'82 XJ750 Maxim Build Summary + Links to Tech threads

Ooooh. It's got the "QuanTanium non-stick coating"! You sure you want to paint over that? Mmmmm...QuanTanium!
All kidding aside, clever re-purposing! Made me laugh!
I wonder if the life time warranty will still work!

 

Lol it was a tough decision to make but unfortunately the Quantanium (seriously. Quantanium?) coating has to go.

Also please note the "corrugated surface for even browning." I prefer "corrugated surface for effective heat dissipation."

I really don't think I could have scored a better tray without spending 6 hours measuring, cutting, and welding up something of my own.

 

Agreed. It works, it's cheap, it'll look decent, it'll save time! Good thinking. Serious question, though: will the non stick coating take paint? You may have to scuff it to make it work.

 

Well if Quantanium is as non-stick as the label implies then no it won't.

I'll hit it with something coarse before I paint it.

Another fun fact: I received my MV-32 form from the troopers that came by last week. Those guys really saved the day otherwise I would have had to load it up and drive to a station (read my "In desperate need of VIN help"
Thread for more details).

I almost got bold and asked them to VIN verify my Title-less cb750 so that I can send off the info and fees to register it in Vermont (a non-title issue state if the bike is over 15 years old) and then transfer it to PA (who recognizes their title-less registration). By law they will recognize that VT is a non title issue state that also registers motorcycles to out of state-ers, and will have to issue me a PA title.

I decided against that as I had something to prove already, but Laws are fun.

 

I have followed your VIN thread... seems almost as challenging as the work on the bikes themselves. Which would I rather, deal with DMV and troopers and their paperwork, or rewire the Seca? I know which would make me feel better!

 

Haven't updated in awhile. Today I picked up my seat from the upholsterer and he did a fantastic job. It's just mocked up at the moment, but the big news is that with the help of two friends much larger than I, we were able to ride/push it out of my basement.

At this point I have all the parts I need at home except my radiantz led tail/blinkers and some other odds and ends. Now comes the fun stuff! Rejet, wire, and paint! Happy spring!

 

that's impressive.

FU

 

I like the fitment where the tank meets the seat. A lot of custom seats don't look as good in this area as yours does. Not much padding there, though. Your kids will have headaches, and that seat is to blame!

 

That fitment took many hours of me fiberglassing. I took the pan I made to him. I'll be happy if I never have to work with the stuff again.

But I still have to give him credit.

It's not thick, but it's good high density foam, and I live in the city so typically my rides aren't super long. I'll buy a gel pad for any extended rides.

 

Still need to post lots of pictures and complete many little cosmetic tasks, but we're on the road! Need to weld up the exhaust, but I went up two sizes on the main jets and put two shims under each needle and the plugs look fine. It's extremely loud which I dislike, but I've got to say that it runs a million times better than it did when I put it away for the winter, even with the pods and open exhaust.

 

Looks really good!

 

Thanks everyone. So after actually pulling the plugs after a long ride, I'm definitely running lean.

The plugs are white. Now, it could be because of the open headers that they're all white (I'll put it away until the exhaust comes in) but number 4 is totally black. I noticed that the #4 exhaust doesn't get nearly as hot as the others.

I went up two sizes (from 120-124) on the main jets, and also added two washers/shims to the needles.

Should I look into adding larger pilots as well? Any suggestions there? And Why would one cylinder's plug be so black? Guess I should just buy 4 new ones and start from there.

But I definitely don't want to run it until I get it running richer. I should add that my air screws on top are out 3-1/12 turns. Suggestions appreciated folks.

 

double check your float levels. I am guessing that #4 is high and the other three are low.

FU

 

Will do. I've got a lot of painting/tuning to do so now is as good of a time as ever.

Now, exhaust: not too confident in my abilities here...I wanted to go 4-2 with the cans pictures above, but that involves buyin cone eng. collectors, paying the welder, and waiting. Which I'll do...but a quicker solution might be to go 4-4 and use four of those mufflers set side by side.

Fitment of four under the frame aside (I could send 2 of them back if they're too wide), I am assuming I will need to tune it even richer compared to a 4-2 correct?

I know I'm asking a lot of questions, but I have no problem spending an hour or two after work trying different jets for a good result.

