Putting things in places they ought not to be (250R Hybrid Motor build)

[atc007]

Update;

I think I got my cases suitably surfaced and smoothed out. I ended up after some extensive checking with a feeler gauge found I had up to a .018 gap in the cases right in the crank case area. Upon closer inspection, I've found that atleast one of these cases looked like it had suffered a pretty catastrophic crank disconnect and failure. The gasket edge was actually bent outwards, and wasn't sitting totally flat with its counter part. Plus there was a spot I knew that had a crack in it. Remember, these were junk cases when I started and I knew that

I've preached this in the past, but it is absolutely imperative that a motor have a good seal in the crankcase, cylinder, head, exhaust,intake, etc. If you can't pass a leak down test you are GIVING away HP and you will endlessly chase your tail for fueling and electrical issues when it is infact an airleak of some sort. I have a stock 250R motor with bolt ons only that embarrassed quite a few "built" 250Rs. But I had it where it would hold 12psi over night. So I am making sure that I am able to get the best performance possible out of this build while everything is apart and loose. If it doesn't run right, I want to eliminate as many variables as possible obviously.

I ended up surfacing each side of the cases on some sand paper taped to a piece of glass and found where my bad spots were. I just went over the whole gasket surface with a black magic marker and then sanded till it was gone pretty much everywhere else, to determine my spots.

Attachment 184289Attachment 184290Attachment 184291

As you can see in the pictures, the edge just wasnt sitting flat. I ended up working on this a bit more and got it really close, and then I ended up welding and building up 2 other areas (No finished picture yet, I'll get some). Working on these case edges had intimidated me a lot, but ended up being easier than I had thought it was. Rules being: Cleanliness is godliness on aluminum, pre-heat the entire work piece with a torch, and use appropriate sized filler rod. I ended up dressing these areas back out with a couple different stages of filing and my cases now seal within .003 without a gasket when bolted together Cometic center case gasket is .020 thick.


As they sit right now, I've assembled the bottom end with the crank, main bearings, and seals. Installed the topend with the base gaskets, spacer plate, the head with its o-rings. Intake, and exhaust flange both installed. The only things I need is a rubber intake boot, a couple 5mm odd ball sized bolts for the intake, and the dang right side crank seal collar which is actually discontinued from Honda. When I get that put together I'll get to leakdown test the whole she-bang finally.

Where is the LOVE this post button? We really DO need one..

[Billy Golightly]

So, I figured today basically the short list of what all has to be done on this thing assuming the leak down test goes well;

Make and weld water necks onto the head, and also the cylinder to tie into the 250R coolant system.
Machine my shifting shaft and shifting shaft seal area on my center cases.
Drill/tap new drain plug since the old one was stripped and I welded it up.
Buy and install all new case bearings.
Buy and install a 4mm stroker crank (been testing with a stock crank I had)
Finish zeroing in my deck heights and head squish.
Build a pipe...this is going to be as much of a project as the motor itself was probably.


All thats left is well...everything


I was hoping to have this done by TF, but especially with the pipe work, that is probably bit more ambitious than I can rationally handle and complete successfully.

[Billy Golightly]

As soon as I get a free weekend from work...

Also forgot to mention I have to clean up the welds in the transfer ports to match the cylinder but that's not more than an hour or two at most.

[Billy Golightly]

... My dad and I say it different, and he knows of them since back in the 1960s when they sent a snow machine to test out in the Everglades working on power line right of ways and he worked with FPL on that.

[Yamada]

www.youtube.com/embed/KdmefIovkDM
The women say Bombardier right at 0:47

[atc007]

So, I figured today basically the short list of what all has to be done on this thing assuming the leak down test goes well;

Make and weld water necks onto the head, and also the cylinder to tie into the 250R coolant system.
Machine my shifting shaft and shifting shaft seal area on my center cases.
Drill/tap new drain plug since the old one was stripped and I welded it up.
Buy and install all new case bearings.
Buy and install a 4mm stroker crank (been testing with a stock crank I had)
Finish zeroing in my deck heights and head squish.
Build a pipe...this is going to be as much of a project as the motor itself was probably.


All thats left is well...everything


I was hoping to have this done by TF, but especially with the pipe work, that is probably bit more ambitious than I can rationally handle and complete successfully.

How hard could a pipe be?? Cut a MXZX 800 pipe in half,same to a 250R,and weld them together! Lol, , Fullwell, knowing the exhaust will be the single most important part of this project. As far as extracting all of the horsies available and having them at the desired rpm/powerband. Wish I could help,but I can't,and I know you'll handle it It will have to resemble a 500 pipe in volume.. Cool stuff.

[whitetail hunter]

hows it going Billy. any more progress made did it pass leak down?

[Billy Golightly]

It did better than I expected but it still needs some tweaking to it. my base gasket surface on the cases is going to need some fine tuning, but the center cases seem to be holding better than I expected in the repaired areas. The northerners will laugh, but its been so cold here, I've not been motivated to go in the shop after dark when I get home. And I've worked like the last 3 weeks and weekends in a row, I just haven't had any time to work on it hardly.

[RIDE-RED 250r]

No laughing here. You guys down there just aren't used to weather like that. Let alone the municipalities being prepared for snow removal that far below the Mason/Dixon.

But keep your chin up, while you have been having the weather you have had, we up here in northern NY have been well below zero and in some cases 20 below or colder at night and struggling to get out of single digits during the day! And yes, it IS wearing on me too! We have been in a clod snap for pretty much 2 weeks now with nary a break. It is a bit warmer today though, we hit 24 deg! LOL!

I havan't touched the wife's 350x project I have going in the garage lately. Between being busy with other things and the frigid weather, like you I haven't had the desire to work in the garage.

[Billy Golightly]

hey El-Camexican, does this contraption ring a bell for you?

[atc007]

Dammmmmmnnnnnnnn!

[Billy Golightly]

I think I'm going to end up redoing the top surface of my cases just to be on the safe side since it was a little bit questionable on the alignment anyways. Also strongly considering putting in time serts threaded inserts for the cylinder bolts just as a precautionary measure.

This thing has turned into a money pit but I'm learning a lot and by the time this one is done I should be able to replicate and crank out another one very easily actually.

[yaegerb]

hey El-Camexican, does this contraption ring a bell for you?

Ok, call me an idiot....what is that?

[rg97]

Its a 1-2-3 block (or thats what I call it) connected to who knows what. Hopefully some will explain it because I'm : too

[Billy Golightly]

Sweet! I’ll bet that comes in handy when you go to modify the second set of “slightly more pristine” cases. So tell us, did your lathe darn near walked out the door while making that hex shaft round?

Not much lathe walking with this beast...