Cylinder compression bad?

[foreda]

Mechanic

foreda,
his words to me (paraphrased) were:
#2's compression is less than half what it's supposed to be.

I would guess he knows what it should have been, but "never assume", right?

Still disconcerting if one cylinder is woefully less than all the others.

He then went on to tell me to take the bike back and soak it in something (I thought trans fluid, but I may have remembered wrong) for about a MONTH!

I assume he was telling me to soak the cylinder somehow. I read MMO and saw on here something about Seafoam. Not sure I am armed with knowledge enough to consider those as options.

Im leary about running it at all right now. If it is a problem in the cylinder, the last thing I want to do is make it worse by riding it. I will likely borrow a trailer and drag it home. This is all based on my meager understanding of possible problems.

He did tell me that at least one boot is cracked through completely. He pointed out the boot on the second from the right carb (as you sit on the bike) as having a hole that was obvious when engine was running. I couldnt see it since I was holding the clutch on the other side. What cylinder is THAT boot to? Where did I put that manual again?

This guy is supposed to be an honest, knoweldgable mechanic, but Im struck by his lack of enthusiasm to tackle anything.

He may very well know what the compression is suppose to be but I bet the bike is probably older than he is. The thing is to not panic. As far as the carb boots go, these are easily attainable, as a matter of fact I am about to auction off a really good set on ebay sometime next week. I will post them here to my fellow bretheren before listing on ebay. Tell us more of what you know about the bike.. Did it sit up for a while, if so , then it may be a matter of stuck rings of which it may just need a little riding(I prefer using Marvelous Mystery Oil for soaking). The cracking and popping could very well be caused by the carb boots, like I said, that's an easy fix.
There are other members located in Florida that may be able to help you out with getting her going. Like I said, don't panic, these old machines are not that complicated to work on.

[Redshirt]

I must assume the bike has been sitting in the POs garage for no less than a year. Possibly 2. Any work he tried to perform was likely in the first year he had it of the 3.

foreda, Im very interested in the boots if they'll work on a 79 Special. I will watch for your post.

I have a local friend who just offered to help me open up the top and take a look. He has experience with valve replacement and seems convinced it might be a sticking ring also. Im encouraged by the support you folks are shooting my way and now that I have a pair of hands to help me in person, Im feeling my anxiety levels drop.

Is it a bad idea to duct tape the boots temporarily? or am I playing with fire by doing so?

Keep in mind, Im also on a quest for an airbox if anyone has one laying about.

[foreda]

Boots

I would not use duct tape, I would use silicone and let it cure good. I will let you know about the boots when I get home possibly on Saturday. I am trying to fly home but weather sucks so I am stuck!!

[slow mo]

carb boot fix it works as have done this on my bike!! buy a spray can or 2 of a product called ;;plasti-dip;; black ! i used a small brush and painted them 10 times allowing a hour between to dry cost about 20 bucks and available at most hardware stores it works and looks ok too,,ride safe ,,slow mo!

[TopCatGr58]

Hey there Redshirt,

Glad to see you made to the site, and have already met many of the folks that make this site great!

Don't be afraid of riding the bike, running it with that low cylinder won't hurt it as long as you don't run it and keep it at 7krpm! Again, no aspersion to the paid mech, but we can't assume that he did the comp test totally correctly...that is with the THROTTLE HELD WIDE OPEN!? I forgot that after a few years, and tested mine, and found them very low on a few! Then remembered I needed to CRANK the throttle plates wide open, after doing that, the levels came up quite a bit!! If your friend is mech handy, perhaps he will have a comp tester you can use/borrow to retest it!?

Yes, MMO is the stuff to soak the top end/rings, but with it being GARAGE kept, climate controlled in FLA....I don't necessarily think it has stuck rings! A quicker way to clean/degrease the innards of the engine without having to wait a month is to first, make sure it has enough old oil in it...see manual, centerstand, site glass level check! Then add about 1/2 bottle of MMO to oil. Start bike, idle it to normal operating temps...put a fan in front of engine to help prevent overheating. The warm up can take 5-10 minutes. Don't REV the engine much, or drive it, NO LOAD on the engine while the MMO is in it, just mostly idle with a little blip or so. Then drain oil/change filter, this will clean the stored oil sludge from the engine, clutch plates, etc....oh yeah, on center stand, operate clutch and roll thru the gears a bit letting rear wheel spin a bit.

