Topic: My first complete build 72 CB750 - completed for now...

[algophobe]

currently working on the battery box and mountings for the solenoid/mainfuse and the rear lights/signal mounts. I came up with this set up... but it looks horrendous. I drilled some holes into the aluminum rear cowl and is regretting it. any suggestions on fixing 1 cm to 2 cm holes in aluminum?

[algophobe]

There’s no magic using a Pamco with the m-unit. Power the Pamco from an AUX port. Those mini gauges need diodes for the turn signal inputs to prevent bleeding power across the same line.

I read somewhere that if you're using incandescent lights, even with LED gauge lights, you shouldn't need diodes, however I found out that it did. diodes are in!
I had a head scratcher wiring the signal lights and figured it out. the emgo comes with 2 wires, and I thought initially that there would be no running lights... but they keep bleeding over till I figured out that the housing of the emgo turn signals was the ground and they were grounding each other out thru the headlight bucket. and in fact they were double filaments! duh!

btw. the m unit blue has separate ignition port, was aux used with the prior m unit?

[algophobe]

I drilled some holes into the aluminum rear cowl and is regretting it. any suggestions on fixing 1 cm to 2 cm holes in aluminum?

You can either weld them up, or if you can't weld aluminum, you can use Aluminum Bronze fill wire and "braze" them closed. Using a propane (preferably MAPP) gas torch, you can heat the cowl up enough that the wire will stick. A few dabs, cool, then grind flush and smooth.

possibly an opportunity to learn TIG

[algophobe]

finished the wiring, fabricated a mounting bracket for the tail light and rear signals, then fabbed new battery box. tested fitted the rear seat. I opted to mount the tail light this way instead of mounting directly on the cowl simply because I can't find a tail light that would fit the contour of the cowl. hopefully its not too tight in the electrical tray.

[algophobe]

Just got the new exhaust in from Cycle Exchange. I went with the rapid fire system (picture to come). I have to find bolts for them, they're M8's 1.25 threads of about 25-30 mm in length and thinking of using allen bolts. Anyone have any experience or warning about using specialty bolts from Lowe's or Home Depot?

[algophobe]

Thanks for the input. Would you recommend an all thread stud then the nut to bolt it on or just go with a allen bolt? I measured the original Phillips type screw that mounts the original flange/spigot (if that's what they're called) to receive the pipes and it measures about only 20 mm length of thread with over all length of maybe 22-23 mm.  The CycleX rapid fire flange sits a little proud therefore I'm estimating it to be 25-30 mm. Ever since I saw a pic on here of a crankcase with the inside blown out from over torqueing..

[Godffery]

 A rather ambitious first build, so far looking pretty good.
Interesting cherry picker you made for Removing / installing the motor!   As for a frame kit to allow for top end work, I have installed at least 3 or 4 in past builds and LOVE'em!!! (Recommend the weld in kit, I know there is a bolt in kit now available but call me old fashion.  )

 G~

[algophobe]

A rather ambush first build, so far looking pretty good.
Interesting cherry picker you made for Removing / installing the motor!   As for a frame kit to allow for top end work, I have installed at least 3 or 4 in past builds and LOVE'em!!! (Recommend the weld in kit, I know there is a bolt in kit now available but call me old fashion.  )

 G~

Ambush or ambitious. Yeah in retrospect I wish I had thought about it the frame kit and putting a kick in the rear hoop. But I was always worried about losing the strength of the frame in my mind. I never really intended to be this complex but definitely a great learning experience.

[Godffery]

A rather ambush first build, so far looking pretty good.
Interesting cherry picker you made for Removing / installing the motor!   As for a frame kit to allow for top end work, I have installed at least 3 or 4 in past builds and LOVE'em!!! (Recommend the weld in kit, I know there is a bolt in kit now available but call me old fashion.  )

 G~

Ambush or ambitious. Yeah in retrospect I wish I had thought about it the frame kit and putting a kick in the rear hoop. But I was always worried about losing the strength of the frame in my mind. I never really intended to be this complex but definitely a great learning experience.

Yes, ambitious.     Sorry, All I can say there in my defense is, it was late at night. 
It is possible to install the frame kit post build...
www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/RVs+750/Fraim+Kit/

[algophobe]

Your handy work? I will have to take a closer look at those pics when I have a little more time

[Godffery]

Yes, a little tricky doing the welding with the motor in place but just requires a little extra effort.

[algophobe]

has there been some screwy technical issues with the forum? a few of my posts disappeared.

[Terry in Australia]

Yeah mate, the server crashed yesterday and everything back to the 10th of December was lost. http://forums.sohc4.net/index.php/topic,169783.msg1970743.html#msg1970743

[algophobe]

I guess ill just do a short repost. pipes from CycleX goes on. she starts up but runs quite rough. from the pipes you can tell coils for 2/3 isn't running. found to be a bad ground wire from harness. she ran like a v twin until i figured where it came from.

[algophobe]

next step is timing. i just barely realized that with the PAMCO system, you can't adjust the pickups separately... am i missing something?

[Davez134]

next step is timing. i just barely realized that with the PAMCO system, you can't adjust the pickups separately... am i missing something?

I emailed Pete about this when I first got my PAMCO. when I set 1/4, 2/3 was just a bit off. (first make sure your advancer shaft is true with a dial gauge though) You can move the black units on the outside of the plate closer to, or away from the plate itself to make small adjustments. I cant remember which way does which though so you may want to search or contact him. What I did was set 1/4, then adjust the 2/3 side in small increments moving away from the timing plate. It has been spot on since. (Use a small flat screwdriver, and of course with the ignition off)

[algophobe]

next step is timing. i just barely realized that with the PAMCO system, you can't adjust the pickups separately... am i missing something?

