1150 Kat.. time for engine mods... advise requested!!

[Arronduke]

The 1135 is in need of some attention.
I have spent the best part of a week reading post and have gathered what I think will be a good reliable street engine.

What I am asking for here is good advise for a street build. I don't have bags of cash. Its bang for your buck .....

Here is what I seem to have accumulated from 150 pages of threads.

Oh and I have a set of RS38's... can I use them or do they need to be sold for 36's? Yes I tried them on the stock motor. Open the tap and yes I noticed the difference but I could not get the engine to stop reving at about 3k... hard to change gear at 3k...

1229 big bore kit... wiseco with cams or GS1150SSR1230 $1114.26 1230cc piston kit, WGS348 cams, racing valve springs
10.5-1 comp

530 chain conversion... I might add I like that 630 chain... looks big and mean.

Not sure about the 750 oil pump gears... seems for street they are not required. Also some say use them for extra cooling?
Top end oiler
Slotted cam sprockets... obviously dialled in.
Standard clutch with new fibre and steel plates and springs.. all stock.
Heavy duty cylinder studs
Dyna coils
Standard valves but new valve springs,
Polished head

I am currently rebuilding an RG500 and this is next... I am starting to accumulate parts and want a recipe... sick of buying parts only to change my mind and have to get other parts.
Any one want to buy some cheap Busa pistons?

cheers for your time and comments.


.

[boingk]

My list from those options would be:

• Use your 38's. They'll dial in fine.
• Bigbore + cams & springs will be awesome!
• Fit the 530 as 630 won't be made for much longer.
• Oiler, coils & clutch are good mods for any bike.

The bits I'd steer away from to keep your bang-for-the-buck are the slotted sprockets, heavy duty studs, polished head. They are most likely not necessary if this is going to be used on the street and will not provide significant gains in power or usability.

I would also double check the 750 oiler gears with the use of a cooler - you do not want to overcool an engine. Most likely one or the other would suffice for your cooling and oiling needs. If you do install a cooler, check around and make sure you size it properly or you will not get proper running temps while street riding.

That's how I'd do it, anyway. Good luck!

- boingk

[ozman]

cam sprockets are about 60 bucks and allow you to degree the cams its one of the cheapest parts of kit and can give good results when your using different cam setups
i like the gs750 oil pump gears never had a motor "overcool" yet
switch to 530 heaps better

ozman

[steve murdoch]

What ever you are going to do i will be following the build.
To my eye, the Kat and spokes belong together. Has the rear been widened.
There is a guy near me with an RG that has Jolly? pipes on it. It sounds fantastic.

[John Kat]

I'll be following this closely also
What size rims are you using?
Can't provide much advice as one of my Kat's is 100% stock and the other has an 1135 engine but I have never looked inside?

[posplayr]

Here is a thread I started about doing low cost headwork. The TSCC engine is very sensitive to headwork.

http://www.thegsresources.com/_forum/showthread.php?t=137631&highlight=low+cost+head

I can't imagine getting big cams and trying to save money by not slotting the cam gears to degree the cams in.

If anything the 38 RS's are likely to be too big for the street.
(see Gearhead he is selling a set of RS38's right now )

The bigger the engine the hotter you are going to run so you need more cooling( 1150 cooler, top end oiler, 750 gears).

[boingk]

Scratch my earlier comments, looks like the guys that have been there and done it have showed up! I still maintain that for street use degreeing the camshafts is probably not necessary, but if you're chasing horsepower then yes, go the extra mile.

Very nice writeup in the thread you linked, posplayr. Valvework is one thing I love, people will drone on about polished heads and tighter springs etc but often neglect a proper modern seating arrangement for their valves - the seals that hold in the pressure that makes all your power!

