Valve guide size

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10 Apr 2016 07:59 - 10 Apr 2016 08:00 #720170 by zed1015
Replied by zed1015 on topic Valve guide size

bromz wrote: Well guys a 200 shim a valve stem ground and still no clearance!! Any last ditch ideas before I take it in to the machine shop??

There are a few things that can be done machining wise with your existing valves and retainers which I won't go into now but they are for someone who really knows what they are doing with these engines.
That aside the simple fix is to start by trying a new unworn valve (which may also need tipping) .
This may be enough to get the clearance back if your existing valve heads are worn or have been re-faced.
Failing that fitting 1mm larger valves is the usual bolt in solution.
This puts the valve face further out on the un-cut , un-worn portion of the seat and brings the stem height back down to the low end of the specs.
You can also use 'J' valves which also have a shorter stem if you were in the same situation but larger valves were already installed.
After this you are looking at having new seats fitted.

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
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Last edit: 10 Apr 2016 08:00 by zed1015.

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10 Apr 2016 08:07 - 10 Apr 2016 08:08 #720172 by SWest
Replied by SWest on topic Valve guide size
Not just any repair shop can do these heads. Any heavy handed old time shop can do old style heads but these don't have the large tolerances they do. Even my old Ford 390 has a limited range. Once at that point, only new cintered valve seats will make the heads runable again.
Steve
Last edit: 10 Apr 2016 08:08 by SWest.

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10 Apr 2016 13:12 #720206 by bromz
Replied by bromz on topic Valve guide size
The valve that is in it is brand new. He just cut the seat too deep I think.

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10 Apr 2016 15:23 #720217 by zed1015
Replied by zed1015 on topic Valve guide size
Your next option is to try an oversize stainless valve which should fix the problem and you should really do the other three to match.
Obviously the seat will need cutting wider starting with the 45 first and then check the installed stem height of the new valve as you go.
Aim for the minimum height (which is in the manual ) so you have plenty of shim range.
Once that is ok cut the 30 and 60 to get the correct seat width.
If the machine shop cut the seat too deep they probably don't know what they are doing (or didn't care) and you should find someone else.
Any shop you take it to should check the existing installed height first and this would tell them how much room there is to play with before cutting the seats or tipping the valve.
Knowing the installed height tells you roughly what size shim will fit and how much to tip the valve before any work proceeds.
It sounds like this wasn't done.

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11 Apr 2016 05:15 #720277 by bromz
Replied by bromz on topic Valve guide size
Ok guys I'm gonna call ape and talk to them. Please explain to me how an oversized valve might work or even a j valve??

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11 Apr 2016 05:25 #720281 by SWest
Replied by SWest on topic Valve guide size
The valve is wider so it will contact a undamaged area of the seat. I didn't know J valves were shorter. Good to know. If money is tight, one valve could be done. See what they say.
Steve

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11 Apr 2016 07:36 #720310 by zed1015
Replied by zed1015 on topic Valve guide size

bromz wrote: Ok guys I'm gonna call ape and talk to them. Please explain to me how an oversized valve might work or even a j valve??


The explanation to the oversize valve solution is in my reply 2 posts back.
As for the 'J' valve length. That only applies to the older kickstart motors and I notice that you are working on the later one so it doesn't apply in this case.
I would contact Larry Cavanaugh or Joe Hooper (Pitstop performance) to do the work.

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
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11 Apr 2016 07:52 #720313 by PLUMMEN
Replied by PLUMMEN on topic Valve guide size

bromz wrote: Ok guys I'm gonna call ape and talk to them. Please explain to me how an oversized valve might work or even a j valve??

Check out larry cav ,He can probably fix it as good if not better than APE.
Probably a little cheaper also. ;)

Still recovering,some days are better than others.

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11 Apr 2016 08:29 - 11 Apr 2016 08:33 #720325 by bromz
Replied by bromz on topic Valve guide size
Try a +1 so 33mm or 32mm
valve?
Last edit: 11 Apr 2016 08:33 by bromz.

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11 Apr 2016 08:57 #720331 by pete greek1
Replied by pete greek1 on topic Valve guide size

bromz wrote: Try a +1 so 33mm or 32mm
valve?

If you send the head to Larry, it'll take all the guess work out, since he specializes in head work, & there may be other options
Pete

1980 LTD 1000..,1976 LTD 900, have the 1000&900 now. the rest are previous= 1978 KZ 650 B.., 1980 Yamaha XT 500..,1978 Yamaha DT 400.., 1977 Yamaha yz 80..,Honda trail ct 70.., Honda QA 50...5-1/2 hp brigs & straton CAT chopper mini bike...3-1/2 hp mini bike (WHEN GAS WAS ABOUT 45 CENTS A GALLON)!!!!

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11 Apr 2016 09:32 #720341 by bromz
Replied by bromz on topic Valve guide size
I dont have 3 to 4 hundred to put into this head. I will push it to the curb with a free sign before i do that

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11 Apr 2016 09:58 #720362 by zed1015
Replied by zed1015 on topic Valve guide size

bromz wrote: Try a +1 so 33mm or 32mm
valve?

You need a 33mm valve.
32mm is standard on the exhaust of the CSR.

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
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