This is what happens when you get the wrong bearing clearance!
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- เผยแพร่เมื่อ 23 ก.ค. 2024
- I have an extremely “Boring” couple of days and I let you guys into some secrets on crank bearing clearance so you don’t make a mistake, it’s a fine line between correct and catastrophic failure!
- ยานยนต์และพาหนะ
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The reason for the error on the ruined crank was that they listened to a previous video where someone was perpetrating a joke...
What? Too soon? 😖
Just teasing, mate.
Even with all the numbers, this was enjoyable. As usual, thank you. See you on the next one.
Oh, could you tell us how you decide which weight of oil to recommend for the various uses of your engines. We seem to be well beyond factory specs. Thanks from the colonies.
Hahaha
More bike stuff please and other oddities.
It's good to see the different things you do.
GT750 was not particularly prone to boiling but it was at the time rare to be water cooled. This was enough reason for it to gain the name "kettle".
👍😎
I bought one for £250. Drove it for a week and someone offered me £400 so I sold it. It was like riding a buffalo. The GT500 was more my size and it went round corners a little bit better. I could of been rich now if I had saved it.
Great video Lee.
I found this particular one really interesting.
Loads going on.
Really liked todays video, very interesting and a lot of memories surfaced when watching, great to see an expert and see the correct way to build an engine.
The first water cooled two strokes were made by a British company called Scott circa 1929. The engine was still being used in a Silk motorcycle from 1975 to 1979, manufactured in Derbyshire.
The first Scott motorcycle, water cooled parallel twin, was 1908!
Who can forget the Scott Squirrel (1922, 486 cc twin), the Super Squirrel (498 cc or 596 cc) or the ultimate... the Flying Squirrel (1926, also 596cc)!
Tosser
Right I've had enough now of trying to post replies..and being revoked....that I won't do it anymore.
@ast6537 only joking
Really interesting, as a viewer find your explanations fascinating and as someone who years ago worked on my own cars, purely as diy, puts a whole new perspective on how and what is involved with building engines, stuff I never really knew, thank you.
'Kettle' just because of the water cooling. Nothing to do with boiling up or making tea or anything like that. 🤣 Same bike was called the 'Water Buffalo' in the US. Some of those 'Hardly' liners looked very thin after you'd bored them.
we call them water bottles in australia,great old bike.
Maico were a beast of a machine, My 450 had a decompression lever fitted, And it was needed
Quite a while back, you had an episode about big end clearances. I suggested then that these clearances are based on journal diameter of .001"/ inch of journal diameter, for internal or external combustion engines @ 100 deg C and yes you can manipulate tolerances with oil viscosities, but you will find most if not all high revving performance engines use very low weight oils
1971-1977 Suzuki GT750 2-stroke but Liquid-Cooled, therefore the name "Kettle".
Here in OZ known as hot water bottles
I remember the GT750 as the original 0-diorhea in about a quarter of an inch throttle movement! After a push rod triumph it was quick.
On Mini A-series engines used to use basic 20/50 SAE oil plus a can of Wynn's or STP gloop. Was a good combo for the gearbox as well. No probs in winter or a British summer.
I have ran a few minis and the thing is people who try and make the A series a sports engine.They end up not lasting long .1380 was big but people actually tried 1400.They lasted a couple of hard runs and popped.Terrible heads in the first place siamesed as they were.
I remember that well. This is the way ..... as they say 😀
They can last well in my experience. My 1420cc A series has about 65k miles on it and revs to over 7k RPM at times like hillclimbs. It's done track days, autotests and quite a bit of motorway use and still has life in it. The 1420cc is a 1380 bore with a 2" mains 1098 crank.
Alfred Scott designed the squirrel/flying squirrel water cooled two stroke engine in 1912 ! So kettles have been around longer than you thought!
Regards,
Sandy 🔧🏴
The GT750 was very very thirsty, one of the lads I rode with in the group had one. He used to have a carry a can of petrol on his back as it could not get between service stations on the motorway without running out.
Loved the old Maico motocross bikes.
GT750’s never boiled over to my knowledge. They actually ran rather cool. Mine, a 1973 LeMans was a hot rod; smoothbores, ported, polished, expansion chambers. Very fast in a straight line if you could keep the front wheel down. Mine wouldn’t corner well, even with aftermarket rear shocks and decent tires; I’d set off a shower of sparks on any decent corners as I scraped the expansion chambers on the road. I wish I still had it though.
Harley V-twins, a classic engine. But have been really struggling with emission rules in recent years. Think they have been trying to sort that out with fuel injection and an array of suitable sensors and an electronic software control box.
Yes, they got EFI. About 10 years ago, they went to a 4V cylinder head. They call it the Milwaukee Eight.
