New bike, lots of questions (xj750 seca)

So I am picking up an '82 750 on Wednesday with the intent of riding it while turning it into a cafe racer of sorts. Bike cost me $750, I've got $450 to play with, and a little more (about 300) every month.

All the electrics work, it's in great shape, all original, never been dropped or modified. 44k miles.

Firstly, the issues with the bike, maybe you guys can help.

Front brake felt "mushy." not really weak, no shudder, just not strong or "immediate." Seller says that he just has it dialed back, and it can be adjusted. Any other possible causes?

Idle isn't great. He says that it's controlled by a thumbscrew, and when he dials it in, after you pull the throttle, it shoots very high. As a result, he has it set low, and it can be controlled with the throttle. If left to idle on its own devices in this way, it will die. It pulls fine, hard, doesn't stutter when riding.

The clutch takes a long time to engage. I start releasing the lever, and about 1/2 way out, it finally starts grabbing. It may have been that I haven't ridden in a long time, but it slipped once on me. Seller says he never noticed it by himself, but with a passenger, it will slip. Guy weighs more than me. Is a clutch job hard? I find EBC kits for as little as $80 plus 10 for a spring.

I have extensive knowledge modifying cars, doing custom fabrication, bodywork, old carb'd chevy 350's and newer SR20DET's

But I have absolutely no experience modifying bikes. The most I ever did was swap mirrors out on my first bike, a virago 250.

So I have a few questions. Keep in mind, all these modifications will be done with a VERY limited tool set (think wrenches, hacksaw, ratchets. I'm in Washington, and all my tools and shop are in arizona)

I've read about the differences between clubman and clip-on bars, and I'd like to go the clip-on route. I'm a tall guy, and I like being leaned way over. I sat on a cb750 with both, and clip on felt more natural. How do I figure out what size clip-ons to get? Do I need to make sure the stock bar diameter (what is it, by the way?) is the same as the clipons? What about the fork diameter that I'll be mounting them on to? Anyone have a lead on where to get some cheap ones? What makes sense to do about mirrors? are they even necessary? I've always just looked behind me, even when I had good ones.

Next comes lowering. I've read around here about harley struts, but I'd like to keep this ultra cheap, so cutting springs is first on the list (unless this will just wear out the struts so fast that I NEED to run different shocks) I'm not big on cutting springs in the car world, as I run a SCCA 240sx, I'm all about legitimate modification. but this is a "rat rod" style build, and I don't plan on racing this bike, so cut springs should be fine. How much should I cut on these springs to get maybe 1.5 inches off the rear, 2-2.5 off the front? I'd like to bring the tank a little more in-line when I lower, and am just assuming this is how to do it. I know bike weight will affect the overall amount of lowering based on how much I cut off (cutting off an inch will result in less than an inch of drop under load.) any risk of bottoming out/rubbing with that kind of drop? I'm a light guy, only 160lbs. When the bike is lowered, the nose will be aimed farther down, and I won't be at the point of changing the headlight yet, so will it be possible to adjust it higher? With clipons, will I need to shorten my throttle/clutch linkages? If so, how is this done?


Next comes the seat. Is there any place to get a premade cafe seat for a reasonable amount? Can I have a shop modify a stock one?

What are my options for aftermarket turn signals? the stock ones are awful.

What are the common reliability issues to keep an eye out for on these bikes? I've heard the shaft drive is bulletproof and very awesome.

That's all I can think of for now. Thanks for the help!

 

I would like to make a suggestion here. Before you start in on making any mods. Why not try to get all of the problems sorted out first. Make sure every thing functions as its supposed to.

Fix the brakes first , then the clutch and go from there. Study up on rebuilding the front forks and lowering by changing springs (also look at the anti dive function in your forks), and cutting the rear shock springs.

Carb issues is another brian teaser all in its self. Plan on 300.00 in seals gaskets, carb dip and about 30 hours to get those right.

Electrical issues will drive you insane untill you understand how the systems work on your bike. Read up on that too. If you change the signals out your self cancel will not work and the stock flasher may not work either. Read up on Sql Guys mods to the signal system.

Good Luck
MN

 

I planned on fixing the problems before diving into any mods at all. this is, for now, a daily bike first, project second.

Are you serious about 300 in parts? I'm only familiar with carb builds on v8 engines, but a "carb rebuild" kit is only ~30 per carb, 4 in total.

http://www.oldbikebarn.com/Yamaha-XJ650 ... urce=M7989

Parts wise, is there anything more than this to obtain?

What are you referring to by "lowering by changing springs?" Are there aftermarket springs out there? I spent a good few hours searching, and found nothing of the sort.

I never owned a bike with self canceling blinkers, and I don't think they worked on this bike, as I had to press the blinker switch in (as with all bikes) to turn them off. not an issue with me, but I'll read nonetheless.

Everyone has been mentioning that I should swap the brake fluid first, as that's probably the issue, so that's where I will start. Is a clutch job hard on these bikes? as in, can I do it with a basic tool set? I know the clutches are much smaller, and can be more complex, but is it a DIY over the course of a day?

I know the front forks have an anti dive function, and it does work on this bike, but will lowering it cause much issue? will it constantly be sending pressure into the forks and causing problems? Is bypassing and removing the system altogether an option, or will the bike try to go nose over itself every time I brake?

 

What MN- Maxims said and get a workshop manual,yes do the carbs clean and new seals, check rear brake shoes are not seperating too. A ton of very helpful info available here,search the forums. One thing at a time, good luck.

 

Man I can answer a lot of those questions, but first of all. STAY AWAY FROM OLDBIKEBARN.COM They are slow as heck in getting stuff shipped to you and their customer service stinks. If you need parts and quotes there is nothing better than our local parts guru CHACAL. No joke on that.

