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Discussion Starter · #1 ·
This is my 1st bike and Im not very knowledgeable when it comes to motorcycles. It starts and idles perfectly (no problems revving it), but once in gear it feels like its hesitating, shaky, and will not idle further than 4500 rpm. When I 1st got it I took it to a mechanic to install new floaters, the originals were cracked. They said everything else was great on the bike. It ran well but this problem occurred just weeks later. I assume the carbs are fine because he seemed sure they were in good condition. So any thoughts on what the problem could be are appreciated thanks. I was thinking it could be transmission-related but idk?????
 

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Sensei
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You'll need to do a couple tests to narrow down the possibilities.......
check that the carbs are getting fuel from the tank......
Check that there is no debris in the carb bowls (rust flecks, etc...)
Check the plugs for a "reading'.....
Check compression....
Check timing.....

If you are unsure of how to do any of this, ask....I'll post step by steps....
 

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Discussion Starter · #3 ·
Thanks for responding so soon. The carbs are getting fuel and the bowls are clean. And someone already helped me check the plugs and they're good. That leaves the compression and timing. I'm completely inexperienced with bikes and I wanna do this myself so if you could post the steps for checking these, that'd be great. Thank you.
 

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Sensei
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Easy one first.... Warm up bike...shut down and Remove both spark plugs....screw compression gauge adapter into one plug hole.... Gas off, key off, throttle wide open ...10 kicks (or until gauge "stops' rising)...read gauge and record number of PSI....Repeat on other cylinder.... PSI should be 170ish, below 150/155 is re-ring time, as is a difference in the two cylinder readings of 15 PSI or more.......Post what readings you got....
 

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Discussion Starter · #5 ·
Took me a while to get the time/gauge to check the compression but it read 50 psi for both cylinders when i tested it. I know thats way off from where it should be and i followed the directions exactly so it seems that's an accurate reading unless the equipment wasn't working properly. What do these numbers mean? Thanks
 

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If you held the throttle wide open while performing the compression test, and the choke was fully open, then those numbers mean that either the valves don't seal at all, or the top end needs rebuilt. You're sure that you performed the test correctly? Several kicks until the gauge quit rising?



GB :mrgreen:
 

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Discussion Starter · #7 ·
Ok I realized that I didn't have the choke fully opened, that was left out of the instructions that I got. Thanks for the tip, I'll retest them soon and post the results
 

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Be sure that the throttle is all the way open and the choke is as well. Basically you want the most air possible going through the carbs. You want a straight open passage. Opening the throttle and the choke will do this for you.


GB :mrgreen:
 

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Discussion Starter · #9 ·
I redid the test with the choke and throttle completely open and got the same results, 50 psi on each cylinder. If this means the valves aren't sealing at all or the top end needs to be rebuilt, then how complex/time comsuming is it to check and fix this problem?
 

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Sensei
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It's about an hours work to rebuild and adjust the top end once you have the parts ready to assemble.....You'll need to tear it down to figure out what size pistons and rings, (and the bore) and check the valves are sealing...... (acetone test)...... Remove the old gaskets, etc, etc, etc....


The first thing you need to do is get the engine out of the frame.......So, disconnect the wiring, coils, pipes, and anything else that's in your way......

Feel free to phone me if you get stuck or have questions....540-427-4256..... I screen calls so start talking at the beep..... Steve
 

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Discussion Starter · #11 ·
I'm about ready to remove the engine from the frame, so I was wondering when/how I should do the acetone test for the valves and supplies I'll need, once I remove the engine?
 
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