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Discussion Starter #61
So, I put the engine case back in the frame so it would be a little easier to torque on this nut. This was really hard to break loose but I was able to get it. It also had a good amount of locktight on it.


After that nut, and the two on the counter balance shaft, I used two screwdrivers to slowly pry off the gears. They came off without much trouble.
 

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Discussion Starter #62
Next stop was the shifting stuff. The problem here was getting the two hex screws out. I ended up stripping one and had to drill it and use an easy-out to get it out. Unfortunately I used too large of a drill and the screw broke off. It let me continue for now but it means I'll have to get the end of the screw out at some point.


After that is off its just a matter of pulling some parts off and then one bolt to get the cam thing off. Here it is off but siting in the case; you can see the other side of it.
 

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Discussion Starter #63
Now, finally, it's time to split the case. Since they make a special tool for this that I don't have I was guessing it might be a hassle. There are bosses at the front and back of the case that can be used to pry them apart and as it turns out they came apart with ease. No big deal and no damage. Nice when things work out.


With a little care all the stuff will stay in the left case half.


Good shot of two of the shift forks.


I pulled the gear shafts out. For the drive gear shaft there was a bushing which has what looks like a seal on it. It came apart as can see here. Anyway, this bushing came off to the outside of the case as the shaft was pulled away on the inside.


So here are the gears. The gear on the right, second from the top has a lot of wear on every tooth and the dogs that connect it to the sliding gear next to it have their leading corner rounded off.
The gear that matches up with it on the other shaft has wear on the edge of every tooth as well.


Lastly, and I think this is the main issue (but I'm not really sure why things went working right) is the third shift fork. This slides the middle gears on the right shaft in the previous picture. You can see that there is a lot of wear on this fork where it shouldn't even be rubbing. I'm guessing that this is a bent fork but I'll have to get a new one to compare to be sure.
 

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THAT is really screwed. Ray Charles could see that. It's always nice to get in there and find something obvious. Wish I had a nickle for every time I've done something like this and found nothing obvious. Great work, keep it up!
 

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Discussion Starter #65
Called my local dealer today to check on availability of parts.
Here is the list I asked about...

P/N NAME COMMENT
8000 97970 Engine gasket set
8000 97973 Circlip kit Piston Ring Set
8000 79690 S.s.3rdgear(Z=27) Output shaft 3rd gear. A little wear.
8000 79688 M.s.3rdgear(Z=20) Primary shaft 3rd gear. Beat up.
8000 79687 Gear 5th - 6th speed Out or spec because of bent shift fork.
8000 71158 Fork gearchange (3rd-4th) Bent shift fork.

Anyway, none of these items are in stock. Said it would be a week or so to order the parts.
Total quote for these items was around $439.

There are a few more small things not yet on the list (cam chain, reed valve, screws & washers) so we'll see how it goes.
I guess the wait for parts is not a huge issue (yet) since I have to head back to Santa Barbara and won't have any time to work on this 'till Christmas.

Anyway, might be another month 'till I'm back to work on it and posting more pictures.
 

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Discussion Starter #66
I guess I'll bump my own thread.

A week before Christmas (I think it was) I ordered the parts that I needed from my local dealer (GP Motorcycles in San Diego).Several weeks went by and I was out of town and didn't care about the wait. Anyway, last week I gave a call to see what was up and they said all the parts were in except a couple screws that I ordered. None of the screws are important to the build so I guess I'll go pick stuff up and see if I can find time to start putting it back together.
My problem is that I'm working in Santa Barbara so I don't get down to the house much which is where the bike is. I'm planning on being in SD next weekend so I guess I'll try to pick up the parts and then we can figure out where to go from there.

Everything takes time. At least we have progress.:thumbup:
 

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Discussion Starter #67
OK, I have all the parts.
Now if I can just find time to put it all back together.

