ADVrider

Go Back   ADVrider > Bikes > Old's Cool
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-23-2011, 08:07 PM   #91
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Working on the seat


When I first made the decision of eliminating the seat that came with my CB, I opted for using what I had in the garage -- that is, a spare KLR 250 seat.

Some people questioned my wisdom, while others were curious as to what it would look like.

I must admit that the thought of putting a dual-sport seat on a street bike sounds insane. Nevertheless, the curves worked out rather well, in my humble opinion, and the seat pan was paid for, so why not.

After chopping the seat pan to a single seat length and figuring out its basic position on the bike, I went ahead and molded the rear section. Once the rear section was fiberglassed and painted, I started with reassembly.

As you probably know from previous posts, I spent a lot of time working on the brakes, fixing the carburetors, and all the other stuff that makes the bike run, drive, and stop.

Well, while waiting for some brake piston seals, I decided to work on the seat itself. And here is where the challenges started.

When I first laid down the pan and molded the tail, I had the inner fender removed. It was no surprise that once I installed the inner fender in its place, that nothing fit the way it did before. Faced with the options of either not having the inner fender, or reworking the seat and tail, I decided against removing the inner fender. yes, I can be stubborn and this adds a ton more work. But, the thought of every piece of gravel and sand hitting the frame and battery, was the deciding factor.

So, the first step in this saga was to remove some more material off the seat pan. This went along smoothly (doesn't it always?). I then had to figure out how to attach the pan to the frame. At this point, I have the rear attachment brackets figured out and fabricated, but I still have to work on the front.

I started with some 1/4 inch aluminum flat bar
Which I then bent in a vise to offset for the frame mount, drilled a hole for the mounting bolt, and rounded off the ends.
Next, I found the proper mounting point on the seat pan, drilled a hole, and cut the end at an angle to accommodate the angle of the pan.
And, voila, it worked.
It is attached to the seat pan via stainless steel carriage bolts, which will hide nicely underneath the seat foam. I still have to smooth all the edges and polish the brackets, but I'm one step closer to finishing the seat.
henrymartin is offline   Reply With Quote
Old 08-24-2011, 07:43 PM   #92
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
UPDATE:

Tonight I finished making the front bracket. Actually, I used the "lip" method, where an aluminum lip slides underneath the gas tank mounting bracket, and holds the seat in place by friction. Since the seat is attached in the back by two bolted brackets, there is no way the seat will move. All the lip does is to hold the front of the seat in place, and to prevent it from rising.

First, I cut a piece of 1/4 inch aluminum plate to the desired length. Then, using a double-sided tape to temporarily hold it in place, I marked the location where the lip would attach to the seat pan. Since the seat rises up against the tank at an angle, I had to bend the lip to follow the contour of the pan. Once that was done and the desired amount of friction achieved, all I had to do was to drill two holes in the pan and the lip, and attach the two together with stainless steel carriage bolts. I then cut the excess bolt length to prevent it from snagging on the wiring that resides under the seat. To minimize frame scratching, I used a piece of protective door molding (self adhesive half-pipe used on car doors) on both the front of the lip, as well as the frame bracket.

Next, I'll be cutting the seat pan to copy the contours of the side panels, and carving the seat foam to the desired shape. And then it will be upholstery time.


henrymartin is offline   Reply With Quote
Old 08-28-2011, 07:27 AM   #93
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Working on the seat, part II


There was some trimming to be done on the seat pan, so it would follow the contours of the side panels. The seat pan, being nylon, was easy to cut. Dremel was out of the question, as the high speed cutoff blade melts the nylon, immediately sealing the cut it just created. However, the old fashion approach, using a hacksaw with metal blade never fails. After cutting the pan to the desired shape, I smoothed all edges with a 100 grit sandpaper, to prevent future rips in the seat cover.

Next step was to glue seat foam onto the pan. I opted for using the old KLR foam, as it is more rigid that any foam I can find locally. To adhere the foam on to the pan, I used 3M spray adhesive.

As you can see, the KLR seat is of a completely different shape than what I was looking for. In addition, since I trimmed the seat pan, the foam came over the edges.

After cutting the excess foam, I bolted the seat in place and started on shaping it.

