XJ750 Seca Starter Stats and Opinions

Hello (again
I'm still trying to figure if I should buy a Seca or not. If it had a kickstarter I'd buy it w/o much hesitation. In fact, if this were 1985, my Dad and I might design a kickstarter and sell them for this mostly otherwise great bike.

So, I'm trying to figure out WHEN, or maybe IF, I will have to push it to start it. Conveniently, Yamaha forgot to add a kick starter, which is the saving grace to start any bike, whether it be because of a dead battery, or a starter (clutch) that fails.

So -

* will ALL Seca clutches fail at some time or another, or only a percentage ?
* depending on the above answer, about how many miles/starts should I expect out os a Seca ?
* Will the clutch fail gradually, allowing one to get somewhere besides the side of the road, or all at once ?
* will they fail (see above) more likely when the engine is cold or hot ?

I still can't believe Yamaha designed it so the cases have to be split.

M

 

Generally if regular oil changes are done, with correct oil, the starter clutch should virtually last forever in any bike.
This is of course if your bike starts quickly and correctly, rough or long starts are the worst enemy of a starter clutch one way bearing.
Also, any large displacement bike I've seen, is nearly impossible to start with a kicker, even when warmed up, which is why they were phased out.

 

Harlety's used to be KS only...I remember Dad's friends kicking them. I also used to KS a Maico 490, which is an ankle breaker done wrongly, so a 750 Seca should be EZ in comparison. I've also been starting my 750's with a KS for 30 years or so. I start my XS650's with a KS all the time, as well as my H1's, as well as my 750 BMW's...piece of cake. used to have a 750 that after warmed up, I could it over by hand! I would use a KS on a Seca 750 when it's on a hill, not level, cold maybe, but I'd have no prob starting it, especially of the elect one is broke. No excuse not to include one.

I have a rule of thumb in 55 years of riding...if I can't kick it over, I shouldn't be riding it.

This is progress they say.

 

My CB 750 K2 was easy to kickstart as was the Z1. I think the kickstart is the most reassuring piece of metal on a bike.

 

I'd say less than 5% of the engines have a failed starter clutch, and as Colin pointed out, incorrect oils (or any additive with a friction reducer in it) will tend to render the starter clutch (and the clutch plates) inoperable..........however, such a problem can be remedied, usually, via multiple oil changes and/or engine flushes with some type of solvent.

The 2nd biggest killer of starter clutches is poor tuning, etc. and the hard starting (lots of cranking) associated with it......this puts an incredible strain on the starter clutch housing and components.

Although the clutch could have been designed in other ways..............for example, putting it on the starter motor itself, or somewhere external to the engine case, and using a direct drive to the countershaft via a chain or gears.........this would make for a mighty bulky starter motor and, I assume, much added expense. And a much more costly starter motor, which actually do fail at a much higher rate than the starting clutch.


However, even more common than starter clutch failure is PRIMARY CHAIN GUIDE failure, it's hard rubber and can eventually start chunking off bits which then get everywhere, and fixing this also necessitates an engine split to remedy. Again, this depends on maintenance and, perhaps even more than the starting clutch, the luck of the Gods to determine when, or if, its number comes up short........

 

Mine slips sometimes only when hot hit a few times and it starts ,eventually I will tear into it , I have a spare engine to swap in . If your battery is fully charged,carbs synched and clean , starter brushes in good shape you can expect to get alot of mileage and use out of bike. Sorry to say 30 plus years eventually might require splitting case and repairing, should it scare you away my answer is not me " no guts no glory" the upper right corner of the page is xj4ever he will have the replacement parts . Cheers