News:

This forum is run by RPM and donations from members.

It is the donations of the members that help offset the operating cost of the forum. The secondary benefit of being a contributing member is the ability to save big during RPM Holiday sales. For more information please check out this link: Membership has its privileges 

Thank you for your support of the all mighty FJ.

Main Menu

Megacycle cams

Started by Bozo, January 09, 2011, 07:08:34 AM

Previous topic - Next topic

Bozo

Has anyone fitted 26 400 megacycle cams to their Fj1200, I didn't degree the new cams thinking that these are close enough to standard cams not to worry. The outcome was a hesitation to 3000rpm (no matter what I did to the carbies the miss was always there), power lose midrange and minor power increase top end.
Maybe someone can let me know what to expect once the cams are dial'd in.
P.S the engine is otherwise standard apart from pod filters and different exhaust tail pipes.
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

andyb

Don't see a listing for a part number anything near that in the megacycle catalog.  Old ones maybe?

268-00
268-x6
268-x7
268-x2
268-x3
268-x8
268-x4
268-x5

Are the current cams for the FJ in their catalog.  Anything after the first 3 requires shim under followers, so that would narrow it down a bit.  Do you have a measured lift on them, maybe?  The 268-00 is the smallest cam they list, so that may be it.

Bozo

AndyB, my mistake the 268-00 is the one I am fitting. Once I get the cams degree'd I am hoping to see an improvement. I just want to know what I might expect. I'm currently away at the moment and should be back home in two weeks
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

JMR

I have installed those cams and they work throughout the RPM range. I set LC @ 105/105 (just like the old Yoshimura FJ cams).

Bozo

Quote from: JMR on February 05, 2011, 09:16:46 AM
I have installed those cams and they work throughout the RPM range. I set LC @ 105/105 (just like the old Yoshimura FJ cams).
Thanks JMR, I did eventually dial them in to the Megacycle specs (104.5/106.5), I found the bottom end slightly lower torque, mid range about even to standard and the topend gave extra 1500 rpm but the power curve to 10,000/10,500 rpm (standard max power was around 9,000rpm) is the same as before (no sudden pickup).

If you think your power is better then what I described I'll reset the cams to 105/105

I believe I'll need to do a bit of work with the carbies to achieve a better mid/ high range, although the mixture is very close to perfect.

Just to be clear, I have main jets at 110, and the rest is standard. The filters are K&N. The front to bottom exhaust is standard with 2007 R1 end pipes fitted.

Obviously a higher comp piston kit would help, but my budget is low and the engine still has tons of life at 143K/Klm. Compressions are spot-on
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

JMR

Quote from: Bozo on February 15, 2011, 06:37:28 AM
Quote from: JMR on February 05, 2011, 09:16:46 AM
I have installed those cams and they work throughout the RPM range. I set LC @ 105/105 (just like the old Yoshimura FJ cams).
Thanks JMR, I did eventually dial them in to the Megacycle specs (104.5/106.5), I found the bottom end slightly lower torque, mid range about even to standard and the topend gave extra 1500 rpm but the power curve to 10,000/10,500 rpm (standard max power was around 9,000rpm) is the same as before (no sudden pickup).

If you think your power is better then what I described I'll reset the cams to 105/105

I believe I'll need to do a bit of work with the carbies to achieve a better mid/ high range, although the mixture is very close to perfect.

Just to be clear, I have main jets at 110, and the rest is standard. The filters are K&N. The front to bottom exhaust is standard with 2007 R1 end pipes fitted.

Obviously a higher comp piston kit would help, but my budget is low and the engine still has tons of life at 143K/Klm. Compressions are spot-on
I would advance the exhaust cam to 105 as that late closing pulls some charge out during overlap. Not much but it makes some difference. Closing valves earlier will help compression too. As you correctly stated....more compression will really wake that engine up especially with those cams.
I like the Megacycle cams in general especially the hardwelds....that's why I became a dealer for them. Kibblewhite too. :good2:

Bozo

JMR, you're input is exactly what I needed, I have similar (mild) hard weld cams (still look new after 90,000km) on my 1978 Z1R with a 1080 MTC kit and 36mm ZRX carbies, J valves and that bike has the same power as a standard FJ1200 (everywhere even in torque) but it gets 55 to 63MPG compared to the Yami around 45MPG. Both bikes have pro's and cons and both are fantastic to ride.
The yamaha had a flatter power curve which is why I fitted these cams to give it a little extra in the top end. Brilliant bike overall.
Just curious what carby jetting changes have you made or had to make to your bike.
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

