Camshafts for 1316

[Thomas]

Hi im looking for the collected knowledge in camshafts for my restomod/tribute/replica build.

Obviously  i want as much horsepower as possible but needs to be streetable.

so far the engine (1052 block) is ported by a skilled engine builder,oversize valves,

13,6 compression yoshi exhaust,dyna ignition,fcr 41.

initially we tried cams from webcams (don’t have exact specs handy ) and heavy duty springs but i doesn’t last.

Camshafts pitted and springs broke after max 800km last summer.

And yes i knew it was a gamble without extended hardweld rocker arms.

Anyway is yoshi stage 3 including their springs still sold anywhere? And does anyone know the specs on those?

where do you guys go to for camshafts?

Im having trouble finding a good supplier.

 

Im also adding another oil cooler for next season,and planning on a little milder cams to get it a bit more reliable.

the cams we used had a bit extreme  lift for street use, whats your experience,what works?

thanks for your input!

 

 

[Thomas]

[Thomas]

[dupersunc]

The Web cams are designed for drag racing,  800miles is  20years of competition, don't know anyone who has made them last on circuit.

The Yoshi stuff is fantastic, but costs. 

I've had good results with  Kent cams.

[Thomas]

Yes  the webcams were just to much, i guess i was blinded by my wish for hp..

Anyone knows the yoshi stage 3 specs?

[george 1100]

yosh stage 3 in 10mm lift, from memory 252 duration @1mm

yosh stage 2 in 9.5mm lift, form memory 248 duration @1mm

I might be wrong but I think the stage 3 are discontinued but too big for street use anyway. 

I'm using st2 in my build with shimmed 750 springs. Certain aftermarket hd springs have way too much spring pressure for street or circuit use imo. 

[Thomas]

Whats your setup otherwise?

Thanks 

[Gixer1460]

Not knocking your ambition but f**k me thats a lot of compression and certainly to much to be 'streetable'. At those levels you need 110-120 octane fuel or so much retard it kills the power. I would guess finding cams for oil cooled GSXR's is harder as everyone's moved on and 'these' are the new Dinosaurs LOL!

[no class]

.....boost will net you more than the NA power you seek 

[dupersunc]

3 hours ago, Gixer1460 said:

Not knocking your ambition but f**k me thats a lot of compression and certainly to much to be 'streetable'. At those levels you need 110-120 octane fuel or so much retard it kills the power. I would guess finding cams for oil cooled GSXR's is harder as everyone's moved on and 'these' are the new Dinosaurs LOL!

Depends on the cam timing, run lots of over lap and you bleed a lot of combustion pressure lower down the rev range,  but tune the exhaust to work with the cam timing at high revs where the valve area is restrictive to volumetric efficency.

At least that's the theory.  I ran a 996 motor at 14/1 cr on super unleaded with out detionation, the guy who did my heads reckoned 14.5/1 was ok!!

I know keeping oli boilers cool at these c.r. is tricky though, and not sure I'd be brave enough to go as high as the OP.

[Sandman]

Static CR of 13.5:1 does not tell me much. But the dynamic CR depends on specs of camshafts. Some of the US-made valve springs are way to stiff. Therefore the cams does not last for long time. Yoshimura ST2 and valve spring kit is still available and are made for racing and are useable for the street.

[Sandman]

On 12/17/2020 at 7:47 AM, george 1100 said:

yosh stage 3 in 10mm lift, from memory 252 duration @1mm

yosh stage 2 in 9.5mm lift, form memory 248 duration @1mm

I might be wrong but I think the stage 3 are discontinued but too big for street use anyway. 

I'm using st2 in my build with shimmed 750 springs. Certain aftermarket hd springs have way too much spring pressure for street or circuit use imo. 

The old st3 is now  ST2 and old st2 is now ST1. Both are still available. 

[Thomas]

23 minutes ago, Sandman said:

The old st3 is now  ST2 and old st2 is now ST1. Both are still available. 

Thanks,yes i finally figured that out myself.

I will most likely order the stage 2 and the springs but damn the price on the spring kit.

Looks like “performance parts ltd” have it in stock.

The compression has not caused any problems, the engine builder runs a lot higher on the dragbike engines he has done before.

well except it runs pretty hot,hence adding another cooler.

[Gixer1460]

3 hours ago, Thomas said:

The compression has not caused any problems, the engine builder runs a lot higher on the dragbike engines he has done before.

