S3 Race Custom Modified EC250 Complete Rebuild

[adv rider]

Oh OK I see, you are dropping the crank off to be rebuilt. That's good ,because a 3 jaw puller would not get that bearing off the crank. You Need a bearing separator style- it has knifed edges,so as you tighten up the nuts. Its forces the puller behind the bearing-get it real good and tight. Then use a press on the WELL supported crank assy.
Its the only way I have ever done main bearings.

[GMP]

That bearing should not be that tight of a fit on that crank that it takes a crazy effort to remove, the case press fit should be tighter. Only the inner race of the two part rollers are supposed to be tight. If the bearing bore in the case is so loose it allows the bearing to slip in and out easy, I would use some bearing retainer compound after a proper degreasing. This works in this application, but not so well if the inner race/crank journal fit is loose.

As advrider suggests, a bearing separator will get under the bearing. Retain this in a vise, and a few good taps on the end of the crank with a plastic hammer should do it.

[flybars]

Great stuff Jakobi! I appreciate U taking the time.

[Jakobi]

And thats why I love this place. Knowledge!! I never even knew such a tool existed but my logic was the same that if I could hold the bearing in a vice and then tap the crank end it should slide out. Makes perfect sense to have something holding behind the bearing that is the right shape to clamp into the vice.

The crank has been in the freezer over night, so I think we'll probably try a bit of heat on the inner race again this morning. If thats no go I'll head out and buy a bearing separator. Once the cases are cleaned up I'll check the new bearing to see how easily it will push in or out. On inspection it doesn't look like there is any wear on the case side.

[Jakobi]

The freezer/heat trick worked the second time round. Popped it off at the dealers this morning and then left it with him along with the Vesrah rod kit. Replacing with the same brand of rod as I've been happy with the life and performance of it. All the measurements were still in spec.

Is it normal for the rod to feel like it can rock a bit side to side? I'm not sure if it was actually rocking or just felt like it. Zero noticable up and down. Needles looked good. The side clearance was right in the middle of spec.

[twowheels]

Originally Posted by Jakobi

The freezer/heat trick worked the second time round. Popped it off at the dealers this morning and then left it with him along with the Vesrah rod kit. Replacing with the same brand of rod as I've been happy with the life and performance of it. All the measurements were still in spec.

Is it normal for the rod to feel like it can rock a bit side to side? I'm not sure if it was actually rocking or just felt like it. Zero noticable up and down. Needles looked good. The side clearance was right in the middle of spec.

Vesrah seems to know what they're doing - I haven't seen one fail either.

You've got quite a bit of leverage on the rod at the top end so a little 'rocking' play is to be expected.

Can't wait to see the build-up pics

[Jakobi]

You know how to keep me motivated Steve. Today I'm only going to clean up all the gasket surfaces, lay out all the new parts and double check I have everything. Might get the old bearings out today, but will probably wait until tomorrow. I have other tasks to do too (such is life).

Back onto Daves comment about the UCCR and how it may be contributing to some of the extra heat in the piston. I was thinking after a comment on another forum. Basically, the other option I have at this point is also sliding in a single 0.1mm base gasket. That will take my squish up to 1.35mm, but will raise the ports a touch, and add an extra 0.35cc's of volume It should net some better over rev in both aspects. I might lose a touch off the bottom as a result. I might do that as its the cheap and easy option and I have everything here to do it myself.. and if I'm unhappy its easy to switch back. I'll crunch some numbers tonight to see just how much difference to the UCCR this will make.

[GMP]

I don't know, my setup is pretty tight and on the edge for pump fuel and piston looked perfect when I had the jug off. Perhaps it's just a result of jetting being a bit crisp for the setup.


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[Jakobi]

Originally Posted by GMP

I don't know, my setup is pretty tight and on the edge for pump fuel and piston looked perfect when I had the jug off. Perhaps it's just a result of jetting being a bit crisp for the setup.

I think this plays a part too Glenn. I think that the 175 main with the Yamaha needle was cutting it really fine. Couple that up with my riding continuing to improve and more time spent in that rev range and its pretty likely. The needle clip position is definitely in its ideal position. At half a clip richer the bike loses snap and doesn't want to stand up as much when coming onto the pipe. Noticably decreased performance. The pilot circuit I have been running a bit on the richer side for torque.

The other consideration is that the bike fell totally flat in the top end coming home at the end of the last ride. Enough to make me decide I wanted to pull it down. It was having issues idling, either stalling or racing when adjusting the idle speed. On pull down I noticed a weeping main seal on the stator side. Was this enough to allow for a hot run? Who knows? If you know a way to ascertain which it was I'm happy to investigate further, otherwise I'm going to assume it was a result of all of the above. I'll probably drop comp a touch more, as well as fattening up the main jet a size or two.

[GMP]

So your going back to the PWK, no Lectron or SmartCarb?


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