vtrider

How were the results?

mikstr

I was wondering about the same thing. I ran across one chap on the MicaPeak registries who mentioned installing them and getting a decent boost in mid-range but that is the only mention I have ever seen of them as most seem to have gone with Moriwaki cams.

cliby

If you have the specs of the cams you can compare them - I would imagine if both listed as stage I they would be comparable - I have never heard anything bad about yoshimura cams. I can get you the specs of the moriwaki cams if you can't find them on the search engine - they are somewhere at home.

bill

mikstr

Yosh cams specs below

spdrcr

How much performance gain can you get from stage 1 cams anyway?

mikstr

less than Stage 2....

cliby

I'll get the moriwaki specs and post tonite or tomorrow

mikstr

great thanks

cliby

OK, I found the Moriwaki Stage 1 cam sheet. I listed below and then the Yosh cams and then stock. They actually are timed differently though you could set them whereever you wanted to I suppose with adjustable sprockets. Seems the Yosh, especially on the intake is even further retarded and slightly shorter duration. I believe the intake timing has the greatest effect and seems to be where the biggest difference in the 3 is. Some of the tuning gurus can chime in what it means when the lobe centers are closed up versus separated regarding power, but I believe this is to increase midrange. Its late though and I may be remembering that backwards!

MORIWAKI:
Open/Close/Lift (mm)/LC (my calculations)
IN::BTDC 22/ABDC 53/10.3/105.5
Ex::BBDC 53/ATDC 16/10.1/108.5

YOSH:
IN::17/53/10.7/108
EX::55/15/10.7/110

Stock
IN::20/45/?/102.5
EX::50/15/?/107.5

mikstr

thanks, now can someone try to explain the "expected" results/changes vs stock

cheers

mikstr

Me again

I e-mailed a chap from the MicaPeak registry who listed them among his mods and here is what he replied:
"I got these installed when the 24,000km valve inspection was done. Might as well I thought since it was apart. Yoshimura claims their stage 1 cams for the VTR add 5 more horsepower from mid range to top end. I was more interested in the mid range power boost and it feels noticeably stronger there with these installed. The downside is that the stage 1 cams decrease fuel economy and as we know the VTR in stock form sucks down fuel like a 2 stroke when you play with its power, so be forewarned. The stage 1 cams are not radical. Your bike will idle and run quite smoothly with these installed. "

So there you have it

cliby

Again, in the absence of other engine work I think the benefit is minimal. I've posted my results before of just the cams alone, minimal change on dyno or otherwise.

here is a nice link briefly on the topic

http://www.muzzys.com/articles/lobe_centers.html

bill