PlanetMinis Forums banner
Cancel
Create thread New Forums

im stumped (locked up motor)

Jump to Latest
1 - 20 of 77 Posts
3

3rdGearPinned

· Registered
Joined
·
6,564 Posts
Discussion starter · #1 ·
Earlier tonight i was riding around in the driveway. The motor locks up. Doesnt give any signs of anything going wrong. It just locked up and stalled out in a instant.



It seems like it got stuck in second gear, it wouldnt shift so we figured it broke second or something. Heres the kinda confusing part, even with the clutch lever pulled in the bike would not roll and kickstarter would not budge.



Got it to the garage and pulled the clutch cover off, everything looked fine. The top end spun freely. So we took the motor out of the bike and split the cases. NOTHING was broken in the tranny. No metak shavings or anything and every gear looked fine.



The motor had been running for 2-3 hours and shifted and ran fine. I know i cant totally say it wasnt a install error but you would expect a install error to be noticable right away when you first start the bike up.



We are totally stumped. All we can come up with is the tranny some how got wedged between gears or something.



I would really like to know what happened so it doesnt happen again, i got lucky and was just rolling around the driveway when it happened. If i would have been on the face of a jump i would have been screwed.



It happened under fairly "light accerlation" but the motor was being dogged on pretty good a couple minutes before it happened.



BTW its a 124SE motor with a kitaco clutch and tranny kit.



Im just wondering if any of you motor builders have ran into anything like this before?
 
#2 ·
You might want to make sure that the shift drum is secured in place with the bolt and flat washer on the stator side of the engine (behind the rubber plug). I had assumed (incorrectly) that the flat washer was still in place when I installed the bolt, and then put the rubber plug in place. It had been quite a while since the reassembly when the bolt head worked it's way into the hole, allowing the shift drum to slightly shift out of place, binding up the shift forks while in second gear.
 
Discussion starter · #3 ·
thanks man!



That looks like its my problem. Stupid me, we didnt even have a bolt in there in the first place. Nothing was holding the shift drum from moving. I feel pretty stupid but hey stuff happens, it was our first tear down and rebuild of a bottom end and it sat in peices for like 5 months, we just forgot.



Im glad its nothing major though. I should have it back running again tomorow.
 
Discussion starter · #5 ·
yea i was pretty upset but i wasnt like crazy upset. I knew whatever it was could be fixed. And ive been around high performance stuff my whole life so breaking parts is just part of my life. I mainly just wanted to get it apart to see what happened and get it back together.



Game on!
 
#7 ·
YOu are a lucky man

3rdGearPinned said:
thanks man!



That looks like its my problem. Stupid me, we didnt even have a bolt in there in the first place. Nothing was holding the shift drum from moving. I feel pretty stupid but hey stuff happens, it was our first tear down and rebuild of a bottom end and it sat in peices for like 5 months, we just forgot.



Im glad its nothing major though. I should have it back running again tomorow.
Click to expand...


I once failed to put on some locktite on this particular bolt and was ripping down a trail full throttle on a 110 build in 4th gear...about 50mph. The back wheel locked up solid when upshifting to 3rd to take a turn and threw me approximately 25 feet. That little bolt worked its way out, locked up my tranny, and destroyed both 3rd and 4th gears. It is not enough to put that bolt and washer in there. I say put some blue locktite on it. as well.
 
Discussion starter · #8 ·
Well i put the bolt in there this time, put the cases back together and was still locked up.



We had the cases apart and togeth atleast 20 times to figure out what was wrong. All we can come up with is that one (or both) of the shift forks bent just a tad keeping the tranny locked up. It is keeping first and second locked together (on the counter shaft sprocket)



So i guess i gotta get some new shift forks and try it from there.
 
Discussion starter · #13 ·
JohnnyB said:
Does the kick starter turn the motor over ??
Click to expand...


No



Even with the clutch pulled in the kickstarter would not budge and the bike would not roll. (normally with the clutch pulled in the bike rolls and the kickstarter just easily blows through its kick not actually turning the motor over)
 
#14 ·
- Pull off the clutch cover and see if it'll kick over then ..

- If it turns over ok , then you need to remove some metal from the left side case where the kick starter gear is hitt'n . You should be able to see where the gear has been hitt'n the case ???
 
Discussion starter · #15 ·
JohnnyB said:
- Pull off the clutch cover and see if it'll kick over then ..

- If it turns over ok , then you need to remove some metal from the left side case where the kick starter gear is hitt'n . You should be able to see where the gear has been hitt'n the case ???
Click to expand...


I already ground out the case where it would be hitting.



Im way passed pulling the clutch cover off, the cases have already been split, put backtogether and split again a couple times haha.



I know for a fact its in the tranny, im thinking its a bent shift fork.
 
#16 ·
If you ever want to come

3rdGearPinned said:
kitaco 3 speed. well basicly all the kit does is replace 1st gear, the kickstart pinion gear, and of course the mainshaft for the clutch to be mounted on.
Click to expand...


If you ever want to come down and have me look at anything, I'm in Arlington VA. I am king of troubleshooting when I see it in front of me.
 
Discussion starter · #17 ·
Thanks for the offer fatcaat, ill make sure to use it up if i ever need it.



We are 99% sure its just a bent shift fork(s)



Gonna order some new ones and see if thats it.



i can see where 1st and 2nd were getting locked together (nothing to need new gears for. Im sure its just the shift fork(s) were holding them together.



Ill make sure to post an update when i find out.
 
Discussion starter · #18 ·
Well i replaced both the shift forks and it didnt fix anything at all. The motor is still locked up.



All that i can come up with now is the counter shaft and/or the mainshaft is bent. With just the tranny loaded without the right side case on, the tranny spins fine. As soon as i put the cases together the tranny will spin about 4 or 5 turns then lock up. But if you put a vice grip on the mainshaft and apply some torque it will spin past the locked up part, spin for about 5 more times then lock up again.



WTF



Im thinking about just replacing the whole tranny. Fatcaat do you any 1 down 3 up 4 speeds that will hold up to a 124 on the dirt laying around?
 
1 - 20 of 77 Posts
About this Discussion
76 Replies
18 Participants
Last post:
3rdGearPinned
PlanetMinis Forums
posts
2.1M
members
63K
Since
2003
PlanetMinis forum is the internet's largest mini bike community. View thousands of photos, event coverage, tips, tricks and performance mods.
Full Forum Listing
Explore Our Forums
CRF50 KLX110, DRZ110, TTR90 Chinese/Import Minis - General Discussion Z50, CT70 and JDM Monkeybikes Complete Bikes For Sale - All makes and models