intake and exhaust valves needed

[cdwl7]

Hi guys,

on my 81 xs11 special

so I am not sure how, but my cam chain slipped on the gears and the bike went a 180 degrees out of time, and had no compression. After sitting for a couple of weeks I pulled the top end off, was checking my valve clearances, which were all off. In the process realized that i had several bent valves, assuming that it happened when the cam chain slipped, as it was making some serious clanging noises.

So i take the head over to my bike shop, and discovered that some of the valves are discontinued. Does anyone have a source for the valves aftermarket, or have a used set in good shape they are willing to part with?

I hope to replace the valves, get the head worked over, replace the cam chain and reshim the valves asap.

As always any help is greatly appreciated.

Thank you, Darrell

[SFerinTEXAS]

Hi guys,

on my 81 xs11 special

so I am not sure how, but my cam chain slipped on the gears and the bike went a 180 degrees out of time





Thank you, Darrell

always a devils advocate. That is not possible. Maybe a tooth. Should just ask for valves without the story.How many do you need?

[cywelchjr]

Additionally there are only two valves, intake and exhaust. Last I had heard the late model valves were still available, however, Geezer on the site has sourced aftermarket SS valves that are actually superior to the originals. Normally they only skip a few teeth which is all it takes to bend a bunch of valves on these engines, and all that takes is the cam chain adjuster which is the weak point in the system to slip and let the chain loosen under operation and boom, bent valves. Many on here are now recommending replacing the adjuster with one off a Venture Royale, which is self adjusting and will NOT slip, does NOT ever again need adjusting and will keep this from happening again.

[crazy steve]

Here you go....http://www.oregonmotorcycleparts.com/Valves.html

This is the same 'Geezer' that Cy mentioned. You could send him a PM to see about what he has in stock.

[SFerinTEXAS]

Depending on how many valves you need it may be better to get another head. Put an inquiry in WTB thread. There are several people in your neck of the woods.

[bikerphil]

If Geezer can't help you out, try here, look under motor parts...

http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

[Jarion]

Since we're on this subject...
I'm still adding lead to my gas.... because the owners manual (which came with the bike) says the bike requires it.
What say you guys?

The cam chain adjuster is a weak point in the system? - interesting and concerning at the same time (for me).

[DGXSER]

I have yet to add lead to the fuel.

As to the cam chain tensioner, it has been problematic. A weak point, well, sort of.

Basically, the stock tensioner depends on a bolt through the side to apply force, through torque, which ain't alot, to the tensioner to hold it in place. Under heavy loads, like running high RPMs and such, the tensioner can slide against that bolt and loosen a bit. Thus the need to check and retighten periodically. Also that bolt and or its lock nut have been known to strip out, and as infrequently as one might hope. So you have to go gentle on them. Kind of tough to apply the torque and go gentle.

Bad thing is, this is an interferance engine, so if the tensioner loosens to much, the chain slips, and good valves go bad!!

[tcoop]

I have been running my 78 on 87 oct without any additives and it runs just fine.

When I got mine I adjusted the valve shims and the cam chain tensioner. The next timer I revved the engine the cam chain slipped and bent 3 intake valves.
Got a set of intake valves from Geezer and it's been running strong since.

EDIT: I also changed to the auto adjusting tensioner.

[Jarion]

Thanks for the info.

[crazy steve]

Since we're on this subject...
I'm still adding lead to my gas.... because the owners manual (which came with the bike) says the bike requires it.
What say you guys?

I'd like to know where you're finding that info... my owners manual and service manual makes no mention of leaded or unleaded fuel, merely noting that 'regular fuel' is required. Surprisingly, no mention is made of a minimum octane requirement.

Now, when this bike came out leaded regular was still commonly available but everyone knew it was on it's way out; they'd already started reducing the lead content in some gas. The big issue with running unleaded in a 'leaded' motor at the time was the cast-iron heads of the day with their unhardened integral valve seats would suffer exhaust valve seat problems under certain conditions, usually extended high loads. The XS, with it's pressed-in steel valve seats, is immune to this. As the phase-out date for leaded got closer (and the amount of lead in the fuel got less and less), they improved unleaded with additives until most pre-73 vehicles could run it with no issues.

