Everything tight after engine rebuild

Dex94

Member
Dec 29, 2015
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Hi gents,

I just finished rebuilding my blaster engine. New crank, bearings etc. The full works.

when Iam tightening the cases together the transmission and crank is getting stiff. Somethings not right. I’ve tore it back down and can’t see any obvious signs. Any common issues to cause this?

appreciate it.
 
A bearing or bearings are not seated all the way in case halves. It doesn't take much.do cases close up. But when you try to tourqe them they get tight?
 
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The cases close up to maybe 3mm gap. The rest was torqued in sequence. My guess was a bearing so will go at that tomorrow. Everything was built on the left side. Right side was slipped over onto transmission and crank.

I removed the crank. And tried torquing together just with transmission. Same deal, when torqued the transmission won’t turn by hand.

so pretty much rules there’s issues with bearings somewhere. This wouldn’t cause the crank to tighten up though so the main bearings must have issues too right?

thanks
 
The cases close up to maybe 3mm gap. The rest was torqued in sequence. My guess was a bearing so will go at that tomorrow. Everything was built on the left side. Right side was slipped over onto transmission and crank.

I removed the crank. And tried torquing together just with transmission. Same deal, when torqued the transmission won’t turn by hand.

so pretty much rules there’s issues with bearings somewhere. This wouldn’t cause the crank to tighten up though so the main bearings must have issues too right?

thanks
First off do not use the bolts. To pull cases together.thats bad and hopefully didn't throw your crank. Out of truness. If you look at crank you will see why.nothing but air between shafts. Need a crank puller/ installer. Or make one.or have the block that goes between flywheel weights .
The cases should go together. All the way easy with crank removed.
 
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Also make sure the pins for shift forks are all the way seated. This should not cause binding but can keep cases apart.take your time and check everything!! Good luck. Get cases to go together without crank first.cases have to go evenly
 
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yeah Iknow it’s bad practice. Iam actually working out my own garage, all my tools are at my work right now which is very frustrating and it’s too easy to just go for it.

rebuilt with transmission only. Same same. One of the transmission bearings does not have a seat. So you can fit it and it will be too tight when the cases are brought together if this makes sense?

I chapped the bearing back a couple mm and everything’s turning smoothly on the transmission now. Tranny won’t shift no more though. Haha Iam at my wits end with it man .
 
Check the output shaft bearing in right case half. It’s a straight through hole, bearing doesn’t bottom out. Try tapping it 1mm towards clutch . DO NOT use the screws to pull it together. You should be able to tap it right with a rubber mallet. Assemble without sealer until you get it right, then final assembly with sealer.

BTW, it took me three tries before I figured this one out. Had heated the cases and that bearing fell out.
 
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Check the output shaft bearing in right case half. It’s a straight through hole, bearing doesn’t bottom out. Try tapping it 1mm towards clutch . DO NOT use the screws to pull it together. You should be able to tap it right with a rubber mallet. Assemble without sealer until you get it right, then final assembly with sealer.

BTW, it took me three tries before I figured this one out. Had heated the cases and that bearing fell out.
Yeah the right case bearings can get you when the cases are hot.they can shift allitle.
 
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Yeah that’s what I mentioned above man. I was trying to figure it out and noticed it. Like I say I chapped a couple mm. Thanks though!

yeah I just pulled the crank onto the bearing using the closest case bolts to the centre of the crank.. as would a crank installer that last extra 2mm. Small pop on the bearing.. good to go. I don’t see a major issue pulling it in that extra couple mm if Iam being honest.. I’d say that safer that chapping it together. It should just go straight together this time as the cranks installed on the right case and left case is a slip fit, so we shouldn’t have that issue next time round Anyhow.... wtf is up with this transmission now not going through the gears!!! The guy I bought it from said it was stuck in 1st gear before he stripped it down. I found a broken shift shaft, the spring etc was damaged, the shift shaft has been replaced now but Iam just not 100% it’s going through every gear. Seems to be going into gears sometimes and then not the others!!
 
Yeah that’s what I mentioned above man. I was trying to figure it out and noticed it. Like I say I chapped a couple mm. Thanks though!

yeah I just pulled the crank onto the bearing using the closest case bolts to the centre of the crank.. as would a crank installer that last extra 2mm. Small pop on the bearing.. good to go. I don’t see a major issue pulling it in that extra couple mm if Iam being honest.. I’d say that safer that chapping it together. It should just go straight together this time as the cranks installed on the right case and left case is a slip fit, so we shouldn’t have that issue next time round Anyhow.... wtf is up with this transmission now not going through the gears!!! The guy I bought it from said it was stuck in 1st gear before he stripped it down. I found a broken shift shaft, the spring etc was damaged, the shift shaft has been replaced now but Iam just not 100% it’s going through every gear. Seems to be going into gears sometimes and then not the others!!
Are you rotating the tranny shafts enough for it to engage the gears. You have to keep turning them while shifting
 
Yeah sure am sir. Turning whilst shifting. It’s being a nightmare!!

It’s times like these I wish the KOC assembly vids were still on YouTube. I tried to purchase from him in the past and it’s not cost effective shipping the DVD to the UK.

Iam sure I’ll get there. Thanks for your help so far guys.
 
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The right side case is the one without the interference fit on crankshaft bearing.(clutch side)
 
The right side case is the one without the interference fit on crankshaft bearing.(clutch side)
Yeah Iam getting mixed up. It’s on the interference fit side now.

is it possible to fit the shift forks on wrong? I.e upside down?
 
The reason I ask. After looking at diagrams. I think I might have No.2 the independent fork on upside down. Therefore we ain’t getting the travel up when shifting ??

I can’t work out in my head by looking at the diagrams if the locating pin would still go into the shift drum if it was flipped.
 
Yeah Iam getting mixed up. It’s on the interference fit side now.

is it possible to fit the shift forks on wrong? I.e upside down?
Transmission and crank are in stator side cover? If so. The forks have numbers 1-2-3
. 1 and 3 are on same rod and 2 is by itself
All numbers need to face down towards stator side case. Also put a little bit of grease on the pins on each fork where they go shift drum
 
Transmission and crank are in stator side cover? If so. The forks have numbers 1-2-3
. 1 and 3 are on same rod and 2 is by itself
All numbers need to face down towards stator side case


Yeah that’s how I’ve got the forks fitted. Slydog
 
Yeah that’s how I’ve got the forks fitted. Slydog
Then that should be good.it is hard to test sometimes because when you turn the shift drum. Ussualy 2 forks are moving.plus just the one case half. Are you shifting. With cases together?