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Dominator 99 valve clearance

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Depending on what literature I have , the valve clearance varies from 0.002” inlet, 0.003” exh. to 0.003” inlet , 0.005”  exh. Any advice as to the recommended settings ?

I don’t know whether the cam is standard or not. I have rebuilt the top end.

George

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The factory Maintainance manual and instruction book lists 0.003 '' inlet, 0.005 '' exhaust., Roy Bacon shows 0.002'' inlet  and 0.003'' exhaust for  up to 1959 and 0.003'' inlet and 0.005'' exhaust after that.

I would go with the factory recomendation.

Good Luck.

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... in Moto Guzzi circles: A tappy Guzzi is a happy Guzzi - in other words, loose rather than tight. That's the way I would go....

My own V50 is quite rattly from the top end when cold but quietens down nicely when warmed through after 15 miles or so.

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Hi George.......your question is almost impossible to answer when checking all the usual sources for information. As you have found out yourself there are numerous suggestions and some  contain errors as they do not appear to allow that for the fact that early Dominator engines had all-steel pushrods inside the barrels. Whereas by 1957 these had changed to pushrods with alloy shafts which need a greater clearance due to differences in expansion of the respective metals. Checkout the attached well respected Garratt Service manual page which contains such mistakes.

I would suggest 0.002" and 0.003"  (In/Ex) for the early engines with iron heads and all-steel pushrods. I note that BMS suggests 0.005" for the Ex.

But 0.003" & 0.005" for Alloy heads and Alloy pushrods.

If  someone has fitted the SS camshaft inside your engine then 0.006" & 0.008" will help stop the valve heads tap dancing on the pistons.

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Thank you for the replies to my query. I will go for the 0.003” / 0.005” with the alloy head and alloy pushrods to be on the safe side.

 I don’t know what I would do without the wise advice  that I have been getting over the last year ! Cheers, George

Hello George,  you say you're not sure if your cam is standard or not,  is there any reason for you to suspect that a previous owner might have fitted something else. Tappets should never be adjusted on a "near enough is good enough" basis. For instance , if a PO had fitted a cam that required 008" clearance and you were to set it to  003" this would affect the cam timing , hence the reason for knowing if possible what cam you have in your engine. Hope you get it all sorted. 

Ian Hay. 

 


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