Engine upgrade

Hey people....a few questions...
1. how do you remove the engine from the bike frame.
2. how do you take that rear shocks off, and put the suckers back on
3. what upgrades can I make to make my bike faster, and run smoother.

and also is the dual carb thing, actually something that can be done?

 

I also want to reduce my bikes exhaust to a one can system. is that a Good think or no?

 

I guess the first thing we need to know is what bike are you working on. 550,650,700,750, seca maxim. It makes a big difference. As far as the fastness part and running smooth. Check out rick-o-matics carb cleaning how to's. Also the colortune posts here one more thing balancing the carbs. The basic maintinance makes these bikes screem down the road. Good luck.

 

I am working with a 83 Maxim Special 750.

 

I ran NOS 25hp with i 7oz bottle and wow what a rush. Befor you run NOS you better make sure the valves, carbs, and compretion are good.

 

I ran NOS 25hp with i 7oz bottle and wow what a rush. Befor you run NOS you better make sure the valves, carbs, and compretion are good.

 

1. From the left. Read the manual.
2. See second portion of #1
3. Best/easiest way is to install an XJ900 engine. Hotrodding your 750 the right way will not be cheap, nor will it produce the power that a stock 900 engine produces.

Stick with stock carburetion.

Avoid nitrous.

 

Will a 900 engine fit into a 650/750 frame? I thought someone had mentioned that it is too tall and hits the frame rails or the bottom of the tank or ????

 

Yes, occasionally you'll see one on Ebay.

The engine's not all that much bigger externally, although you may have to pull the engine in order to remove the valve cover. The 900 Seca engine in a 750 is very do-able. The hard part will be in finding a good donor 900 engine.

I have a 750 YICS engine in my 650 Seca; it went in without any problems. You notice a bit less finger room when switching to reserve, but otherwise there's no noticeable difference on the outside.

The mounting points for the 650/750/900 XJ engines are all the same.

 

So no nitrous, no Meth injection, no Co2 cooling...no nothing will make that sucker faster but tunning and clean your carbs, and switching to the 900 eng?

 

That's what the man said. And I'm inclined to agree with him. Nitro is asking for trouble if you shoot it in there without the necessary boost in jet size and RPM range. One can exhaust is fine but necessitates the rejetting of the carbs. This will net you some improvements in the top end but will introduce a nice flat spot that you will spend months trying to get rid of (and it won't go away).

 

750 Maxim = 4 cylinders, 750 Special = 3 cylinders, which one is it ?

 

what!?!, and to danno, or yeah whatever...lol the max special is a 4 cyl.

 

LOL,whatever... a Maxim is a Maxim, and a Special is a Special...these are 2 different bikes. A Maxim Special does not exist,at least not on this planet. Perhaps you mean Midnight Maxim?
The Midnight Maxim was indeed different from the standard Maxim,in that it had a blacked-out treatment that adorned the fenders,engine,and exhuast,amongst various other components.It also had various "gold" plated parts that helped to distinguish it from the average Maxim.
Although this Maxim is certainly special to you,to call it a "Maxim Special" is technically incorrect.
Now if you'll excuse me,I think I'll take a drive in my "Ford Camaro".

 

Turbo and EFI it!

Head flowed and hotter cams would do the trick but cost alot and require re-jetting etc. Put a 900 in and work that up, cams and flow work as well.

How much more grunt do you want? Why? How much $$$ you willing to spend?

If you really want more XJ speed for all the $ you can end up spending have a look at a nice new FJR1300, twice the ponies and all the suspension etc is set up to handle it too.

My 750 goes fast enough for me .

BTW I had a XJ650 Midnight many years ago, the guy who brought it after me is still riding it 15 years later. It had a 4-1 exhaust and no flat spot. Might even have been called a special here too. Next time I see it I'll have a look.

