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Re: Cali. crank balancing companies? [Re: MarksterTT] #796307 01/22/20 6:57 pm
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Markster summed it up I think.
On the subject of rods, T140 rods are quite substantial and can take a hell of a beating, but the last iteration of 650 rods weren't far behind either, and they see much less force.
Taking into account the lower loads from the lighter pistons and the advantageous rod to stroke ratio, a 650 will, on average, vibrate less. No balance factor can alter that.
The big bore pistons I have had or worked with are mostly around the same weight as standard 9-1 650, so many big bore kits will vibrate much the same as a 650.
Jim Schmidt of Norton fame produces light weigh pistons and longer rods to combat (no pun intended) the infamous Norton shakes.

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Re: Cali. crank balancing companies? [Re: Stein Roger] #796315 01/22/20 7:41 pm
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Jim Schmidt has done some fantastic work with Nortons to remedy their poor rod to stroke ratio and piston design with low pin location. MAP also has nice long rods and light alloy pistons along the same lines for Nortons. The MAP steel rod for Nortons at 6.362" is the same rod used in his stroker Triumph 89mm cranks...makes sense.

I noticed that MAPs latest forged pistons with different alloy and fully CNC'd are even lighter than the figures I gave for my older style MAP's and my old Carillo T140 rods weigh 466 grams...41 grams heavier than the MAP.

I'm glad I don't have a Norton because I'd go broke buying all the aftermarket stuff available but it would be fun.

Last edited by MarksterTT; 01/22/20 7:44 pm.
Re: Cali. crank balancing companies? [Re: HawaiianTiger] #796318 01/22/20 7:56 pm
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Originally Posted by HawaiianTiger
I haven't ever built a 750 from the bottom up so I've never had the chance to play with balance factors. I believe that the factory changed the 85% BF of the 650's to around 70%. Others will perhaps know exactly when this was done. I'm not sure what they were after, but apparently it didn't work or only partially worked. According the HB, 85% would probably be a bad move. That leaves moving to a lower BF as an option. My balancer did ALL Triumph street motors at 58-62% but I'm not sure that takes into account the chassis or not. It seems to me that 750 frames are a bit more rigid than earlier frames. At this point we need more info on the effect of different balance factors for 750's short rod motors in OIF type of frames. If someone here has done this, it would be good to hear from them.
Cheers,
Bill


Funny you mentioned your old balancers preference of 58-62% factor, I have a Sonicweld track bike restored by my deceased friend George Mann who put a T140 engine it. He conferred with Dick Mann (no relation) on balance factor and was told by Dick to use 65% so that's where it is. I can't report on how it feels as I've ridden the bike once and then it was mothballed. At the time I was more concerned with the racket, the neighbors and the cops.

Re: Cali. crank balancing companies? [Re: MarksterTT] #796352 01/23/20 2:34 am
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Hi Guys, This is the only person I've seen post balance sheet. Thanks lovecuba!!

Here's a link. I don't understand the 2nd balance sheet with all the degrees. I've weighed parts on '69 650 & had that motor dynamic balanced 68%.

Here is link to lovecuba's conversation. RAT group.

https://www.triumphrat.net/threads/t140-crankshaft-balance.224953/#post-2434175

I don't have the experience to give insight on his sheet & how it relates to real life. He reports it worked good.

Don


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Re: Cali. crank balancing companies? [Re: MarksterTT] #796357 01/23/20 3:29 am
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TR7RVman...Don't know about 7.4-1 pistons as I didn't pull them out to weigh but STD. T140 8.6-1 cr are within .2 gram (2 tenths) of STD. 7.9-1 Hepolites so I'd be surprised if the 7.4-1's aren't within a couple tenths lighter yet but I don't remember the maker of the 7.4-1's so won't know without actually weighing. If you have a need to know, Iwill pull them out and weigh them...they go with a nikasil Gilardoni 750 kit so possibly different piston mfg. Mark

Re: Cali. crank balancing companies? [Re: MarksterTT] #796407 01/23/20 6:18 pm
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Hi MarksterTT, Thanks, but don’t bother. I’m going to use LF Harris 7.4. I will look into MAP though.
Regarding your new crank it’s 360deg?
What factor is it balanced to? Or are you having it balanced?
Thing is with steel rods they can weigh more up high on the shaft which skews balance formula.
New LF Harris rods are chubbier near big end than original rods on ‘69 Bonnie. The upper shaft is similar. Overall heavier.
This is very complicated subject. In truth way over my head. My thing is long rides. Excessive vibration is very fatiguing. A 400 mile day at 62-65 mph can leave inner thighs feeling “funny “ for a few days. I don’t know if it causes nerve damage or not.
Don


