Triumph Manual wrong

[beezerboy]

hi.... new guy here. I just bought a 96 Tiger (just in time for winter in AK). anyway, it came with a bunch of stuff including the Triumph factory manual. I was thumbing through it & noticed the instructions for fitting valves to the seats is confusing and actually wrong in at least one place. if you grind the seats how they tell you they may not fit right.  check pages 3.18 and 3.19

the 45* major face angle cutter cleans up the seat and ALSO moves the valve contact line out towards the margin. in the last diagram on 3.19  they show a 60* cutter performing that  task but that is wrong. the 60 (when used on 45* seats) sets the final width of the seat.

order of operations would be to clean up the seat with the 45* cutter.  then, adjust the contact between valve and seat with the 30* cutter. the more 30 you put on the seat, the farther the contact line will move down the valve face (toward the stem). once you have your contact where you want it, you check the seat width. if it's too fat, you use the 60* to narrow the seat face.

thats your standard 3 angle grind on a 45 degree seat.  many vehicles use 30 on the intakes and there are other angles used for racing or special applications

[nickjtc]

From south of your border. (The one that will hopefully not end up with a wall. :icon_wink:) I never got into this with my '96 so will be interested to hear what the others say.

[Beernard]

From a bit further south. Thanks for the info. Sounds like you know what you are talking about. Hope your steamer days are as good as mine. Although, my blue girl was in bits yesterday when we had a major get-together. The local fun-police are trying to establish ridiculous speed-limits on our local hill.Its a crackin ride (google Oxley Highway). The same fun-police have done this to a number of our best roads around the country in recent years and should face the firing-squad for their efforts. Anyway, hope you don't have this poor behaviour going on in your area. Its also got nothing to do with the subject! All the best.

[threepot]

I'm hoping to fit new inlets to my super3. I know I'll need to 'lap' them in,but depending on the condition of the 'seats',I may have to cut ? Or will 'lapping' be sufficient?

[Sin_Tiger]

They should be "cut" after you fit them to get them set to the guide centre, then they should only need a quick "lap" with the new valves. Most machine shops will do the cutting after fitting the seats, although they might ask you for the angle specs

[threepot]

They should be "cut" after you fit them to get them set to the guide centre, then they should only need a quick "lap" with the new valves. Most machine shops will do the cutting after fitting the seats, although they might ask you for the angle specs

I was under the impression I only had to replace the valves? Thought the  'soft' valves caused the problem,not the 'seats'?
When I spoke to Clive Wood,he didn't mention replacing 'seats'. Only 'lightly' lapping the valves? Suppose I'll have to see what the head looks like..when I get around to it!

[beezerboy]

you may get by with a lap, depends on the condition of the seats... sometimes they get beat out of shape as well as the valve. if there is any pitting (common on exhausts) then they will need to be re-cut to clean them up. any time you replace a seat or a guide, the seat will need to be cut to re-establish concentricity.

if both the seat and valve are properly cut there is no need to lap... they don't lap valves at the factory.  and some valves are coated & lapping destroys that coating. (not running titanium are you?)

lapping compound can only do so much. long ago, low on money & needing to fix my car for a cross country move, I used old valves & coarse compound with an electric drill to "recondition" the seats & then lapped in new valves. it worked

if you do you own & lap, test by installing the valve & pour kerosene in the port... if it leaks through, it needs more work

if there is any doubt, it's best to re-work them & make it right since taking the head off is a pain.

[Sin_Tiger]

Sorry mate, I read "inserts" where it was actually "inlets" 

[threepot]

Sorry mate, I read "inserts" where it was actually "inlets"