Can I run a stock 750 head & shim setup with a Wiseco K844 & #118 Web Cams?

[Z32650S]

Hi all, I'm hoping to pick the brains of a few knowledgeable engine builders. I'm planning out a GS750 (2 valve) build and am contemplating using the pistons & cylinders off a 79 GS850 I have lying around. However, I have been researching info on the forums about dropping in the high compression K844 Wiseco big bore kit (10.25 comp ratio). Seems it would be a decent and relatively easy power gain if the 850 jugs are within spec. I also have a fresh set of hot street (#118 grind) Web Cams (.365 lift) which I will use.

My question is, can I reliably run the OEM head (stock springs, retainers, followers, shims over bucket, etc.) with the Wiseco high compression pistons and these Web cams? Or might this setup require aftermarket heavy duty springs or other head work? Web Cams claim stock internals with these cams would be ok, basically a drop in affair, do experienced builders agree? Read some conflicting advice. Would any goodies (Dyna S, RS34, etc.) affect in anyway the shim placement or springs, or is shim under bucket and aftermarket springs mostly dependant on cam lift?

I was also suggested to try larger intake valves to further increase the overall power gains. I'm trying to figure out if OEM GS1000 intake valves be a good option (would they even work in a 750 or 850 head with OEM guides)? Would adding larger valves to the mix noted above change/require anything if using an otherwise OEM head? I would assume matching the seats, etc. Any piston work involved on K844?

Obviously I have much more reading to do, but always welcome any suggestions, questions and advice!

 

[Nessism]

According to the Web Cam's web site grind #118 states "Good mid and upper end performance for hot street-strip. Requires High Compression Piston, and Performance Valve Spring Kit".

http://www.webcamshafts.com/index_blank.html?pages/vehicle_search.html

 

[rapidray]

When Web Cams says "high" compression, they mean 12 to 1 or more. You won't be happy with that cam in a street bike.
Ray.

 

[Z32650S]

According to the Web Cam's web site grind #118 states "Good mid and upper end performance for hot street-strip. Requires High Compression Piston, and Performance Valve Spring Kit".

http://www.webcamshafts.com/index_blank.html?pages/vehicle_search.html

Thanks Nessim, Ray, but I'm not sure we are talking about the same cams. The description I have for part# 70-051 (Grind #118) off the web cams site says: "High performance street profile for stock engines. Very broad power range. Stock base circle. Price Per Set (2)." Despite the stock engine claims I had read conflicting advice and wanted to clear things up. They seem to be the most mild cams for the 78-82 8v GS. (here is the spec sheet)

I was wondering if adding the K844 would require additional head work beyond stock internals. And if GS1000 intake valves were compatible with an otherwise stock 750 head.

 

[Nessism]

Thanks Nessim, Ray, but I'm not sure we are talking about the same cams. The description I have for part# 70-051 (Grind #118) off the web cams site says: "High performance street profile for stock engines. Very broad power range. Stock base circle. Price Per Set (2)." Despite the stock engine claims I had read conflicting advice and wanted to clear things up. They seem to be the most mild cams for the 78-82 8v GS. (here is the spec sheet)

Please go back and look again. #86 is the most mild and for a stock engine, #118 requires pistons and valve springs, and I believe you should be fine with that big bore kit.

 

[Z32650S]

Hi Nessim, I did, and I certainly don't mean to stick on this point, but I think you are referencing specs off the GS 550 8v web page which match exactly the specs you're quoting.

There is no #86 grind listed for the GS 750 8v (or even the 16v). Check the part #s.

Seems the K844 will work with the cams and stock head, still looking to see if the valve cut outs on the hi-comp pistons would allow for larger valves. I might just call Wiseco to see what they have to say.

Ray, now that we cleared up the cam confusion, any reason to believe these .365 lift cams and hi-comp pistons would not be good in a street bike?

 

[gearhead13]

http://www.webcamshafts.com/pages/motorcycle/suzuki/install_data/tc_001736_000663.html
High performance street profile for stock engines. Very broad power range. Stock base circle. Price Per Set (2).
Drop in cams just set valve lash. Should be a torque monster with the 844 kit.

 

[Nessism]

Hi Nessim, I did, and I certainly don't mean to stick on this point, but I think you are referencing specs off the GS 550 8v web page which match exactly the specs you're quoting.

There is no #86 grind listed for the GS 750 8v (or even the 16v). Check the part #s.

Seems the K844 will work with the cams and stock head, still looking to see if the valve cut outs on the hi-comp pistons would allow for larger valves. I might just call Wiseco to see what they have to say.

Ray, now that we cleared up the cam confusion, any reason to believe these .365 lift cams and hi-comp pistons would not be good in a street bike?

I apologize, you are correct. I was looking at the 550 page. That grind is fine with the stock valve train parts. Oh, and a bunch of the 8V GS engines shared valve springs, including both the 750 and 1000.

No idea about the piston to valve clearance.

 

[gearhead13]

Hi Nessim, I did, and I certainly don't mean to stick on this point, but I think you are referencing specs off the GS 550 8v web page which match exactly the specs you're quoting.

There is no #86 grind listed for the GS 750 8v (or even the 16v). Check the part #s.

Seems the K844 will work with the cams and stock head, still looking to see if the valve cut outs on the hi-comp pistons would allow for larger valves. I might just call Wiseco to see what they have to say.

Ray, now that we cleared up the cam confusion, any reason to believe these .365 lift cams and hi-comp pistons would not be good in a street bike?

You should always check piston to valve clearance. I would suggest getting adjustable sprockets and setting lobe centers to what Web says they should be.

 

[Z32650S]

Thanks Gearhead, I do plan to degree the cams with adjustable sprockets and will be sure to measure all clearances.

I also understand from other performance threads that an offset intake and exhaust cam timing can help boost power in the mid to high RPM range. Basically, a result of how close/far the lobe centres are apart. This is where things get tricky as I'm no expert with cam settings, but if the proper timing/overlap is achieved, I would stand to benefit with greater flow through the head and increased power!

I don't plan to build anything close to a drag bike but am interested in getting the most I can out of what I hope to be a rock solid hot street setup. A torque monster would be fun indeed. This is where I go off scouring the GSR forums for info. Web Cams say 105 lobe centers, yet some claim greater gains with offsets (e.g. 104 & 106 and such). Just not sure if such offsets would; a) apply to these cams and b) maintain the reliability I seek for a street ride.

I'll be posting up a build thread soon to help everyone follow along with my plan.

 

[rapidray]

Those cams will work well with your combination. I am about 40 minutes from Web & am a dealer for them, along with Wiseco & many others. Let me know if I can help.
Ray.