As to the PREMIUM gas, that makes me think that perhaps some of the other cylinders may have a fair amount of carbon buildup, from infrequent riding, and probably running in very low rpms, not running it at 4K + for any decent extended time...like highway trips/speeds. And this can contribute to excessively higher comp levels, and could then require the higher octane gas that wouldn't preignite as quickly under the abnormally higher comps!

Also, if it wasn't properly tuned, as well as JETTED with the Indy filters, that could also cause performance issues that they treated with hightest!

The intake boot can be temporarily sealed many ways. There's some nifty rubber plumbers tape I found at LOWES, that combined with the aforementioned silicone sealant can make a good airtight seal, but still recommend double checking the boot once you take the carbs off to clean!! The separation between the inner and outer layer is significant.

So...getting it cleaned up, tuned up, and you'll have a great investment.
Read the thread in the tech section by Trbig about the cam chain tensioner and getting defeated...I'll do a search and add the link to it to this post soon. It's rare, but doing the cam chain tensioner adjustment can cause a problem if done incorrectly!

T.C.

Important thread to read regarding cam chain tension adjustment: http://www.xs11.com/forum/showthread...light=defeated

[Redshirt]

Thanks again everyone.

Ok so I understand this correctly:

1. Put a teaspoon of MMO IN the cylinder in question (and replace plug)
2. a quantity of "half a bottle" of MMO added to engine oil (ive seen rectangular cans of MMO that are approx a quart. That bottle?)
3. Wrap the boots (temporarily)
4. Drive it home (without prolonged 7k rpm) [short city drive in traffic so it wont be fast anyhow]

Now once I get it home, I need to beg/borrow a compression gauge and test again(following service manual proceedure).

If the compression come up, that indicates possibly stuck ring (?)
If the level doesnt, Im going to bug you fellas again

Also I will be on a mission to clean the carbs. Ive never done it, but it looks to be less daunting than other things (did one of you just laugh?).

Im already on a quest to find an airbox and a filter to dump the pods. Coincidentally, if anyone wants them, theyre new. When I replace them, I will put them up for grabs.
Once I get the carbs cleaned, airbox and filter (stock), Oil changed, boots replaced, check other fluids, I plan on sync and tune. Is this plan flawed in its order of execution?

Oh and the cam chain tension adjustment.

[natemoen]

Here is a thread to follow for the carb cleaning.

http://www.xs11.com/forum/showthread...b+cleaning+101

Let's see if this link works, ebay has several airbox units right now, some reasonably priced and some not so...

http://shop.ebay.com/?_from=R40&_trk...All-Categories

Here are some carb boots.

http://cgi.ebay.com/ebaymotors/YAMAH...Q5fAccessories

May as well get a k&n filter if your looking for a filter too. It is filter YA-1400

Your plan of attack sounds good, just don't expect it to go as easy as it sounds though they never do! Ask questions, its how we all learn and its much easier to ask before hand than to wish you had afterwards!

[mack]

Biggest Problem

The biggest problem your going to face in the future is catching the bug. Sure you start by just fixing it up till it runs good, then you sit and look at it with drink in your hand and think, that wasn't too bad. Next winter I should clean this, do that. Then once this bike is finished you see an ad someplace for another XS for a good price that needs some TLC and you just can't help yourself. Next your convicing the wife that the garage just isn't adequate. You really should have a work shop for all the garden tools, lawn mowers and daddy toys so HER car won't get scratched.

[Ken Talbot]

...you see an ad someplace for another XS for a good price that needs some TLC garden tools, lawn mowers and daddy toys so HER car won't get scratched...