Flush your brake line (empty and fill and empty a few times) and then fill it and bleed it like you would on a car. But don't pump the handle too fast, slow and smooth pumps. keep the reservoir full at all times. On the XJ750 the resrvoir in behind the headlight (pain in the butt) I switched to one that mounts on the bar. If you needa new one that will fit your bike you can check out mike'sxs.com if Chacal doesn't have one available, I know mikesx is for the older generation bikes but a lot of parts are swapable.

Read up on Ease's build, lots of good info there and he ended up using clip ons. his build thread is on the modifications section as well. I got a lot of info from him before I kaff'd my bike.

I think you might as well get the new master cylinder with reservoir that mounts onto the bar. they're about $65 to $85 brand new. I would do it simply because you're going to get clip ons later on anyways. But to bleed your current master cyl. you will have to remove the headlight (s) out of the way. that will give you an idea how things work in there and if the head lights can be adjusted (yes just like a car, they have aiming tension screws)

I would get mirrors, for safety issues regardless. You need to see what's behind you at all times and you don't want to be looking back all the time and getting your site of the road. Get mirrors.

Check ebay for cafe seats, first measure the width of yuor frame, figure out where you want the tail to end on your bike and measure so you have an idea of what you want. When looking at the seats most provide measurements. If I'm not mistaken you need at least 8 1/2" wide at the front and the widest part is 10" maybe 9" you will have to fab something to hold the seat in place etc..

The turn signals can also be found on ebay, but don't get ones that are too cheap ( you get what you pay for)

I highly recomend a manual for your bike, it has all the electrical diagrams that you will need when you start messing with the electrical stuff.


I almost forgot. WELCOME TO THE SITE

 

Thanks for all the advice in such a short period of time!

Is the carb rebuild kit posted (there are other places to get the same kit for a similar price) the right one? Also, would it be murderous to rebuild them myself, or is syncing them obscenely difficult?

Is there info about what size clip ons to get on Ease's build?

 

alot of times you dont even need a rebuild kit, i took my carbs apart and cleaned everythin up good and re adjusted everything and just bench synced them and they ran beautifully. just follow the carb faq on here its written by a guy named rickomatic (idk if thats spelt right) but hes got a real long faq on that and as long as you follow it your carbs will be good as new. these carbs arent as bad as they seem cuz hell im 16 and i had em off, apart, cleaned, reassembled, and back on the bike in about 3 days and i was takin my sweet time with those. another thing i would highly recomend though after you clean em is to put in an inline fuel filter, you can get them for about $3 wether you get em from chacal or a place like menards. as soon as i put one in i realized how much crap was bein pumped through the carbs and it sucks to do all that work just for em to get dirty again in a few days

 

Pop: Yes ease's build has the size. If i'm not mistaken they are 7/8's and they are 36mm clip ons, here is his build thread link
http://www.xjbikes.com/Forums/viewtopic ... +cafe.html

Check out page 5 for the clip ons

 

Pop

Go to the supporting vendor Chacal and look at his parts list and read in the house of clean, and his carb cleaning tips.

First things first. You can try to cut corners and use 27 year old peices parts in your carbs but you will find out quickly that the only thing in "kit" form is just a bowl gasket and needle and seat. ALL the othe parts are sold seperately. Every O-ring, seal, screw, spring all those little parts that the PO lost or screwed up.

You can read here about all the guys that pull their carbs 10 - 15 times before they get them right. or there might be a lucky one like Midnight that pulls them once and gets them close enough to get call it good. Trust me and what Rick and Len say about carbs and clean and not leaking air from the wrong places (throttle shaft seals). See Len's comments on those.

We like to hear how things go when the guys pull their carbs apart. Be sure to let us know.

MN

 

While you’re changing the master cylinder to a bar mount (you’ll have too do it when you change your handlebar, the cable will be to long!) go ahead and get stainless steel brake lines, they will make a BIG difference.

Here are a couple of pics.

If you’ve ever rebuilt a Quadrajet you won’t have any trouble with these HITACHI. The biggest problem is all your troubles are multiplied by 4.

Just in case you missed it here’s the link to the cab rebuild.
http://xjbikes.com/Forums/viewtopic/t=2908.html

ab

 

Alright, I picked up the bike today, and after playing with the adjustment, it was just the bias was very soft. Front brake works great now.

After looking at the carb intake boots, i noticed that the boots from the carb to the cylinder head are REALLY ancient and cracked. I'm thinking that a vac leak is causing the idle problem.

It DOES slip the clutch under hard acceleration. but the thing runs like a raped ape. It hauled arse all the way to 80, and I didn't want to push it harder.

and it's now sans the right mirror. I park it at home, and the first thing my hippie roommate does when he sees it? sits on it. doesn't realize it weighs 550lbs, and it falls over. He's now buying me new mirrors, heh.

It has some problems starting though. It can't crank for very long. I'm thinking the battery, as when it was worn down and wouldn't start (push started just fine) after about 35 seconds riding, it had regained SOME charge, but not enough to crank the bike. thank god I was going downhill. Rode it another 25 minutes, and it had enough charge to turn right over and fire. So I'm thinking the battery just must be ancient. Where should I look at getting a gel cell?

Anyways, I'm glad I bought it. this bike should be insanely fun once I get a few niggling little issues sorted out. And I've decided to go clubman bars before clip ons. will probably be one of my first mods, including SS brake lines and a bar mounted master cylinder.

 

u got some awesome info here and there is a plethera of info anailable on the forums lists already. Welcome aboard friend and keep us advised. I too own a couple o seca's and just love em.!!

 

What did you ever do with this bike???