 

Lookin good brosef! That seat & pan came out great! I used those same mufflers on mine & you can't beat them for the price. The fiberglass packing on the baffles didn't last very long though so I would suggest ordering a package of fiberglass matt to repack them. I did it on mine after the original stuff blew out in the first 100 miles. It's pretty simple and it made a big difference in the tone.

FtUp could be spot on with his advice on the float levels. Have you tried adjusting the air mix on that one cylinder to bring it up? I wouldn't worry about rejetting now if you're going to be putting mufflers on soon. I bet you'll be real close with a little bit o' back pressure.

 

if you could get a collector box from a 750, that would stabilize the back pressure and make the muffler choice easier. You have to have one part finalized to get the other right.
get fancy
http://www.coneeng.com/motorcycle_components.html

 

All good responses. It's my understanding that turning an air screw counter clockwise (out) will lean it out, no? I I feel as though any more than 3 1/2 turns is pushing it, and I should look to my floats. Does anyone have a DIY on how to make a rack for the carbs?

Bike is parked until I can let the paint on the wheels dry and fashion up an exhaust. May just bite the bullet and get 2 of the cone engineering 2-1 collectors and pair them with 2 of the emgo shorties above. I don't see why I couldn't tack it in place and drive it a mile down the road to the welding shop.

But I'm still considering a 4-4...I'm just a little worried about width. Will measure tonight and have a solution this weekend.

Also I'd like to take a moment to say that plasti-dipping this wheels last fall was a huge mistake. It took me two cans of WD-40 and about 5 hours to get it all off so that I could paint.

If you have a media blaster it's no problem to remove it, but heed my warning. It was miserable without one

 

Can you share wher you got t he frame hoop from? and how is the build going?

 

No. Out is richer.

 

Out = richer. Correct.

Might want to look into getting a Colortune 14mm set for your tool arsenal. Awaiting mine now so I can dial my carbs in for good

 

It's been awhile. I haven't done a ton lately besides have the wheels coated with appliance expoxy (which so far looks great and seems durable. It's easy to clean up too.) and clean the engine for paint in the near future. I also still need to order that exhaust so I can do some riding.

Also the colortune is something I'm very interested in.

 

Awesome thread! Just read through the whole thing. I really love your seat!

 

Brosef hasn't been on in over a month... must be busy riding! I hope he posts more updates soon. Wanna know how the exhaust + pods worked out.

 

I had an Xj650 with pods and 4 into 1 mac - it ran like a charm!

 

did you rejet for all that though?

 

Yes I used Dynojet.
Basically I took the biggest jets in the kit and followed the rest of the dynojet's instructions. First try and it worked great.

 

oh wow, nice!

 

And you're sure that your mixture is close to ideal? What is the fuel mileage like?

 

I was getting about 45 MPG and even when I rode it really hard it never went below 40 MPG.

 

Sybe, I got the hoop from Speedmotoco, I believe it was the 15 degree upswept, and it fit perfectly.

I actually have not been riding a ton, as I've been busy and still havent purchased the 2-1 collectors to be welded on. Also I'd like to get the CB750 on the road by fall so I've been doing some basic maint on that.

I leaned the bike up a bit for when I DO. ride and don't go higher than 4500 rpms until I can get the muffler sorted out.

I did get new shorter clutch and throttle cables, and added a 7 inch round headlight. Now I need a speedo cable though, as the little spinning nipple on the top of mine seems to have gone missing.

I am wondering if I'm having transmission issues though. The shifts are quite stiff, but I also don't have any problems slipping out of gear or anything. Further, Neutral is always pretty hard to find and I usually have to shift up to second, then press down very lightly. You guys have any suggestions before I make a thread in the other forum?

I'll post some detail pics soon guys! Ride safe.

 

your clutch could need adjusted, try taking some of the free play out at the lever and have the arm at 90 deg or slightly before when it gets tight.

 

Polock, thanks for the advice. I'll try that tomorrow evening. I hope it isn't the chain guide or worse. I'll have to do some reading about those symptoms.

