Victoria! Zeke's CB175 Build

Hey Tex just so you know ,theres no cam end play specs available for the 175's/200's. The question gets raised every now and again over on Hondatwins, but I think the prevailing wisdom is that it's not an issue on stock builds and cam/journal wear on the plain bearings happens before side play becomes an issue
 
I think I am going to weld the advance wide open, grind the end and then I can bolt the rotor down and not have to worry about it needing to move...hold my beer watch this


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Texasstar said:
ok hold on a second...it is the rotor that has the play not the cam..I can move the rotor and the advance mechanism .050 mm http://youtu.be/A0h8Kmg8MrQ


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Click to expand...
well shim that then
that is what i would do shim it to barely have any play and test
if that cures the mis then you know right away the jetting is not far enough off to cause the mis
if it does not cure the mis then move on to points, see if that cures the mis,if it does , you know it was the dyna
if it doesnt then it is jetting
process of elimination
 
xb33bsa said:
well shim that then
that is what i would do shim it to barely have any play and test
if that cures the mis then you know right away the jetting is not far enough off to cause the mis
if it does not cure the mis then move on to points, see if that cures the mis,if it does , you know it was the dyna
if it doesnt then it is jetting
process of elimination
Click to expand...
shimming


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shim my own best definition:to use a precision sized piece (thickness in this case,a washer) to adjust the clearance of an assembly
you can probably use a carefully selected araingement of washers out at the end under the bolt head to keep if from moving much at all
 
Are you still using the stock mechanical advance? What's your idle speed? Stock's 1200 but I thought yours might need to be a little higher. Full advance kicks in at around 3.5 k do you need the advancer at all ?
 
simo said:
Are you still using the stock mechanical advance? What's your idle speed? Stock's 1200 but I thought yours might need to be a little higher. Full advance kicks in at around 3.5 k do you need the advancer at all ?
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Simo we shimmed behind the rotor on the mechanical advance brought the magnets inline with the trigger. Talked to dyna and the trigger has a sweet spot approximately in the middle depending on who did the circuitry and poured the epoxy. Or as in our case since they don't make one for our model some R & D is required.

Dyna told me they tried to make one for an xs650??? but something about the advance mechanism causes a misfire. Limey down in Austin said they weld the advance open for their flat trackers.

Bolted down the rotor in full advance. We are idling at 3k.


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Thanks guys we learned quite a bit from that jolting jaunt...still going to weld that advance open.


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This is one for the Guru(s) since idle is pretty much full advance anyway couldn't tex/Zeke simply remove the advancer all together and have the rotor driven directly off the cam and set the advance from the pickup?
 
simo said:
This is one for the Guru(s) since idle is pretty much full advance anyway couldn't tex/Zeke simply remove the advancer all together and have the rotor driven directly off the cam and set the advance from the pickup?
Click to expand...

It's not uncommon to run race bikes at full advance all of the time.
 
Sonreir said:
It's not uncommon to run race bikes at full advance all of the time.
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Thanks Matt that's what I thought, it seems that like the tach drive on the other side of the cam.... The advancer is just an unnessicary parasite
 
simo said:
Thanks Matt that's what I thought, it seems that like the tach drive on the other side of the cam.... The advancer is just an unnessicary parasite
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When we have some more R/D time we will move the dyna to the crank :) I wish y'all could be here to rev her.


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Here is the data from our best run with U4.4 race fuel as you can see we were running lean for .5 second. You can see the misfire with the 27 ft lbs torque blip and you can see why we want to keep this jetting at 10.8k rpms. We are planning an 11.5k redline if we keep making power on the next dyno runs. We are also working on the cam chain tensioner problem with our friend Brian Hobbs but that will be after CafeRacertv.

avyqyben.jpg



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Sorry Tex, I forgot to mention that. The magnet has to be in the right spot and there are several different rotors with different magnet positions. When I fit a rotor I have to shim or skim the rotor or space teh backing plate to get that spot on. I figured you had worked that out already. Ah well. You got it now.

Good work.

Got to love that U4.4
 
teazer said:
Sorry Tex, I forgot to mention that. The magnet has to be in the right spot and there are several different rotors with different magnet positions. When I fit a rotor I have to shim or skim the rotor or space teh backing plate to get that spot on. I figured you had worked that out already. Ah well. You got it now.

Good work.

Got to love that U4.4
Click to expand...
Thanks Teazer Mr12 is next.


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