Tim
I am on the valve shim job again and would like some new collets.
Are there any suppliers of 'good quality 1.5mm valve collets that fit well and last some miles?
My original collets on my 1991 851 are 1.5mm and seem to be stainless, being bright and nonmagnetic.
I picked up 6 new ones at the weekend from Woods Ducati in Abergele (dull and slightly magnetic) but they would not seat correctly.
I fettled the ends to remove any burrs and got one to fit.
They not only are poorly finished at the ends, but also the inside diameter seems to be incorrect.
Is there a knack to get new collets to fit?
I tried tapping the top of the valve but still no go.
Do they need a tool to push/force them home?
I contacted Mike at EMS to see if he has 1.5 collets or even MBP retainers but he doesn't do the 1.5's in either form, which is a shame as his electro polished 1.7 look well made.
What are my options?
Thanks
Tim
Tric
Steve R will be along in a minute Tim, he knows. 😎
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Mr.R
Hi Tim,
IIRC? Tony Brancato of Brancato Engineering in Oxford had some magnectic collets made and sold them as a kit back in the day...They were a useful upgrade at they were a useful upgrade.
It's probably worth giving him a try, he might still have some hanging around.
Failing that I might have a OEM ones kicking around if you're desperate.
TBH If it were my bike I'd modify the valves to take the later much better 1.75mm ones (it's a pretty simple job for a decent engineer to carry out, I know some one who can do it for you*) or better still fit MBP/EMS collets.
I've got MBP collets in all of my Ducati's now, money well spent IMHO.
*He's modified Big valves for my special engines from various other engines to fit Desmo collets.
My '79 900SS has modified Moto Guzzi inlet valves and BMW car exhaust valves fitted.
Steve R
brad black
what part # did you get? 66910011b are the 1.5, which may be nla now, haven't tried to order them for years. 66910011e are the 1.7mm.
if you were going to pull the heads to get the grooves done i'd get a set of 748 heads and fit them.
Tim
Thank you for the comments.
On checking the clearances for the closing shims, all were fine, except one that seemed to double in size for some reason. Previously I had found that the collets distort, so I have been marking the top with a red marker and ensuring they always go back in the same way up. This helps considerable, but I am wondering if this heavy set is an indicator of excessive wear on the collets. Inverting them can change by 0.06mm.
My collets are nonmagnetic, which is a real pain. The one valve I was working on was the front inlet left. So, dropping a collet is not to be recommended. Mine found its way into the valve spring for the exhaust closer on the left. I had to unload the spring, remove the rocker pin and retrieve the collet from the rocker pin hole. Incidentally I have found that a cheap Endoscope for use with smart phone or tablet (off eBay) was very useful in the search for the collet.
I am also paranoid of losing a collet down the oil return holes. I lost one down there once on my 750F1. At the time Steve Wynn said that he only knew of one motor that had exploded when a loose collet had found its way into the gearbox. So, I removed the head and barrel and found the collet on the crankshaft.
The new collets are I believe 66910011b, as Woods has 6 in stock I bought the lot. I did not know that they may be hard to find.
I am sure I could get the new collets to sit OK, but I would have thought that they would then set after a few miles and open the gap up again. I believe that used collets are better, but I have no data on this. Hence the request of a 'better component.
It seems that my options are limited.
I contacted Tony Brancato, but he does not have any 1.5 collets.
Reworking the valve to use the 1.75 collets sounds a good idea, but I would be concerned that this may weaken the valve and the tolerance of the fit must be key.
How much would this cost for a full set of 8 valves?
My bike is an 851 Strada with small 32/28 valves, so 748 heads would be an improvement. I will have to look into this.
Do they just bolt straight on? What benefit would they give me in performance?
This sound like a winter project.
The bike is going back together now.
I will start recording how far the valve go out each time.
I would like the MBR retainer system to extend the service interval as the valve job is quite a strip down.
Tim
