XJ650 pick up with XJ750 TCI Unit

Hi guys, just a quick question. I’ve got a customers bike in to try and get running right. It’s a 1981 xj750 maxim imported from America. I’ve been through everything on it to try and get it right. Compression test, valve clearances, jetting, coil resistance etc. The issue we think has to be electrical as it’s temperamental with jetting. I have checked the pick up coils and it looks like it’s got 650 pick up with a 750 TCI. What are people experience with this set up?
( just so you know. This is a “nearly finished” project bike he has bought so it’s been converted to pods and a lot of other alterations

thanks in advance

 

Do you know any model numbers or part numbers?

The 750 Maxim showed up in the model year 1982 with model ID code 15R. That model ID code should be stamped on the steering head, on the VIN sticker, and stamped on the engine. Can you verify that?

 

Most 81 - 83 XJ650 and XJ750 models used the same pickup coils. Are you able to confirm what pickup you have? What are the symptoms?

 

Such as ?Also pods get a poor press on here. No direct experience myself but I hear stories of flat spots etc..

 

the 650 and 750 use the same tci except fot the 80 650 and the US 650 seca. so what years of 650 are you using.
I do not think the tci cares which pickups are used there is an ohm difference between the early years of the 650.
I have started and run my 750 with both black lable and green label tci from the non yics motors. the 650 yics motor uses the same tci as the 750

pods if you connect the pods to the airbox boots then to carbs bike will run much better. the airbox boots work like velocity stacks

 

I’m not sure what year 650 the pick ups are off. I am just confident they are 650 with the colour of the wires vs 750.
I have attached a few pictures

as for the pods. If it was me I wouldn’t have used them as it’s a lot of effort for what they are but the previous owner didn’t think so. I don’t have any of the std parts

 

Ooh that's some ugly wiring... Going back to the initial post what is meant by 'not running right'?

 

Most of the wiring has been messed with and none of it is very pretty.

The bike was temperamental when it came to starting because it has pods the initial presumption was that the jetting was incorrect. I spent hours trying to get it set right where it would rev up. After realising that the bike would have different outcomes with the same jetting I come to the assumption that it must be something electrical. I’ve checked the coils (aftermarket) they are both have a little too much resistance. Caps are fine.

that takes me to now. Had a look at the wiring in the TCI Unit and followed it back every which way and noticed that the 20amp fuse was a little crusty and didn’t look nice so I changed that and then it would start up and rev up with a bit of bopping.

turned bike off left it for the night went back and now it won’t even try to start. The starter solenoid is clicking with a full battery

 

If the starter solenoid is clicking then either the solenoid is bad and not making the high current connection, the starter is bad with a likely open at the brush / commutator, or the battery is too weak or there is a poor connection. It's easy to verify the battery voltage when the starter button is pressed, and then check the output side of the solenoid when the starter button is pressed - both cases looking for >10 volts. Sometimes tapping the starter will get it going if the issue is a poor connection between the brushes and the commutator.

As for the TCI pickup coil combo:

The TCI is from a 650

"HCP8108 Aftermarket TCI case ID DECAL, black foil decal with TID14-02, 4H7-10 wording. Used on all 1980-81 XJ650 Maxim and Midnight Maxim model TCI (igniter) boxes. NOTE: the silver "date code" box is left blank/unstamped."

The pickup base plate is from a 750 Seca

"1981-83 XJ750 Seca USA: 5G2"

The reluctor should also be stamped 5G2-10 if it is from the Seca, I don't see any labeling in the photo you provided and it does look different than the one on my 1982 750 Seca

And yes there are subtle differences in the reluctors, TCI timing, and pickup coils, so it is best to keep them matched to the engine

 

Seems you've uncovered a different problem with the clicking solenoid... As Rooster suggests the battery has flattened, the solenoid is duff or maybe even the starter got tired. Shorting the solenoid terminal with a thick screwdriver will eliminate a number of issues.

Piecework or hourly rate?

 

The battery is fine I’ve even used a jump lead to another battery aswell as a jump pack. I’ve tried the screwdriver trick to the solenoid and still nothing. Only thing that’s left is the starter motor itself but I don’t get why it was fine before and all of a sudden it’s not even trying I’ve already tried giving it a tap but still nothing

trouble is with wiring also. I can see any of the diodes or wiring to things like the side stand switch etc

 

I'm gonna guess with the poor quality wiring job that you've shown us already that that stuff is long gone. If the bike ran already then I can assume it's not necessary with the current wiring.

That's usually how a starter goes, you might be able to remove and spin the starter over to get it working again but that'll be temporary. I have an old golf cart that does the same.

Back to your issue, do you have a timing light? You can hook that up to each coil (plug 1 then plug 2) and hit the ignition rotor to see how consistent your spark is and if it's advancing. If the spark is erratic then you know you have an electrical wiring or component issue. Also like Rooster mentioned keep the components matched if you can.

Are the starter jets in the carbs clean? In the well in the bowl there is a super tiny jet that gets plugged easily. If those aren't clean it'll be hell to start.

I'm still betting on a fuel issue if the symptoms aren't consistent. You mentioned PODs and "other alterations". What else is done?

 

I’ve been through the starter jets everything is clear and how it should be.

the trouble is, this bike has never been properly rode since it’s been built. When I got it the bike had 0 miles on the clock and the customer has only ever had it ticking over it just leaked fuel

 

Built or rebuilt ? This picture suggests the bike has quite a few mile on it since it left the factory.




if you're confident about the fueling and valve clearances then I would concentrate on those shoddy electrics and starter motor.. OR ..hand it back and
tell him its taking too long to fix economically.