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Got my 75 MT250 back on the road
https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=3101
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Author:  4x4_Welder [ Tue Sep 27, 2011 8:09 pm ]
Post subject:  Got my 75 MT250 back on the road

Well, after scrounging for parts I finally got my Elsinore back to rideable condition tonight. In the end, the two parts that held me up were the gas cap and the tank petcock. I found quite a few caps on evilbay, but I had a really hard time spending $35 on it. The petcock was another matter, but I managed to install one for an XL250, it took some creative hose routing but it bolted on and more importantly was available. Of course the correct one went up for auction right after I bought this one-
Now I can get in a few weeks of commuting before the cold weather sets in.
I'll get some pics posted in a few days.

Author:  4x4_Welder [ Tue Sep 27, 2011 9:44 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

I have an issue with the electrical system- Everything I find says I am supposed to have a battery, yet it does not have one. It has a battery compartment, and a two terminal plug that doesn't seem to have a matching half anywhere in the area, is this where a battery should plug in?
I do need to get the lights and turn signals functional as this is going to be a commuter for a while.

Author:  ~JM~ [ Wed Sep 28, 2011 12:00 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

Here is a post on what I've done on my MT250. I think you'll find the battery portion interesting.
viewtopic.php?t=2943

Sounds like the plug your looking at is where the battery connects. It also sounds like the battery side of the connector is missing. I'm looking forward to seeing some pics of your bike.

Good luck
~JM~

Author:  4x4_Welder [ Wed Sep 28, 2011 10:21 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

That is an interesting battery mod. I'm not too overly concerned with the weight, and the stock battery is $12 so I'll probably just go stock.
Which wire is positive/negative?
I have downloaded the FSM, and it has some carb tuning info that has helped me get it closer to running right. I did find I have a bit more in-depth of a problem though: When I was replacing the piston, I noticed that there was damage to the mating surfaces of both the case and cylinder, like someone tried to cut them apart with a hacksaw. The previous owner gooped it all together with red RTV, which I removed and I used Hi-Tack along with the new gasket. Apparently the gap was too big, though, and the Hi-Tak didn't create a seal. Oddly, though, this engine is running so rich even with this leak that when I spray it with starting fluid the engine stalls. I don't have any aluminum deposits on the plug, and there were no noises or issues that made it seem to be going lean when riding, so I'll just pull it apart and try a different sealer.
My other option is to take the case and cylinder to a machinist friend and have them both cut true, and then (hopefully) use two gaskets to make up the thickness lost. I really don't want to go this route as I don't want to tear it all the way apart.

Author:  ~JM~ [ Thu Sep 29, 2011 12:48 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

On my bike the green wire is negative. All the others gang into the positive side.

You might want to look into using an AGM battery like I did. They don't cost much more (mine was less than $20) & they don't require any maintenance. Plus they don't off-gas or spill any acid no matter what direction you mount it.

Good luck
~JM~

Author:  4x4_Welder [ Thu Sep 29, 2011 8:11 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

I may then, I'm going to pull the jug off, weld build up the damaged area, and have it trimmed back flush. It would be way too much material to to get the damage out, I'd have two gaskets and a shim.
I'll probably build up the case surface as well, and bring it back down by hand. It'll take an eternity to do it right, but that's still less time than removing, splitting, and emptying the case. Plus, once I was in there I'd want to replace the clutches, any bearings, crank seals........
Luckily it's just the transfer port area and the cave dweller didn't go completely psycho on it.

Author:  woosh [ Fri Sep 30, 2011 3:58 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

Ya people love to pry the cylinder off with a screwdriver but I have never heard of a hacksaw. I have a spare bottom end with just the bearings in it if you need one. Its not as hard as you might think to take it apart. I have had my case split three times now due to bad seals and then the tranny went bad too. You do need a cranksplitter I think a steering wheel puller might work too. I also have a spacer and two gaskets on my mt as I had a new rod put in thet was a tad to long.

Author:  4x4_Welder [ Sat Oct 01, 2011 7:38 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

Pics:
Image
Image
Area of damage:
Image
It's hard to see there, but the bit of orange goop residue is what's left of a po's hack repair. Since it came to me with a very nice lightly worn bore and no piston I figure it burned down because of this issue.

Author:  Texas77 [ Mon Oct 03, 2011 12:58 pm ]
Post subject:  Re: Got my 75 MT250 back on the road

4x4_Welder wrote:
Well, after scrounging for parts I finally got my Elsinore back to rideable condition tonight. In the end, the two parts that held me up were the gas cap and the tank petcock. I found quite a few caps on evilbay, but I had a really hard time spending $35 on it. The petcock was another matter, but I managed to install one for an XL250, it took some creative hose routing but it bolted on and more importantly was available. Of course the correct one went up for auction right after I bought this one-
Now I can get in a few weeks of commuting before the cold weather sets in.
I'll get some pics posted in a few days.

Can't wait to see them. Just got my 75' two days ago and it needs work! Any advice or references?

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