Installing a 90's Katana head on a GS1100

[RacingJake]

Going to give it a try and let other know whats involved when doing this.

More to come as i learn, pic's too

First what I've seen is that a 88-89 gixer 750 J head is the same one on the Kantana 750's up to 97. One way to tell is a casting dot on the side of the cylinder head and this head has a 22cc combustion chamber. I think the bigger combustion chambers like 26cc may be on the 1100's???

I'm using a 90 750 Kantana head with the dot on the sides. It has the small combustion chambers, 22cc and the intake valve is 1.115 (28mm) and the exhaust valve is .982 (25mm). The camshaft I got has a 320 intake lift and exhaust lift is 280. Maybe on the gixer's they get hotter cams, like more lift.

GS1100 head has 27mm intake and 23mm exhaust valves....est flow around 70cfm
GS1150 head has 28mm intake and 23mm exhaust valves....est flow around 80cfm
750 head has 28mm intake and 25mm exhaust vales...........est flow around 90cfm

There are some other heads with 26mm intake valves and you want to stay away from them, they also do not have the casting dot on the sides.

Things to changed

Gotta use 1150 studs with open head nuts

Gotta use GS cam sprokets on 750 cams. The GS sprockets have a smaller diameter than the 750's

Gotta plug the valve cover oil holes on the rear

Gotta plug the 2 big oil return holes on the front of the head above the exhaust outlets

Gotta plug the 4 drain holes located on the cylinder block cause the 750 head doesn't have them and they are exposed

Gotta weld or mod the front cam chain slot cause it doesn't come up high enough to keep the GS guide inplace

Gotta grind down the flange aliitle on the exhaust pipe to fit the head

Gotta use some rtv at the rear of the cam chain tunnel or a longer head gasket

 

[RacingJake]

Here I'm using 13.5-1 pistons but the problem is they won't fit the sides of the domes hit the small combustion chambers of the head 22cc.

So I just file down the side and re-weight them after I'm done

 

[michael mathews]

gsxr head

gsxr head

Gentleman named Bob Bertaut did quite a few of these.There is a bunch of info on dragbike.com

 

[gsx1100e]

Is it possible to use Gsxr head in gsx road bike or is this mod only for drag race engines.

 

[RacingJake]

I don't see why not, the only big concern would be the compression.

If a stock head is 9.5-1 then a 22 cc chamber head would bump it up to around 11-1, may need to back off the timing some and use 92 octane.

 

[Richie]

jake looks awesome cant wait to see how it runs compared to the 1100 and 1150 head. good luck, richie

 

[Dink]

Is it possible to use Gsxr head in gsx road bike or is this mod only for drag race engines.

It is a streetable mod, attention has to be paid to fuel quality though, & timing may need adjustment.
BTW Jake what cams will you run in it??Do GS ones fit?

Dink

 

[RacingJake]

Thanks Richie, It should be a good comparison between all 3 heads.

Hey Dink, I'll have to use 750 cams due to there's one extra cam journal on each cam assy. I'll be using GS cam sprockets on 750 cams and intake lift is 320 and exhaust is 280. With the exhaust valve's being 25mm I'm not to worry about the cams since redline on the Katana 10.5 I think??

The only thing I'm wondering is how a 36hp shot of NOS is going to act with 14-1 compression. I'm still using a copper head gasket which is a plus.

This year I'm not running wheelie bars cause I'm trying to hang with a ZX14 and a friend's Bandit that's built to the max. This should be alot of fun this year. The biggest change will be leaving off the bottom bulb again using the hand clutch.... I foresee a few red lights.

 

[Richie]

oh man no bar youll have lots of fun with that....you should be ok with the 14-1 comp and the 36hp nitrous.....my no bar bike has a 17-1 comp 1500 and well be running a 100 hp shot maybe more if needed....just make sure you retard the timing enough...good luck, richie

 

[rapidray]

Been there done this!

Been there done this!

Jake, if you want I will send you pictures of my bike. It runs 9.20s @ 142 & push button starts. I run NHRA Division 7 & have been doing this conversion since 1988. Also, there are only TWO oil holes in the block that have to be plugged. And if you use the 88/89 cams they are .350 lift intake & .330 exhaust. Those are the cams in my motor with 40MM Mikunis. If you run juice make SURE you back the timing back to 28 degrees MAX! Ray.

 

[RacingJake]

Thanks Ray, go ahead and send them.

When I'm done I'll be the only bike at our track with this combo. I'm hoping to run faster than 6.50's in the 1/8 and with the nos ????

 

[rapidray]

Also, you don't use the GS front cam chain guide. You use the GSXR guide & grind the bottom of it to fit in the GS case. Ray.

 

[RacingJake]

Got the two 28mm plugs today

I just use two 28mm brass plugs and knock them in the oil return holes.

I also installed the gs sprockets on the 750 cams, the sprocket numbers 1, 2 and 3 won't line up due to the bolt pattern so you'll just have to rely on the notches on the side of the cam to time it.

I decided not to weld on the head and just use the stock oem front cam guide, may just needing alittle grinding at the bottom to fit.

Also if I use my solid MTC block no need to work on the front two studs. But if you use a oem block that's has exposed studs in the cylinder block you'll need to seal up the drain holes that flow through the head casting on # 1 and 3 studs.

I'm thinking when I install the block I'll install three o-rings on each #1 and 3 stud and wedge them in between the stud and the block hole This should keep any oil from leaking down the 2 studs.

 

[lecroy]

When I'm done I'll be the only bike at our track with this combo. I'm hoping to run faster than 6.50's in the 1/8 and with the nos ????

I thought you were trying to run quicker?

 

[RacingJake]

Those are the time's I'm hoping to get without using wheelie bars so I gave myself a 1/2 second loss for a baseline.

It may run quicker cause a few years ago when it was a 1166 with the 1100 head 6.80 was the best I could do.

 

[RacingJake]

I decided not to weld on the head instead I ordered a new Katana front cam guide. All I have to do is grind down the bottom to fit.

So far 35 bucks for the guide and 2 bucks for the plugs. All that's left is some high temp RTV gasket maker and I'll plug up the oil holes in the valve cover and the 4 drain holes in the block.

Now I just need to get the cases back together!!

 

[RacingJake]

Jake, if you want I will send you pictures of my bike. It runs 9.20s @ 142 & push button starts. I run NHRA Division 7 & have been doing this conversion since 1988. Also, there are only TWO oil holes in the block that have to be plugged. And if you use the 88/89 cams they are .350 lift intake & .330 exhaust. Those are the cams in my motor with 40MM Mikunis. If you run juice make SURE you back the timing back to 28 degrees MAX! Ray.

Hey Ray I see what you mean. On my MTC block the studs are not exposed and will not leak, but on the oem block where you can see the studs....the center two on the exhaust side will. I'm thinking of a quick fix like when the block is installed I'll just use about 3 O-rings on each stud and press them in flush with the block. This should seal the stud to the block and prevent any leakage.

 

[lecroy]

Those are the time's I'm hoping to get without using wheelie bars so I gave myself a 1/2 second loss for a baseline.

It may run quicker cause a few years ago when it was a 1166 with the 1100 head 6.80 was the best I could do.

Just hate to see you throw in the towel when you were so close. Sounds like thats not your plan.

 

[RacingJake]

Don't forget about the nitrous, that should make up the differance on the topend.

Who knows maybe she'll get in the 5's after all

 

[RacingJake]

Took about an hour of playtime with a hand file to remove the lip around the exhaust flanges then it went right in. Still waiting for the oem front cam guide to show up then I grind it down to fit. No welding the head this way.