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Oh check out the other thread as the 750 of heads sometimes had minor issues that r readily rectified. The pushrod tube bosses in the head are variable Fer depth as well. A rather learned fella was quite gracious. And showed me alot of the info I've passed to you n others . If not for his wisdom I'd be still pulling my hair out.as to the out of shape... yeah you'll find some are even not spaced centered over the crank throws.... they sure r forgiving old engines! Dressing all the flat faces is a great thing. I pull the studs do that myself.
 

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Discussion Starter · #42 ·
Hi all . Back again. Been busy with other stuff that took priority though now have the barrel bored and honed out to plus .040" and new pistons all ready to fit.
Question. I have gone for Harris low compression pistons the same as came with the engine and original fit I believe.
There is nothing stamped on the crowns to indicate orientation front to back. The valve head reccesses , exhaust and inlet appear identical and there's nothing to suggest they should be fitted oa certain way which in my experience is unusual.
Can anyone confirm if there is a recommended orientation ? Thanks for your help and info.
 

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That's a very goid choice, however there is an orientation to their installation. Look into it further.. lf Harris website has more info. No paperwork came w them? Mine have in marked....
 

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Discussion Starter · #44 ·
That's a very goid choice, however there is an orientation to their installation. Look into it further.. lf Harris website has more info. No paperwork came w them? Mine have in marked....
Thanks Brent I will do that. Yes had some paperwork but it was just explaining the ring fitting etc nothing on orientation. (y)
 

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The 750 pistons seem like valve cuts r same, but look closely measure, the smaller cut is exghaust valve, and needs tp tint forward. Just looked at 2 sets, plus a pair of origionals... about .020 difference in width of relief cut. It probably wouldn't make a difference , but.... I'd still try to put larger cut towards rear for the intake valves... measure, yes it's a wonky pita. But I marked mine w a sharpie... once together all well. Mite scribe the inside of skirt if ya ever wanna tear it down again. The jcc are just a bit taller than the lf Harris pistons I have, plus both are lower than the origional pair from this 79 140 I have... easiest way to see that was to put upside down side by side... thickness of the thin oil ring retainer ring difference. Hope this helps.
 

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Discussion Starter · #46 ·
The 750 pistons seem like valve cuts r same, but look closely measure, the smaller cut is exghaust valve, and needs tp tint forward. Just looked at 2 sets, plus a pair of origionals... about .020 difference in width of relief cut. It probably wouldn't make a difference , but.... I'd still try to put larger cut towards rear for the intake valves... measure, yes it's a wonky pita. But I marked mine w a sharpie... once together all well. Mite scribe the inside of skirt if ya ever wanna tear it down again. The jcc are just a bit taller than the lf Harris pistons I have, plus both are lower than the origional pair from this 79 140 I have... easiest way to see that was to put upside down side by side... thickness of the thin oil ring retainer ring difference. Hope this helps.
Many thanks Brett I will check that out when I come to assemble. I did though contact Harris whos main warehouse is no more than a few miles away from where I live and they explained that the engraved/stamped part no etc on the top of the piston should be read the right way up when your sat on the bike.
Your knowledge is always gratefully received though and you may be able to help with the latest query I have regarding the oil pump. What arrived with the engine in boxes was an old style two valve oil pump and I believe this bike should have the later four valve pump. Just need to be 100% sure before I purchase a new pump as this is the later electric start bike. I have read they can be retro fitted to earlier engines with conventional kick start but the inner casing has to be ground away to make way for the bulkier pump body.
Thanks again Brett.
 

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U can put a 2 piston pump onbit, they make a great aftermarket 4 ball pump.. easily retrofitted to earlier engines, it's the cover needing a slight"adjustment " tho the regulator 2 check ball pumps work fine even on the es motors.. yer making more progress than me!! Bestreguards, brent
 

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Discussion Starter · #48 ·
U can put a 2 piston pump onbit, they make a great aftermarket 4 ball pump.. easily retrofitted to earlier engines, it's the cover needing a slight"adjustment " tho the regulator 2 check ball pumps work fine even on the es motors.. yer making more progress than me!! Bestreguards, brent
Thanks Brent much appreciated Pretty sure it should have the four valve pump as thats the type listed in the parts book I downloaded.but its an old bike with a long past and chequered history. Whats holding you up on your build Brent?
 

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The only gain to a 4 valve triumph pump is half of it can clog n it'll still work n keep yer engine alive. The aftermarket 4 valove pumps seem to be held in fairly high reguard. I've a like new 4 valve to put on my 750. As for my lack of progress... heheheheh heheheheh short answer.. life. We allow far too much traffic to get between what we love to do and enjoy in the name of all the crap we hafta do.. work, paying bills.... my to do list is far too long... my wanta do list is not short , but keeps getn pushed off. I've spent 9 years gathering everything to refurbish my 64 ... save new tyres n tubes. Lotsa hours of research to find the correct parts even the paint... I'll be committing sum sorta sacrilege when it's done. It'll have a nacelle from a 64 thunderbird n the large tank too.. the original tank n stuff Fer instruments are all here n in working order, n will be kept safe. I'm so ocd with it I've even got borannis n dls front hub to fit original front end... the 79 n a redhead got in the way, then work n 79 n redhead.... heheheheh seeing the pattern? But I enjoy helping if n wen I can so others can get their scoots back in the wind..
 

