Different heads on 550s

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Alan H
Posts: 10216
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Different heads on 550s

Postby Alan H » Sat Mar 28, 2020 7:29 pm

Just an information post for anyone interested.
It's well know that there's two different types of cylinder heads for the separate carb engines and linked carb engines, but as I've been more involved with this model for that last eight years or so, I've found that there's more than two types - at least three and probably more.
I had three cylinder heads cleaned at my local friendly aluminium oxide blaster man's emporium recently (see pics for top and bottom views) and you'll see the different types I had done. There's two for the non-linked carbs motors and one for the linked one.
Heads up.jpg

Heads down.jpg

I know there's at least two types of ram air cowl too, but at the moment, I'm not sure if both cowls will fit one style of cylinder head - I'll find out soon as I'll get the different cowls out of 'stock' and check - but the cowls are definitely different as there's at least two styles of 'RAM AIR' on the sides of the later cowls - one with stickers and t'other with metal carriers that fit to the cowls.
As for the barrels - well the red 550 that I bought as a spares bike had a very early engine which is only 14 numbers away from what should be in the J, and it turned out to have a mishmash of bits fitted, barrel-wise. Fortunately I have an original set of J barrels 'spare' so they will be going on.
barrel styles.jpg
Proof that four strokes are over complicated

Apexxn
Posts: 9
Joined: Wed Mar 25, 2020 6:37 am

Re: Different heads on 550s

Postby Apexxn » Tue Mar 31, 2020 1:26 am

Excellent post.

Add pics of the different cylinders detailing the differences and I'll be your friend for life.

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Alan H
Posts: 10216
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: Different heads on 550s

Postby Alan H » Tue Mar 31, 2020 7:43 am

Like that you mean?
viewtopic.php?f=2&t=9972&p=76953&hilit=Cylinders#p76953

viewtopic.php?f=16&t=11245

One of my very early posts on the subject.

viewtopic.php?f=2&t=1970&p=12996&hilit=Gt+550+cylinders#p12996

PJME do an alternative - like thise on Mike Yeadon's bike.
https://www.pjme.co.uk/acatalog/Cylinde ... eving.html

viewtopic.php?f=16&t=11250&hilit=Scem

Lots of stuff on most subjects if you do a search! Hours of fun!!! :lol:
Proof that four strokes are over complicated


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