I emailed Pete about this when I first got my PAMCO. when I set 1/4, 2/3 was just a bit off. (first make sure your advancer shaft is true with a dial gauge though) You can move the black units on the outside of the plate closer to, or away from the plate itself to make small adjustments. I cant remember which way does which though so you may want to search or contact him. What I did was set 1/4, then adjust the 2/3 side in small increments moving away from the timing plate. It has been spot on since. (Use a small flat screwdriver, and of course with the ignition off)

thanks for the info. i used the timing gun to get 1/4 timed and noted a little drift in timing for 2/3. i'm assuming that you have to have ignition off to get access to the screws for the sensors?

additionally you're talking about one of these dial gauge to test for the shaft being true?
http://things-i-learned-this-week.com/wp-content/uploads/2014/02/Yamaha-timing-adapter.jpg

[Davez134]

Yes that's the dial gauge. My sensors on my pamco did not have screws on them, just kinda bent out. I looked at pictures of a newer one and see what you're talking about though. Would maybe have to unscrew, adjust, and make a tiny shim?


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[algophobe]

I finally had a little time to mess with the bike this weekend. two main issues i'm finding. to recap, i'm running the PAMCO ignition, with Keihin CR31 special carbs. two issues i'm running into now after having figured out there was a loose wiring causing coil 2/3 to not fire.

1. i'm using the strobe light to do dynamic timing at this point only at idle after warming up the engine. according to convention, one is supposed to use cylinder 1 or 4 to do the timing. I timed the ignition to #1 with the timing light clamped around plug wire one. then double checked with the clamp around #4 and it seems to be off or positional. I also compared to #2, which seems only slight off but acceptable, but the strobe light does not fire as regularly as #1. when checked with #3 it is even worse. at this point more or less both coils and pick ups on the ignition unit is working. so what's causing the misfires? it can't be the timing gun itself as #1 consistently produced good results and #3 consistently bad. but other wise the engine sounds like it runs fine.

2. with the Keihin CR specials, I manage to solve an issue with the engine idling better using the "wonderful fully detailed" manual that comes with the carbs (sarcasm). previously I noticed that the engine idles fine, but cuts out when giving anymore throttle than 1/8 turn. the air screw was too far out. I closed all 4 screws down and back it off 1/4 turn at a time. and seems like 1/2 turn was enough. she now revs smoothly. it seems when Dime City put it together, they set the screw 1.5 turns out (running it too lean.. am I right in this thought process?). but now, I'd like to balance the carbs as soon as I figure the timing issue... where the hell is one supposed to attach the vacuum gauge? I've search everywhere and no answer except making a hole in the rubber adapter going into the header. i'm assuming adjustments are made with the top cap off and the screws on the link lever. only thing I can think of is the small air leak jet underneath the link lever (see pic).

[Godffery]

 The CR's have NO vacuum ports.  =/
I have installed aftermarket ports in the intake boots and that work pretty well, but you need to make sure they are all installed exactly the same on each boot and with a nice clean drill hole.

 Here is a example (not my work)
 http://draftcycleworks.blogspot.com/2015/04/installing-vacuum-ports-for.html

[Terry in Australia]

CR's are a pain in the arse to set up, I was always going to tap the screw-in manifolds for vacuum ports, but I never really felt like mine were out of synch, so didn't bother. You could always take them off and bench synch them using a piece of wire for a gauge, but it won't be as accurate as a vacuum gauge.

With your timing light, I've had exactly the same issues with my old Dyna III ignition, looking at the erratic light on 2 & 3 you'd think it was missing, even though the engine was running well. The advice I got from members here is to ensure that the lights pickup is pointing in the right direction, apparently there's an arrow on the pickup to tell you which way to connect it to your plug leads? I haven't tried it since, so I don't know if this will make any difference. Good luck!

[algophobe]

thanks for the info guys! happy new year! to think how much money one puts into the CR's they and just drill a hole into the carbs themselves for you. probably because its modular but why not. I was beginning to think I was crazy not being able to find the damn ports. I may just tap directly into the carbs with threads that matches the carb sync system (if i'm ballsy enough)... have to do a little thinking.

as for the clamps on the strobe light, yes I did orient the arrow correctly. but I lateral realized that the knob on the timing gun was set to some crazy advance. i'll have to be more careful and retry the timing tomorrow.

[Godffery]

 I have found that when timing a modified motor like yours, I get the best results about 10 degrees advanced.

[algophobe]

I drilled some holes into the aluminum rear cowl and is regretting it. any suggestions on fixing 1 cm to 2 cm holes in aluminum?

You can either weld them up, or if you can't weld aluminum, you can use Aluminum Bronze fill wire and "braze" them closed. Using a propane (preferably MAPP) gas torch, you can heat the cowl up enough that the wire will stick. A few dabs, cool, then grind flush and smooth.

possibly an opportunity to learn TIG

A had a little time while waiting for some part. Decided to repair yhe holes i drilled into the rear cowl. Thanks to calj's suggestion of brazing with aluminum rod. Not bad for a couple of hours of work!

[algophobe]

so after a little bit of frustration and waiting for part for the issues of the timing and carb balance, I took a hiatus from that issue and worked on the front end for a little bit. bought some new parts for the front brakes, which I was not able to extract the frozen piston. I derusted and did a zinc recoat using the Eastwood kit and buff them to near new. I used a single SS brake line from the master cylinder to caliper. I initially was not going to run front fenders as the ones that came with the bike was chopped for some reason of the front 1/3. but I wanted to have a safe way to keep the lines off the tires, no I decided to chop what ever is remaining of the front fender. new horn from Joker machine.