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Found a not bad looking Ducati 998 with very low mileage (4000miles) for sale. It it esthetically perfect, no apparent oil leak and ultra clean, looks brand-new. However, the owner went through some earlier than normal maintenance. Valve clearance had to be done at 3000miles and the* clearance were way off by 2x the recommended spec at almost all the valves. So valve clearance were all set to spec. Is it something that can happen on normal use or do you think the bike was really abuse. Second thing is the bike is rough idling..... It looks perfect but I am a little worried that it might be a lemon. What are your thoughts. Cheers*




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Hard to answer the question without knowing where the valves were and what the guy doing the work considered good. There is an assembly spec for the valves Ducati uses at the factory, and then there is a range used for inspection later. Most consider that inspection range to be a little too liberal and tend to go for the tighter side of the spec or whatever spec they may use that has proven good over time. The valves will deviate the most during the first inspection or two. Sometime after 12K or so things seem to settle in and the valves hold their spec better.

If the bike was beaten on enough to effect valve spec (if that is even possible) then I think it would also show in its general condition.

The rough running may just be that the guy doing the work didn't finish the job. TB balance, TPS sync, CO set, idle speed set etc. Getting the valves in spec is only a small part of the work to be completed during one of these major services.

If you're concerned, have someone else look at the bike as a part of the deal before purchase.
 
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I bought my ST4 used many years ago, it had 7,000 miles on it. I did the first valve adjustment on the bike and my clearances were way out spec. After doing a number of valve adjustments on a number of 4V bikes, I found the first valve adjustment to be the most important. I dont know if wayward specs are due to new parts settling in, or that the clearances were not set correctly at the factory. But once they are set properly, I found them to change a little bit for the first 20 or 30,000 miles, then the change in the clearances tends to decrease. After 30,000 miles, I changed the valve check interval to 10,000 miles and even then all clearances never changed more than 1 shim size (.05 mm). I am at 60,000 miles I may even go another 10,000 miles before I check them again.

I wouldnt worry about the clearances being out of spec initially. If you ride the bike alot, just check them again at the required maintenance interval and adjust as necessary. I am believer to set them to nominal clearances, meaning if they are out by over 1 shim size (.05 mm), then adjust to bring them back to nominal.
 

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Discussion Starter #4
Hard to answer the question without knowing where the valves were and what the guy doing the work considered good. There is an assembly spec for the valves Ducati uses at the factory, and then there is a range used for inspection later. Most consider that inspection range to be a little too liberal and tend to go for the tighter side of the spec or whatever spec they may use that has proven good over time. The valves will deviate the most during the first inspection or two. Sometime after 12K or so things seem to settle in and the valves hold their spec better.

If the bike was beaten on enough to effect valve spec (if that is even possible) then I think it would also show in its general condition.

The rough running may just be that the guy doing the work didn't finish the job. TB balance, TPS sync, CO set, idle speed set etc. Getting the valves in spec is only a small part of the work to be completed during one of these major services.

If you're concerned, have someone else look at the bike as a part of the deal before purchase.
Thanks a lot for the advices... Appreciated

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ime the first time i see a 998/749/999 (including ones that have been serviced elsewhere locally) all the clearances are at the top of the range, which is 0.10 - 0.25mm. i pull them all down, even if they are still within the ducati spec.

if it wont idle then you do the throttle body stuff. if it won't idle at all maybe look at the closing springs. i recall we had one that (when fairly new) would drop the vacuum on one cylinder at idle. never got to the bottom of why. thought later it may have had a broken closing spring. probably had loose clearances too, but we didn't pull the covers of it.
 

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Post up pics if you get it and let us know how you go with the idle. Could have clogged air filters, when i got mine the filters with full of bugs. Or dodgy plugs or something simple. Does it have fresh fuel even?
 
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