This was done with a metal hacksaw blade. This method, while fast, only gives marginal results. Although the blade cuts through the foam with ease, it flexes too much to achieve any accurate results. To produce the final shape, I used a belt sander with a 100 grit paper on it. I tried using an orbital sander, but the edge of the disk was cutting into the foam too much -- the belt sanded worked much better. During the process, I sat on the seat numerous times to ensure it will feel right. Since I plan to ride this bike, a comfortable seat is more important to me than a good-looking one.
A quick session with an electric stapler, some vinyl, and a lot of cussing later, I had a decent seat to test.

I drove up and down my road (no lights, no front brake - so I was limited), and I really liked the way it felt.
henrymartin is offline   Reply With Quote
Old 08-28-2011, 08:27 PM   #94
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
CB750F Project: Part X


Today, after clearing gutters, digging trenches for the water to run away from the house, and getting soaked, I decided to spend a few hours in the garage.

And it appears that it was a wise decision.

First, I was able to finish wiring the front turn signals and the horns. With everything wired and connected, I struggled fitting all the wires into the headlight housing, but I ultimately prevailed.

Second, I was able to find the cause of a glitch I experienced while test riding the bike yesterday -- a constantly turned on neutral light. It turns out that when I installed the sprocket cover, I have accidentally pinched the switch's wire between the engine case and the cover, giving it a constant ground. After I removed the sprocket cover and found the cause, it was as easy as wrapping the damaged insulation in electrical tape, and re-routing the wires where they won't get pinched.

And third, I finally started on fitting the tail section. After cutting out a radius matching that of the fender, I set it down on the frame to mark the location where the tail section would attach to the frame. Initially, I wanted to leave the entire cowl without any visible fasteners, but I had to abandon the idea. When I first planned this, I was going to attach my rear turn signals where the passenger footpegs should be, but faced with the choice of having ugly screws on the cowl, or using the turn signal bolts to attach the cowl to the frame, I opted for the latter.

In the end, all I had to do was to modify some nylon spacers (to fit between cowl and frame), enlarge the existing holes in the frame, and separate the signals from the stems (which are the mounting bolts).

While the end result is not as aesthetically pleasing as a smooth cowl, it looks better than a set of mounting screws. Tomorrow I'll work on some sort of latch system that will allow me to tilt the tail section to the rear, pivoting around the turn signal stems. I'm thinking O-rings on the stems, and a latch up front. However, if I don't like it, I'll just make a bracket for the front that will bolt to the inner fender.

There is still a ton of work left to be done, but here is some progress.













Is it me, or has it been really quiet here?

henrymartin is offline   Reply With Quote
Old 08-29-2011, 05:28 AM   #95
Transalp Jas
Studly Adventurer
 
Transalp Jas's Avatar
 
Joined: Feb 2006
Location: Corner Brook,NL
Oddometer: 806
Looking great. The seat came out very nice. Looks like a professional job.

I'm not a big chrome fan, but the exhaust would have looked nice in chrome with the white and blue color scheme. Not that the black looks bad, mind you- it just stands out against all the brightness.
__________________
Chuck Norris can blow bubbles with beef jerky.

Chuck Norrris has never gotten a Jeopardy question wrong. Jesus has missed two.
Transalp Jas is offline   Reply With Quote
Old 08-29-2011, 07:24 PM   #96
MacNoob
Beastly Adventurer
 
MacNoob's Avatar
 
Joined: Jun 2010
Location: The mosquito-y Center of Canada
Oddometer: 1,524
Quote:
Originally Posted by Transalp Jas View Post
... the exhaust would have looked nice in chrome with the white and blue color scheme.
The black matches the tires and wheels!

How about a white ceramic coat on exhaust....

The dirtbike seat looks awesome.
MacNoob is offline   Reply With Quote
Old 08-29-2011, 07:51 PM   #97
brucifer
Beastly Adventurer
 
brucifer's Avatar
 
Joined: Nov 2007
Location: Eureka, Ca.
Oddometer: 2,214
I think you're doing a really nice job. You have a talent of visualising what you want along with the ability to make it a reality. It's just... well, I keep having this internal battle of feelings because you have done this to an F.
__________________
2005 KTM 525EXC-2000 Buell M2 Cyclone-1996 XR600R-Plated 1995 XR600R-1993 Kawasaki KX500-1984 Honda XL600R/XR650L Hybrid-1984 Yamaha TT600L-1980 Honda CB750F
brucifer is offline   Reply With Quote
Old 08-29-2011, 08:33 PM   #98
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Quote:
Originally Posted by MacNoob View Post
The black matches the tires and wheels!