I'll admit I ran leaded regular in mine the first few years, but mainly because the early unleaded fuel had a slightly lower octane rating and the bike performed slightly better on the higher octane fuel. I switched when the octane came up, as unleaded is less prone to carbon build-up and it extends spark plug life. These days, regular unleaded is all you need unless you're stuck with a ethanol blend, in which case you might need to step up to a mid-grade. No additives needed....

[cywelchjr]

I'd like to know where you're finding that info... my owners manual and service manual makes no mention of leaded or unleaded fuel, merely noting that 'regular fuel' is required. Surprisingly, no mention is made of a minimum octane requirement.

Now, when this bike came out leaded regular was still commonly available but everyone knew it was on it's way out; they'd already started reducing the lead content in some gas. The big issue with running unleaded in a 'leaded' motor at the time was the cast-iron heads of the day with their unhardened integral valve seats would suffer exhaust valve seat problems under certain conditions, usually extended high loads. The XS, with it's pressed-in steel valve seats, is immune to this. As the phase-out date for leaded got closer (and the amount of lead in the fuel got less and less), they improved unleaded with additives until most pre-73 vehicles could run it with no issues.

I'll admit I ran leaded regular in mine the first few years, but mainly because the early unleaded fuel had a slightly lower octane rating and the bike performed slightly better on the higher octane fuel. I switched when the octane came up, as unleaded is less prone to carbon build-up and it extends spark plug life. These days, regular unleaded is all you need unless you're stuck with a ethanol blend, in which case you might need to step up to a mid-grade. No additives needed....

I too see no reference to leaded gas in the owners manual. Now to be fair, it's for the H model, but that engine is pretty much identical to the G model engines except for the centrifugal timing being moved to the TCI, and my engine actually IS an H engine.

[Jarion]

I'll dig the manual out of the back of the Bike and review.
It's entirely possible that my interpretation of "regular fuel" is related to my age.
This bike always get's the highest octane available at whatever station I stop at.... but it also gets a splash of lead from a bottle as well.... and that's because of my concern for the valve seats.....

It's always a good day when I learn something new (which is about every day).... the reality of "splooge holes" was a GREAT day....
Sounds like I may be learning something new on the fuel for this bike... which may prompt an additional beer that I owe you.
JT

[crazy steve]

It's entirely possible that my interpretation of "regular fuel" is related to my age.
This bike always get's the highest octane available at whatever station I stop at.... but it also gets a splash of lead from a bottle as well.... and that's because of my concern for the valve seats.....

Heh heh... yeah, 'back in the day' it was 'regular' (which was leaded) and that new-fangled 'un-leaded' which had a slightly lower octane rating.

The common 'fix' for pre-74 motors (that was when unleaded became required for most vehicles) was to install new steel exhaust valve seats and valves compatible with the new seats; which the XS had from the factory.

As far as using higher-octane fuel, you're wasting your money there too. As octane goes up, the actual energy content in the fuel goes down. I tried running premium in mine fairly early on, but saw no performance gain and a decrease in my mileage (1-2 mpg). To take advantage of the higher octane, you really need to bump the compression ratio up (new higher-dome pistons or a big-bore kit). If the bike runs poorly on regular or mid grade fuel, then you have a problem with carbon build-up in the combustion chamber or your timing is too far advanced.

[cywelchjr]

I find mine runs best on mid grade down here in Ca. That may not be the case up there in Wa, as the gas quality varies from area to area for sure. I know it even varies from brand to brand, and for all the bad press often given to Arco/BP gas, I find the Brutus actually seems to run best on either that or Chevron (mid grade for both) although he does seem to like 76 gas as well, but there are not nearly as many of those around. They do have one with race gas which is actually real gas, but unfortunately the octane it also too high for me to take advantage of.