1973 Tiger 750
Re: Cali. crank balancing companies? [Re: MarksterTT] #796411 01/23/20 7:05 pm
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I should add a note of caution. Balancing the pistons and rods together without balancing the cranks gives you only a 50% chance of getting a smoother motor. You also get a 50% chance of making it worse. That's because the crank is the culprit usually out of balance.
Cheers,
Bill


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Re: Cali. crank balancing companies? [Re: MarksterTT] #796414 01/23/20 8:01 pm
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Vintage Bike issue Vol. 2016 #4 Nov. 2016 John H wrote a very good tech tip on balancing. Also Ed G. @ offsetcrank.com does 90 degree cranks for Brit Twins.

Re: Cali. crank balancing companies? [Re: MarksterTT] #796419 01/23/20 8:52 pm
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Bodine: There is an error in the article. Where I said the factor went up when I used heavier pistons, it actually went down. I will note this in the next issue.
That issue was published November 2019. Because of we only publish when we have enough to fill the magazine we have fallen back on the issue number. We do make sure you get at least 4 issues for your subscription.


Re: Cali. crank balancing companies? [Re: MarksterTT] #796424 01/23/20 9:18 pm
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HT " Balancing the pistons and rods together without balancing the cranks gives you only a 50% chance of getting a smoother motor. You also get a 50% chance of making it worse. That's because the crank is the culprit usually out of balance."

Absolutely. It's only worth going to the trouble of balancing the pistons and rods if you know the crank itself has been dynamically balanced.

And both those things should be done prior to the final balance factor adjustment.

The 1st 2 actions will eliminate any rocking couples, the last will determine the rpm range where the worst primary imbalance vibes occur.

The shorter rod of the T140/TR7 inevitably introduces some extra "buzzy" secondary vibration (twice the frequency of rpm) because of the greater differences in acceleration of reciprocating mass between above and below 90 deg crank position (the angle of the rod to the vertical is that much greater with a shorter rod, affecting the movement, speed and acceleration of the pistons throughout the stroke).

Re: Cali. crank balancing companies? [Re: MarksterTT] #796431 01/23/20 11:15 pm
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I had my A65 crank balanced recently as shown. I'll ask the vendor but it occured to me that all the holes are drilled dead center.
How was any rocking couple dealt with?
[Linked Image from i.imgur.com]


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Re: Cali. crank balancing companies? [Re: MarksterTT] #796442 01/24/20 2:16 am
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Hi John Healy, If you were going to build '73 TR7RV for long distance pleasure riding. Seldom cruise faster than 65mph. I'm a gentle rider, no hot rodding. All stock 7.4:1 pistons.

What you put the factor at with dynamic balance?

I'm quite certain everything on bike & chassis, exhaust mounts,handle bar mounts, seat mounts etc are as good as can get. Both wheels are balanced as perfectly as I could get even to the point of trimming spoke weights. Any further improvement must come from crank balance.

After going over everything on bike I made big improvements. Starting at 3900 the vibration starts coming in. Higher gets worse. Finally when tach is reading near 5000 it calms from the hard vibration to a buzz. Sort of like Honda 350 at high rpm. Motor is quite smooth 3600-3800.

Replacing worn clutch center & basket made no difference at all. I made road tests before & after. No difference whatsoever.

Of course I just what your thoughts. I know how fickled Triumphs are.
Don


1973 Tiger 750
Re: Cali. crank balancing companies? [Re: TR7RVMan] #796451 01/24/20 5:01 am
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Originally Posted by TR7RVMan
Hi MarksterTT, Thanks, but don’t bother. I’m going to use LF Harris 7.4. I will look into MAP though.
Regarding your new crank it’s 360deg?
What factor is it balanced to? Or are you having it balanced?
Thing is with steel rods they can weigh more up high on the shaft which skews balance formula.
New LF Harris rods are chubbier near big end than original rods on ‘69 Bonnie. The upper shaft is similar. Overall heavier.
This is very complicated subject. In truth way over my head. My thing is long rides. Excessive vibration is very fatiguing. A 400 mile day at 62-65 mph can leave inner thighs feeling “funny “ for a few days. I don’t know if it causes nerve damage or not.
Don


