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Author Topic: 1995 bullet forks and head gasket  (Read 112 times)

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Seipgam

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on: October 12, 2018, 05:52:51 am
Hi Guys, I'm new to Elfields.
1995 Bullet requires head gasket replacement, looks like I should be able to handle that but do I put anything on the new gasket or go bare?

Front fork seal replacement - Looking at Snidals manual it seems a bit different to what it looks like on Hitchcock's parts guide for a 95.
Snidals shows what I presume is an older setup with serviced bushes and a single thin looking seal, but it looks like the 95 has a double seal arrangement and no separate bushes (??).
Is the servicing the same procedure?  Or can I drop the lower legs off without removing the complete fork from the bike? (Surely it wouldn't be that easy).
Been looking for a you tube video or something for this but can't find anything.  Does anyone know of one?

Cheers, Geoff.

Update- Just found Hitckock's fork seal replacement guide (excellent), but could do with the head gasket advice - Cheers.
« Last Edit: October 12, 2018, 06:38:08 am by Seipgam »
1954 Francis Barnett, Kestrell 66 125cc
1984 Yamaha SRX250
1995 Royal Enfield Bullet 500


mrunderhill1975a

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Reply #1 on: October 12, 2018, 01:09:33 pm
My head gasket on my 1999 went on without any adhesive goop and worked just fine.  However, I think in your case it will depend on how flat the mating surfaces are.  Has the head ever been overheated ? Has there been any warping? If the surfaces are not flat you may want to get some grinding paste between the head and the cylinder and grind off any high spots.  I seem to remember ACE had the procedure for this listed in one of his posts here years ago.  ACE, can you chime in here with advice?

You may want to look at this post:

https://forum.classicmotorworks.com/index.php/topic,4053.msg46666.html#msg46666

Here are two pages from an article on lapping the head:
http://royal-enfield.net/articles/creasey_article_4_p1.pdf

http://royal-enfield.net/articles/creasey_article_4_p2.pdf
« Last Edit: October 12, 2018, 01:24:55 pm by mrunderhill1975a »


ace.cafe

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Reply #2 on: October 13, 2018, 07:48:11 am
Okay, there are 2 different mating surfaces to deal with.
The fit of the spigot into the head recess seals the compression.
The gasket seals the oil.

So, take off the head and gasket, place the head back on by hand and push it down as far as you can by hand. No bolts. No gasket in place.

Take some automotive feeler gauges and measure the head gasket gap in at least 4 different spots all around the head. Write down what the measurements are. If the head tilts one way or other, the spigot needs to be filed flat to make the head seat evenly all the way around. It also needs filing if it has irregularities on the top of the spigot where hot gases can blow out. Don't file any more than needed to clean up the fit, and don't let filings get into the engine

Put the head back on by hand again and measure the gasket gap again. It wants to be around .025" gap. If it is more than .025" -.027" then file the spigot down until you get that size gasket gap. If the gap is too small, then get the top of the barrel skimmed down(making sure they know to not cut the spigot) at a machine shop by the necessary amount to give that .025" -.027" gasket gap.

The stock head gasket is a copper/fiber/copper sandwich type gasket, and is typically about .035" thick. When this gasket is in place it holds the head about .010" too high, but it can crush about .010".  So, when you torque down the head(20 ft- lbs) it will crush the gasket down enough to seal the oil, and  it seats the spigot fully home into the head recess to seal compression at the same time.

It is important to get these 2 planes of sealing done simultaneously when the head is torqued on.

Once you do this once, it won't leak, and you can change head gasket(same stock type) any time and still have it perfect. The only time to need to re-do this is if you get a new head or new barrel.

If you don't it this way, you have a strong chance that you will fight oil leaks or compression leaks for the life of the bike.
« Last Edit: October 13, 2018, 07:54:34 am by ace.cafe »


Seipgam

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Reply #3 on: October 13, 2018, 05:32:09 pm
Once again, some great information.

Thanks Guys.

Geoff.
1954 Francis Barnett, Kestrell 66 125cc
1984 Yamaha SRX250
1995 Royal Enfield Bullet 500