Disengaging clutch while in motion?

G

Giselle

Guest
So I was riding my motorized bike the other day. I'm going about 15 or 20 mph and I decided to squeeze my clutch lever to disengage the engine. I was trying to stop but something weird happened. It happened really fast so I'm not really sure what it was. It made an odd noise and my bike tilted sideways. Luckily i didn't crash or anything but i just want to know what that was. Is it okay to disengage the engine while going relatively fast?
 


Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
464
yes its normal to disengage the engine at any speed preferably disengage it during low engine rpm low speed all it does is take the friction off the plate. You should make sure you have little slack in your chain since it could bind when it gets loose with no tension from the motor driving it
 
G

Giselle

Guest
yes its normal to disengage the engine at any speed preferably disengage it during low engine rpm low speed all it does is take the friction off the plate. You should make sure you have little slack in your chain since it could bind when it gets loose with no tension from the motor driving it
Yeah my chain was pretty tight. That may have been it. Thanks!
 

The_Aleman

Well-Known Member
Joined
May 2, 2007
Messages
1,046
Yeah, does sound like your motor drive chain is too tight. Roll the bike with the clutch in to check it.

If you're using the kit idler, make sure the chain crosses the plastic pulley wheel straight.
You may need to put a slight twist in the bracket to achieve that. You can run up to 1" of slack.
 

FurryOnTheInside

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Joined
Sep 23, 2013
Messages
3,685
You should check your chain carefully in case it is damaged. The chain can sometimes "jump off" "skip" or completely derail from the engine sprocket when the clutch is disengaged and the top run of chain suddenly goes slack.
Sometimes this can cause momentary very high tension in the chain as it rolls over the tops of the teeth, which could perhaps flex your frame like a banana or pull the wheel out of alignment in forward or rear facing dropouts.
It has been known to trap the chain inside the corner of the sprocket cover and jam the chain, causing the rear wheel to lock up!

There are several ways to make sure the chain feeds onto the engine sprocket reliably and can't skip, jump or derail and be damaged in the process, or jam inside the sprocket cover and cause a crash.
I tried a few of them, because I like disengaging while shutting off throttle and engaging the clutch while rolling onto WOT at relatively high speeds 15-37mph, with no idle so the engine actually dies and bump starts every time. :giggle:

View media item 61320


View media item 61367Ignore the Zee sprung tensioner that was a test of an idea. :geek:
 
Last edited:

LewieBike

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Joined
May 21, 2014
Messages
684
Remember that most of these engine chain drive sprocketrs are machined slightly eccentric to some extant. and will need a bit of fettling to run good. I've bought 3 replacement narrow 410 chain sprockets, and all 3 of them have the sprocket teeth at some out of roundness in addition to not fitting ( too wide..) any of the 1/8" chains they claim they fit.
 

BIG BOBBY

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Joined
Mar 22, 2019
Messages
124
only time my chain got bound up in there (the drive sprocket recess) was when I stupidly installed that POS "spring loaded" kind of tensioner on my first build,...at startup.

pedal to speed,,..... pop the clutch,...top run of chain goes COMPLETELY floppy-sloppy,,..... floppy chain binds in drive sprocket recess,....almost cracks the crankcase,... rear wheel locks up,... heart attack. (lesson taught,..lesson absorbed.)

it happened at least 10 times before i put on my sherlock hat and found out about that $%#&@((# spring loaded tensioner hunk of JUNK that almost destroyed my engine on the first day. got the standard stock one on there rock solid and it never, ever happened again. coasting, or whatever. clutch pulled, clutch not pulled, uphill, downhill. never again. I will state for the record that im a REAL stickler for chainline alignment, chain tension and lubrication,.. and sprocket mounting concentricity and alignment. ill readjust it all day long until im happy.

that day when my rear wheel locked up in my driveway taught me how disastrous a chain malfunction can really be... not only to the motor and/or wheel,...but ME. but i'll coast with the clutch pulled in a straight line all day long. but,....LEANING while coasting with the clutch pulled? at high speeds? no way. NOPE. leaning makes a slack chain droop and ride off the sprocket. (possibly) and a derailed chain/locked up rear wheel can KILL you. potential death makes me pay attention to detail.
 

Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
464
all of the drive sprockets i had that where new bind up on me after some wear and some 1000ths of the sprocket get worn down they never bind again
 

Sumsloppymeet

Active Member
Joined
Aug 7, 2017
Messages
654
Thats one thing im glad the military beat into my character as well lack of attention to detail will get you killed kinda why i like this hobby really its all about the small things in the end
 
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