not long had a 3tj 1989/90, import, rather disturbing seeing all the peeps putting 600 lumps in, is there anything basically wrong with the 3tj, reliability, etc?mines only done 16000 k,s ,any advice appreciated,!

I'm unaware of there being anything wrong with the 400.
Think you'll find the multitude of 600 swops is all about getting some extra urge in such a lovely little bike.

One reason that a lot of people are fitting 600cc motors to their FZRs is because good 600cc engines are more readily available and cheaper than good 400cc lumps.
Another reason is that there is a substancial increase in reliable horse power to be had from doing this relitively easy transplant, which is always good.

Change your engine oil regularly with good quality oil and a genuine Yamaha oil filter, get the valve clearences checked, and let the bike warm up properly before you thrash it and you shouldn't have too many problems.

thanks lads, youv,e put my old mind at rest, i,m freshmans dad, and 68!!with a 3tj, and a fzr250! hope nobody minds me coming on, but can,t register, as our email addy is the same!!

400's arent any more realible than 600's. It's just that 400's are a little more scarce and hence are more expensive to find a good 400. Also the 400's lend themselves very well to thrashing around, and as oolit said, if you don't let then warm up and start thrashing em cold (which unfortunatly happens alot) it'll cost you a bigend or a gearbox.

If you take into account the age of the bike then the engines are very reliable. There was an issue with oil supply to the big ends but that was mainly race bikes. I'm not saying they're mainenance free - no bike is, but as long as you look after it the TJ will take a lot of punishment.
The 600 swap is a way of getting cheap power. While people put a can on and may get 1-2 hp difference a 600 will take the TJ from 55 or 60 up to 80 or 90 and because the 400's have alloy frames they're about 20kg lighter than the 600. Basically you get a bike that's more sporty than the ThunderCat but not quite an R6

I spent Sunday doing about 200 miles on my 3TJ with my mates on Thunderaces & thundercats.

It was on full throttle for about 25% of the time and never missed a beat.

So I would say it's pretty reliable.

thanks for all replies, here,s my babies..

As many have said no probs with the 400 but a standard 600 is faster and more reliable than a tuned 400. The 400 is such a wonderfull bike and it handles the 600 motor superbly. When i was at the last performance bikes trackday i suggested to Matt Wildee that he could do a back to back comparison with his r6, to which he replied "your fzr will run rings around the r6".

That would be interesting huh ??? to see if the R6 really is so far ahead ???
I doubt that the FZR4/6 would win though ... but would it be close enough to get an article from ???