 

Danno, Now come'on man check out Yahmaha's history before you go making people seem to be ignorant now. There is a Midnight Special that was both a XJ, and XS. The special only indicates the body painting like you said, but there is a 1983 Yamaha Midnight Maxim Special Edition. That is the reason why I call it Maxim Special; although, this may not be technically correct to you, it is ok for me to call my bike that....Regardless it is 4cyl engine.....it's not a big deal..lol

KiwiXJ750D
Turbo and EFI it!
I wouldn't even know where to began with such an application. My goal is, not to spend more than 1000 fixing up the bike making it sweet again...so what do you think I can do with a grand? What I plan on doing, is just keeping my headers and the collector, and just making a single exhaust flange, and hooking up a sports can. Cleaning the carbs, and using the pod filters, resealing the tank, new head lights, and fairings, new welbers adj. shocks (btw these guys are sweet! http://www.wilbersusa.com/wilbers/products.htm) new petcock, new speedo, and controls(if i can find some) new clutch, and brake lines, new gasket, new starter, and a crap load of other stuff...including body decals, new paint, new engine gaskets....... :twisted:

 

Also would the rear tire off of the 900 seca fit the 750maxim, because i would like to put disc brakes on the back...No sense in making a faster bike, and you cant stop it

 

Call it what you like,it REALLY isn't a big deal. Just thought you might like to know what you have. And having owned four xs 650 Specials,an xj 650 Maxim,two xj 750 Maxims,an xj700 Maxim X,and an xs 750 Special,I think I know a little bit about "Yamaha's history".

 

Granted, You probably do...but thanks I know what I own...It isn't that big of a deal...I have the owners manual and the original brochure. But people understood what I meant...sorry if I gave the wrong vibe...your right it doesn't matter. I need more help with my questions then knowing the name of my bike...lol

 

Okay, so it will mount in the frame properly, how about driveshaft hook-up, etc. Did the 900 use a 5- or 6-speed tranny?

Are there any considerations in (currently) buying replacement parts for the 900 motors......like if it needs a rebuild, can you buy the valves, rings, pistons, bearings, etc.?

How much of a clearance problem is there on the valve cover? Pulling the engine every time you want to adjust valves or fix a leak doesn't sound too interesting. Could the valve cover be surfaced down (on the mounting flange side) a bit to make it possible (maybe difficult, but at least possible) to remove it while the engine is still in the bike?

Thanks for the info!

 

Kiwi, did you need to rejet when you swapped the exhaust? If you were fortunate to get a good aftermarket exhaust, you may well have not needed to. The cruddy MAC that is all I can find for my ride and it will need to be installed with new jetting (CV carbs gotta have their back-pressure to work right). I will not say that mine is the only opinion that counts but, in the world I've wandered through, re-jetting was necessary to optimize the exhaust swap. It can be said that no jetting is needed but I'll bet dollars to doughnuts (a lousy habbit in this hemisphere, not sure about the southern part) it will run better if you do.
In addition, I would jump all over an EFI or turbo if I could source one at a reasonable price ($400 or so). More than that and it's just not worth it yet.
Turbo's ain't cheap and are a pain to plumb. Both are an excellent way to put the snort into the machine but in practice, unless you were born to one of the families producing these things or work in the industry, they are really expensive. Not something for the average Joe in my reckoning. I hope that folks find a way to prove me otherwise, it would be great to be wrong in this instance. And yes, I saw the Mega Squirt kit back when you could get it for $120. Some choice junk yard scores could set you up but I'm not sure I would place a lot of confidence in a set of used yard injectors.

 

It's THE SAME below the cylinder base gasket. Other than some beefier drivetrain parts, the only change inside the cases is a slightly taller secondary reduction gear pair. The only external difference is paint and trim details.

Buy a decent runner, and you shouldn't need anything beyond a valve adjustment and carb freshen-up. Remember-the idea is to upgrade without buying a bunch of parts and splitting the cases. You can buy a wadded XJ900 for ~$500, and have parts left over to sell when you're done.

I can't say for certain, as I haven't played with that particular combination of parts yet. All I know is that there will be a bit less room to wiggle out the valve cover. The 900 top end is not all that much bigger than the 750's, so it should be removable.

If there is an interference problem preventing the valve cover's removal, you can remove the engine and exhaust mounting hardware and lower the engine a bit on a jack: half an inch is all you'd need. That would add perhaps an extra hour to a valve adjustment.

It's likely that some minor clearancing on the top of the valve cover could remove the points of interference, making it a non-problem.

Aside from owner-caused incidents, these engines do not leak.

Bad idea, and the wrong approach to this. If you took enough off the gasket surface to make a difference, the mating surface would no longer match the engine side. Creating clearance, if needed, should be done on the non-oily side of the valve cover.

 

Yeah I wouldn't even know where to begin in Fuel injecting a cycle....but I do have tons of experience with mega squirt and if taught properly, i could maybe do that...But do you think rejeting would be required if I used my stock headers, and just put on some extentions, and some new cans...or a new can?

