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  1. #1

    Ultra 150 Porting

    Hi guys , Im new to the ski world but have been involved with snowmobiles and 2-strokes for awhile. I recently purchased a 2005 ultra 150 which i am rebuilding. I am going to be putting on a set of coffman pipes , big carbs and ignition. My question to you is this , are there any gains in porting this motor? are they worth the time? We have porting software and have done quite a few motors just no jetskis. Aswell what kind of compression ratio does this motor like when running pipes on pump gas?


  2. #2
    btldigger's Avatar
    Join Date
    Feb 2007
    lebanon tn.
    Better keep that compression down about 120psi to stay safe on the pipes. Prety much leave the stock heads on it. What kind of water are you going to be ridding in? Anything done with the hull such as plate sponsons grate?

  3. #3
    steve45's Avatar
    Join Date
    Feb 2008
    Welcome aboard, onestockone!

    Can't help you with the porting question, but wanted to throw out a few things that are good to know.

    Some people want to remove the oil injection system on the Ultra 150. DON'T do it! There are balance shaft bearings that also get their oil from the oil pump. If you remove the pump, you have to modify the crankcase and pull the engine periodically to change the balance shaft oil.

    The oil lines are known for getting brittle, cracking, or coming off when old. Good time to replace them!

    Check the cable on the oil pump. They fray easily.

    Look into installing the triple pisser kit. This allows you to monitor water flow from each cylinder.

    Installing a strainer in the cooling water line will keep trash out of your cooling system. Carry a 1/2" barbed splice connector in case the strainer develops a crack and leaks water into the 'Ski.

    The 'Ski is a LOT more fun if you modify the trim to give more UP.

    Pull out the Multi-Function Display and re-seal the rubber plug on the back. It will leak water when it gets old and ruin that $800+ speedometer. Put some 3M 5200 on it.

    Never, never, NEVER run the flush hose water unless the engine is running! Water can flow backwards from the exhaust into the cylinders. Start the engine, turn on the water. Turn off the water, shut off the engine.

  4. #4
    Hey guys thanks for the quick responses, I will be running a shred master plate with beach house sponsons and a 16/20 solas, I have been reading as much as possible and have seen many tips from everyone which is great! I will also modify the stock grate as you have mentioned on the ultra forums . this will be 100 percent fresh water / flat water ski , the most I see on the lakes I ride is a 2 foot chop and that is rare. Anyways thanks a lot , and keep 'em coming!

  5. #5
    btldigger's Avatar
    Join Date
    Feb 2007
    lebanon tn.
    Since as you stated at the start you are new to skis I would almost suggest to set it up with a single pipe and aftermarket carbs. Ride that arround for a bit and get the hull and pump set up. That would put you up arround 70mph if its all rite. Then when you put the pipes on your not chasing other problems. When you put those pipes in your going to be looking at a 75+ mph ski. Trust me when I say that mph difference makes the ultra a whole different animal. The ultra has some handling quirks, thats why we suggest to do the plate and sponsons first. The mod stoc grate is the fastest but can make the ski feel very loose and twitchy on the top end. Those things mean there is a learning curve to ridding an ultra, starting out with pipes could mean the lesson you learn is much more painful..... Im just sayin

    Tripples are fun and definately addicting I have run them on my level2 and plan to try them on the 1350 big bore I have in the ski now. I want to try it with the hull freed up to see how close it will run to 80. I dont think it will break it.

    Sounds like you have read through the mods thread if you havent already go check out the project progress thread on the ultra 150 board. There is alot of info in there on setting up the ski for tripples. There are several of us here that have tripples to help you out.

  6. #6
    Yes from what I hear they are a tricky ski to handle up top , and as much as I would like to set it up with the single I have to many buddies on supercharged 4strokes lol I am going to be sure to take it easy and respect the learning curve of riding with a set up of this caliber. Do you think setting it up with a top loader grate that would hold it to the water better may be a good idea the first while? Anyways thank you for your help! It should be an interesting summer!

  7. #7
    btldigger's Avatar
    Join Date
    Feb 2007
    lebanon tn.
    If they are stock then a good setup single pipe will outrun them if they got a few mods then yes you need the pipes. The grate will help pin it down and make it more stable. My single pipe with the novis has run 72 with the r@d grate on and low fuel. The same setup will run 74 full of gas with pipes almost 76 with low fuel. With the mod stock grate it should do 77+. That is with a level 2 motor a stock motor shouldnt be far behinde.

  8. #8
    captainoverspray's Avatar
    Join Date
    Jan 2009
    Milwaukee, Wisconsin, United States
    PM johny5 for info on porting. He ported his 1200 stx-r and had good results.

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