Yeah and so did I with my Kat hybrid 14.5:1 but it needed offboard 24v starter, idled at 2k, needed 120 octane fuel and only ran for less than 180 seconds! And FYI I used G21/G28 cams - think they were Cammotion, got them from Skip at Orient Express.

[george 1100]

What are you planning on revving it too?If you keep the redline at 10,500 rpm I don't see the need for yosh valve springs

[Sandman]

By using stock valve springs and retainers you may run into retainer-to-seal clearance problems with 10 mm cam lift?

[Sandman]

On 12/16/2020 at 10:37 PM, dupersunc said:

The Web cams are designed for drag racing,  800miles is  20years of competition, don't know anyone who has made them last on circuit.

The Yoshi stuff is fantastic, but costs. 

I've had good results with  Kent cams.

I have buildt a lot of H ONDA CBR1000RR race engines using KENT cams. They are really good. What kind of grind no. have tried for the GSXR 1100? SUZ1 or SUZ7?

[dupersunc]

2 hours ago, Sandman said:

I have buildt a lot of H ONDA CBR1000RR race engines using KENT cams. They are really good. What kind of grind no. have tried for the GSXR 1100? SUZ1 or SUZ7?

I cant remember. It's the milder of the 2 grinds suz1? I've a worked 1216 motor with the Kent inlet cam and stock 1127 exhaust cam. Lovely flat power curve. 156bhp on stock valve sizes and fcr41s. Not sure on the camtiming, sprockets are slotted but it was built by a known tuner, so leftit as it was when I refreshed it.

 

Had a bog stock 1127 fitted with suz1 on inlet and exhaust at 109/109. Definetly breathed better at the top end. That motor is being built with 1216 pistons and a big valve head.

[Sandman]

I am building two engines this winter. One 1340-engine with bigger valves, Yoshimura ST2 with spring/retainer kit. The other engine is 1216. I am interested in testing different cams specs in the 1216 engine.

[opalmanta]

Any one have experience with Mega cycle cams as far as life expectancy on the street . I have similar concerns as Thomas when it comes to longevity .I see they do the hard face welding and grinding mods to the followers.  I would want to get more than 1000 miles of riding out of them.  1340 big bore and custom pistons to keep comp. to around 11.0:1 .  

[Sandman]

I'm pretty sure some of the heavy duty springs sold by some US manufacturers give way too high a valve spring pressure for street and circuit use. This leads to loss of power and reduced service life.

A cheaper alternative could be to use springs from GSXR 750 88/89 or GSX750F? I know that these springs have almost the same stiffness as the Yoshimura spring kit. However, I am unsure which retainers should be used to achieve proper retainer-to-seal clearance for high lift cams? Is it possible that I can find a solution to this problem within a few months?

Edited December 20, 2020 by Sandman
Tying error

[Crass]

FWIW as regards quality, I had a worn set of stock 750L cams reground to OEM spec and rehardened by KENT Cams and I was very happy with the work. Several thousand miles of street use later and no problems.

[Thomas]

I have decided to try the yoshi stage 2 & their spring kit.

Everything possible done to the head otherwise so why stop now ....

From what i have been told/read yoshi has very high quality on the materials, fingers crossed. 
Does anyone know what compression yoshi recommend with their cams? I was going to send them an email and ask but cant find any adress.

 

Edited December 25, 2020 by Thomas
Spelling

[cnap504]

Yoshimura does make good stuff, their cams make good power and don’t punish the valvetrain. Reasonable power band for street or road course.  Are you going to use fuel?  In the U.S. the highest pump gas commonly available is 93 octane and most of the guys street racing won’t go over 12.5:1 on a big bore motor with the 93 octane 

Edited January 18, 2021 by cnap504
typo

[Thomas]

Some more questions..

The engine is finally done and been setup on the dyno.

As it is big bore it has external lines for the head cooling and lube.

My engine builder had some concerns about the oil pressure. If i remember correct something about original oil routing has ”restrictor” but my external oil hose has not also the yoshi cams has the added lubing through the cam shafts themselfs.

any thought’s on this?

He was actually not very happy with the exhaust cam lift, to mild in this so called stage 2 kit. But thats another story.

Still a lot of work needs to be done on the bike,primairly sort additional cooling and i think ill install an electrical fan.