 

Thanks bosozoku! (what's that name mean?). So it's still a 5-speed tranny I assume. Are the ratios similiar to the 650/750 ratios (1st thru 5th) so that it might work okay without changing the final drive ratio at the reat wheel?

 

One more time.. :roll: ..it's not just similar, they are all the same, except for the secondary reduction pair, which is slightly taller in the 900. Aside from that one gearset, the XJ 650/750/900s all have the same internal gearing and final drive/rear end ratio.

The attached pic shows where the secondary gear reduction lives.

The engine itself is a drop-in. There are some other very minor things to take care of, but sliding the big lump into its' nest will not be any problem.

There are several threads here that discuss this- feel free to do some digging.

 

Was already fitted when I brought the 650, never had any reason to take her apart or have a look at the carbs. Don't know if any jetting work was done by PO. Had a 4-1 with short (12 inch) muffler, don't remember what type of baffles but was a bit louder than my 750D. But if someone did rejet they got it spot on! Smooth as, no dead spot and as good on the gas as my EFI 750. Wish I still had the 650 too.

I paid $800 NZ for the EFI bike 2 years back. Not many EFI XJs round, Jap home market only.

I would not bother myself, the EFI 750 goes fast and quick enough for me

 

yeah.....well Im thinking just a new exhuast system, and cleaning the carbs will do just fine for now. But if I can find a 900 engine around, then I'll swap it out....My 750 is really quick...and with the new mods to the frame and the rest of the bike...it should be a pretty cold ride by summer time.

 

bosozoku you said to stay away fron NOS. I ran NOS on 2 of my bikes and had no problems, mind you my gs1100 was pro built but my 81xj650 was blue printed and balanced. The 650 pulled real hard buy didn't go aney faster on the top end.You seem to know alot (not to be rude you know your stuff) and would your in put on this subject.

 

Dang Kiwi, I wish I could get my hands on an injected XJ. I'll bet there are only a handful here (I've never seen one in all my years, at least not in person). I'm an injection fan and would love to tinker with one.

 

Let's just say that Nitrous is very unforgiving of tuning errors, and quickly rewards your little mistakes with big broken parts. I've got several friends that went to the dragstrip after installing NOS, and fragged their engines big-time, by getting greedy and trying to go that little bit quicker.

Even under the best circumstances, you can only enjoy it until the bottle is empty...you get a few minutes of assisted performance, then it's time for a re-fill. End of ride :x , go back to town, and find a welding shop for some more squeeze.

Assuming you've got things set up properly (colder plugs and ignition retard), your bike will be a slow, sullen ride when the bottle is empty....
If you haven't, I hope you enjoy a long push home when it finally lets you know where the weakest link is.

NOS only works at WOT...playing on the roads that I like, that sort of performance enhancement would not be a good thing. My bike has a slight advantage in that I can get on the gas really early when exiting a corner, so I can gain ground on bikes with more power by getting an earlier drive. Having to wait until upright before pulling the trigger is not my idea of fun. It wobbles enough as it is, and adding a sudden 15-20HP hit would not improve things.

Having a NOS bottle in plain view (there's no place to hide it on your bike) is a justifiable reason for curbside conversation with a LEO. If the conversation happens after you are stopped for something else, the big blue bottle will not please the LEO. Your impromptu chat will get ugly very quickly.

In many areas, being caught on the street with an enabled NOS system results in an immediate impound of your vehicle. It'll cost more to get it back than you can imagine.

I don't hate nitrous, but see no point in peformance enhancements that cripple your bike for street use. Power upgrades that are single-focused the way nitrous is belong at the dragstrip, not on the street.

 

How can I argue with logic. That all makes good sence.My bike is a bit slower from light to light but out on the back road at the cotage its a blast.The bottle is not out in the open for the same reason of the LEO. The bottle is under the seat I made. You don't want the bottle in the open incase you fall on it nothing like a bomb on the side of your bike. Hope to learn alot more from you in the future.

 

yeah...NOS on some bikes is very cool, but on a Xj.....yeah...I can see your point. but really im just looking for power....So i've looked into rejetting the carbs...and that seems to have a big gain too

 

One more thing to ponder- if you were shopping for a good used bike, would you want one that had been sprayed?.

If you want an easy permanent power increase for your 650, stick a 750 engine in it.