LCGB Forums

The ability to post messages is restricted to LCGB members. Any questions contact us at lcgbadmin@googlemail.com

Drive side oil seal .

Need help with a tuning kit, how do you tune your scooter, which kit should I choose, and all general tuning and modifcations questions are for in here.

Drive side oil seal .

Postby neil64 » Sat Jul 27, 2019 8:33 am

Hello.

Seem to have quite a bit of smoke coming from scooter when running ,how do you check the drive side seal is good ?
neil64
 
Posts: 35
Joined: Mon Sep 08, 2014 7:28 pm

Re: Drive side oil seal .

Postby MickYork » Sat Jul 27, 2019 9:05 am

Check your oil level. If your losing oil and unless there's a visible leak the oil seal would be a good bet.

A leak test would be the next step.......
MickYork
 
Posts: 1054
Joined: Sun Jun 01, 2014 8:37 am

Re: Drive side oil seal .

Postby ULC Soulagent » Sat Jul 27, 2019 12:59 pm

Put ur hand ( protected) over the end of the exhaust tailpipe and providing u don’t have any leaky joints then if ur seal has gone then the engine will still run :?
User avatar
ULC Soulagent
 
Posts: 839
Joined: Sun Apr 03, 2016 3:26 pm
Location: Milton Keynes

Re: Drive side oil seal .

Postby Scooterlam » Mon Aug 12, 2019 8:37 pm

ULC Soulagent wrote:Put ur hand ( protected) over the end of the exhaust tailpipe and providing u don’t have any leaky joints then if ur seal has gone then the engine will still run :?

Heard this many times.
Can anyone explain this
Scooterlam
 
Posts: 1280
Joined: Mon Jun 09, 2014 10:59 pm

Re: Drive side oil seal .

Postby Tractorman » Mon Aug 12, 2019 9:14 pm

If the exhaust gases cannot get out the inlet gasses cannot enter. Ramming a potato up a car exhaust was a popular trick!
User avatar
Tractorman
 
Posts: 4323
Joined: Mon Jun 02, 2014 3:07 pm
Location: Lincoln

Re: Drive side oil seal .

Postby Scooterlam » Mon Aug 12, 2019 10:03 pm

So what were led to believe is if the DS oilseals gone and the pipe is blocked. At bdc the exhaust gas is exiting via the opposite transfer into th pc chamber without mixing withor igniting the new charge and out thru DS oil seal whilst simitaniuosly fresh charge iis drawn thru the remaining transfer?
Scooterlam
 
Posts: 1280
Joined: Mon Jun 09, 2014 10:59 pm

Re: Drive side oil seal .

Postby Warkton Tornado No.1 » Mon Aug 12, 2019 10:49 pm

Scooterlam wrote:So what were led to believe is if the DS oilseals gone and the pipe is blocked. At bdc the exhaust gas is exiting via the opposite transfer into th pc chamber without mixing withor igniting the new charge and out thru DS oil seal whilst simitaniuosly fresh charge iis drawn thru the remaining transfer?


It's nothing to do with the exhaust pipe being blocked.

It's all to do with the pumping process of the bottom end. If a crankshaft oil seal fails, particuarly on the drive side, then the primary compression chamber will effectively 'communicate' with the chaincase & suck in oil & air from it in exchange for exhaust products when it is not sucking, but blowing. To sum up, when the engine should be pushing spent fuel gases only out of the exhaust, some will get blasted into the chaincase.

If a drive side oil seal is doing it's job, as quite rightly mentioned, a hand over the tailpipe should cause the engine to falter, or stop.

(I've long since concluded that primary compression, or the raising of it, is not something worth pursuing, particuarly when the engine is being run with good expansion chambers in conjunction with other tuning measures to raise power. I have known people run engines for thousands of miles with a blowing drive side oil seal & they just kept topping up the chaincase until a time of convenience in which to change it.... ;) )
Warkton Tornado No.1
 
Posts: 1383
Joined: Sun Jan 11, 2015 1:27 pm

Re: Drive side oil seal .

Postby Scooterlam » Mon Aug 12, 2019 11:44 pm

Wt1

We must really meet up over a pint and bore the pants off everyone around us. :D
I'm trying to put all the pieces together.
And I'm having trouble with a weeping seal allowing a cylinder to purge a cylinder of enough gas to not allowing ghosting to occur. Or in the case of piston porting the air flow in the ventura stalling as the piston skirt opens the inlet
Scooterlam
 
Posts: 1280
Joined: Mon Jun 09, 2014 10:59 pm

Re: Drive side oil seal .