JMR

 I currently run FCR 39's and have run 36 and 38 RS's on my FJ. I did run stock carbs with a Stage 3 Dynojet kit but it was so long ago I cannot remember the settings! :scratch_one-s_head: I'm currently running Web 540's (.384) @ 105LC with shim under bucket....I got a great deal on them from a fella who lost interest in a project bike. If I had bought new cams I would have gone to Megacycle.
I should have been more specific about closing valves earlier as it has to do with the intake valve on the compression stroke. The sooner it's closed the sooner you start building compression. If you put some higher compression pistons and took .015 to .020 off the head you'd compensate for the Megacycle's higher lift/longer duration and get some good snap out of the engine.
 I really enjoy the FJ engine (except taking it out and putting it back in the frame). It is challenging to get real HP out of it secondary to valve angle/chamber shape but it is a well thought engine considering how old it is. I'm a bit prejudiced because I really enjoy older Japanese bikes and I still own my first real street bike which is a 75 CB750F. I've gone as far as to manufacture custom billet cylinders to safely take the old SOHC 750's out to 1000cc. Machining the fins (up to 2.25" deep) was a real challenge. :biggrin:

JMR

Quote from: Bozo on February 16, 2011, 06:04:56 AM
JMR, you're input is exactly what I needed, I have similar (mild) hard weld cams (still look new after 90,000km) on my 1978 Z1R with a 1080 MTC kit and 36mm ZRX carbies, J valves and that bike has the same power as a standard FJ1200 (everywhere even in torque) but it gets 55 to 63MPG compared to the Yami around 45MPG. Both bikes have pro's and cons and both are fantastic to ride.
The yamaha had a flatter power curve which is why I fitted these cams to give it a little extra in the top end. Brilliant bike overall.
Just curious what carby jetting changes have you made or had to make to your bike.
BTW....that sounds like a nice street combination. :good2:

Bozo

Sucking up to the wife, maybe one day a set of pistons and a refreshed set of valves would be the go. I tried enquiring about some pistons, my preference was for MTC, I've had Wiseco's previously but they didn't compare to the MTC after equivalent millage.
I really appreciate your comments. As for the carb's they'll have to wait till they die.
The Honda sounds cool with a block specifically made for it. Probably not the place but how does it go?



First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

JMR

Quote from: Bozo on February 17, 2011, 03:01:32 AM
Sucking up to the wife, maybe one day a set of pistons and a refreshed set of valves would be the go. I tried enquiring about some pistons, my preference was for MTC, I've had Wiseco's previously but they didn't compare to the MTC after equivalent millage.
I really appreciate your comments. As for the carb's they'll have to wait till they die.
The Honda sounds cool with a block specifically made for it. Probably not the place but how does it go?




I'm building the 1000cc engine now. It is currently 915cc and dynoed at 98 rear wheel HP and 60lbs of torque. Many, many mods (5mm valve conversion kit, 30 hours on the headwork/chamber design etc). It goes great!. Unfortunately it eats primary chains for breakfast. :lol: The 1000cc engine has heavy duty primary chains that originally were used as cam chains in a European turbo diesel engine. This new engine should be good for 110HP and high 60's of torque on pump gas. It is hard to find the time to work on my stuff as I have 6 CB750 heads, 2 CB550 heads to port, a 750 engine to build and a CL175 race engine waiting to be freshened up. I guess I'm vintage through and through :yes: (though my busa has 186HP and 102lbs after porting, Yosh cams, pipe and air box mods). :biggrin:
  I still love my FJ ....I will never sell her (or any of my other bikes)!

Bozo

98hp at the rear wheel is bloody good, my friend has a z9 with a1200 kit, full web cams, 38 carbs, way over sized valves (recessed into the head) etc and he gets 96hp but it pulls like a steam train from 4.5Krpm. It nails my fj at the topend and pulls away as speed builds up. Although I hope that I can at least keep close to level with these Megacycle cams.
I took the fj for a run yesterday after re-adjusting the idle mixtures to 2.5T out and it feels more responsive at the bottom end and mid range, I'll play around a bit more when I have more time and adjust them properly. I still need to work out if the pilot needs to be changed because of these cams, I assume I might need to go down in size. The main jet has already gone down from 112.5 to 110 and feels ok but again I'll work on that later.
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

Bozo

JMR, read my enquiry about the restrictive intake manifolds to see the outcome of how I went with this bike.

A super thankyou to everyone for helping, my bike is now a missile I believe it always should've been.
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it