Date: 29-03-24  Time: 15:34 pm

Author Topic: Gen 1 top end rebuild  (Read 1328 times)

Stinka

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Gen 1 top end rebuild
« on: 24 February 2021, 10:36:31 am »
So my guy is getting the head off as the valves and cam are worn


Anyone got a decent inlet cam about ?


Also is it worth fitting an r1 head Gasket to bump compression a bit ?


Where is the best supplier for valves and gaskets ?

Stinka

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Re: Gen 1 top end rebuild
« Reply #1 on: 24 February 2021, 10:40:10 am »
Also do 4xv cams fit ? As loads about and cheaper than fzs1000 cams

Falcon 269

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Re: Gen 1 top end rebuild
« Reply #2 on: 24 February 2021, 03:05:37 pm »
IIRC, if you fit an R1 head gasket you can gain benefits by tweaking the valve timing slightly.

Not sure about the 4XV cams but I bet there's something on't t'internet about it somewhere. :)

Falcon 269

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Re: Gen 1 top end rebuild
« Reply #3 on: 24 February 2021, 03:21:38 pm »
I knew I remembered something Ivan posted about this on the US FZ1OA forum years ago:

07-31-2012, 01:20 AM
Using the R1 race gasket will give a compression ratio around 13.3-1.... this will still run well on 93 octane pump gas.

The FZ-1 stock gasket is appx .032" thick and the R1 race gasket is .020".

Using the R1 stock gasket will give 12.4-1 compression...

Lowering the head (using a thinner gasket or milling) will cause the cams to need to be re-degreed due to adding more slack in the cam chain.... the FZ-1 has slotted sprockets, so no need to buy a set.

This is the easiest way to increase compression... for the rpm range that this engine runs, the added compression will not cause the powerband to end early.

Using the gasket and setting the cams to 107in/101ex will give great results... using 105in/100ex will give better midrange at the expense of some top end.

Stock cam timing is 105/105...

105 on the exhaust doesn't really add any top end as compared to 100ex, but costs some midrange.... this is another area that this engine is detuned.

The good power cam timing window for 5 valve Yamahas is pretty narrow...

Increasing compression will give more power across the entire rpm range, but in order to make the most increase across the range, an ignition module becomes necessary as well as re-degreeing the cams.

A Yosh full system is a necessity as well due to the need for the longer header tubes to make the midrange.

Might as well clean all the valves and replace all the valve seals while you are in there.


Ivan

Original thread here:  http://www.fz1oa.com/forum/forum/fz1-fazer-owners-association/exhausts-carburetion-performance/gen-2-exhausts-fueling-performance/126444-squish/page2

If you join that site and do a search using 'R1 head gasket' as the search words, you will find quite a few performance-related threads which should answer your question.

Stinka

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Re: Gen 1 top end rebuild
« Reply #4 on: 15 March 2021, 05:40:45 pm »
So that says the cam pulleys are slotted ?! They are not, and all the pictures I can find shows they aren’t


So putting r1 cams in at stock cam timing is going to kill my midrange


Ah well

Gaz66

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Re: Gen 1 top end rebuild
« Reply #5 on: 15 March 2021, 09:03:00 pm »
You could always slot the cam sprockets a little & degree em in to Ivans recommended specs, already considered doing this to mine next time heads off.

Stinka

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Re: Gen 1 top end rebuild
« Reply #6 on: 18 March 2021, 12:54:42 pm »
Okay so the shop have built bike up and now they are saying the 4xv r1 cams won’t fit as there is no oil way in the cams

Stinka

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Re: Gen 1 top end rebuild
« Reply #7 on: 18 March 2021, 07:51:47 pm »
So after a second set of 4xv cams again with no oil ways through cam, I’ve got a set of fzs1000 cams


So. Early r1 4xv cams 98-00 will not fit from my experience, which is counter to everything Ivan has recommended in the thread posted by falcon

Falcon 269

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Re: Gen 1 top end rebuild
« Reply #8 on: 19 March 2021, 06:41:35 am »
So after a second set of 4xv cams again with no oil ways through cam, I’ve got a set of fzs1000 cams


So. Early r1 4xv cams 98-00 will not fit from my experience, which is counter to everything Ivan has recommended in the thread posted by falcon


Sorry but you misread my posts.


I linked you to a thread answering your question about fitting the R1 head gasket but there is no reference in that by Ivan or anyone else about using 4XV R1 cams.


I said from the outset that I wasn't sure about fitting 4XV cams to the Fazer 1000.  Unfortunately, you have learned the hard way that it isn't possible.


Hope the rest of the rebuild goes well. :)