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Discussion Starter · #51 ·
Hey have you made any progress?
[/QUOTE
Hi Brent. All been on hold for the last couple of months for various reasons including some illness and my garage workshop being stacked up with building materials for my house extension. Too much dust and disorganised to continue the build but hoping to get back to tackling it soon. Rest assured I will update with pics as I progress. Bound to be returning also for advice on any thing Im not 100% sure about. (y)
 

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Discussion Starter · #53 ·
Hi all. Will be back on the rebuild after xmas and have a simple question regarding refitting the engine back into the frame.
Its a fair old lump and haven't even got the pot on yet and just wondered if there is room to get the complete engine, fully assembled into the frame. Have read the older bikes didnt have the removable front mounting bracket and had to be partially assembled in frame. This is a late 81 bike so hoping I can rebuild the entire engine unit out of the frame as I have no means of lifting bike to eye level.
Thanks for any info and a very Happy Christmas to all.
 

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Well you can build the engine but leave the head n pushrod tubes off, that you can put in to the frame. You should have help w that as it's 100 lbs plus. I thing whole engine is about 137lbs complete.
 

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Well your mostly assembled engine will fit... oil in frames ya gotta leave the head , rockerboxes, n pushrod tubes off.. they get installed once engine is in frame... what cheer! But try to have help putting the engine in. Even w head n stuff off it over 100 lbs.
 

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Discussion Starter · #56 ·
Well you can build the engine but leave the head n pushrod tubes off, that you can put in to the frame. You should have help w that as it's 100 lbs plus. I thing whole engine is about 137lbs complete.
Thanks Brent! Reckon that 's the way to go and would leave me some wiggle room with less weight . Hopefully the owner will give me a hand to mount in the frame. Cheers Pete
 

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Your welcome, the earlier frames ie non oif. You can fit engine without rockerboxes. However lots of heads have had fins damaged and I cant help but wonder if at least sum were beat up trying to put it in alone n dropped! I am certain that they can be done alone, I have done it. But if ya gots to do it solo, set up a block next to frame so ter just walking it in, or a sling / cherry picker idea. One very sharp fella used a cantilever like a cherry picker, w dumbell weights to counter balance it on wheels no less.. made it look easy indeed! His reason, too costly to rusk dropping, or hurting himself. As I'm no longer in gr eat shape, nor over whelped w testosterone... I'll use some sorta assistance.
 

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I have had my best luck with singlehanded (1) removal and (2) installation by (1) laying down a tarp etc. and tipping the stripped frame w/engine over on its port side. Remove the motor mounts that you can get at. Pick the frame up, wiggling it deftly to clear the engine. The frame will clear the lump, rocker covers and all.

(2) is more or less the same process in reverse. Lay the engine down; insert appropriate scrap lumber underneath so it lies with the crank pointing straight up. It's possible to put the frame down, although a helper speeds up the process a lot. NB: This is harder to accomplish than the engine removal, helper or no. And note that I've never been too much concerned about keeping the frame paint pristine.

(1) and especially (2) are nearly guaranteed to give you a backache. Hopefully a minor and temporary one.
 

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Discussion Starter · #59 ·
I have had my best luck with singlehanded (1) removal and (2) installation by (1) laying down a tarp etc. and tipping the stripped frame w/engine over on its port side. Remove the motor mounts that you can get at. Pick the frame up, wiggling it deftly to clear the engine. The frame will clear the lump, rocker covers and all.

(2) is more or less the same process in reverse. Lay the engine down; insert appropriate scrap lumber underneath so it lies with the crank pointing straight up. It's possible to put the frame down, although a helper speeds up the process a lot. NB: This is harder to accomplish than the engine removal, helper or no. And note that I've never been too much concerned about keeping the frame paint pristine.

(1) and especially (2) are nearly guaranteed to give you a backache. Hopefully a minor and temporary one.
Appreciate the reply Ratso and for your solution to the problem. Today I wheeled the frame out of the garage and cleaned of all the old ingrained grease and dirt in readiness to mount the engine at some point soon.. Haven't really looked at it all up until now as it was dumped on me and stored away and wondering if anyone can clear up some of the wiring from the images. As you will no doubt appreciate this is a well messed with bike, if it were in standard factory form I would have a better chance of identifying the various wires etc. Seems to be an unused rectifier mounted on the rear mudguard and possibly the finned, made in Taiwan, Electronic ignition module mounted with just one bolt under the seat with three white wires with bullet connectors on the end. Hoping the wiring will speak for itself as the assembly progresses. The seat is crudely bolted down through the mudguard so may have to remove to trace everything back and remove the battery etc. A few images of the bike in its current form which I have to say Is not my cup of tea and well messed with over the years. If done properly these bikes can look great but this one has been constantly bodged over the years.

Tire Wheel Fuel tank Vehicle Automotive fuel system
Tire Wheel Bicycle frame Bicycles--Equipment and supplies Bicycle tire

Automotive tire Motor vehicle Tire Automotive design Rim
Tire Wheel Bicycle frame Crankset Bicycles--Equipment and supplies
 

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Ugh.

I drifted off at some point, evidently. My engine removal/replacement advice applies to pre-OIF bikes, not yours. Sorry to clog the thread with it.

That's a bike in the throes of a bad identity crisis, huh? Makes you wonder what the PO could have been thinking.
 
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