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-   -   xt600 3 aj head and barrel (https://www.horizonsunlimited.com/hubb/yamaha-tech/xt600-3-aj-head-barrel-59532)

kenymact 4 Oct 2011 05:03

xt600 3 aj head and barrel
 
So I,m thinking of changing the barrel and head on my 86 tenere 1vj model.....I understand the 3aj had a modified cylinder head and 30 percent more fin area for better cooling- can I fit the 3aj head and barrel to my 1vj engine or can I get away with just using a 3aj barrel only?....all help welcome...

Mezo 4 Oct 2011 09:55

Good question. http://www.tenere.co.uk/forum/images...s/popcorn2.gif

Mr Lambeth? over to you.

Mezo.

dblunn 12 Oct 2011 12:35

I asked the same question some time ago. Change the barrel and head if you can. The studs on the 3AJ head are set further apart and there is an extra 6mm bolt at the front of the cam chain enclosure, Dave Lambeth told me that you can grind/file the stud holes a bit oval in the barrel to make the head fit. The base to crankcase interface is the same so a head plus barrel swap is easier.
Regards, Dave

kenymact 14 Oct 2011 22:31

Hi Dave, e mailed dave lambeth and he told me I need to modify my barrel on the ivj and use high tensile bolts.....I ll e mail him again on more mod info and if I can buy the bolts from him.....

Mezo 15 Oct 2011 07:40

You could always weld on some fins (enlarge what you have) the old fella used to do this for the classic race guys back in England it works, but your better off saving money & finding a scrap head off an early Maico or one of the other old school air cooled heads from back in the day, chop them off & file to suit & take it to your local welder & bobs your uncle, 40 or 50% more cooling.

Heres a Maico 250 head (with loads of metal) :thumbup1:

http://thumbs1.ebaystatic.com/m/mhTv...Q3AITw/140.jpg

Mezo.

skip 15 Oct 2011 09:16

Hi you can put the 3aj barrel straight on to a 1vj bottom end but you have to use a 3aj head with the barrel and bewere do not over tighten the head bolts as it is easy to pull the threads make sure you use the proper copper washers with the bolts, you should not need stonger bolts but if you do use them the i would helicoil the threads. hope this helps Skip

Mezo 16 Oct 2011 09:27

Other things you can do is fit a hugger front guard like the factory did with the 3AJ, and use the oil cooler off the MK2 3AJ (twice as big).

Was wondering why you need all this in Kiwi? i lived there & its freezing cold not hot.

Mezo.

Von Trippenhof 16 Oct 2011 20:59

Quote:

Originally Posted by Mezo (Post 352617)

Was wondering why you need all this in Kiwi? i lived there & its freezing cold not hot.

Mezo.

For my tuppence worth, what he said.

I live in the uk and my 3AJ (with the big cooler) runs noticably more efficiently in hot weather than in the winter - about 40-50 more miles before switching to reserve. My riding is pretty similar all year.

Am going to blank off some cooling this winter and see if it improves things. There's no thermostat, remember.

Also, the bike has already made 20+ years. Probably not too bad...

kenymact 17 Oct 2011 22:52

This came about due to the head gasket blowing....I thought it was a cooling problem but its a design problem,I ll wait on the reply from Dave Lambeth and just modify my own 1vj head and then bin the oil cooler too........


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