Postby Scooterlam » Tue Aug 13, 2019 12:32 am

Wt1

We must really meet up over a pint and bore the pants off everyone around us. :D
I'm trying to put all the pieces together.
And I'm having trouble with a weeping seal allowing a cylinder to purge enough gas to not allowing ghosting to occur. Or in the case of piston porting the air flow in the ventura stalling as the piston skirt opens the inlet

BTW thanks for your explanation and hopefully patience
Scooterlam
 
Posts: 1280
Joined: Mon Jun 09, 2014 10:59 pm

Re: Drive side oil seal .

Postby Fast n Furious » Tue Aug 13, 2019 12:49 am

neil64 wrote:Hello.

Seem to have quite a bit of smoke coming from scooter when running ,how do you check the drive side seal is good ?

Warm your engine up and leave it ticking over.
Place a piece of cling film over the breather plug and secure with a tight elastic band. ( you can also use a balloon but this is not usually a part of the wife's tool kit!) :lol:
If it tries to suck the clingy down the breather hole then this is indicative that the chaincase is pulling a vacuum when it should be producing a slight pressure.
If it pulls a vacuum or pulses with each rev, chances are your DS seal or DS bearing is knackered.
User avatar
Fast n Furious
 
Posts: 742
Joined: Sat Nov 19, 2016 3:56 am
Location: York

Re: Drive side oil seal .

Postby Raveydavey » Wed Aug 28, 2019 4:31 pm

Warkton Tornado No.1 wrote:
(I've long since concluded that primary compression, or the raising of it, is not something worth pursuing, particuarly when the engine is being run with good expansion chambers in conjunction with other tuning measures to raise power. I have known people run engines for thousands of miles with a blowing drive side oil seal & they just kept topping up the chaincase until a time of convenience in which to change it.... ;) )


I did just that to get back from Poland. Used over a litre and a half :lol:
User avatar
Raveydavey
 
Posts: 287
Joined: Wed Jan 28, 2015 8:32 pm
Location: Kettering Massive

Re: Drive side oil seal .

Postby Warkton Tornado No.1 » Wed Aug 28, 2019 5:07 pm

Raveydavey wrote:
Warkton Tornado No.1 wrote:
(I've long since concluded that primary compression, or the raising of it, is not something worth pursuing, particuarly when the engine is being run with good expansion chambers in conjunction with other tuning measures to raise power. I have known people run engines for thousands of miles with a blowing drive side oil seal & they just kept topping up the chaincase until a time of convenience in which to change it.... ;) )


I did just that to get back from Poland. Used over a litre and a half :lol:


Ha! Good to see a Kettering tradition continuing. Mind you, with your experience rolling off the throttle & nipping up, you are risking leaning off the carburation with any additional oil.

I would bet that you have Viton seals fitted :?:

With all the scare stories about petrol additives, I researched the 'problems' of the effect upon Nitrile seals as I found Viton not so durable. (If memory serves, the independent (non-biased!) 'research papers' that I found were by an American organisation, probably SAE) I concluded that, all things considered, in the UK we are some way off the additives being an imminent threat to Nitrile, & as I had not had them leak, so continue using them, despite having Viton equivalents to hand. Personally, I think that two-stroke oil does a Hell-of-a-lot to obviate any likelihood of the affects of additives to our engines, a fact substantiated by it's use in older four stroke Classic vehicles to that & other issues that they encounter.

I reckon I may have heard you(!) going down Pytchley Road & guessing you use Tesco's top petrol, which is a good thing. I suppose it would be worth you fitting a new drive side bearing with seals fitted, when you get around to it........ :roll:
Warkton Tornado No.1
 
Posts: 1383
Joined: Sun Jan 11, 2015 1:27 pm

Re: Drive side oil seal .

Postby Raveydavey » Wed Aug 28, 2019 7:17 pm

Warkton Tornado No.1 wrote:
Raveydavey wrote:
Warkton Tornado No.1 wrote:
(I've long since concluded that primary compression, or the raising of it, is not something worth pursuing, particuarly when the engine is being run with good expansion chambers in conjunction with other tuning measures to raise power. I have known people run engines for thousands of miles with a blowing drive side oil seal & they just kept topping up the chaincase until a time of convenience in which to change it.... ;) )


I did just that to get back from Poland. Used over a litre and a half :lol:


Ha! Good to see a Kettering tradition continuing. Mind you, with your experience rolling off the throttle & nipping up, you are risking leaning off the carburation with any additional oil.