Or, if you're really lucky as some un-named members are, you find one for free in a barn, or get given one for free "just to get it out of my yard", etc, etc. Next thing you know, your signature line takes half a page.

[Ken Talbot]

...you see an ad someplace for another XS for a good price...

Or, if you're really lucky as some un-named members are, you find one for free in a barn, or get given one for free "just to get it out of my yard", etc, etc. Next thing you know, your signature line takes half a page.

[DAVINCI]

Thanks again everyone.

Ok so I understand this correctly:

1. Put a teaspoon of MMO IN the cylinder in question (and replace plug)
2. a quantity of "half a bottle" of MMO added to engine oil (ive seen rectangular cans of MMO that are approx a quart. That bottle?)
3. Wrap the boots (temporarily)
4. Drive it home (without prolonged 7k rpm) [short city drive in traffic so it wont be fast anyhow]

Now once I get it home, I need to beg/borrow a compression gauge and test again(following service manual proceedure).

If the compression come up, that indicates possibly stuck ring (?)
If the level doesnt, Im going to bug you fellas again

No, the oil in the cylinder is done DURING the compression test to identify what is causing the leak. I'm not saying that the MMO won't help free up the rings, I'm saying find out the issue, then you'll have the knowledge to address the problem.

[Redshirt]

ah Thanks for clarification.
I also noticed I had my order wrong. First thing to do is drive it home (i.e. no load with MMO in oil...)

Then I can go about testing the compression. If I bought a compression tester, will I go insane trying to use it? or broke?

Im already getting "the bug". The wife is already convinced to get a bike shed (we dont have a garage and HER bike needs a cozy home). Dont think I havent already looked for a "parts bike".

The first step to recovery is admitting you need more bikes.

[DAVINCI]

You should be able to get a decent one for under $50 at a chain store, like Auto Zone or Advance. You got both in Titusville.

[xsroadrunner]

Also be aware that any removal of the carbs will require you to have them re-synched as well. There are other members in Fla. maybe some are close to youand might be willing to share their expertise. good luck with it.

[DGXSER]

Thanks again everyone.

Ok so I understand this correctly:

1. Put a teaspoon of MMO IN the cylinder in question (and replace plug)
2. a quantity of "half a bottle" of MMO added to engine oil (ive seen rectangular cans of MMO that are approx a quart. That bottle?)
3. Wrap the boots (temporarily)
4. Drive it home (without prolonged 7k rpm) [short city drive in traffic so it wont be fast anyhow]

Now once I get it home, I need to beg/borrow a compression gauge and test again(following service manual proceedure).

If the compression come up, that indicates possibly stuck ring (?)
If the level doesnt, Im going to bug you fellas again

Also I will be on a mission to clean the carbs. Ive never done it, but it looks to be less daunting than other things (did one of you just laugh?).

Im already on a quest to find an airbox and a filter to dump the pods. Coincidentally, if anyone wants them, theyre new. When I replace them, I will put them up for grabs.
Once I get the carbs cleaned, airbox and filter (stock), Oil changed, boots replaced, check other fluids, I plan on sync and tune. Is this plan flawed in its order of execution?

Oh and the cam chain tension adjustment.

Compression test is, pull all 4 plugs out, put compression gage into one cylinder and test, crank the engine around 4-6 times the needle will stop moving. Note the pressure. repeat for the other three.

Next, if one is really low as stated, put about two teaspoons of regular motor oil in the cylinder, put the compression gage back on that cylinder, retest. If the pressure goes up, you have rings not sealing, if not, you have have valves not sealing.

If it is a valve issue, first step is reshim the valves. Check the service manual for how. If it is rings, follow the info on MMO to free them up.

If it were me, I'd focus on the compression and get that resolved before you go digging into carbs and such. The biggest thing to watch out for on the carbs is the float post. If the pins are even slightly stuck, I'd make the tool Ken has posted before. I made on form a piece of aluminum angle stock. Best time and money I ever spent! I am sure it saved me a few broken post on the last set of carbs I worked on.

When you have it ready to ride, pause a moment and look in the manual and do ALL of the service items listed.