My engine has been swapped

I think my engine has been swapped.

Vin # on frame neck JYA1FG004FA005888

VIN # on right side engine case 4H7-100834

I was under the assumption that I had a 85 XJ700. While cleaning the carbs I realized they had all the jets for a 650. Then I found the numbers on the float bowls HSC32-1. So I started checking numbers. 653cm on the front of the engine. So I guess I got a 650 in a 700 frame. I still can't get it to run right. seems to run lean. snapping and popping @ idle. hesitates on take off. Flat when accelerating hard or wide open. I checked the comp. and adjusted the valve shims, but I thought it was a 700 at that time. Have to check in on that. I completly cleaned the carbs and sync them as best I could with the idle serching up and down. Any sugestions are graetly appreciated

 

Howdy and welcome.
A picture is worth a thousand words, try to post one.
I'm fairly sure someone here will give you a definitive answer shortly.

 

Have you checked for air leaks yet? Do you have the right plugs in it.

 

going by chacals vin decoder its an 85 maxim with an 80-81 650 maxim motor

 

Here's where they went wrong - - you can't (or shouldn't) mix-up the ignition components from the 700's and the older 650 - - specifically, I bet you have the "pickups" still original to the 650 and the TCI and coils from the 700. Can someone help sort this out??

Welcome to the site !!

 

can't find any air leaks. the plugs are NGK BR8ES my manual says BP8ES for the 700. Not sur what I need for a 650. Guess I have to get a manual for a 650 also! Not sure how to check for the right coils and ign. I'll need some help with that one. I'll go look for numbes now.

By the way, thanks for all the help. I've all ready recomended this site to a friend with a xj750 who was asking for carb help. This is my first yamaha and I can't wait to get it out on the road!

 

Do you have a camera? If you do take a pic of the pick up coil under the l/s crankshaft cover the 650 and 700 have different pu coil even tho they have the same stroke crank and we will go from there

 

Plugs should be 7s for the 650. What Time said makes sense the tci advance curve could be wrong for that motor that would explain the poor throttle response you were having. The TCI needs to match the cams profile. The easy way out would be to contact Chacal at XJ4ever send him a PM (personal message) at this link. http://www.xjbikes.com/Private_Messages ... u=743.html

 

To be more specific, plugs should be BP7ES for the 650. Gap should be .7 to .8 mm or .023 to .032 inches.

 

OK, Got some pics and #s from the bike and I tried to post them but i'm on a dialup connection right now so it would take a week to upload them. I'll Post them when I can get WI-FI.

The pick-up coil has PU212-01 stamped on it.
The RH coil (cyl. 2&3) has 1FG-01 CM12-09 on it
The LH coil (cyl. 1&4) has 4H7 CM-09 on it and does't mount correctly to the frame. The bolt pattern is to wide. So it appears that my Lh coil is right for the engine and the rh was original to the bike. Anyone got an extra coil for sale!? Sounds like I need A new TCI also. Anyone know the part #s for the TCIs

 

. . . so it would take a week to upload them. :lol: :lol: :lol:

I figured a mis-match but didn't think they would use one-of-each on the coils - - hillbilly engineering. The 700's have a different OHM range and the TCI was just plain confused.

 

http://www.xjbikes.com/Forums/viewtopic/t=14577.html going by the number system lh coil is off the 650. You need to fix that for sure. I am not sure if you checked out chacals vin# (link above) but if you have not lots of good info there. Sorry your having such a hard time but when you figure it all out will be worth it. I am going to try and post a pic of the 650 pu coil and the 700 that might help. Both pics look the same so that wont work.

 

Uh... you mean 0.028~0.032" gap, right SQL?
I'll agree with the spark plug #.

 

XJ700 coils differ from the XJ550/650/750 coils a tiny bit in primay resistive load, but not enough to make a difference:

For all models except XJ700, XJ750-X, and XJ900 models:

Primary (input from TCI): 2.5 ohms +/- 10%
= 2.25 ohms - 2.75 ohms acceptable range

Secondary (output to spark plugs): 11K ohms +/- 20%
= 8,800 ohms - 13,200 ohms acceptable range


For all XJ700 and XJ750-X models:

Primary (input from TCI): 2.7 ohms +/- 10%
= 2.43 ohms - 2.97 ohms acceptable range

Secondary (output to spark plugs): 12K ohms +/- 20% (XJ700 and XJ750-X)
= 9,600 ohms - 14,400 ohms acceptable range


They differ quite a bit in physical SIZE because of the space constraints on the XJ700 frames..........the XJ700 coils are quite a bit smaller, with different (lesser) coil mounting hole center-to-center spacing. How someone shoe-horned a XJ550/650/750 coil onto the 700 frame is a feat of engineering that must be a sight to behold.......

You could use either the 1980-81 650 Maxim "non-YICS" (TID14-02, 4H7-10, black-is-beautiful label) igniter or the 700 air-head igniter (TID14-44, 1FG-10, a really pretty shade of purple label) on this bike, but I think that since it's a 1981 XJ650 engine (4H7-100834) that the 4H7 igniter box (black label) is going to be a better "match"-----however, that box does not have the terminal provision for the sidestand (kickstand) switch and safety interlock associated with it, since the 1980-81 XJ650 Maxim's didn't use it.

It may be that the 650/750cc "YICS" igniter box (5G2-10, TID14-06, better-red-than-dead label) might be the way to go, since it has a very similar advance curve to the 1980-81 650 (non-yics) TCI box, plus it has the correct extra terminal for the safety switch system.

 

Yeah. Sorry. Typo. If you squint, .023 looks like .028 ;-)

 

First of all the 650 coil does not fit, they only mounted it with one bolt! I'll have to do some fab. to make it fit better. second, I got the numbers of my TDI, its a TID14-44 1FG-10 original to the 700, and the pick-up coil PU212-01. So I will try to locate a YICS 5G2-10 ignitor box. Should I get a 650 coil or will it be OK to have them mismatched? What about the pick-up coil, is that going to be a problem? Thanks

 

Don't feel bad, I just bought my first set of bifocals today... dang I feel old.

 

Funny. I got my first glasses ever last week, and, yes, they're bifocals too.

 

Getting old sucks huh guys. Got mine 2 years ago I think, im not sure if my memory is still.... What was I talking about?

 

this will make lots of people feel old a good percentage of people that own xjs are not as old as the bike is. Most of the riders are so young that they don't remember cassettes or the clunking 8 tracks.