I would bet that you have Viton seals fitted :?:

With all the scare stories about petrol additives, I researched the 'problems' of the effect upon Nitrile seals as I found Viton not so durable. (If memory serves, the independent (non-biased!) 'research papers' that I found were by an American organisation, probably SAE) I concluded that, all things considered, in the UK we are some way off the additives being an imminent threat to Nitrile, & as I had not had them leak, so continue using them, despite having Viton equivalents to hand. Personally, I think that two-stroke oil does a Hell-of-a-lot to obviate any likelihood of the affects of additives to our engines, a fact substantiated by it's use in older four stroke Classic vehicles to that & other issues that they encounter.

I reckon I may have heard you(!) going down Pytchley Road & guessing you use Tesco's top petrol, which is a good thing. I suppose it would be worth you fitting a new drive side bearing with seals fitted, when you get around to it........ :roll:


Actually it was a Rolf seal. I now have Viton. I've been using EGT to keep an eye on things so the all day hoon down the autobahn and Dutch motorway on the way to Amsterdam was fine. I have noticed the temp is lower now though. So it was definitely running hotter when the seal was going. It was a weird one actually. On some rides I burned through a load of oil whereas on others not so much. It seemed to be related to the speed I rode. I figured it might have been a twisted crank that ran more elliptical at slower speeds, thereby creating a seal leak which smoothed out at higher revs. Had the crank checked when I got back and it was only a couple of thou out. I guess I'll never know. All fine now though
User avatar
Raveydavey
 
Posts: 287
Joined: Wed Jan 28, 2015 8:32 pm
Location: Kettering Massive

Re: Drive side oil seal .

Postby Raveydavey » Wed Aug 28, 2019 7:22 pm

It might have been me coming up Pytchley road. You can tell it's me by the noise :x :lol:
User avatar
Raveydavey
 
Posts: 287
Joined: Wed Jan 28, 2015 8:32 pm
Location: Kettering Massive

Re: Drive side oil seal .

Postby Warkton Tornado No.1 » Thu Aug 29, 2019 11:41 am

Raveydavey wrote:It might have been me coming up Pytchley road. You can tell it's me by the noise :x :lol:


'She' sounds really fit! VERY torquey, pulling from nothing, fuss free. You must be aching from grinning :D

I've never owned a SI or SII, but freely admit that the curvy bodywork has grown on me, & if the money & time were mine, I'd love to ride a passionate 'unrestricted' Seniorita ( ;) ) once more, in two wheel form.....I must go for a lie down :oops:

As we are on the subject of seals, does your engine have the mag-side seal fitted? In other words, does it run the roller bearing in grease or petroil? Much depends upon the belief (or not!) in crankcase compression, but a reed valve engine such as yours might stand to benefit from having lower crankcase compression, which has the knock-on effect of giving the remaining drive side seal a slightly easier life. Just a thought, & nothing new to some of us :idea:

I hope this makes sense, but my belief is that if a crank is only a little twisted, then it will pump oil via the drive side seal journal, as you found, only over part of the rev range. Once the revs increase, & the crank starts to flex (as it should) then that appears to stop the seepage as the seal is 'too busy' coping with the flex to let oil past. That is partly the reason that I have gone back to Nitrile, because I believe that it's material properties enable it with more flexibility. I reckon that had your seal been Viton, it would not have endured so well as the Rolf seal!

Call me outspoken, or cynical, but there are a lot of products that people buy into because of unproven or ill-founded scaremongering, or simply the Kudos! I wonder if I am alone in considering that the profit margin of Viton over Nitrile might come into why they tend to be sold.....

The journals that oil seal lips run on should be a surface texture that can retain oil, to stop the lip from wearing out. Scotchbrite is our friend when we install crankshafts, rather than polishing. Sometimes, dependent upon which power transmission stockists I order from, some seals have arrived with twin lips, which I tend to keep for those journals that might have wear evident, reasoning that there should be a void of lubricant retained twixt the two.
Warkton Tornado No.1
 
Posts: 1383
Joined: Sun Jan 11, 2015 1:27 pm

Re: Drive side oil seal .

