working on a friends scoot, no top end power

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working on a friends scoot, no top end power by: hondarider - Apr 27, 2013 10:30:31 GMT -5

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Post by hondarider on Apr 27, 2013 10:30:31 GMT -5

Before anyone flames me for a common issue without doing a search. I have searched and complied with the suggestions. Still at a loss for a solution. This is a buddy's ride and I am used to working on FI motos mostly.

-2007 Honda elite ch80 29xx miles
-lives at 6500 feet and doesn't winterize his ride
-Was running poorly at cruise and had lost about 5 mph on the top end.

work completed;
New gas, cleaned the carb/float/needles (2x)
Valve check
tested bystater operation -good
tested vaccum petcock -good
dumped CCBreather - not sure it had ever been done before!
New OEM airfilter
Proper gap for plug
New 11g sliders (vs 12g OEM rollers)
removed variator grease cup and grease
Belt good at 16.22mm -New is 17mm, replace them at 15mm
Oil good and topped off final drive oil.
Adjusted throttle cable tension
Adjusted drum brakes, no dragging

Scoot starts up immediately, idles, lowers idle once warm etc. Peppy enough off the throttle and goes to 30ish, can get to 35ish with enough space but bogs/slight surging at WOT.

Now been working on the air/mixture screw and idle settings. Any suggestions for turns out on the air/mixture screw at 6500feet with OEM setup? Idle set 1/2 turn below wheel engagement.

Tell me what I'm missing. Complete tune up and haven't been able to fix the top speed/WOT issue. He wants the ride back and I haven't been working on my rides due to this taking longer than expected.

Thanks

Last Edit: May 1, 2013 9:34:46 GMT -5 by hondarider

hondarider PM hondarider hondarider's Posts hondarider's Threads New Rider Currently Offline Posts: 4 Likes: 0 Joined: Apr 22, 2013 9:43:26 GMT -5	working on a friends scoot, no top end power by: hondarider - Apr 28, 2013 21:24:39 GMT -5 Reply Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by hondarider on Apr 28, 2013 21:24:39 GMT -5 No suggestions? I guess that makes me feel better about getting stumped... Anyone have mixture and idle settings for higher altitude?

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working on a friends scoot, no top end power by: alleyoop - Apr 28, 2013 21:52:56 GMT -5

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Post by alleyoop on Apr 28, 2013 21:52:56 GMT -5

Well if it bogs or stumbles at WOT, follow this procedure to determine what it needs less fuel or more fuel.

When it starts to ACT up back off the throttle about 1/8-14 of an inch and hold it there.
A. If it speeds up it is LEAN
B. If it just settles down it is RICH

That way you know which way to go, richen up the mixture or put in the next higher MAIN JET JUST the next higher size no more it is on the EDGE of either RICH OR LEAN.

There is less air available at higher altitudes which means less fuel needed for a good mixture setting which in turn equates to less power. It is almost like you have a smaller engine at high altitudes. So you may not be able to get the 5mph back if it used to run near 40 at lower a lower altitude.
Alleyoop

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PST150H 62mm BBK, 60mm Crank, 16/37 Tranny Gears..MOW-POWER

WATCH OUT...THOSE WHO DO NOT KNOW, DO NOT KNOW THAT THEY DO NOT KNOW

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working on a friends scoot, no top end power by: hondarider - May 1, 2013 9:32:21 GMT -5

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Post by hondarider on May 1, 2013 9:32:21 GMT -5

Alleyoop, thanks for the response. I have been away at work and haven't been able to try your method. I'll post up the result.

The elite has been living at altitude since new. So the loss of top end isn't due to altitude. That's why I assumed new rollers/sliders and a carb clean would fix the issue. But it's never that straight forward when you offer to fix a buddy's bike ehh?

Thanks

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working on a friends scoot, no top end power by: urbanmadness - May 1, 2013 9:50:29 GMT -5

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Post by urbanmadness on May 1, 2013 9:50:29 GMT -5

I'd also think about putting the stock rollers back in it, until it's running properly.... why? Becuase then you know what the Scooter should be doing. Then see what the sliders do when the scooter is running correctly. Always change one thing at a time to see what the results are. That way if something doesn't work, you know exactly what part or adjustment made it better or worse.

Did you clean the jets as well? I'd also look for vacuum leaks. A large vacuum leak will cuase a lean misfire, it won't idle correct and in general misbehave. You have taken the carb off the engine a couple of times now, so, check that intake manifold. They like to crack.

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115MM Hoca variator
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300lbs rider
top speed (58mph on GPS)
Upgraded valve stems after a blow out

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working on a friends scoot, no top end power by: hondarider - May 3, 2013 20:40:46 GMT -5

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Post by hondarider on May 3, 2013 20:40:46 GMT -5

Urbanmadness- I swapped the rollers out since they had flat spots. So unless I order new ones I'm SOL for going back to the original setup. Otherwise I agree in changing one thing at a time.

Alleyoop- using your method, it's supposedly running rich, backing off the throttle it burbles once and smooths out. However, leaning the air/mixture as a little effect on top power until its well outside of the range for other throttle settings. In fact I was surprised how little of an effect it had when setting the A/M screw per the service manual and your method. There is almost a full half turn of 'play', where it has no effect on idle speed. It's runs at the same idle between 1-1 1/2 turns out. And within this 1/2 turn of play there is little to no effect on the WOT (subtle) stumble. Is this normal to have that much play?

I ran out of time to kill it at speed and check the plug. Ill do it this weekend. At this stage it runs well enough to give it back to the owner and have him give me better feedback since I've never ridden one properly sorted.

working on a friends scoot, no top end power By hondarider (Read 1,106 times)

Post by hondarider on Apr 27, 2013 10:30:31 GMT -5

Post by hondarider on Apr 28, 2013 21:24:39 GMT -5

Post by alleyoop on Apr 28, 2013 21:52:56 GMT -5

Post by hondarider on May 1, 2013 9:32:21 GMT -5

Post by urbanmadness on May 1, 2013 9:50:29 GMT -5

Post by hondarider on May 3, 2013 20:40:46 GMT -5

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