KX Riders
Maintenance & Technical => KX500 Original => Topic started by: Mike Grant on January 17, 2015, 12:11:09 PM
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Hey guys.....finally started to tackle my engine rebuild this weekend and I have run into a problem that is stopping me dead in my tracks. I installed new bearings in the transmission + cranks bearings this morning and have moved onto assembling the transmission. I have the transmission completely assembled in the right case half along with the external parts on the other side (shift star + detent)
The input / output shafts turn smooth but cannot get the shift mechanism to work by using the shift shaft and shifter (need more hands to hold the engine secure which I don't have any at the moments. I also turning the shift drum with Vice grips which I electrical taped the hell out of the vice grips jaws to avoid damaging the bushing surface......didn't work either
How the hell are you supposed to run this thing through the gears prior to assembling to make sure everything works ?
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Mike,
I assemble both case halves together, and then will turn the output shaft while shifting thru the gears to confirm I have all gears....
Hope this helps,
DoldGuy
Edit:
With your current setup if you remove the shift fork pins can you move yhe shift drum?
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Yes If I remove the shift fork locater pins I can turn the shift drum
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Can you spin both the input / output shafts with the pins out & the shift forks riding in the slots? If you are sure you have the forks in their proper spots, I would assemble both case halves together & check the shifting by spinning the output shaft.
DoldGuy
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Yep I can spin both shafts and there is no binding or any other problems. I took everything apart and quadruple checked all shift forks are correct against the manual and checked both gear clusters that all washers/gears are in the proper position. Everything is 100% correct according to the manual. Biggest problem I have right now is I don't have shifter to attach to the shift shaft so I was trying other methods to make sure this thing was going to shift before it went back together
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I'd put it together...
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Cranks been in the freezer overnight......Impact sockets are in the oven. I sure hope this crank drops in like everyone says it should.
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Cases are together. What kind of clearance should I have between the crank and the cases
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this is something i have been toying with at present see my crank overall width topic, i have ended up shimming my main in gear side 0.4mm to get my crank to sit bang in middle, i had a overall clearance of 0.8mm. which appears to be normal and a lot of people have kindly confirmed it. this site and members has helped me no end, if i could work out how to post my pics on here i could show u what i did.
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I ended up just giving the crank a few light taps to move it back towards the stator side. I was going by feel for the smoothest rotation possible. Turns smooth as butter and the only drag I can feel is the crank seals. Still looked like the crank was closer to the output in comparison. I just installed the top end and I can turn the motor over by grabbing the crank with one hand. Sure hope this is correct setup
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& you have a 5 speed? :roll:
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Nope......f**king engine is about to get smashed on the garage floor
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Mike,
Do you have the shifter on the shift shaft? If so, spin the output shaft by hand (if the counter sprocket installed its easier) & try to shift, what happens? Have you installed any oil (I use ATF initially to check / then drain prior to running)?
If you need to remove the top end for any reason leave the head on the cylinder to save the head gasket.
Don't give up yet! I'm sure with patience & everyone here, you will get it! :-D
DoldGuy
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Hey DoldGuy.... I installed the transmission with no oil besides soaking the needle bearings on the input/output shafts and a few drops on the roller bearings. I didn't use any lube on the shift drum or shift forks because I was building the engine in my kitchen and didn't want to makes a mess.
If I disconnect the detent spring which rides on the shift drum I can turn the shift drum a few degrees in both directions smoothly before it stops. I have the sprocket on and it turns smoothly and currently is in gear. I have installed the shifter to try and get it too shift with no avail
I bought the transmission and shift forks off Roostius Maximus and had to install new bearings so I double checked all gears were in correct order with the thrust washers and circlips. I bought the shift drum off Sandlblaster and it should be the correct one for my bike.
Appreciate any ideas or help you can give
Thanks Mike
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I think if the gear in the red box is installed backwards it can cause it to not function properly. I will double check when I get home later (http://i.imgur.com/0D09zPB.jpg)
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Hey Mike, A few thoughts,
If you replaced your circlips on the trans is it possible that a gear may have gotten flipped around during assembly ?
Is the dowel pin on your shift drum still there? Just a thought, if its missing you might not have the drum matched up right on either side of the case.
You are sure all of your forks are sitting correctly in their grooves and nothing is jumping loose on you?
What year is your crankcase, what year is the trans from?
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I think if the gear in the red box is installed backwards it can cause it to not function properly. I will double check when I get home later (http://i.imgur.com/0D09zPB.jpg)
The reason I mentioned it is because it happend to me
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The crankcase is an 87. The transmission was 86 or 87.......he never 100% confirmed with me
The transmission is as delivered to me and I just installed a new pair of roller bearing on both shafts. The only gears that I installed would be high gear and low gear on the output shaft and second gear input. New Circlips were used
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Vagassasson. I passed this information onto the guy who is looking at my engine for me know........appreciate the lead
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Hey mike I used the wrong picture on my previous comments that was the tranny picture for my 98 kx500.I was comparing the 2 side by side and got them mixed up. Here is the 87 diagram.don't know if it can cause the same issue in your year or not. Sorry for the mix up (http://i.imgur.com/Q2tAcoI.jpg)
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Well the guy building my motor thinks I he has it figured out ............mixed the shift forks up on the output shaft.........feel like a retard but at least it is shifting gears fine now
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If you build motors it will happen from time to time :lol:
Thanks for the update.
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Yep that can do it to glad to hear you got it fixed
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Great news! We All make miscues like that...Now get some video of it...Ringa Ding Ding. :-D
DoldGuy
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When I rebuilt my motor I put the crank in backwards. I didn't realize it until I tried to slide the drive gear onto the flywheel side of the crank. Had to resplit the cases. A mistake I won't make twice!!!
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On the last rebuild on my 83 KX250 I put the washer that goes under the idler gear on the output shaft inside the case instead of on the outside because it was shown in the diagram outside of the circlip on the clutch side. It all worked fine until I torqued the case bolts to the proper setting. Then it would lock up solid. Drove me nuts! Took it apart twice thinking it was correct. Then I looked at the kick start assembly diagram and the light bulb went off... This stuff happens.