Ultra 150 Project

[axgrider73]

Ok guys, I bought the ultra. It is a 2000 with 85 hours, super clean. It has 120 psi compression on the front two cylinders and 0 psi on the pto cylinder.

Three years ago it had a SBT engine insatlled that lasted one season (15 hours.) It has been sitting for the last two years. I pulled the plugs and the front two were black and the pto was white. I am guessing that the rear cylinder has run lean and the caused of the problem. Hopefully this was only a carb adjustment issue.

Here are my questions:

What is the stock bore for this engine?

I have read that the cylinders are plated. What is the deal with that? Can
I bore a cylinder without replating it?

What are the chances that the crank seals need replaced? Do I need to split the cases to replace them?

I have also read that you can't convert this thing to premix. Is this correct?

Where is the cheapest place to get carb kits?

I am sure that there will be more questions. Please don't hesitate to comment. I need all of the help I can get.

[axgrider73]

Well, I got the motor out this evening. The mag and center cylinders look good. No rust or scuffs. The pto piston looks like hell and the cylinder has some minor scuffing.

The main thing that I am concerned about is the mag rod and crank journal. The other two crank journals have a washer on both sides of the rod, but the pto journal only has one. There is also a mark on the top of the rod that looks like it has been grinding on something. I am not sure how well it will show up in the pictures.

Any thoughts on this crank? I would like to save money when posible but i don't want to put together a time bomb.

[btldigger]

I would split the cases just to make sure there is nothing in the bottom. There could be a small piece of something that has been rubbing. You also want to be sure the bottom case isnt cracked. The crank looks ok from what I can see. From what I understand sbt sleaves all thier cylinders with regular steel sleaves so it could be bored its not nicasiled like stock ones. You might want to find a stock one and a std size piston. Yours definatly looks like it ran lean the other thing on the ultra is check those oil lines they tend to crack and starve it for oil. Alot of guys run 100 to 1 in the tank and leave the oil injection in place just as a precaution. This is what you get with a bad oil line.

[thesepaperwings]

Ok guys, I bought the ultra. It is a 2000 with 85 hours, super clean. It has 120 psi compression on the front two cylinders and 0 psi on the pto cylinder.

Three years ago it had a SBT engine insatlled that lasted one season (15 hours.) It has been sitting for the last two years. I pulled the plugs and the front two were black and the pto was white. I am guessing that the rear cylinder has run lean and the caused of the problem. Hopefully this was only a carn adjustment issue.

Here are my questions:

What is the stock bore for this engine?

I have read that the cylinders are plated. What is the deal with that? Can
I bore a cylinder without replating it? Yes you can but when you order pistions its better to get the flat tops from skiworks instead of going crazy with a huge bore.

What are the chances that the crank seals need replaced? Do I need to split the cases to replace them? The seals are prob ok but I would check it if you have it out anyway, better to be on the safe side.

I have also read that you can't convert this thing to premix. Is this correct?
The oil injection system has 5 different outputs, it oils the bearings on both sides of the crank. Trust me, you want to leave it in, and I would also put a little oil in your gas with every tank.

Where is the cheapest place to get carb kits? Kits, as in rebuilds?? Dont do it. The CV carbs are a pain in the arse. The kits are a min. 100 bucks a pop and they dont have everything you really need. I would start looking for a pair of buckshot 44's, 46's or some NOVI 48's. The 44's wouldn't cost much more then rebuilding the CV's and they will give you a lot more options if you every dicide to make it faster.

I am sure that there will be more questions. Please don't hesitate to comment. I need all of the help I can get.

[axgrider73]

Well I talked with Ronnie at Sharps today. He said that there should be a thrust washer on both sides of the rod so, I am going to have the crank rebuilt.

[thesepaperwings]

You should build a monster!!!

[axgrider73]

I thought about it, but I prefer reliability. I am going to talk to Sharps and see what they can do to goose it a little with out hurting the reliablity. Maybe a little porting and carb work.


I will keep you posted.

[axgrider73]

Ithe other thing on the ultra is check those oil lines they tend to crack and starve it for oil. Alot of guys run 100 to 1 in the tank and leave the oil injection in place just as a precaution. This is what you get with a bad oil line.

Talked to Ronnie at Sharpe's again today, and he said he could (and would recomend) drilling out the cases so that I can convert this thing to premix.

I just don't have a lot of faith in those oil pumps.

Everything will be on its way to New York this week. I hope to have this thing running again by Labor Day.

[btldigger]

The pumps dont fail very often most of the oil related failures with an ultra involve cracking oil lines. How did he propose dealing with the counterbalancers needing oil? Thats why most dont convert the ultra or the stxr. What most do is to leave the oil injection then just add some extra oil in the gas. That way if you loose an oil line the cylinder is still getting oil. Thats how I run mine, I wouldnt want the hassel of changing the oil in the counterbalancers. Just my 02 cents worth but I would spend the extra money on go fast parts.

[thesepaperwings]

I'm with digger, everyone I have seen try it says it can be done but is a pain in arse. With the money it would take to do that you could get your self some flattops or at the very least the stinger mod.