Cheers - boingk

[chef1366]

Yes degree in the cams I like 106-107
36mm carburators will work well for the street. 38s are too big
I like the 1230 kit but with the overhead oiler and cooler you should run the higher volume oil pump gears.
With the .348 cams you will have to grind off the oil bump on the rockers or run some .340s which are drop in.
The stock springs will not work for you so get some Barnett heavy duty clutch springs and use stock fibers. (Make sure the clutch basket is good so you don't grenade your motor. I recommend an aftermarket hub or get a new backing plate welded on)
Do not mess with the stock ignition with this kind of HP. It barely can keep up with stock. Dyna green coils with a Dyna 2000 or Dyna S
Don't forget the new valve stem seals if you are replacing the valve springs.

[dorkburger]

Sorry, I cant provide you with advice, but am looking forward to seeing the project unfold. I'd also love to see, and especially hear the gamma project! Good luck with both.

[stetracer]

I am a little backwards.
I like a lot of head! My 1150's in my sig. are street bikes and the 85 is a big head, big valves, big cams, big carbs, little piston motor with Busa power that runs great on the street and the track. As far as porting the head a lot of extra power to be made there without hearting reliability at all if you know what your doing. You can mess things up if you don't know where to remove the material though. But yes it can get expensive to do it right. Until you have riden a bike with a properly ported head you will never know true power

[stetracer]

Yes degree in the cams I like 106-107
36mm carburators will work well for the street. 38s are too big.

Your carbs size will be decided by the head work you get done and the size of your intake port not by street or track use. The smallest carbs I use are 38mm RS Mukuni's and I run 41mm FCR Keihin's on my 98 Bandit street bike and 40mm RS Mukuni's on my 85 GS1150 street bike they are not to big for it. With a little bit of clean up on his head and if he opens up the intake port to 36mm then his 38mm RS Mukuni's will be perfect.
Oh I have 39mm FCR Keihin's on my stock head 1175cc 84 euro GS1100 and it runs great.

Arronduke,
There is something wrong with your set of carbs if they do not run right.
Either jetting is off or it could be a broken slide or leaky fuel valve or even a weak return spring.

[chef1366]

Your carbs size will be decided by the head work you get done and the size of your intake port not by street or track use. The smallest carbs I use are 38mm RS Mukuni's and I run 41mm FCR Keihin's on my 98 Bandit street bike and 40mm RS Mukuni's on my 85 GS1150 street bike they are not to big for it. With a little bit of clean up on his head and if he opens up the intake port to 36mm then his 38mm RS Mukuni's will be perfect.
Oh I have 39mm FCR Keihin's on my stock head 1175cc 84 euro GS1100 and it runs great.

Arronduke,
There is something wrong with your set of carbs if they do not run right.
Either jetting is off or it could be a broken slide or leaky fuel valve or even a weak return spring.

You're right.
I wasn't aware he had head work done.

[gs scott]

1150 Kat

Depending on what you do to the engine in terms of airflow, you should know that original 84/85 1150 black chrome exhaust pipes will mount and align perfectly on your stock Kat frame. To the untrained eye, it'd look stock.

[Arronduke]

What ever you are going to do i will be following the build.
To my eye, the Kat and spokes belong together. Has the rear been widened.
There is a guy near me with an RG that has Jolly? pipes on it. It sounds fantastic.

cheers... the rear is a 5.0inch, 170, 18inch and the front is 3.5inch, 120, 17inch.

And using the standard forks it did bugger all to my ground clearance.
Just rejetted the 1135 with a second air jet in the mouth of the carb. Needed to tap the front with a 5mm tap and screw in a air jet on top of the original. Also went from 175 main to 155. Starts and revs much better now so I am looking forward to a road test.


(cheers... the rear is a 5.0inch, 170, 18inch and the front is 3.5inch, 120, 17inch. )
rear is 5.0inch 17, front is 18inch.... dropped 1inch front and back

[Arronduke]

Oh and to add I just purchased a GS1100EZ, 1983.

This one will be getting the treatment also.... but it might mean the Kat motor does not get the fruit until after the EZ project.

Mean while its work on the RG for now...