Timing Hybrid

[Kara25]

Ok so i got an ongoing 550 to 673 project going on and tore down my 550. Besides a crumbling front camchain guide who will be replaced with a way better looking one from a 650G i also found out that my EX cam has 2 lobes below the service limit and one of my IN cam lobes has a scratch that my nail can catch... Originally i wanted to use the 550 cams bcs i like the high revving characteristics of the 550 cam profile but after those discoveries thankfully the 650G cams that came with the head are immaculate and well within specs so i am inclined to use those. So the questions are. 1. How in the name of GOD do you remove cam sprocket bolts???? I dont have a vice and as you can imagine is a nightmare! Those things are tight! Any tips or should i go to a mechanic with the cams so he can UN-bolt them and put the 550 sprocket on the 650 cams?? 2. The big question. The 550 sprockets (30) teeth will go into the 650G camshafts making the whole setup eventually a 550 sprocket setup but with 650G camshafts. With which mindset will be the motor timed?? Like a 550? Meaning counting 20 pins at TDC of 1-4 OR like a 650G meaning counting 19 pins at TDC of 1-4?? In general my question is what determines how a stock GS engine is timed? Its all about the 2 sprockets on top and the one in the crank or it tottaly depends on the camshafts themselves??? I dont want to mess with any cam degreeing etc as many others who did this swap did ,its way over my league just want if possible to put 550 sprockets into 650G cams and time the motor as a stocker without all the extra search for the few ellusive HP from cam degreeing. Thank you very much in advance!

[Kara25]

[Gixer1460]

Cam wheels have to match the crank as cam wheels have to be twice the number of teeth compared to the crank. As regard timing, i'd follow the 550 method to match the wheels and pins between. The issue that may occur is how the wheels bolt to the cams in relation to the lobes - align the lobes looking at the end of the cam of both and ensure the angle of the bolt holes is identical - your 1st picture shows the lobes are closely matched but the mounting bolt angles 'seem' slightly different ! !

If the above is true, then the stock timing marks won't work for you and you'll have to use the 650 timing data / angle specs and use a timing wheel, dial guage and ideally some slotted sprockets !

[Kara25]

Yeah the pic of the cams i believe is a little bit misleading bcs as you can tell the 650 cams have a bigger sprocket than the 550 so i cant tell for sure if the bolts are exactly the same alligment. I will have access again to the cams in a couple of days and look closely. 

[wraith]

Last time I did this, (some years ago) I used the 550 cam sprockets and the 550 timing.

[Kara25]

@wraithMr wraith i assume you mean you put the 550 sprockets on a 650 camshaft correct? Are the 550 sprockets align normally on the 650 cam or did u have to degree the new cam/sprocket combo?

[wraith]

Yes, put the 550 cam sprockets on the 650 cams, use the 550 timing. I didn't need to do any degree in just bolt up and ride 

But that cam chain blade/guide looks fucked to me

[Kara25]

@wraithyeap i already have on order a 650G front camchain guide. Good news is that the rear guide is in perfect condition with minimal wear which seems weird because its actually the one that gets pushed toward the camchain in comparison to the front one but oh well. From what i gather here you must be one of the first persons who did this 550/673 swap. Is the difference in torque that much noticable that everyone says about the final hybrid motor? Is yours still holding up??

[wraith]

Yes you do notice the difference  can't say I was one of the first, as this this was a early thing to do (like putting the 850 top end on a 750 or putting a 1000 engine into a 750)

Can't say how the engine is going now as I sold it and put a gsxr1052 in the frame instead