It's been a while since I've posted any pics so here goes. Please note that I've basically let the bike surface rust quite a bit, but It's cosmetic and will get taken care of soon. Funny thing is, I get tons of compliments on the way it looks and I can't stand it personally, but I haven't had the time to correctly paint it.

Close-ish side view



A bit closer. I used a road bicycle shifter lever for the starter circuit/choke, which was an idea I found in this thread: http://www.xjbikes.com/forums/threads/hidden-choke.47575/#post-422990 I decided to paint the fiberglass portion of the seat with black appliance epoxy, since it's pleased me on the wheels and the passenger peg mounts so far. I painted it a week ago, so now that it's gassed out I'm going to sand it down and either use gloss clear or matte clear on it. It's mainly being used as a test piece before I fork up money for good paint and 2 part clear.




Being that this is a Maxim that came stock with the tall buckhorn bars, I used motionpro throttle and clutch cables for a seca, which fit the drag bars much better and look a ton cleaner. Plus 33 year old cables need replacing anyway. I did get a smaller clutch perch and short lever, but the new MC/lever I ordered have not yet been installed. I still need to relocate the ignition and switch it to the auto style so that I can eliminate the kill switch/starter button which are mounted under the tank at the moment. At that point I'll install the bracket I have for the gauges that will bring them closer together.



I had a trip planned to Snowshoe, WV for 4th of July weekend, so I packed the bike up and took it with me to get a short mountain ride in, since I haven't left the city much (remember how loud I am right now, and I don't want to push anything until I get the exhaust on.

 

They're right, it does look cool.

 

I dunno if it's the rear shocks or the missing exhaust or the chopped rear section, but when I see that pic, it looks like a mini-bike. Something about the proportions... Looks hella fun to ride! Maybe it's all the lightness you added. Looks like it just wants to wheelie!

 

It's a blast to ride! I understand what you mean about the proportions. It's so vastly different looking from what it started out as. To be honest I don't particularly love the 19 inch front wheel, and would love to buy that conversion kit that makes the rear wheel fit the front...but then I'd have to lose a rotor and I don't really want to do that. Also, the lack of an exhaust definitely takes away from the "Meaty-ness" of the center of the bike. It'll be on soon I promise! I'm going run 12 inch shortys under the bike.

Also...can these bikes even wheelie lol? I've never tried to power wheelie, and I certainly haven't popped the clutch for fear of breaking something.

You probably shouldn't answer these questions...

 

I don't think I wanna wheelie, it seems like the bike does, though! And I agree about the rear to front conversion. Seems like you'd be adding rotating mass while removing the stuff that stops it from rotating. Has anyone compared stopping distances before and after the swap?

 

Oh yeah, the Maxim's can definitely wheelie. First gear clutch ups.

 

Can these bikes wheelie? Oh you are a young one aren't you lol.
Maxim 750


Seca 2 (600 cc version of the XJ550 in a different frame)


And my favorite; an '82 Seca 750



Now you won't be pulling an all-throttle wheelie like you can on a short-wheelbase bike, but the front can be made to lift quite easily with a little help from the clutch.

Not unlike what this fella is doing here...

 

Jeez! It don't get much bigger than a Goldwing. If that old dawg can get it up, our sport bike cruisers sure should be able to!

 

Hah, wow! Well considering how mad at myself I'd be if I dropped it...I think I'll leave the front wheel on the ground, but good to know the power is there! If anyone in the Pittsburgh area is going to be at the Vintage Grand Prix this weekend let me know!

 

Quick updates: Got some new cables, fashioned up a rear fender/light/plate mount instead of the mount/light down at the axle. I also crudely polished the sides of the tank while leaving a strip of rust along the top, and finally found an exhaust collector to use from an 81 Seca. I imagine that with some slip on mufflers this will make the bike run even better than it does now, thought I'll need to tune the carbs again.

I sort of need to do that anyway, as over the past two weeks the bike has developed somewhat of a hanging idle when I pull the clutch in, or rev it over 2,500 at a standstill. I don't know if it could be that I need to adjust the valves again also, but I'm going to do that when I pull the carbs to clean the slides, jets, etc. These were zestfully cleaned last winter and the bike didn't sit for more than 3/4 days at a time since it was warm enough to ride.

I'm a little stumped about that hanging idle though, since it hasn't done it until very recently.

