help in advance.
roughrider2015
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Post by roughrider2015 »

you need to pull the plug and check the color, bone white is lien, dark tan is rich, light tan is perfect, black spots is detonation=hole in piston or broken rings.
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Skeeter64_LV
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Post by Skeeter64_LV »

I pulled the plug and it was light tan/mocha colored. Replaced with a fresh one to see if it did the same. Still mocha colored.
roughrider2015
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Post by roughrider2015 »

I would check the amount of oil going into the engine, it sounds like it isn't being lubricated and is starting to cease up, when it cools it goes back to normal tolerances and runs good until it gets hot again.

I remember reading that you can count the drops per minute that the oil pump puts out, in order to do so you have to mix the gas with oil as the oil pump is removed while counting the droplets. There is a way to adjust the flow of oil into the engine. If someone was inside your engine or it was apart its possible they turned the flow down causing you this problem.
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agrogod
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Post by agrogod »

Do a complete carb removal and clean it out with carb cleaner. Sometimes just running a cleaner like Seafoam doesn't get all the junk out.
"When your mouth is yapping your arms stop flapping, get to work" - a quote from my father R.I.P..
always start with the simple, it may end up costing you little to nothing
SlickRick
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Post by SlickRick »

It's not out of the question your exhaust is clogged remove the bolt on the pipe before the muffler and see if it improves. Crappy 2 stoke causes all kindsa problems. Don't go counting your drip drops that's kind of obserd either the oil pump works or it don't and if it don't it would be doing 0 mph cause the motor would have quit. There is a possibility you could have a roller problem as well but go with exhaust clogged first
roughrider2015
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Post by roughrider2015 »

an oil pump does NOT either work or not...if its not adjusted property it may be it can providing too much oil or not enough.
SlickRick
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Post by SlickRick »

I'd love to say your wrong.

But prove me wrong. I am not saying there is no adjustable oil pump on any bike on the market. I don't see anyway your going to adjust the gear driven oil pump found on the r50.
roughrider2015
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Post by roughrider2015 »

the cable is adjustable
just read this post
http://49ccscoot.proboards.com/thread/3 ... adjustment
SlickRick
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Post by SlickRick »

As I said I'm not saying there are no adjustable oil pumps out there... The R50 has no relation to that Chinese bike described in that post. The Chinese 2 stroke bikes use a horrible split throttle design that infact does pull on the oil pump and does have some adjustability. The R50 does not have an adjustable oil pump. It has a regular old throttle cable going right to the carb. Oil is delivered based on engine speed. If you don't believe me consult an R50 manual.
lovemysan
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Post by lovemysan »

Surging/bogging is almost always carb related. After cleaning the carb I would check compression and exhaust flow. Clean the carb, don't lose the emulsion tube like I did my first time. Rent a compression tester from
Autozone to rule out engine issues. Take the exhaust off and Run water through the exhaust to make sure it isn't restricted. While you have the exhaust off you can visually inspect the piston condition by looking directly into the exhaust port. Have an assistant lay the bike over o you can get a good view.
161cc big bore kit, NCY big valve head Hand ported, NCY transmission kit, jetted and tuned. I can port your cylinder head.
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