How about a white ceramic coat on exhaust....

The dirtbike seat looks awesome.
Thanks. One of the reasons why I left the forks black, and the airbox as well. I think it would be too cheesy if it was all white and blue. The forks were almost going to the powdercoater, but I stopped myself just in time. The mirrors and the controls are also black (once installed), so it should bring it all together.

Quote:
Originally Posted by Transalp Jas View Post
Looking great. The seat came out very nice. Looks like a professional job.

I'm not a big chrome fan, but the exhaust would have looked nice in chrome with the white and blue color scheme. Not that the black looks bad, mind you- it just stands out against all the brightness.
I know, but see my response above. Oh, and the seat is likely not permanent. I could not find any 4-way stretch marine vinyl locally (in white), so I had to go with just a 2-way stretch, which makes it a pain in the (_!_) to stretch smooth, especially over the bends. As soon as I find the right stuff, I'll be redoing the seat. In the mean time, this gets me by once I get her on the road.

Quote:
Originally Posted by brucifer View Post
I think you're doing a really nice job. You have a talent of visualising what you want along with the ability to make it a reality. It's just... well, I keep having this internal battle of feelings because you have done this to an F.
No, what I have done to an F was to rescue it from an untimely death. hey, when I got the bike, there were plenty of "wrongs" on it already. I know, I'll never be a purist. But, I kept all the stock parts just in case...

Anyway, the crappy garage pics don't do the bike justice. I finally figured the front mounting for the cowl (but then the Mrs started complaining that I'm always in the garage), so I'll do that and then take some outside pics once it is all in place.

And then I have to try to chase the invisible vacuum leak I have somewhere. The bike starts and runs fine, but sometimes hangs at 3-4k rpm (not a throttle cable, nor throttle body, AFAIK), and takes several seconds to come down, sometimes even a minute. If I unscrew the idle screw down, the RPMs will drop, but once the surge passes, the bike dies as it drops to a really low idle. This does not happen all the time, but often enough. Carbs are clean, cables lubed, I have a new air filter, new plugs, in-line fuel filter, new fuel lines, new plug wires...and I checked for leaks with WD-40 without any signs of a vacuum leak. I'll try replacing the cylinder/exhaust gaskets, but I doubt it will clear the issue.

Oh, I have the occasional backfire under load at around 6500rpm if that means anything to you long-time owners.
henrymartin is offline   Reply With Quote
Old 08-30-2011, 05:08 AM   #99
brucifer
Beastly Adventurer
 
brucifer's Avatar
 
Joined: Nov 2007
Location: Eureka, Ca.
Oddometer: 2,214
A couple things I've experienced on different bikes over the years with a hanging idle not related to vacuum leaks were too high a float level and a sticking advance mechanism.
You might pull the left side crankshaft cover off and have a look at your advancer. Make sure it moves freely and the return springs are strong and are pulling the flyweights all the way back.
__________________
2005 KTM 525EXC-2000 Buell M2 Cyclone-1996 XR600R-Plated 1995 XR600R-1993 Kawasaki KX500-1984 Honda XL600R/XR650L Hybrid-1984 Yamaha TT600L-1980 Honda CB750F
brucifer is offline   Reply With Quote
Old 08-30-2011, 11:35 AM   #100
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Thanks. I'm thinking the float level is okay (remember my shims ), but I'll look at the advance. When i got the bike, it had a ziploc bag instead of a gasket under the cover. Some of the bag was caught in the spinning parts.

I thought further carb tuning. So, this morning I started the bike, and tried removing the air filter (thinking maybe it is too rich, which would improve with no filter) to see if it reacts differently. The bike was choking without the filter at any speed above idle.
I still have my pilots set at 1 3/4 turns, so I may try to turn them an extra 1/4 out to see if it reacts any better. Maybe it is too lean. It's too soon to read the plugs, as I only have about 2 miles on the new set. .
henrymartin is offline   Reply With Quote
Old 08-30-2011, 03:06 PM   #101
jeffs900s
Prophet of Doom
 
Joined: Feb 2004
Location: New Hampshire, USA
Oddometer: 1,159
Henry,

I may have missed it, but have you tried synching the carbs? I couldn't get a consistent or correct idle speed on mine until I synched the carbs. Granted, I had one that was out by a mile, but until I fixed that it would hang at high idle and when the idle eventually dropped it idled very rough. Synching was a PITA because it idled so poorly, but once I got it close enough so that it would idle, and I could adjust the idle speed with the adjuster knob, it all fell into place. (This is is my '80 CB750K BTW).