They got VVT now as well 😱
I am going to sound like my dad who was an engineer.Theres a very good reason engines leave the line as they are.Dont change it because something will fail.From my own ill doings with an A series and an old ford Pinto my dad was spot on.
Ah , the kettle, yes they boil up , and YES they are almighty fun to ride.
Seeing the MAICO barrel brought back memories, evil power band , but hilarious to ride.
I thought Harley barrels are meant to have torque plates on them when being machined. Suzuki were by no means the first to manufacture a water-cooled motorbike despite their claims. (But then the Japanese manufacturers have never felt obliged to hold fast to the truth). The most famous being Scott motorcycles of Yorkshire, who first sold water-cooled two strokes from 1908 onwards.
The best way to prevent water-buses from overheating is to fit electronic ignition, but timing must be checked for all cylinders using clock gauges or degree wheels. The points were driven by a crappy nylon gear form the crank and they could pick up harmonics from the crank; they also had a habit of splitting.
And yes, I did guess all the motorcycle parts.
Wouldn't it be quicker to rough bore those single Harley Davidson barrels on a lathe ?
7:05 I wonder if rigging this flat alloy head on the machine wouldn’t better be done by 2 studs through the outer 2 sparkplug holes....
Like this,to me,there seems to be a fair chance of ‘pulling the middle of the head down’...???
Was it checked before and after rigging it on the machine???
Lee, I'm not a machinist but I have to disagree with the way you have that motorcycle head held down, with the center pulled down it seems to me that you would end up with a reverse banana. Me thinks you need bolts thru all of the sparkplug holes pulling against precision blocks to get a truly flat surface.
I agree 👍🏻
If you look carefully you’ll see that the outer plug holes are at an angle. You’d be hard pushed to clamp it down though them .
Yes I have to agree that the set up is a little sketchy. He has stand off blocks under both the ends of the cylinders in fact it looks under the cylinder head bolt holes. What I would have done is blocked under the centre cylinder too, and used the same locking down fixture to the table as there is no alternative that I can see.
We always referred to the Suzuki 750 as the 'Waterbus', but never heard of many overheating.. Maybe NZ is a better environment for them?
Read set, read check, then check again.
Equally devastating is to run too tight clearances which will overheat the oil and result in a seizure, or spun bearing. Without naming specifically, some plonker, say, with a Golf, uses 0W-20 and expects oil pressure and doesn't understand where it's gone ;-)
Both Mike and Keith and Lee and Paul make them proud!!!! Legends!!! , please 🙏 Lee and or John or Paul do a service to the amazingly amazing Mike Costin and Keith Duckworth!!!! ❤ and you know that for fact!!! !!! , helped us win touring car races in the group a series in the 80s and 90s please acknowledge that !!! Tom walk-in shawl is not a defector!!.😊
Easy done imperial makes more sense to me 👍👍
Glad that I use a machine shop that has been around for awhile, he has done a number of engines for me, both stock and stroker versions and have had damn good results.
First water cooled 2 stroke engine?!?? Scott had a water cooled 2 stroke in the 1920s!
How do you know you don't have that 3 cylinder head pulled down in the middle a touch before it's skimmed as it's supported on the outside but pulled down only from the centre cylinder plug hole ?
I thought the same thing
I was waiting for it to fly off into the wall 😂😂
This idea may be a little "out there" so to speak, but would you think Lee measured before, then after nipping the nut down?
That was really cool Lee thanks bro 😎!!!nz mate Dave!😊
The yb is the marksman’s engine and you do it best !!!
Lee.....What superbike team did you work for?
In my research for my 2-stroke, I discovered the reason they overheat is because the squish band is too big or too small. the skimming you've done might just be enough to get it right so it doesn't overheat again.
My father's GT750-A never had an overheat issue. looks like the barrels you had there are from an earlier model.
That's where memory has failed me. It was on the air cooled RD info that was online. The story of a racer who raced Yamaha RDs for about 14 years. He discovered it by accident, too. Helps to keep performance during endurance racing too
To make it really juicy interesting, you should measure the things like those big end and crank dimensions so we can see exactly what's going on. It is good practice to measure and get less vague numbers. It would take only a little extra time. When investigating a failure, like the seized engine, you should film it as a matter of course for evidence, and it would make top quality TH-cam videos. Edited for Steve Kelly to relieve his constriction. (An*l)😸
@@stevekelly5166 PS How do you know Barum engines doesn't own a caliper that measures to an infinite number of significant figures? You know, so they get their ring gaps correct.
@@stevekelly5166 I was annoyed reading that, hence about ten replies in two minutes. But I concede it was a very poor use of the word. And stupidly, I really do know the difference between accuracy and precision! I use precision electronic measurement devices daily. I edited original comment and removed the others.
