Yamaha XJ 900f TCI

Hi XJ Owners

I got a spare TCI and there are no identification marks on it and I don't know if it works but here is a picture. Has anyone seen a TCI like this? It has two black wires from the pick up coils and no rev limiter wire on the 6 pin feed from the TCI.

 

Are there any markings on the case?

 

No markings at all k-moe. I bought a spare wiring harness off e bay and the seller gave me the TCI with it. He said he did not know the manufacturer but it worked great on the XJ 900f he was breaking. I think it is from an earlier XJ 900f the one with the air pressure forks. I am tempted to try it on my bike providing I can be sure it won't damage anything. It certainly is not a Yamaha unit.

 

It's not the original TCI, or at least not the original TCI case, for any XJ.

If it were either a factory part, or an aftermarket part, there would be a label on the case to identify it.

The case has a seam, and looks to be held together by the machne screws and nuts.

It's either a homebrew TCI. or a TCI that was repaired and re-cased.

 

Yes k-moe I agree and I have opened the case and here are photographs on the inside of the unit. The man told me it works great but if it was used on the early XJ with the 850 engine will the timing curve be the same as the XJ900f? What do you think? I checked with Carmo Electronics and an Australian Company (I forget the name) and they confirmed it was not manufactured by them.



As you stated it's either a home made one or re-cased. If it works it would be great for me to have this as a spare. It looks as if it was home made.

 

K-moe the company based in New Zealand not Australia was Hyperpak Performance Ignition.

 

Somebody made that. It's not a repackaged stocker.

I don't have specs on the 900, but Hogfiddles probably does.

The advance curves should be pretty close if they are at all different. I'd just swap it over and go for a short ride to see. Take the Yamaha TCI with you so you can swap back while a way from home if needed.

 

Cheers k-moe I think I will try it on the bike cannot do any harm and it might be a great unit.

 

Bike runs great on that home made TCI k- moe whoever built it knew what they were doing.

 

if you could map it out it would be nice to see. but thats not an easy thing to do

 

To be honest XJ550H I would not have any idea how to map it out. Could you explain the basics of how it would work thanks, I know there has to be advance etc and at one time it was mechanically controlled with centrifugal spring loaded weights on car distributors to alter dwell angle. All this must be electronically controlled nowadays. Is this what you mean by the mapping it out to see at what engine revs the advance and retard functions happen?

 

no I mean drawing out a schematic from the layout so it can be duplicated. not an easy task at all. it starts with parts ID then moves to how they connect to each other.
no easy to do .
just thinking out loud mostly.

 

This is not a model I have heard of. There are 550s, 600s, 650s, 700s, 750s, 900s, 1100s, but no 850s. Unless the displacement was lowered in some markets for tariff reasons, like the 700s in USA.

 

There were 2 versions of the 900 one of of them should be really called 850 as it was 853cc in 1983 and 891cc in 1984 onwards.

 

.

 

I thought of that possibility after I posted, but was too lazy to update, plus I didn't know any of the specifics. Thanks.
I guess rounding up is better for sales than rounding down. Ask any guy!

 

550 is only 523cc but a 525 maxim just does not sound right when every one else is selling 550cc as 550. might have affected sales

 

Ok XJ550H yes I see what you mean now.

 

Yes the early 1983 XJ 900f had a handlebar mounted fairing which caused handling problems. When yamaha redesigned the fairing so it was frame mounted the increased the capacity of the engine too according to the Haynes manual.