Jeff
__________________

jeffs900s is offline   Reply With Quote
Old 08-30-2011, 08:44 PM   #102
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Quote:
Originally Posted by jeffs900s View Post
Henry,

I may have missed it, but have you tried synching the carbs? I couldn't get a consistent or correct idle speed on mine until I synched the carbs. Granted, I had one that was out by a mile, but until I fixed that it would hang at high idle and when the idle eventually dropped it idled very rough. Synching was a PITA because it idled so poorly, but once I got it close enough so that it would idle, and I could adjust the idle speed with the adjuster knob, it all fell into place. (This is is my '80 CB750K BTW).

Jeff
Jeff,

I did not synch them, but while I had the carbs out, I opened the throttle a little, and checked the opening of butterflies with a gauge -- all four were just about the same.

The idle screw actually works on mine, and idle rises or drops.

So, today, after not doing anything to the bike except letting it run with petcock off to use whatever was left in the bowls - and it still runs for a while, I could not recreate the problem. It seems that once I let her run dry, whatever was going on cleared itself. i started the bike about 5 times today, and no matter what i did, the RPMS would not hang in any particular spot.

What I need to do is to ride it, give it a good throttle, and let everything fall into place So, instead of finishing mounting the tail, I finished on my front brakes, all assembled and filled, and bled. New pads from Marshall but they look good. Bleeding the brakes sure was fun
There are times, when I work on this bike, that I miss working on the little KLR250. taking the engine in and out was a single man job. Working on the single carb was actually rewarding, and tuning the rear drum brake was a breeze.

But, I know this CB is going to make me smile from ear to ear. I got the taste of it when I rode it down the street without lights or front brakes, sitting on a semi-attached seat. Going in first, about 3krpms, just roll the throttle feeling my arms stretch. Yup, its going to be fun.
henrymartin is offline   Reply With Quote
Old 08-30-2011, 08:49 PM   #103
Skowinski
Chordate
 
Skowinski's Avatar
 
Joined: Nov 2009
Location: Mojave Desert
Oddometer: 4,719
Hanging Idle

I haven't read through all the posts, but on several bikes I found it was related to the pilot jets being too lean. Have you tried going richer on the pilot (idle) circuit?
__________________

"Nature never hurries, yet everything is accomplished."
- Lao Tsu


In memory of Nika: http://advrider.com/forums/showthread.php?t=990697
Skowinski is offline   Reply With Quote
Old 08-31-2011, 06:14 AM   #104
henrymartin OP
Mr. Tourguide
 
henrymartin's Avatar
 
Joined: Sep 2010
Location: South of the Great North Woods
Oddometer: 3,262
Quote:
Originally Posted by Skowinski View Post
I haven't read through all the posts, but on several bikes I found it was related to the pilot jets being too lean. Have you tried going richer on the pilot (idle) circuit?
Not yet, as this is one of the steps I'm planning to take. When i first put the carbs together, I had it out at 2 1/2 turns, which was too much. Upon second disassembly, I went down to 1 3/4 turns out per factory manual. This is just a base setting, which has to be tweaked once I ride it. It is a good baseline though. I have to find a portable tachometer, connect it, and start turning the pilots while watching for increase/decrease in RPMs. The instrument cluster is nowhere near accurate to do this.
henrymartin is offline   Reply With Quote
Old 08-31-2011, 06:40 AM   #105
brucifer
Beastly Adventurer
 
brucifer's Avatar
 
Joined: Nov 2007
Location: Eureka, Ca.
Oddometer: 2,214
If I remember correctly, my 750 is 2.5 turns out. Stock jets, airbox, air filter and a 4 into 1 Supertrapp header.
Come to think of it I THINK an '82 750F I sold a while back was 2.5 out as well. Stock everything.
__________________
2005 KTM 525EXC-2000 Buell M2 Cyclone-1996 XR600R-Plated 1995 XR600R-1993 Kawasaki KX500-1984 Honda XL600R/XR650L Hybrid-1984 Yamaha TT600L-1980 Honda CB750F
brucifer is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 10:15 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014