What’s your opinion on waterless coolant? @BE
Pointless. You want a puff of steam to show engines overheating not 230degrees and a total destroyed engine.
Banned in all race series’ and racetracks.
Snake oil
Suzuki GT750 engine never had common boiling problems here in Australia, and we called them Waterbottles.
No mention of tight running oil clearances Lee . A friend and former colleague had on a Honda Integra 1800 type R engine rebuild. I recall oversize big end bearing shells were hard to come by but he sourced shells somehow and passed on to the local engine shop to get the crank ground. On assembly it was obvious there was little no oil running clearance, almost locking on assembly so he sent the crank back to the engine shop where they just polished the journals and sent it back telling him all was fine despite him not being convinced he went ahead, assembled and refitted the engine. Sounded sweet quite as a mouse on start up with excellent oil pressure but within fifty miles the engine failed with the big ends obviously seized/ spun and crank ruined. When I discussed it with him we both concluded that there was never enough oil clearance on the big ends. A costly error of judgement on both the engine shops part who denied an issue and washed their hands and my very experienced and knowledgeable colegue who struggled to find a replacement crank who eventually sold of the car for peanuts without a useable engine..
If he was knowledgable and experienced, why didnt he check the clearances before he put it together?
Because he left the decision to the specialist engine shop who told him it was good to go. It proves to me that anyone can get caught out, (the guy is hugely respected for his work locally by many including myself ) if you trust others supposed expert judgement and the crank came back polished and the conrods spun freely with the ok from the specialist. I was very surprised by what occurred as we both come from comprehensive engineering backgrounds but didn't press the issue with him or rub more salt into the wounds.
Rings never lasted to long on the 250 Maico
Please shell out something to the men of your showcased business Mike Costin and Keith Duckworth!!!! Are legendary in there own rights!!!
The petal name was because it used reed petals on the induction ports.
Kettle not petal and it is only a piston ported engine no reeds as far as I know
Reed valves are for power band
@@leongaskell1533 Don't be silly
Suzuki gt 750 they called them the kettle, they were always boiling up!!
Old 2 strokes are choice
well done with the naming and shaming. shame about not being to comment on the re edited wideo. but would detailing the job and price owed be an idea to avoid name dropping.
Fairly sure the gt750 was the basis of the bike Sheene crashed at Daytona
Scott motorcycles predated Suzuki by more than 40 years with successful water cooled 2stroke engines with Suzuki ‘s outboard engine experience was a obvious development.
1200 Sportster head gaskets required.
I don't think they build them just the machining work
@@colinscutt5104Harley engines, I do believe you are correct. Lee mentioned that because of the large overbore, they probably need a different head gasket. So my response was in line with that and only to inform what gasket is required. When only the barrels and pistons are brought in for maching, the owner or possibly a motorcycle shop will do the assembly.
Nice explanation. I've got an issue. My rods have big end bearing bore at minimum spec and block main bearing bore is maximum spec. So with +0.001 bearings on both, my clearance measures 0.0018 rod and 0.0028 main. Based on diameter 0.0018 rod matches with 0.0023-0.0024 main or 0.0028 main matches with 0.0022-23 rod. Should I mix main bearings 1 STD half and 1 STD +0.001 half to bring 0.0028 down to 0.0023 to better match rod 0.0018 or bring rod bore out 0.0005 in hopes of 0.0023 rod bearing clearance to match 0.0028 main. 😅
Put the cam on a tripod
Do you not advise using running in oil on a new engine to get a bit carbon built up on the compression rings
Get them plastic strips out again! 😎🙃
Round journals and bed in them white metal bearing linings. On Steam engines in the old days it was more by guesstimation scales. And don't forget the pressurised oil feeds. 🤓🖕
How you get away without any accidents is worring. Health and safety shouldn't be last. The floor and storage of customers needs more work.
If each subscriber were to donate 100 dollars, Lee could have $4, 200,000 to build a proper large facility with shelves ;-)
Omfg that screeching on the pressure test....
Did you really mean a half inch overbore on that Harley barrel?
Another joke? (Just teasing...)
Probably an 883 being bored out to a 1200
@@PeterAngles and my tinnitus
Boring 😅😅 hope this is not improper engineering jokes again 😅😅
Love your videos but why do you mix imperial and metric measurements so much? You always talk about “thou” but shouldn’t you work all in metric nowadays?
When a machine shop is equipped with all metric machines - then it would be 'natural' to use only metric nomenclature. However, the said workshop is largely equipped with perfectly usable Imperial machines - hence the continued use of Imperial measurements coupled with metric because the engines worked on (eg. BMW, VW, etc) use data that specify sizes and tolerances in mm.