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Discussion Starter · #1 ·
I haven't seen any recent posts on this and I'm new to the Ducati world. Started a 748 I picked up and its running rough! Compression is 95 vertical and 110 front cylinder. So I know compression is an issue. I've rebuild many dirt bike motors...( I know it's not a Ducati) but my questions are . 1. Is replacing piston rings a job a weekend mechanic can handle?
2. For a stock 748 do I need OEM rings or what is my best option? And I guess last question without breaking the bank any other things I should address while its apart?

Thank you everyone!
 

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Could be just a valve, you need a leak down test to figure it out.

For your mechanic hability no one can judge except you. Anything can be done if you have the skills.
 

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rings wouldn't be the first thing i'd suspect. leak down test for sure.

std rings are the only option i know of, and are not cheap. generally replacement aftermarket pistons set are cheaper than just oem rings. but they're probably pretty rare for std bore 748 these days.

if you do pull the heads i'd set the squish then the cam timing.
 

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Discussion Starter · #4 ·
Thank you all. I am going to pull the heads. I am sure the valves are way off. I'm going to really go through them and get them to newer condition. If you can help I read the cam holder for later model 748 pre 01 I need a 18 tooth cam holder is this true, because I have a 20 tooth holder coming my way.
 

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Picture of the bike please. I want a before and after if you are so kind.
 

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Discussion Starter · #7 ·
Definitely have some before. So far all new hydraulic and fuel lines, oil change,re lined and sealed the gas tank, fuel filter, clutch, breaks, removed and hydrosonic cleaned Injectors and throttle body. New relays and alot of wiring. The owner is no longer with us so I'm restoring this for me and his parents. It sat for about 5 years. I still have a long road ahead! Dealing with bad valves or bad valve adjustment. One battle at a time
 

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No need to remove heads if it is just a valve adjusment. I am with Belter in that you should start with a leakdown test before removing any hard parts. If you find a issue with the cylinder seal or a valve that does not seal and is not a simple adjustment then go ahead. Were it mine if the cylinders come off the big bore kit goes in, no sense doing all that work for little gain.
 

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Discussion Starter · #9 ·
Thank you for your advice! I will absolutely start there! I have seen that big bore kit, will it also require new tuning?
 

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The airbox is missing the bushing/thing where the tank seats. (directly below the key tumbler)

May not be much. Remove the spark plug and put a couple drops of out in the cylinder with low compression. See if compression comes up. If so, it's the rings. If not make sure you have good spark and ride it around the neighborhood a could of times.
 
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