Postby Raveydavey » Thu Aug 29, 2019 7:03 pm

Warkton Tornado No.1 wrote:
Raveydavey wrote:It might have been me coming up Pytchley road. You can tell it's me by the noise :x :lol:


'She' sounds really fit! VERY torquey, pulling from nothing, fuss free. You must be aching from grinning :D

I've never owned a SI or SII, but freely admit that the curvy bodywork has grown on me, & if the money & time were mine, I'd love to ride a passionate 'unrestricted' Seniorita ( ;) ) once more, in two wheel form.....I must go for a lie down :oops:

As we are on the subject of seals, does your engine have the mag-side seal fitted? In other words, does it run the roller bearing in grease or petroil? Much depends upon the belief (or not!) in crankcase compression, but a reed valve engine such as yours might stand to benefit from having lower crankcase compression, which has the knock-on effect of giving the remaining drive side seal a slightly easier life. Just a thought, & nothing new to some of us :idea:

I hope this makes sense, but my belief is that if a crank is only a little twisted, then it will pump oil via the drive side seal journal, as you found, only over part of the rev range. Once the revs increase, & the crank starts to flex (as it should) then that appears to stop the seepage as the seal is 'too busy' coping with the flex to let oil past. That is partly the reason that I have gone back to Nitrile, because I believe that it's material properties enable it with more flexibility. I reckon that had your seal been Viton, it would not have endured so well as the Rolf seal!

Call me outspoken, or cynical, but there are a lot of products that people buy into because of unproven or ill-founded scaremongering, or simply the Kudos! I wonder if I am alone in considering that the profit margin of Viton over Nitrile might come into why they tend to be sold.....

The journals that oil seal lips run on should be a surface texture that can retain oil, to stop the lip from wearing out. Scotchbrite is our friend when we install crankshafts, rather than polishing. Sometimes, dependent upon which power transmission stockists I order from, some seals have arrived with twin lips, which I tend to keep for those journals that might have wear evident, reasoning that there should be a void of lubricant retained twixt the two.


The mag side is the original S1 without a seal. The compression is high though. Have to stand on the level to kick it over. I guess time will tell if you are right no the seal material. I got about 7k miles before t his one started leaking and then ran it for another 2k miles before I fixed it :lol: so we'll see if we get as far as another 7 k before we fined out. Done about 1500 miles on it already.

Get an S1.. they are the best to ride. My SX doesn't get much of a lOok in anymore :lol:
User avatar
Raveydavey
 
Posts: 287
Joined: Wed Jan 28, 2015 8:32 pm
Location: Kettering Massive

Re: Drive side oil seal .

Postby Warkton Tornado No.1 » Sat Aug 31, 2019 12:16 pm

Raveydavey wrote:
The mag side is the original S1 without a seal. The compression is high though. Have to stand on the level to kick it over. I guess time will tell if you are right no the seal material. I got about 7k miles before t his one started leaking and then ran it for another 2k miles before I fixed it :lol: so we'll see if we get as far as another 7 k before we fined out. Done about 1500 miles on it already.

Get an S1.. they are the best to ride. My SX doesn't get much of a lOok in anymore :lol:


We are going to get sent to the naughty corner for hijacking offences...... :o

I may have heard that the MQ has had issues with compression. That is, cylinder compression. So, it might be worth a check, although Martin @ CST will almost certainly know what he is doing.

For what it's worth, I still believe in using Geometric Compression Ratio, rather than 'Effective' simply because, as Bell & others say, if the exhaust is doing it's job, which will be by varying amounts over the working range of the engine, it can make the 'Effective' method much more of a guessing game.

Have you measured the cylinder pressure via the spark plug hole? That said, there has been banter about the lowest acceptable limit, but I wonder what upper acceptable limit applies....... :?
Warkton Tornado No.1
 
Posts: 1383
Joined: Sun Jan 11, 2015 1:27 pm

Re: Drive side oil seal .

Postby Nigel. S » Sat Aug 31, 2019 3:48 pm

neil64 wrote:Hello.

Seem to have quite a bit of smoke coming from scooter when running ,how do you check the drive side seal is good ?


Bet you're sorry you asked now. :lol:

Fascinating stuff though.
Nigel. S
 
Posts: 212
Joined: Fri May 30, 2014 11:47 pm


Return to Tuning & Kits

Who is online

Users browsing this forum: No registered users and 6 guests