My crank is MAP's 76* offset and will be balanced at 50% per MAP. I'm having it balanced dynamically and why I originally mentioned my conversation with Kenmonth Machine in Sacramento. The steel rods are supposed to weigh approx. 115 gr. small end and 315 big end but total only 10 gr. heavier than stock, my whole rod and piston assy. at either my 774cc or 825cc will still weigh less than stock T140 components. You should ask Rick at MAP what his forged 7.5-1 T140 pistons weigh, I believe they are significantly lighter than stock and probably lighter than cast LF Harris as well. $275 I think? I have heard that the lower compression only lost 2 hp on top but makes for a nice easy kick start. I agree about excessive vibration being fatiguing which is one of the reasons I wanted to try an offset crank, I guess I'll find out sooner or later. Even if this is way over your head, if you can find a good reputable and experienced balancer that does as you ask then you should end up with a good job...should. Stock cranks can be way off side to side which static balancing doesn't address so for me I'll go dynamic and just consider it the cost of a rebuild. Mark

Re: Cali. crank balancing companies? [Re: Nick H] #796452 01/24/20 5:10 am
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Originally Posted by Nick H
I had my A65 crank balanced recently as shown. I'll ask the vendor but it occured to me that all the holes are drilled dead center.
How was any rocking couple dealt with?
[Linked Image from i.imgur.com]


It would be hard to believe that your crank as cast just happens to be balanced perfectly side to side and only required the holes in the center, as if it was statically balanced. One would expect to see holes or preferably a ground off spot on outer webs or added Mallory metal if needed. I've seen welded on plates on the inside of the outer webs also. No idea and can only speculate but a good question all the same. Mark

Re: Cali. crank balancing companies? [Re: Nick H] #796457 01/24/20 6:44 am
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Originally Posted by Nick H
I had my A65 crank balanced recently as shown. I'll ask the vendor but it occured to me that all the holes are drilled dead center.
How was any rocking couple dealt with?
[Linked Image from i.imgur.com]



Did they claim they were doing a dynamic balance?


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Re: Cali. crank balancing companies? [Re: MarksterTT] #796466 01/24/20 12:43 pm
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Originally Posted by MarksterTT


My crank is MAP's 76* offset and will be balanced at 50% per MAP. I'm having it balanced dynamically and why I originally mentioned my conversation with Kenmonth Machine in Sacramento. The steel rods are supposed to weigh approx. 115 gr. small end and 315 big end but total only 10 gr. heavier than stock, my whole rod and piston assy. at either my 774cc or 825cc will still weigh less than stock T140 components. You should ask Rick at MAP what his forged 7.5-1 T140 pistons weigh, I believe they are significantly lighter than stock and probably lighter than cast LF Harris as well. $275 I think? I have heard that the lower compression only lost 2 hp on top but makes for a nice easy kick start. I agree about excessive vibration being fatiguing which is one of the reasons I wanted to try an offset crank, I guess I'll find out sooner or later. Even if this is way over your head, if you can find a good reputable and experienced balancer that does as you ask then you should end up with a good job...should. Stock cranks can be way off side to side which static balancing doesn't address so for me I'll go dynamic and just consider it the cost of a rebuild. Mark

Answers from MAP best from Marino..If you can get him on the phone.......Compression? The first thing every manufacturer does to increase power is increased cylinder pressure..This can be done with pistons, ,squish or camshaft timing. Power gains from higher compression can vary but it does in general make a noticable difference in throttle response and torque..
Lowering cylinder pressure does give the engine a softer feel and less vibration...But this also depends on other factors so it's not a given..Might want to consider less clattery cams than the later Triumph stuff.. If I wanted the smoothest Triumph possible, it would be an offset crank., no doubt about it...
When I bought a well used 79 T140D a few years ago it was the smoothest Triumph I ever rode...I rebuilt the engine, did not balance the engine,,changed cam timing, milled the cylinders for tight squish using Triumph branded earlier 7.9 pistons.The 7.9 .020 piston are about 6 grams heavier than the original pistons.The engine has a measured 9.2 static compression, faster combustion burn means a few degrees less timing is needed and it will not ping on 90 US octane non ethanol gas...The engine vibration felt by the rider is exactly the same as before the rebuild, quite mild especially over 4500 rpm....Several guys here have ridden the bike and commented on the throttle response and smooth power(for a Triumph)...
I suggest anyone here who isn't afraid to make changes to do what it takes to speed up the combustion....



