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New head for gsx1100 kat engine (24bolt)


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Unfortunately as of today as i was going to clean out the head and lap the valves, i discovered a crack between the sparkplugwell and an inlet valve in cylinder 2 and 3.
So i guess ill be needing a new head. The rest of the engine looks REALLY good, pistons, walls, cams, rockers etc. 

What head will be my best option?
I've read that a GSXR1100 (86-90) or GSXR750(87-89 short stroke) would be a good improvement cause of better airflow. 
Are one of these a straight bolt on or what should i be expecting? 

35927177_10216542044847770_2619844748214534144_n.jpg

35749769_10216542041967698_853554011968634880_n.jpg

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1 minute ago, MSteenJ said:

Unfortunately as of today as i was going to clean out the head and lap the valves, i discovered a crack between the sparkplugwell and an inlet valve in cylinder 2 and 3.
So i guess ill be needing a new head. The rest of the engine looks REALLY good, pistons, walls, cams, rockers etc. 

What head will be my best option?
I've read that a GSXR1100 (86-90) or GSXR750(87-89 short stroke) would be a good improvement cause of better airflow. 
Are one of these a straight bolt on or what should i be expecting? 

35927177_10216542044847770_2619844748214534144_n.jpg

35749769_10216542041967698_853554011968634880_n.jpg

Those cracks are quite common ..most don't worry about them and carry on using the head....

 

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I was hoping for a fairly easy swap, dang it.

The reason i think i need a new head is because these two cracked cylinders have 40psi while my other two good ones has 130. Valves are newly adjusted and pouring a bit of oil into the two bad cylinders didn't really help (maybe 50-55psi).

Should i just "hunt" for a new original head?

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That was common with the Triumph 8 stud alloy heads. No effect on performance, so lived with it. 9 stud heads solved the problem. Could be welded, but not cheap. As John says, might be worth looking farther afield to find the cause. 

Edited by Swiss Toni
'Fat fingers'
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Personally i'd say those valves and seats have been cut / lapped to death! The valves look pretty recessed and engines these days don't get 'coked up' with carbon like they used to - unless its burning oil ........ which with the low compression is a possibility. I think there is further investigation required - should have done a leak down test before you pulled the head - that would have pointed to valves or rings ........ wouldn't have stopped a strip down but you'd be fixing a known problem.

BTW - that crack ain't it!

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Thank you all for your replies, still learning about basic engine knowledge. 
Could it maybe be that the cracks have affected the sparkplug holes threads?
The reason i might think this is because i've tried torquing(10nm) the spark plugs in and the two good cylinders are all good but the two bad ones sit 2-3 threads height further up. Can this be where the chamber is loosing so much compression?

Btw. If i keep this head i will be getting new valves then, thank you say what now!? 1460

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You may want to sit down when you price up the valves and you'll still maybe have the same problem - the valve seats are worn out ie. the hole is too big due to the valve seat angle being cut too deep. I've never had a problem winding a plug into a head - cracked or not........ 2 or 3 threads up and the plug won't be seating so running it like that, you'd have to be deaf not to hear the compression escaping. Possibly its a crossed thread ..... or 2 - that'll stop a plug seating!

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23 hours ago, johnr said:

and the gsxr engine is totally different to thee gsx one so the heads arent a swap, although it has been done but with a lot of work.

No it’s relatively easy to do..9_9  .but I would not recommend for it for a road bike 

Air Cooled Bottom End  and block Fitted with GSXR 1100 Pistons Topped of with GSXR 750 Dot Head......Simples ...........:tu

127829745_1260hybrid26171025_1615559161856829_669888855128916258_o.thumb.jpg.e1271fdd444277233c986e285bdc6ac6.jpg

Edited by Duckndive
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  • 4 weeks later...
On 6/22/2018 at 8:41 PM, Duckndive said:

No it’s relatively easy to do..9_9  .but I would not recommend for it for a road bike 

Air Cooled Bottom End  and block Fitted with GSXR 1100 Pistons Topped of with GSXR 750 Dot Head......Simples ...........:tu

127829745_1260hybrid26171025_1615559161856829_669888855128916258_o.thumb.jpg.e1271fdd444277233c986e285bdc6ac6.jpg

Has anyone tested gsx-r head on Road use? It is desinged to be oilcooled, still could it work in oilcooled motor in road use.

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1 hour ago, gsx1100e said:

Has anyone tested gsx-r head on Road use? It is desinged to be oilcooled, still could it work in oilcooled motor in road use.

I did run mine on the road a few times but the head got very hot... ...which I would guess was down to lack of oil flow.....

in the oil boiler there is a lot of oil volume that is directly pumped to the head.

.the air cooled motor even with uprated gears  get's  no ware near close to the same volume :(

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10 hours ago, Duckndive said:

I did run mine on the road a few times but the head got very hot... ...which I would guess was down to lack of oil flow.....

in the oil boiler there is a lot of oil volume that is directly pumped to the head. 

.the air cooled motor even with uprated gears  get's  no ware near close to the same volume :(

The oil cooled motors basically have 2 pumps side by side - once for low pressure cooling flow to the head, the other for high pressure feed to the whizzy bits.

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  • 5 years later...
On 7/25/2018 at 4:41 PM, Duckndive said:

I did run mine on the road a few times but the head got very hot... ...which I would guess was down to lack of oil flow.....

in the oil boiler there is a lot of oil volume that is directly pumped to the head.

.the air cooled motor even with uprated gears  get's  no ware near close to the same volume :(

@slayer61- have you considered this?

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On 12/30/2023 at 1:51 PM, R1guy said:

@slayer61- have you considered this?

I think R1guy is asking about my thread to document doing just this... adding a DOT head to my GSX

 

 

My bike isn't a commuter, or an all day rider. I'm too old and fat for all that. I do enjoy a quick trip up & down the road, however. I have added the 750 pump, and cooler to the mix. I'll keep compression and timing in check in an effort to keep heat at bay... or at least to a minimum on a short trip. Thanks for worrying about me R1guy! 

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