another cam question - removing cams?

[barwel1992]

ok i know how to remove the cams, but what i want to know is can i remove just the exhaust cam without removing the intake cam

and i have read that you can just screw in the cam chain tensioner with a screw driver and then clamp it in place (or get some one else to hold it) so you don't have to remove it at all from the casing

or can some one tell me the best way of removing and refitting the tensioner without the special tool

[TazDaz]

What...maybe I don't understand cams, but I thought it was one thing.

[barwel1992]

theres 2 per head intake and exhaust

http://forum.svrider.com/photoalbum/albums/userpics/10569/timing2.jpg

[TazDaz]

I don't understand the SV cams then...you can tel I've not had mine apart. I thought it was SOHC.

[barwel1992]

naa double over head cam the front one does the 2 intake valves the rear does the two exhaust valves, the cam chain keeps them both in time with the crank (2:1 crank turns twice cam shaft turns once)

[mjc]

You dont need the tool for the FI engine tensioners. Remove the cap and the spring inside and then you should be able to lift the chain off the top sprocket and remove the camshaft.

You may need to displace the inlet camshaft as well to get enough slack, but you can keep the teeth engaged with the chain.

[barwel1992]

^ knew i should have looked at the manual :lol: cheers thats exactly what i wanted to hear, so i dont need to remove them them thats even more money i have just saved on tensioner gaskets

[ice]

^ knew i should have looked at the manual :lol: cheers thats exactly what i wanted to hear, so i dont need to remove them them thats even more money i have just saved on tensioner gaskets

hi mate... why are u removing your cams?

[barwel1992]

fitting first gen intake cam in my exhaust cam side, should give 2-4bhp extra midrange and top end "apparently"

ps done the swap, had to remove Cam chain tensioner ..... didn't have the gaskets so used silicon gasket sealer on them but will get new ones soon

[beabert]

All that ****ing around and expense for 3bhp lol. I used gasket maker on mine too.

[yorkie_chris]

So did it go crunch?

[barwel1992]

All that ****ing around and expense for 3bhp lol. I used gasket maker on mine too.

what the expense of £30 :p

So did it go crunch?

nope, checked every thing about 5 times :D rode it to the chippy and back and was fine, seems smoother

[hardhat_harry]

Sorry to revive an old thread but I'm about to do the cam swap. On these threads I have not head one mention of shimming the cams are shimms not used or required even putting inj intake cams into a carby engine?

[barwel1992]

mine were fine, fit them then check with a feeler gage

ps you don't shim the cams you shim the tappets

[hardhat_harry]

Isnt it the valves you shim?

Thought tappets were for pushrod engines

[barwel1992]

Isnt it the valves you shim?

Thought tappets were for pushrod engines

no there's a tappet on the sv valves (sits over the spring top and calve stem top) and the shim sits under that on top of the valve spring i believe

[yorkie_chris]

Generally that's called a bucket... the SV being a "shim-under-bucket" engine.
Anyway splitting hairs.

Yes.. you use shims in exactly the same manner with any of the cams available for the SV. Some aftermeerkat suppliers suggest you use bigger clearances but they are adjusted in exactly the same way.

Lots of people find no problem using the stock valve clearances. (0.1-.2mm in... 0.2-.3 ex). Many times the base circle of the replacement cams is exactly the same so it will not change the valve clearances... However it is prudent to check after fitting the new cams.

[barwel1992]

Generally that's called a bucket... the SV being a "shim-under-bucket" engine.
Anyway splitting hairs.


picky bugger ;)

any bikes have hydro tappets like cars ?

[yorkie_chris]

I'm not being picky, just clarifying terms used... might save you some confusion later.

I have not heard of any bikes having hydraulic tappets.

[barwel1992]

I'm not being picky, just clarifying terms used... might save you some confusion later.

I have not heard of any bikes having hydraulic tappets.

:) i have been told they are the same thing, could be wrong though

hmm wonder why would reduce servicing cost's obviously its something else to go wrong though but like car using them it could put the valve check intervals at around 50k

[fastdruid]

hmm wonder why would reduce servicing cost's obviously its something else to go wrong though but like car using them it could put the valve check intervals at around 50k

RPM?



Engines with hydraulic tappets (such as the Buick/Rover V8) often have what is in effect a rev limiter by virtue of their design. The tappet clearances are maintained by the flow of the engine's lubricating oil. At high engine speeds, the oil pressure rises to such an extent that the tappets 'pump up', closing the valve clearance and preventing the valves fully closing. This sharply reduces engine power, causing speed to drop.

also


In certain circumstances, a lifter can "pump up" and create negative valve clearance so that its valve cannot close. Typically this occurs in the most upper rpm range of an engine, and limits the engine's performance. Lifter pump-up is serious, as there may be interference of the valve with the piston or, burned valves may result.


Druid

[barwel1992]

RPM?

also

Druid

cheers didn't know that :)

[northwind]

There's been at least one gp bike with hydraulics but I can't remember what. One of the failures. YC is spot on, check the clearances but hope you won't need to change the shims... SV/Strom cam tolerancing is unexpectedly fantastic even across all the years they've been made and the 3 specs of cams, and wear seems low too.

[yorkie_chris]

There has been some experimentation with pneumatic valve springs, that's the only thing I can think of that's similar

[northwind]

Ah, you're right, pneumatic not hydro :smt092

[yorkie_chris]

I think the only reason for hydraulics is to reduce maintenance intervals, at the expense of adding a lot of reciprocating mass to valvetrain... race engine builders don't care about this, it only has to hold together for a while... but it needs to be very light, so they go for shim under bucket or desmodromic.

[zadar]

Harley Davidson :)

[barwel1992]

^ i was thinking along those lines if cars that rev to 6k and can have hydro tappets why cant big singles and big (1600) twins that only rev to 6ish k

could be used on like trail bikes or stuf like that

[yorkie_chris]

Harley Davidson :)

We're on about bikes... not ploughing fields :p

[yorkie_chris]

^ i was thinking along those lines if cars that rev to 6k and can have hydro tappets why cant big singles and big (1600) twins that only rev to 6ish k

could be used on like trail bikes or stuf like that

Compare thickness of a shim-under-bucket to a hydraulic tappet... consider how big heads on SV would have to be to fit that in.

[barwel1992]

the hydro ones i looked at were only about 5-10mm thicker than the sv ones (will see if i can get a pic)

[yorkie_chris]

Bear in mind in TL1000 they made cams chain AND gear driven just to make engine shorter as it affects wheelbase... length of engine was whole reason for stupid rotary damper too.

When you say thicker... bear in mind that only the very thin (<1mm?) top of the bucket only adds to the "height" of the assembly... whereas a hydraulic one has it's whole thickness which must be above the top of the valve spring retainer.