1985 Yamaha Maxim 700 engine

Hi, Not sure if anybody can help? I have just purchased a 1985 Maxim 700 with a seized engine, I have 2 questions:
1/ Is it salvagable with a rebore?
2/ Is there another suitable engine that will fit instead?

Any help greatly appreciated

Paul

 

Paul,

Welcome to the forum, as for the engine you have to do a little more research to see why the engine is seized? If there is anymore damage then just seized from sitting. Take the plugs out and add some PB blaster, oil or your favorite rust busting solution and let it sit for at least 24 hrs. Then turn the motor over by hand if you can.

As for the different engines, there will be others coming along soon to help you out with that. Good luck with your project.

 

from info overload
http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

XJ700 air-cooled models:

Most of the engine-swap modifications in regards to the XJ650 engines above will apply, and recall that the XJ700 engines are rubber-mounted. However, due to the unique frame style and engine mounting positioning, you will need to use the XJ700 frame mounting brackets and hardware.

Please note that we have not attempted such a swap, and welcome further experience from those who have completed such as transplant for any additional insights.







* when putting an XJ750 engine into a 1980-81 XJ650 Maxim or Midnight Maxim frame, please observe the following changes:

- have to convert tachometer to an electrically driven version.
- the original XJ650 oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim).
- the 650 shifter side cover and all internal components needs to be retained, unless you want to keep the 750 Seca style shifter. The 750 Maxim style shifter may not work.
- the engine mounting hardware for the XJ750 engine will need to be used (no rubbers on XJ750 Seca; XJ750 Maxim used the same basic hardware. Use the XJ650 front upper frame brackets when using a Maxim engine; the XJ750 Seca frame brackets when using a Seca engine).
- will need to use XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain XJ650 exhaust system.
- need to retain XJ650 wiring harness, except for the pick-up coils sub-harness. The pick-up coils on the XJ750 engines are different. Need to use the XJ750 TCI box.
- when using an XJ750 engine, be aware that there is a slight gearing difference----the XJ750 Seca used a 18" rear wheel, while the XJ650 Maxim models used only a 16" rear wheel, and thus middle drive gear ratios are slightly different inside the tranny. The XJ750 Maxim models have a slightly different gear ratio, also, even though they share the same size rear wheel as the Maxim. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ750 engine into a 1982-83 650 Maxim frame, please observe the following changes:

- the original XJ650 oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim).
- the 650 shifter side cover and all internal components needs to be retained, unless you want to keep the 750 Seca style shifter. The 750 Maxim style shifter may not work.
- the engine mounting hardware for the XJ750 engine will need to be used (no rubbers on XJ750 Seca; XJ750 Maxim used the same basic hardware. Use the XJ650 front upper frame brackets when using a Maxim engine; the XJ750 Seca frame brackets when using a Seca engine).
- will need to use XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain XJ650 exhaust system.
- need to retain XJ650 wiring harness.
- when using an XJ750 engine, be aware that there is a slight gearing difference----the XJ750 Seca used a 18" rear wheel, while the XJ650 Maxim models used only a 16" rear wheel, and thus middle drive gear ratios are slightly different inside the tranny. The XJ750 Maxim models have a slightly different gear ratio, also, even though they share the same size rear wheel as the Maxim. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ750 engine into a 1982 650RJ Seca frame, please observe the following changes:

- have to convert tachometer to an electrically driven version.
- the original XJ650RJ oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim)
- the 650RJ shifter side cover and all internal components are the same as those in a XJ750 Seca engine. The 750 Maxim style shifter may not work.
- all engine mounting hardware for the XJ750 Maxim engine will need to be used (no rubbers on Seca engines; an XJ750 Seca engine uses the same mounting hardware as the XJ650RJ Seca, except for the front upper frame brackets, the XJ650RJ Seca frame brackets should be used. If using an XJ750 Maxim engine, you'll need to be creative.............
- will need to use the XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain the XJ650RJ exhaust system
- need to retain the XJ650RJ wiring harness, except for the pick-up coils sub-harness. The pick-up coils on the XJ750 engines are different. Need to use the 750 TCI box.
- when using an XJ750 engine, be aware that there is a slight gearing difference----while both the XJ650RJ Seca and the XJ750 Seca models used a 18" rear wheel, the XJ750 Maxim models used only a 16" rear wheel, and thus the middle drive gear ratios are slightly different inside the tranny on some engines. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ900 engine into a XJ650 Maxim, Midnight Maxim, or RJ Seca frame, please observe the following changes:

- it can be done: http://xjbikes.com/Forums/viewtopic/t=29398.html

The same guidelines as generally outlined in the XJ700 engine swap should be observed.


* when putting an XJ1100 engine into a XJ650 Maxim, Midnight Maxim, or RJ Seca frame, please observe the following changes:

- put down the tools and the torch and back s-l-o-w-l-y away from the bike.
- 1100 engines are vastly different than the other XJ650/700/750/900 engines in design, style, size, etc., and attempting to put one of these engines into the smaller frames is likely to be a complete custom job. No other information is available. It would be wise to consider buying an XJ1100 model bike, and riding that, rather than trying to transplant just the engine.....







parts availability
http://www.yamahapartsnation.com/oemparts/a/yam/500426a8f8700209bc788691/crankshaft-piston

 

Basic engine blocks on Xj700n and other xj750's are the same
Different carbs , intake, ignition pickup coils, shift internal selectors.
I do have a Canadian xj750n engine that is available but shipping it might be too costly.