Camshaft questions 86,87 vs 88+

[Rollingmenace]

Ok here goes .. I've kind of heard a little buzz about some camshaft differences.. I've heard a few different opinions.. Basically is there a difference between the 86-87 cams and the 88+ ones .. What I've heard is the 86 ones offer a slight performance upgrade over the 88+ ones... Is his true and will the early ones bolt in to the later modem heads...

[Alex]

It looks like the folks I'd recommend to take a look at this thread already have and haven't responded.

[EMSRacer07]

Originally Posted by Alex

It looks like the folks I'd recommend to take a look at this thread already have and haven't responded.

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the cams from 88-90 had different ignition configuration so got the larger duration cams. before 88 were the ones that the 91-07 used. I have confirmed with my 1990 cams and cams I have from an 04.

[choneofakind]

^^^ I've gone and done the same research, but using the parts diagrams. There's a little inconsistency on whether the last cutoff is '92 or '91, but I'm going to believe Byron over the parts numbers. 88-90 are the ones with the hot cams.

Fun part:
The hot cams shouullllld be a straight swap. If you look at the parts diagrams, every part is the same in the head for the whole run of the 88-07 bike. Everything except the cams that is. This leads me to believe that the cams will work with the same head and same cam covers and same cam chain and same valves/rockers/springs/etc.

I say this with some hesitation though. I've never tried it. I considered it, but saw it as a potentially very expensive modification that reaslitically would only make my bike even more high strung and less streetable than it currently is. Also, if any of my research is wrong... Well, then I'd have a bomb spinning at 14,000 rpm in the head of my motor. Basically I chickened out and wasn't willing to take the risk until i had more exact measurements.

[EMSRacer07]

Originally Posted by choneofakind

^^^ I've gone and done the same research, but using the parts diagrams. There's a little inconsistency on whether the last cutoff is '92 or '91, but I'm going to believe Byron over the parts numbers. 88-90 are the ones with the hot cams.

Fun part:
The hot cams shouullllld be a straight swap. If you look at the parts diagrams, every part is the same in the head for the whole run of the 88-07 bike. Everything except the cams that is. This leads me to believe that the cams will work with the same head and same cam covers and same cam chain and same valves/rockers/springs/etc.

I say this with some hesitation though. I've never tried it. I considered it, but saw it as a potentially very expensive modification that reaslitically would only make my bike even more high strung and less streetable than it currently is. Also, if any of my research is wrong... Well, then I'd have a bomb spinning at 14,000 rpm in the head of my motor. Basically I chickened out and wasn't willing to take the risk until i had more exact measurements.

It actually might have been 92' im not sure. But yeah comparison between the two are the same so they would be interchangeable. But def noticeable difference in thickness (duration).

[kxpower?]

Guys please excuse the whole thread necrophilia thing I've got going on here...

Originally Posted by EMSRacer07

It actually might have been 92' im not sure. But yeah comparison between the two are the same so they would be interchangeable. But def noticeable difference in thickness (duration).

I just happened across this after seeing @choneofakind 's post in the engine part-out thread. I've got 2 bikes, the one with the title is an 89 and I seem to think the one without is a 94 but can't swear to it. So I should have one set of hot cams and one set of regular ones, but I have no idea which engine is which. But I do have the cams off both engines right now, next time I'm at the shop I'll grab measurements of the lobes and the bearing surface diameters with a digital caliper.

Per mrcycles, the 89 part number is 49118-1055, the part number seems to be the same until 1993 when it becomes 49118-1054. Would I expect to see any marking on the cam to indicate the different part numbers? I'll look anyway, and try to report the results.