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Discussion Starter #1
Guys I have a modded 86 GSXR 750. I am considering dropping some 1100 cams into it. The top end is 91 and bottom end 86. What year 1100 cams will drop right in?

I have been told 88-91 will work is this correct ? Who knows for sure? Anyone done this to a 750 , 91 motor. What will be my gains?

Have not been here for a long time good to be back in da family of gixxers

Sven
 

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Discussion Starter #2
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by jeff:
i'll see if i can dig up some info....hopefully in the meantime somebody else can chime in with a definitive answer...<hr></blockquote>


Thanks

Sven
 

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You can use the 88-90 cmashaft in the 91-92 head castings. You have to convert the head over to single lobe rockers weld up the holes in the rocker shafts and make spacers to center the sigle lobe rockers. We have been doing this for years simply because the 91-92 heads are better than the earlier versions and the cmashaft profiles are better and more available for the earlier camshafts. The problem with the 91-92 camshafts is the shim type adjustment they utilize. Under high rpm they can SPIT out and cause you to drop a valve and destroy everything.This is why we racers convert the heads over. The only camshaft that is big enough to make power with the 91-92 heads are WEB CAMS 380 lift grind,but that is about it. If you build the engine and decide you are going to run these stock cams you will need to consider buying APE extra deep TI retainers(they help keep the shims in place).

Your best bet is to have someone convert the head over then all the options are there for you to take advantage of. If you are interested give me a call We have everything to do it.

Thanks
Doug
SPencerCycle.com
1-800-510-1945
 

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Discussion Starter #4
Thanks for your reply,I understand what you have said and now I have to decide if I want to convert the head over to pursue larger cams.

What would a job like this run me to give me an idea, including the cams you recommend.

Sven
 

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You will need to decide what you want to do with the bike.

We run Mega Cycle Cams these are hardweld grinds(you supply the core) when you run these cams it is recommended you run the hardwelded rocker arms.

WEB CAMS makes Hardweld and also Billet cams The billet cams you do not have to run the hardwelded rockers with.

Either way you will need to buy new rockers or supply old ones so they can be welded up and regfround. That can get exspensive. I am pretty sure that Labor for the welding anregind of the rockers is $45.00 each. If you have some factory rockers that are in good shape i suggest you use them to keep cost down.

The head modifications hardware consist of.

1.Rockers arm spacers $100.00
2. Labor to tig weld 91-92 rocker shafts $65.00 for all 4 ( I can sell you a set already done for $125.00)


This is the cheapest way to do it. The cam chain will align the cams and keep them aligned. There is another way but it gets very exspensive and requires milling of the 4 camshaft caps and speacial machine to the caps and special spacers to be made.

This can be averted by just having WEB CAMS or Mega Cycle Cams weld up the cams where they need (thrust surface has 4)to be done(if you choose to buy hardweld cams).

This may be alittle confusing but it really is not.

Buy or find good stock rockers

buy the spacers and send us your rocker shaft or we can supply some weld up your oil holes and put the head together like we explain and install 86-90 camshafts.


OH! I almost forgot!!! When you do this ,it allows the use of the valve springs for the earlier heads (again more to choose from) and the retainers (I suggest TI). You MUST also use 86-90 valves, these are longer than the 91-92 valves(needed to take make up for the different rockers). You could just send the head to us and we culd convert it and send it back READY to bolt on. If this interest you just give me a call and I can get the pricing for a complete job for you.
Thanks
Doug
SpencerCycle.com
1-800-510-1945

[ 02-07-2002: Message edited by: SpencerCycle.com ]</p>
 

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Discussion Starter #6
Doug,

What you have given me is a great reply and set my mind wheels in motion. I am keeping this bike as a project as I will eventually, plan is in the next year to be buying a Blackbird or Hayabusa.

What will this conversion to larger 380 lift grind cams turn out as far as additional performance goes. I realize that along with this mod there are probably some other things that should be done as well which I am open to.

Bottom line is for what it will cost would it be a decent performance upgrade?

Sven
 

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pre-91 cams will definitely not work.....the pre-91 bikes use a single cam lobe per cylinder and forked rocker arms. 91-92's use dual cam lobes and individual rockers...

that said, i'm not even sure that 91-92 1100 cams would work, either....
 

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Discussion Starter #8
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by jeff:
pre-91 cams will definitely not work.....the pre-91 bikes use a single cam lobe per cylinder and forked rocker arms. 91-92's use dual cam lobes and individual rockers...

that said, i'm not even sure that 91-92 1100 cams would work, either....
<hr></blockquote>

Any chance you would be able to find out whether this is something that will work or can you point me in the right direction to get the info I need?

Sven
 
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