I think I've decided not to mess with the crank/rod. Need to still give them a close look but I really just want to get it running and keep the cost down as opposed to making the motor 'new'. This is where you just keep wondering if you are making the right decision.
Anyone want to comment on having the crank/rod reworked?

The other thing I still need to figure out is what to do about honing the cylinder. Back in the old days I would do it by hand with some light oil and emory cloth. But I should probably find a hone and do a more antiseptic job. What do you guys do?
 

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OK, I have all the parts.
Now if I can just find time to put it all back together.

I think I've decided not to mess with the crank/rod. Need to still give them a close look but I really just want to get it running and keep the cost down as opposed to making the motor 'new'. This is where you just keep wondering if you are making the right decision.
Anyone want to comment on having the crank/rod reworked?

The other thing I still need to figure out is what to do about honing the cylinder. Back in the old days I would do it by hand with some light oil and emory cloth. But I should probably find a hone and do a more antiseptic job. What do you guys do?
Cooksey cranks is who I sent my CR 250 crank to get rebuilt. He came very highly recommended. There should be an acceptable tolerance (side to side play) for the conrod in the service manual.

Most new cylinders are NIkasil plated and emery cloth won't even scratch it.........How bad is it?
 

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Discussion Starter #69
There should be an acceptable tolerance (side to side play) for the conrod in the service manual.
Yes, have the specs just haven't measured it yet. Maybe this weekend.


Most new cylinders are NIkasil plated and emery cloth won't even scratch it.........How bad is it?
This is interesting. It's not "bad", just want to make sure the rings seat. The engine had a lot of miles on it.
 

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Cool post!
Thanks for the detailed break down of the engine.

Would you mind confirming something for me ?

When taking off the cam chain tensioner to check the wear levels, do you need to drop the oil from the bike first ?
Do you need to replace a gasket when checking it ?

Thanks and sorry to go slightly off topic.
 

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Cool post!
Thanks for the detailed break down of the engine.

Would you mind confirming something for me ?

When taking off the cam chain tensioner to check the wear levels, do you need to drop the oil from the bike first ?
Do you need to replace a gasket when checking it ?

Thanks and sorry to go slightly off topic.

No to dropping oil, and no gasket needed. Just pull it and count the clicks that it is set at.
 

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Cheers Craigs!

I'll pull mine at the weekend to check the wear, Bike has 3000 Miles on.

Best Regards
Gav
3000 miles should be fine.
 

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Yeah I only brought it the other week so want to make sure everything is up to scratch.

Been talking to Husky Sport regarding the power up kit for the bike too.
They have them in stock @ £32 + Vat and they mentioned the bike should be run through their diag equipment to adjust fueling for another £50 +vat (Including the fitting of kit)

Not sure if I should just buy the kit and fit my self (10 Minutes) because I'm not sure whether they will actually make any adjustments to the bike??

What are your thoughts ?
 

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Nice thread so far, thanks for the updates.

I have a question, I am about to be freshening up my 510 engine, and I will be rebuilding my crank. I was wondering what tool you guys are using for pulling and replacing the crank in the cases?

Can I just use a hydraulic press to remove it, and the pressure from bolting the cases together to seat the crank in the bearings? From what I can tell in the service manual they didn't use a tool to install the crank.

Thanks.
 

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Nice thread so far, thanks for the updates.

I have a question, I am about to be freshening up my 510 engine, and I will be rebuilding my crank. I was wondering what tool you guys are using for pulling and replacing the crank in the cases?

Can I just use a hydraulic press to remove it, and the pressure from bolting the cases together to seat the crank in the bearings? From what I can tell in the service manual they didn't use a tool to install the crank.

Thanks.
Bump. Any info on this topic? Not trying to threadjack.
 

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Discussion Starter #77
Bump. Any info on this topic? Not trying to threadjack.
I believe in this thread I wrote that I opened up the cases by just prying on the tabs on the front and back of the case. Came apart with no hassles. Crank comes out by hand, no issues.
 
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