Bevel Gear Shaft Repair - getting to it!

[legaleli]

OK... what I find frustrating about "shop manuals" is how easy they make it seem. I removed the 4 bolts and the damn thing is in place and won't budge. I am trying to remove the housing for the part of the bevel gear shaft that connects with the propeller shaft. There is clearly a seal between the housing and the engine, but I don't want to force it unless that's all it would take...

Here's a pic of the manual and my bevel housing with the bolts out:

 

[legaleli]

Updated pictures

Updated pictures

I took these pics at lunch. I am nervous about just trying to force the housing from the crankcase - I do not know if there is anything else besides the bolts holding it in... the manual suggests that there is not... but them manual is so vague.

If anyone here has done this I'd love some advice. Also, the gasket that seals the housing to the crankcase is discontinued... will I have to make my own?

 

[SqDancerLynn1]

It will not come out easy !! You may need to hammer on it.. I'v done it... You need a big prybar/screwdriver
Pry between the engine case and beveled gear flange. Just work it back & forth it will eventually come out.
You do not need to remove the side gear..
Do a search for the repair- drill and tap for new bplt..

 

[legaleli]

It will not come out easy !! You may need to hammer on it.. I'v done it... You need a big prybar/screwdriver
Pry between the engine case and beveled gear flange. Just work it back & forth it will eventually come out.
You do not need to remove the side gear..
Do a search for the repair- drill and tap for new bplt..

Awesome - thanks for the tip - I was worried about using force. how did you solve the issue of the replacement gasket?

 

[rustybronco]

The gasket is an O-ring (#11). the thing that looks like a "gasket" (#12) in the drawing is a shim.
be careful not to damage it, it sets the depth of the "driven" gear.

 

[legaleli]

A tisket a tasket - a shim not a gasket

A tisket a tasket - a shim not a gasket

The gasket is an O-ring (#11). the thing that looks like a "gasket" (#12) in the drawing is a shim.
be careful not to damage it, it sets the depth of the "driven" gear.

I am going to have to start to count the number of times this site has prevented me from doing something stupid. Rustybronco - thanks VERY much for the tip.

SqDancerLynn1 - ditto.

Now... off to the lab!

 

[rustybronco]

Note... most likely you will damage the shim some what; try to keep it to a minimum.

think... go slow... and keep a fine tooth file to dress any damage to the aluminum on stand by.

 

[legaleli]

I am doing something wrong

I am doing something wrong

Note... most likely you will damage the shim some what; try to keep it to a minimum.

think... go slow... and keep a fine tooth file to dress any damage to the aluminum on stand by.

It won't budge. I tried a pry bay, a wrecking bar, hit it with a hammer, and I even tried a wedge between the lip of the housing and the crankcase but only ended up cracking the lip of the housing (nothing crucial was damaged thank goodness).

The housing comes off after the four bolts right? Am I missing something? How is it seated in the crankcase?

 

[Nessism]

It won't budge. I tried a pry bay, a wrecking bar, hit it with a hammer, and I even tried a wedge between the lip of the housing and the crankcase but only ended up cracking the lip of the housing (nothing crucial was damaged thank goodness).

The housing comes off after the four bolts right? Am I missing something? How is it seated in the crankcase?

How about loosening that pinch bolt on the crankcase? Should help reduce clamp load on that gear housing plate.

 

[legaleli]

How about loosening that pinch bolt on the crankcase? Should help reduce clamp load on that gear housing plate.

How about I try that! Sweet - I was wondering what that bolt did... didn't have the guts to turn it without knowing... and, well, know I know! Thanks (again) Nessism!

 

[legaleli]

How about loosening that pinch bolt on the crankcase? Should help reduce clamp load on that gear housing plate.

Nessism, it worked! It took some prying and careful work to get it out but it came out fairly easily once the bolt was backed off.

Now time for the repair part, and then reassembly.

 

[jhillier449]

Good show old chap!!!:clap:

 

[Nessism]

Nessism, it worked! It took some prying and careful work to get it out but it came out fairly easily once the bolt was backed off.

Now time for the repair part, and then reassembly.

Great news! You already have a new driven gear or are you going to drill and tap the old one like Zooks? http://members.dslextreme.com/users/storagecliff/images/bevel_gear_shaft_repair_zooks.pdf

 

[rustybronco]

Did you ever have one of those moments on your drive home? well I did! see corrected info below...

So at this point, how are you going to affect repairs? are you going to replace just the secondary drive gear, or are you going to replace the complete assembly you removed?

if you are going to just replace the secondary drive gear there are some things you should know before starting the repair. #5 in the above drawing sets the preload on the two opposed bearings. the "proper" way is assemble the parts and torque the nut, then check the rotating torque (not breakaway torque) with an inch lb torque wrench. you use a thicker shim to reduce the rotating torque, or a thinner shim to increase the rotating torque.

most likely, if you change "just" the the gear, there won't be a need to change the shim. but, if you change the gear with the rear bearing already installed from another unit you may have to change the shim. unlikely because of the high manufacturing tolerances of most bearings, but still a possibility.

next after the assembly is put back together and you install it back in the engine case, you will need to check the backlash (clearance) between the drive and driven gear and the wear pattern on the tooth faces, both on the drive and coast sides. those shims I said to be careful with are what sets the tooth contact. tooth contact is checked by the contact pattern on the drive and coast side of the teeth.

the backlash is set by using thinner or thicker shims on the drive gear side. if the backlash is to little, when the gears heat up it could bind or have accelerated wear. if the backlash is to great, depending on how much the clearance is excessive, it could make a clunking noise when going from accelerating to decelerating and there is also the possibility of tooth breakage to consider. (I'll tell you how to check the backlash and tooth contact patterns when I get more time)

I'm not trying to discourage you, rather my intentions are trying to keep you aware of all the possibilities that COULD arise.

so choose you parts wisely, keeping in mind the are different parts used in different years when you go to finish your repair.

AND, we are here in the ready...

 

[legaleli]

So at this point, how are you going to affect repairs? are you going to replace just the secondary drive gear, or are you going to replace the complete assembly you removed?

....

I'm not trying to discourage you, rather my intentions are trying to keep you aware of all the possibilities that COULD arise.

so choose you parts wisely, keeping in mind the are different parts used in different years when you go to finish your repair.

AND, we are here in the ready...

Thanks Rustybronco, Nessism, Jhillier (and everyone thus far) for all your help to date... I will clearly be asking for much more!!!

I am going to approach this two ways... I have a used bevel gear set coming my way from an Ebay purchase and I am going to hold that one in reserve as a spare. In the meantime I am going to try to fix the existing one using the methods in Mr. Zooks' pdf on the matter.

I get the feeling that a spare is a handy thing to have and the repair of the existing one might be an easier task to complete - my girlfriend's grandfather used to own a manufacturing garage and still has an "in" there so I can get the original bevel gear machined there. Also the existing one is set up for the bike and will (hopefully) be easier to reinstall (thank you Rustybronco for your insight into possible issues from changing out just the gear side of the two gears).

I will be able to get the piece machined this week. In the meantime I also ordered from Bikebandit some new clutch springs (and gaskets) as well as new bearings for the swingarm. If I am lucky all will arrive in time for a good weekend project!

I am going to buy a torque wrench this week - any suggestions as to the type?