Anyway, here's some new pictures:

This is the new rear light/fender setup:



Plenty Bright:


Here's the bike at the Distinguished Gentlemans Ride in Pittsburgh:


And here's the dapper fellow that rides it:



This winter I'm going to have everything painted/powdered/cleaned and I'll probably take the top end off and do maintenance on all of those goodies. I'll also do new brakes/lines/suspension.

I'm happy to say that I was able to get version 1.0 of my CB running and rideable as of two weeks ago, but it needs tuned badly, so it's sitting for now. I also have lots of cleaning up and modifying to do, so I have a feeling that I won't get to take it on any long rides until next year.

 

Looks awesome man! I'm in the 7th layer of tuning hell right now on my newest project & I'm fighting a hanging idle issue almost exactly like what you described. Far as I can tell from researching it's caused by a lean condition and the most likely culprits are a vacuum leak around the intake manifolds or a clogged pilot circuit (but could also be wrong sized jets, leaking throttle shaft seals, or....). I ruled out the vacuum leak on mine so it's time to tear the carbs down again. Ugghgghgh.. I just want to ride it. Then sell it.

 

Interesting, I'll have to check that out. To test the vacuum leak around the intake manifolds, I would simply spray unlit propane around the area no?

Would that catch my throttle shaft seals as well?*

I did replace these before spring, but never hurts to double check.

Thanks everyone.

 

Yeah that's the test that I've read about too. I tried it & didn't notice any increase in RPMs but I wasn't convinced so I pulled the boots and put them back on with new gaskets and some copper RTV just to make sure. It didn't help. Not sure if the propane test works with the throttle shaft seals but I would think so. If that's where air is getting in the it would be sucking in the propane too. I didn't replace my throttle shaft seals because of time, money, and pure unadulturated laziness. Plus I've always been a little scared of breaking the rack apart but I'm sure (just like anything else I've learned on these bikes) it's probably not as bad as it sounds. I got away with it on my first bike and never had a problem but it might be coming back to bite me on this one.

I'll keep you posted if/when I get mine figured out.

 

Have the carbs been synched?

 

Yeah mine have been synched. It was tough because it wanted to either barely run or it would hang at a higher rpm and sometimes race up. Need to double check my jet sizes too I think.

 

Ted, I broke the rack on my carbs with no prior mechanical experience (Well, nothing to that magnitude, not even close). Check my post on it, I think it should really help with anyone weary of stripping them down. TONS of photos and diagrams: http://www.xjbikes.com/forums/threads/first-time-taking-apart-carburetors-lots-of-pics.48063/

My carbs were synced using the two bottle method and did great all summer, but since I've randomly developed a hanging idle AND due to the fact that I need to sync the CB carbs, I think it's time to buy a four gauge setup and a carbtune. I'll have to double check, but I'm pretty certain the CB and XJ have different plug threads which is unfortunate.

I have this other idea (which I hope someone can weigh in on, because I just thought of it) that my clutch may have been adjusted improperly. Two weeks ago, before the hanging really started I decided to do an emergency "Guidectomy" for the hell of it, just to see if I had any plastic guide chain pieces floating around in the engine. I did, however, open the wrong side of the bike where the throwout rod is (DOH) and so I had to put it back together and re-adjust.

I'm wondering if I was too sloppy with the adjustment, and now when I pull the lever, if the clutch isnt engaging fully, leaving me with that idle. Does that make sense?

Regardless, I'm excited to get the exhaust collector in place so that I can finally get this thing to run like a top, and backpressure is definitely the key.

So in the next few weeks I will certainly be pretty active on here again, because there is much tuning to do before winter!

 

if the clutch has too much free play it bangs going into gear, creeps forward at red lights and engauges as soon as you start to let it out. not enough free play and it might slip.
the two bottle sync tool is more accurate than the individual tubes because you can see the accumulated difference over time

 

Good info. It seems that the best method might be for me to use the two bottle sync paired with the colortune.

 

I love the color on that Honda. I'm sure you've already told us, but what year/size is it? SOHC, so 70s, right? Always wanted CB Honda four, but hoped the XJ would suffice. Your posts are making me think "Not so much". Damn. Put it back on the Xmas list.