Some cam questions

[81xsproject]

I have been scouring ebay and bugging Andre to find a set of '78 cams w/o any luck. So I had some questions...
[list=1][*]Does anyone have any they might part w/[*]Does anyone know about what it would cost to have mine welded and reground to 78 specs?[*]Any other suggestions?[/list=1]

One post recently showed someones PRISTINE XS and said they had "webcams." I have yet to check into that but will.

[Pat Kelly]

You might also search for MegaCycle cams

[Dennyz]

I have several sets of cams, but I don't know what they are out of. Do you know of a way to identify the ones you want? I may have a '79 motor that still has cams in it. Would '79s work?

[81xsproject]

I don't but maybe someone else does? I don't think the '79s are quite as hot as the '78s. They are probably still better than the 80-81s though. i see the '79s pop up on ebay all the time but if I wait long enough I should be rewarded for my persistance.
thanXS for trying me, though

[bandet01]

have you thought about a aftermarket cam for the bike there are some companys out there that make cams for the xs1100

[81xsproject]

I have, but from what I've seen so far ebay '78s vs. aftermaket is like $20-50 vs. $350+.

[Dan Hodges]

Re: Some cam questions

Originally posted by 81xsproject
I have been scouring ebay and bugging Andre to find a set of '78 cams w/o any luck. So I had some questions...
[list=1][*]Does anyone have any they might part w/[*]Does anyone know about what it would cost to have mine welded and reground to 78 specs?[*]Any other suggestions?[/list=1]

One post recently showed someones PRISTINE XS and said they had "webcams." I have yet to check into that but will.

The cam's for the 78 and 79 models are the same and have the same part number's.The cam's for 80 thru 82 are the same.The early cam's (78-79) are good for 3-5 hp over 5,000 rpm vs the late one's(80-82) but do not have quite as much torque down low (below 5,000 rpm).If you have a naked 80 through 82 Eleven, the early cam's will give you more top end and they work especially well with a good four into one exhaust but if your bike is equipped with a faring and decked out for touring you do not want them.Both Mega Cycle and Web Cam's offer several different grind's,but you have to send them a core and they hardweld it and it is reground to the new configeration.Either work's equally well.There are several large salvage yard's in California and the early ones are easy to find,but you can also find them on E-Bay.Yamaha's web site has the part number's and both Web Cam's and Mega Cycle also have Web sites.If your bike is stock,the early cam's are enough for what you are doing.If you have head work,a bigger motor,more compression or a combination of all them you can use more cam,otherwise get the early one's and you will be happy.Mention is made, that a fresh(new) set of stock valve spring's shimed .040 will perk up a high mileage Eleven as the valve's will seal better at high rpm.While you have the spring's off,slip on a new set of stock valve guide seal's with new stock keeper's and you are good to go as the piston rings in these thing's will out last the bike if you keep the oil changed.There are some earlier post where the timing figure's for these cam's were given,so I will not list them again as you can look them up.Good luck. Dan

[Dennyz]

The difference between the '78-'79 cams and the '80-'81 is obvious.

I measured the lift (intake) and both measured the same, but the earlier cams have noticeably wider (duration) lob.

The valves on the earlier engines open sooner and stay open longer. Lift is probably limited by valve to piston clearance.

[bandet01]

so a older xs1100 would be faster then a newer xs1100 the reason i ask somebody was asking about drag racing and his times were almost a 2 seconds off what my times were

[Dan Hodges]

Originally posted by bandet01
so a older xs1100 would be faster then a newer xs1100 the reason i ask somebody was asking about drag racing and his times were almost a 2 seconds off what my times were

There are score's of road and drag racing test on these bike's and countless technical article's published in various magazine's over the year's and several have been posted on Channel Eleven but the cam thing and E.T. thing I will touch upon again briefly.The early cam's had 12 degrees more duration than the late one's with the same valve lift on the intake (.347) but had .020 less lift on the exhaust (.327).The early one's had a 101 degree event angle and the late one's had 105 with a coresponding decrease in overlap.The late head's (80-82) flowed ten percent more air than the early one's which equates to five percent more power.Yamaha changed the cam's because wider lobe center's develop fewer emission's and they wanted more low end torque because they were adding lot's of accessories for touring.The big head's got back the power lost in the use of the milder cam's.Starting in 80,the idle circuit's, off idle and mid range circuit's were much leaner than the 78-79's but can be changed to achieve the proper air fuel ratio.Yamaha rated all Eleven's the same horsepower from 78 through 81. A well prepared box stock 78-79 Eleven Standard with a good 150 pound pilot will run 11.80-11.90 et in the quarter mile with the Special a half tenth quicker if it has the same power because of the smaller diameter (lower gearing) back tire.The 80 special will go 12.0's and the 81 Special will go 11.90's because the 81 has a different ignition curve,40 degrees @ wot vs 35 degrees for the 80.People's drag race time's vary all over the place because of the condition of the motorcycle's,the rider's weight and ability,the altitude of the track,weather condition's and the track's surface.Most of these motorcycle's are simply wore out and the subsquent quarter mile times are meaningless.The magazine test on these thing's also varied due to the same circumstance's.I have in my possession every test the now defunct Cycle magazine did on these thing's and the E.T. ranged from a best of 11.78 to a worst of 12.02 and the horsepower ranged from 75 hp to 83 hp.I have been drag racing car's for over 30 year's and I can tell you that in the late seventies and early eighties there were scad's of these thing's at St. Louis International Raceway's running 11.80 and 12.0's on any given Saturday night,with some being much faster and some being a lot slower.One might ask,how much does it cost to build a trick Eleven and my answer is, I have close to $3,000 in receipt's and I'm still not satisfied so the old axiom,speed cost money,how fast can you afford to go certainly applies to the old XS.One can buy a used V-Max for $4,000 maybe less that will eat the thing but it's not the same and I know because I have a really nice V-Max.Will a 78 beat an 81 I believe was the question and like someone once said,it depend's and that's an understatement.Is there a 78 in St. Louis that can spank Attila,I do not think so. A Yamaha shop manual cover's 80% of what we are talking about.That's my story and I'm sticking to it.Good luck.

[motoman]

Could not have put it any better Dan....and also being an X class and bracket racer in mid and late seveenty's with 'real' muscle, there's alot of variables.........mostly driver or rider. Some 6 yrs. ago bracket raced a Legacy we had for grins, and saw I was really out of practice on the lites, starting out having a .871 react, which is embarresing, specially deep staging. So as you well know, react times and 60ft. times make or break a good 1320.....................Anyways, all is very true, plus alot more some would'nt understand, too many variables to list here........kudo's to your input!

[mro]

Short of a fresh engine and a turbo don't expect the XS to be competitive with the stock new bikes. I'm going to keep the 80G stock unless I can acquire the parts in my "wet" dream and have the MNS for my regular ride.

Would like to see pggg run his chain drive thru the quarter and some dyno results too


mro

[81xsproject]

So, my question for the experts now is; how will the '81's 40 degree timing advance work with the 78-79 cams?

[81xsproject]

Anyone?

[GNEPIG]

.. i dont think the cam lift would know the difference between the ignition advancers, but the early cams[78-79s] and the 78 advancer with your big valve head might make your bike quite lively on the big end.. would be cool if you could get a dyno reading before you made the change and then after- so you can see the difference.