[IndyBob]

Has anyone contemplated or actually used stock valve springs with a Speedstar cam? Looking for informed knowledge about this specific combo. I fully understand the theory about spring binding with higher lift cam, and resistance to float with stronger springs, which is important at higher rpm.

I’m in a bind. I have a PR110 kit that I installed years ago, but I used a Speedstar cam, and orient express valve springs (pro-pipe, PCV 5, Ivan’s ECU flash, Barnett clutch plate, Churchkey VBAK, etc.) Its been an amazing bike. BUT, just before an annual bike trip with my pals, I noticed a little oil leak at the rear of the rear head gasket. So, I pulled the rear head. And, lo and behold, several of the inner valve springs are broken! ****! Orient Express is completely out of the Warrior business. Speedstar springs are long discontinued. Did a nationwide search. Patrick Racing has been out of stock now for 3 months, with several months more uncertainty about getting some.

So, the bike sits partially disassembled, and very sad. Do I put the original cam and valve springs back in? It would work, but then I’ll be sad. Or, keep waiting.

But, now the question. Has anyone successfully run a Speedstar cam with OEM regular valve springs?

thanks for any insight
Bob

 

[random_guy]

That sucks. Unfortunately, I have more sucky news for you… I have no idea about your question. I do wish I could help but I just don’t have the experience you need.

My gut feeling, though, would be that any spring would be better than broken ones and since you pulled your heads for a different issue, it stands to reason that it’s not THAT important unless you’re really trying to squeeze out every ounce of performance.

My 2¢ would be to install stock springs and send it. Just don’t go to the drag strip until you locate the right ones.

 

[arizonawarrior]

The stock valve springs just can't do the work needed. There were a couple early members who went that way and said it worked but then they disappeared. The float issue is well known.

I think one member identified the part number of the actual spring manufacturer that supplied S* valve springs. But I just don't remember who that was.

Your only choice might be to ask Nigel Patrick to do you a solid and recommend a replacement that you can buy from them, or even buy local to you at an auto supply. The S* and PR cams are similar enough they should work well with the same valve springs and Nigel would know every detail.

Here is an early technical thread with some heavy-hitters providing insight. Notice the OE valve springs are more rpm capable that S* which play well at 5500rpm. If your rpm is raised then it's something to think about.

But overall, the thread discusses many aspects. Maybe something will help your search criteria.

SpeedStar cam specs

Here are the Yamaha Speedstar Camshaft specifications as published by Yamaha on their website:http://www.yamaha-motor.ca/accessories/en/pdf/04_accCruis_43-54.pdf (see page 47 of the publication, shown as page 5 of 12 in *.pdf format). Lift @ valve intake/exhaust = 9.3mm/9.3mm Duration at...

www.rswarrior.com

Note: Rob Hughes was a bit of a wrench too, but his major role was he rode race Warriors for Patrick Racing and won lots. He was present during builds so he understood the parts used. Nigel Patrick understands the engineering and the technology and the manufacturing results.

 

[alanh]

@IndyBob ... Valve Coil Spring technology is quite basic, and you should be able to duplicate the failed spring by having a custom set wound. You'll need to submit a good spring to the manufacturer. It's quite possible a standard spring can be cut and ground to match the spec's.

 

[Heftysmurf]

I would call NP and speak with Nigel and kinda plead with him and give him the sob story that your bike has been apart for over a year since all the valve springs disappeared one day. Then he will say ok here are the spec you need to control these cams. Then you send over the specs to a company who can make them for you like PAC racing, Comp Cam, Manley....there are others as well.

 

[IndyBob]

Thanks for all the comments and info. Any other suggestions are welcome. This is the kind of stuff that really helps. This forum is lucky to have you guys.
Bob

 

[arizonawarrior]

Some light reading. Notice Resonance. Valve springs are a huge focus worldwide. Things are happening. Happily, the valve springs you need are standard manufacture, they are spec for some range of engine manufacturers. Said another way: OE and PR both selected valve springs that were already being manufactured for other vehicles.

If Nigel cannot help when you call, keep in mind that all you need are the specs for the valve springs you want. Then get help from companies that sell them. They can match specs and take all the other factors into account.

BTW you will never need Warrior valve springs capable of more than 7,000 rpm. These days, that rpm redline is well within street component spec.

Everything You Need to Know about Valvespring Technology

An in-depth look at the tech revolution that lets valvesprings survive over 1.00-inch valve lift, run over 12,000 RPM, and withstand millions of opening/closing cycles.

www.motortrend.com

 

[IndyBob]

I finally measured, and posted my specs

Bob

 

[arizonawarrior]

Cool.

Jump:

Valve Spring specs measured!

OEM valve springs: Outer: free height: 43.0 mm Wire ga: 2.83mm Turns: 7.5 OD: 23.48 mm ID: 17.9 mm Bind height: 21mm (approx) Pressure @ 31mm: 35lbs, 9 oz Inner: free height: 38.31 mm Wire gauge: 2.0 mm Turns: 9.5 OD: 16.0 mm ID: 12.0 mm Bind height: 20mm (approx) Pressure: 15 lbs 6 oz @ 29mm...

www.rswarrior.com