79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
Re: Cali. crank balancing companies? [Re: John Healy] #796473 01/24/20 2:42 pm
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Thanks for the update JH. My brain and fingers sometimes out of sync. Looked right at the inside cover and read Nov. 2019 and put up 2016!
Always get my 4 issues yearly and have quite the pile including Vol. 1 issue 1 Fall 1986 Thanks for all you do in our vintage world. Regards Geoff TIOC #6

Re: Cali. crank balancing companies? [Re: Hillbilly bike] #796499 01/24/20 11:16 pm
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Originally Posted by Hillbilly bike
Originally Posted by MarksterTT


My crank is MAP's 76* offset and will be balanced at 50% per MAP. I'm having it balanced dynamically and why I originally mentioned my conversation with Kenmonth Machine in Sacramento. The steel rods are supposed to weigh approx. 115 gr. small end and 315 big end but total only 10 gr. heavier than stock, my whole rod and piston assy. at either my 774cc or 825cc will still weigh less than stock T140 components. You should ask Rick at MAP what his forged 7.5-1 T140 pistons weigh, I believe they are significantly lighter than stock and probably lighter than cast LF Harris as well. $275 I think? I have heard that the lower compression only lost 2 hp on top but makes for a nice easy kick start. I agree about excessive vibration being fatiguing which is one of the reasons I wanted to try an offset crank, I guess I'll find out sooner or later. Even if this is way over your head, if you can find a good reputable and experienced balancer that does as you ask then you should end up with a good job...should. Stock cranks can be way off side to side which static balancing doesn't address so for me I'll go dynamic and just consider it the cost of a rebuild. Mark

Answers from MAP best from Marino..If you can get him on the phone.......Compression? The first thing every manufacturer does to increase power is increased cylinder pressure..This can be done with pistons, ,squish or camshaft timing. Power gains from higher compression can vary but it does in general make a noticable difference in throttle response and torque..
Lowering cylinder pressure does give the engine a softer feel and less vibration...But this also depends on other factors so it's not a given..Might want to consider less clattery cams than the later Triumph stuff.. If I wanted the smoothest Triumph possible, it would be an offset crank., no doubt about it...
When I bought a well used 79 T140D a few years ago it was the smoothest Triumph I ever rode...I rebuilt the engine, did not balance the engine,,changed cam timing, milled the cylinders for tight squish using Triumph branded earlier 7.9 pistons.The 7.9 .020 piston are about 6 grams heavier than the original pistons.The engine has a measured 9.2 static compression, faster combustion burn means a few degrees less timing is needed and it will not ping on 90 US octane non ethanol gas...The engine vibration felt by the rider is exactly the same as before the rebuild, quite mild especially over 4500 rpm....Several guys here have ridden the bike and commented on the throttle response and smooth power(for a Triumph)...
I suggest anyone here who isn't afraid to make changes to do what it takes to speed up the combustion....



Hi Hillbilly, yes texted with Marino today as he's putting package together for me. 9-1cr lo-quench pistons approx. 260 gr. piston + 58 gr. pin + 16.75 gr. ring set with 77.5mm bore. These are long rod pistons with T140 crown for T140D head. I believe the head gasket is .048" but want to do as you suggest with actual quench so will have to mock up engine to see what deck height etc. is and go from there. I think with steel rods and alloy barrels I can set up some close squish without worrying to much. Cams being sent are 76* version of 1065's but was told if I change my mind to just send back for exchange...I originally liked the thought of the milder 1005's but they weren't in stock so I thought it would be better to have a set of offset cams in hand and decide later. I'm not sure but I could probably also change to 7.5-1 pistons but originally was going to dual plug the heads so wasn't worried about the 9-1's. Of course our gas has ethanol, no way around it.

Re: Cali. crank balancing companies? [Re: MarksterTT] #796501 01/24/20 11:49 pm
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One of my favorite balancers over the years was Dave Dunbar (now retired). When doing the dynamic balancing he would juggle the rods, and pistons, to correct any imbalance from side to side. Instead of hacking, and I use hacking on intentionally, the rods and pistons he would put the heavy set on the light side and the light set on the heavy side to begin to remove any side-to-side imbalance. Then spin it and correct any imbaIance that was still there. Dave operated outside the box, but you got back a job that looked like as good as the day you sent it to him. And most of the time you got a smooth motor.

I hate it when I sent out a set of polished, or shot peened, rods out with the crank for balancing and get a pile of belt sanded (linished) junk.

Nick H: I would be very interested in how that balance job works out.

Instead of taking chances on what I am going to get back, I have been know to send out the flywheels with the balance weights on the crank for the factor I would like, Then have the crankshaft balanced to those weights and have any dynamic, side-to-side imbalance corrected. On average I have had the best results using the factory factor and just have any dynamic imbalance removed. The problem is when the person asking for the balance job doesn't understand it when I ask him if the engine and rolling chassis is DEAD STOCK. This includes things like highway bars or different compression pistons. Once you go away from a dead stock engine, AND ROLLING CHASIS, you are on your own. Changing frames can be a very big deal when trying to come up with a decent factor.


