a question for the xs experts

[DEmily]

Hey everyone,

I am working on an old 79 xs1100 as a few of you might know from my previous threads. I am hours from starting this girl for the first time after a complete rebuild. I have a question for all you xs experts out there. I went to individual air filter and got rid of the air box. Looks real good! my question is: what do I do with the crankcase ventalation? Do I just route a hose down the back of the motor? Will there be enough positive crankcase ventelation?

Also, no that I think about it, what is a good protective coat to put on the tank to protect it against gasoline splashes? We did my wifes Kaw 454 with Duplicolor clear coat and it did not do well when she got a little careless with the gas.

Thanks a ton for all the help you guys have given.

Dan

[Snow]

You need to put a filter on the end of that hose as not only does it blow excess pressure out, but sometimes sucks air in.

[xssiveone]

Re: a question for the xs experts

Originally posted by DEmily
Also, no that I think about it, what is a good protective coat to put on the tank to protect it against gasoline splashes? We did my wifes Kaw 454 with Duplicolor clear coat and it did not do well when she got a little careless with the gas.

Clear polyeurethane works pretty good for this. This may also be sold under Plasti-Kote or something similar. A lot more impervious to gas then plain clear coat.

[Hobbit]

Clearcoat

I talked to the people at Duplicolor and they recommended using the high temperature engine clear coat that they have. It is not impervious to gas, but it is more tolorant than regular clear coat.

[Bud Manley]

I've found that a nice coating of rust, dirt or both will usually soak up those pesky gasoline spills.
DO NOT use Duct tape to patch a gas tank though. thats a bad thing

[newmaac]

I use an inline fuel filter to put on the end of that breather hose.
They are cheap, and with a little creativity, you can hide it well.
Just don't forget to change it! The paper element in the filter WILL clog-up and stop breathing.
I pop in a new one at each oil change.
The size of the breather tube is larger than most fuel filters. I just took a small pc of 3/8"hose,(about an inch long), and put it on the filter end, then the ID of the breather hose will be a nice fit over thr OD of the 3'8" hose.

[DEmily]

A question for the experts.

Thanks everyone for your suggestions. I did actually start the beast today and man what a feeling that was!! She did good. Fired right up to my surprise, after just six cranks for the motor.
Took her around the block and MAN does that engine have power!!! I did notice it was a bit slugish at low rmps.

I started the process of syncing the carbs and found that number three and four are not showing much vacuum, I got 18 lbs on 1 and 2 and about 5 to 7 on 3 and 4. I found that strange considering the petcocks are vacume driven and it seemed to run pretty good. I then realized I had the petcocks on Prim so I moved them to the ON position and after a few minutes the carbs on 3 and 4 ran out of gas. I can only assume the manifolds are bad. When I disassembled the bike the manifolds where drawn up to the head without any kind of gasket, so thats how I put them back on. I plan to spray the boots with some sort of starter spray to see if I have a leak.
I guess my question here is: Does the manifolds need a gasket?
I thought it was rather strang that they did not have any kind of gasket.

I thought maybe was suppose to be metal to metal, but that would make is susceptible to warpage.

I checked compression and I have 160 on all four cylinders.

I'm sure you all have been through this. I would sure appreciate any help you old salts could give a newbie to the xs world.

Thanks

Dan

[xssiveone]

Re: A question for the experts.

Originally posted by DEmily
I started the process of syncing the carbs and found that number three and four are not showing much vacuum, I got 18 lbs on 1 and 2 and about 5 to 7 on 3 and 4.

It's not so important "how much" vacuum you have, as it is that all cylinders are "equal" in vacuum. This is what you are trying to accomplish when you are syncing the carbs, to balance, or equalize, the vacuum in each cylinder.

This is not to say that you don't have a vacuum leak, just that it's not uncommon to have a wide variance in readings untill you have them sync'd. It won't hurt to check them with a spray as you describe. As for thr gasket, I've never had a new set of manifolds, but it's my understanding that they have "use once" crush ring on them. If you have to take them off, a thin coating of gasket maker should seal OK.

[Bill]

Re: A question for the experts.

DEmily wrote:

• I did notice it was a bit slugish at low rmps.
• I started the process of syncing the carbs and found that number three and four are not showing much vacuum
• I found that strange considering the petcocks are vacume driven and it seemed to run pretty good.
• I then realized I had the petcocks on Prim so I moved them to the ON position and after a few minutes the carbs on 3 and 4 ran out of gas.
• I can only assume the manifolds are bad. When I disassembled the bike the manifolds where drawn up to the head without any kind of gasket, so thats how I put them back on. I plan to spray the boots with some sort of starter spray to see if I have a leak.
• I checked compression and I have 160 on all four cylinders.

You're on the right track. The "big kick" starts around 4K RPM, but it shouldn't be sluggish off idle. Synching the carbs is critical and should clean up performance across the board.

It doesn't take much vaccuum to open the petcocks as long as the vaccuum lines are good and connected properly. You can check them by disconnecting the fuel line at the petcock and sucking on the vaccuum line (engine off!). You should get immediate fuel flow.

If you have any fuel filters, make sure they aren't clogged.

A very low tank can sometimes fail to deliver much gas. If PRIME works and ON doesn't, try the RESRVE positioin.

You can also get uneven fuel delivery on a low tank if there's sediment at the base of the petcock towers. Make sure there's pleanty of fresh gas when you're tuning.

There's a hard inner lining in the manifolds. They can look terrible and still be air tight. The last time I checked, there was an o-ring in the face of the manifold. But, after 20 years they get hardened. I think they probably continue to work until they're disturbed. As Brian suggested, a thin coat of gasket maker or high temp silicone should seal just fine. Be sure it doesn't ooze into the intake passage when you reattach them.

160 lbs compression on all four is GREAT!

I don't know what you've done on the intake/exhaust system, but there are a couple of things I've learned on these bikes.

• Response at idle and off-idle is largely controlled by the pilot (idle) circuit. It's controlled by the pilot (mixture) screws and the pilot jets.
• Make sure the pilot screws are set evenly. From memory, I think 2 1/4 turns from lightly seated is about right. Check the Maintenance/Carburetors section for more information.
  
• The exhaust system is the other half of the equation. If it's in good shape, then you can ignore it. However, if pipes are rusted out and sound like gravel when you shake them, you have another problem. They'll provide uneven back pressure which has a similar effect to carbs out of synch.

Good luck and keep us posted on your progress!

XSively,

[DEmily]

A question for the experts

Wow!! You guys seem to know soo much about these bikes. I am very thankful that I found this site. I will take all these suggestion and am sure I will be able to isolate this issue. I really can't say how much help you all have been. I hope some day I can give such great advice on this website about this bike.

Thanks again

Dan