Re: Cali. crank balancing companies? [Re: MarksterTT] #796512 01/25/20 5:05 am
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Hi Mark, the way I read MAP’s website 7.5 is 650 only.

7.5 not available for T140 type.

T140 billet only comes 9.5, 10.5.

On our remote rides 87 10% ethanol & diesel is only fuel sold. 7.4 has proved so good here I’m committed to them.

I’m considering Riken rings. However apparently they are made in Taiwan now?? Does that matter?
Don


1973 Tiger 750
Re: Cali. crank balancing companies? [Re: MarksterTT] #796513 01/25/20 5:10 am
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Hi John Healy, Thank you for the straightforward answer. I have a good direction to go now.
Don


1973 Tiger 750
Re: Cali. crank balancing companies? [Re: TR7RVMan] #796595 01/25/20 9:51 pm
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Originally Posted by TR7RVMan
Hi Mark, the way I read MAP’s website 7.5 is 650 only.

7.5 not available for T140 type.

T140 billet only comes 9.5, 10.5.

On our remote rides 87 10% ethanol & diesel is only fuel sold. 7.4 has proved so good here I’m committed to them.

I’m considering Riken rings. However apparently they are made in Taiwan now?? Does that matter?
Don


Hi Don, text or call MAP, you'll probably get Rick and he'll be more than happy to check on pistons and weights for you. I may have an extra Guilardoni alloy nikasil bore 7.4-1 pistons T140 kit if your interested, not cheap but complete NOS as used on the last of the Harris Triumphs. Mark

Re: Cali. crank balancing companies? [Re: MarksterTT] #796617 01/26/20 2:59 am
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The crankshaft itself only needs to be dynamically balanced once. This has nothing to do with rods or pistons, it is entirely about the crankshaft. Only the crankshaft is spun up, no weights are on it.
From the readings, bits are carved off the pork chops to eliminate any rocking couple. The crank is then in a state of dynamic balance.
It is then necessary to ensure the bits added to the crank are also dynamically balanced. That is done by weighing and equating the ends of the rods, and the pistons.
Then you've got the reciprocating weight that you can do your 50%, 71% or 85% balance factor against.

The good thing about getting the crankshaft dynamically balanced (on its own) is you only have to do it once.

If or when you change pistons or rods, you can balance them without concern of the crankshaft, just with concern of the big/small end & piston weights. Or would you prefer to go back to the balancer every time?

Re: Cali. crank balancing companies? [Re: koan58] #796639 01/26/20 10:07 am
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Originally Posted by koan58
The crankshaft itself only needs to be dynamically balanced once. This has nothing to do with rods or pistons, it is entirely about the crankshaft. Only the crankshaft is spun up, no weights are on it.
From the readings, bits are carved off the pork chops to eliminate any rocking couple. The crank is then in a state of dynamic balance.
It is then necessary to ensure the bits added to the crank are also dynamically balanced. That is done by weighing and equating the ends of the rods, and the pistons.
Then you've got the reciprocating weight that you can do your 50%, 71% or 85% balance factor against.

The good thing about getting the crankshaft dynamically balanced (on its own) is you only have to do it once.

If or when you change pistons or rods, you can balance them without concern of the crankshaft, just with concern of the big/small end & piston weights. Or would you prefer to go back to the balancer every time?

Not quite Dave, if you spin the crank up without weights it'll jump out of the fixture. A crank will be balanced to somewhere close to the design balance factor during manufacture. Using weights corresponding to this factor is a good starting point. Altering the factor with lower or higher weights you will need to balance it statically first, and then dynamically.
I agree it only needs to be done once though.

SR

Re: Cali. crank balancing companies? [Re: TR7RVMan] #797022 01/30/20 6:23 pm
Joined: Feb 2005
Posts: 663
M
MarksterTT Offline OP
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M
Joined: Feb 2005
Posts: 663
Originally Posted by TR7RVMan
Hi Mark, the way I read MAP’s website 7.5 is 650 only.

7.5 not available for T140 type.

T140 billet only comes 9.5, 10.5.

On our remote rides 87 10% ethanol & diesel is only fuel sold. 7.4 has proved so good here I’m committed to them.

I’m considering Riken rings. However apparently they are made in Taiwan now?? Does that matter?
Don


Just to follow up on this question of MAPs 7.5-1 pistons for T140/TR7's...They do have T140 forged pistons in 7.5-1 cr in the following sizes; 76mm, 76.5mm, 77mm, 77.5mm and 79.5mm...the last 2 sizes may be for their nikasil kits but I failed to ask what difference that would make such as in ring material or facing. Apparently their catalog needs to be updated to show these pistons as being available for T140/TR7's....

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