Manfred's TR1. Discussion Boards - XV750E　　Restoration

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13.05.25 at 19:56:09

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XV750E　　Restoration (Read 1661 times)

suzuki Ex Member	XV750E　　Restoration 28.12.20 at 01:52:13 Hello everyone I got the XV750E (5K0) that had been left for a long time and am restoring it. 5K0 is a Japanese local model with the TR1 engine replaced with the XV750. https://global.yamaha-motor.com/jp/showroom/cp/collection/xv750e/ It is necessary to bore up the cylinder and replace the piston and piston ring. There is a problem with obtaining parts, but if possible, I would like to use the TR1 or XV920 cylinder and piston to power up. (1) Is there a difference in the crank mass of TR1, XV920, XV750, and XV1100? (2) If I use the cylinder head of the XV750 to increase the displacement, the compression ratio will be 11.1 for TR1 and 10.5 for XV920 by simple calculation from the volume ratio, but isn't there a problem? * The difference in each piston height is not taken into consideration. If possible, I would like to use the cylinder head and crank of the XV750 to improve performance. Regards suzuki
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nanno TR1 Board Extraterrestrial Member Ich mags halt gern ned ganz so original... Posts: 2263 Gender: Bike: TR1, XT600, SR500-Gespann	Re: XV750E　　Restoration Reply #1 - 28.12.20 at 09:55:02 Hi there, first of all: welcome. I have a set of (like) new first oversize 750 pistons (and cylinders, but you may want to have them bored yourself), which you could have for a decent price. I would recommend new rings though. A 920/981 conversion is possible, but you would have to bore out the crankcase-mouths as the liners have a bigger outer diameter. Fitting 750 heads is no problem at all, but the figures you quoted do not take the headgasket into account plus the fact that pistons usually "sit low" in the bore, i.e. they are recessed by varying amounts. So in reality the compression ratio is more like 10.2-10.3:1 for an 1100 and even less for a 981 or 920. Bear in mind that depending on the version of 700/750 heads you have, the wedge is a different width thus making it more or less prone to detonation. Cheers, Greg
	Frei ist, wer frei denkt! http://greasygreg.blogspot.co.at/
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Ali TR1 Board Extraterrestrial Member Posts: 1279 Bike: TR 1	Re: XV750E　　Restoration Reply #2 - 28.12.20 at 12:14:44 Rods are different, it is not possible to use 750 Rods with 920/1000 Pistons. The small-end has another diameter, the lenght is different. Also the balancing weight of the cranks differ a bit. So in my opinion it is the best way to get a 920 or 1000cc engine, or the needed parts of those. Also Crank, Rods , Pistons and cylinders of the 1100 models will fit with some minor modifications. Using a 750cc head with bigger cylinders should be no problem, compression ratio will be around 10 point something, as Greg mentioned, Ali

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suzuki Ex Member	Re: XV750E　　Restoration Reply #3 - 28.12.20 at 22:58:37 Hello, Greg, Ali Thank you for your valuable information about the XV series. It doesn't seem easy to change the XV750 to TR1 or XV920 specifications. In Japan, motorcycles of 750cc or more were not sold domestically until 1990. The TR1 was for export only, and Japanese riders at that time had a longing for more than 750cc. A few TR1s have been reimported from Europe, but are now hard to find. The crankshaft and transmission of the XV750E are a little rusty, so the crankcase needs to be disassembled. For the engine restore of XV750E, consider whether to use an oversized piston or replace it with TR1 / xv920 parts (with crankcase boring), including the cost. May I email you about the oversized pistons, Greg? Thank you, everyone. For your reference, I will tell you the URL where the interview with the TR1 developer is posted. (But it's in Japanese ) https://global.yamaha-motor.com/jp/showroom/cp/collection/xv750special/story/interview/ Regards suzuki
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nanno TR1 Board Extraterrestrial Member Ich mags halt gern ned ganz so original... Posts: 2263 Gender: Bike: TR1, XT600, SR500-Gespann	Re: XV750E　　Restoration Reply #4 - 29.12.20 at 08:49:38 Quote from suzuki on 28.12.20 at 22:58:37: May I email you about the oversized pistons, Greg? I absolutely insist you do. Kind Regards, Greg
	Frei ist, wer frei denkt! http://greasygreg.blogspot.co.at/
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suzuki Ex Member	Re: XV750E　　Restoration Reply #5 - 09.01.21 at 01:51:42 Hello everyone Congestion often occurs in Japan, so I want to improve the cooling efficiency of the XV750E (1983). Is there a replaceable OVERSIZED OIL PUMP? Or is there any other good way? Regards suzuki
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nanno TR1 Board Extraterrestrial Member Ich mags halt gern ned ganz so original... Posts: 2263 Gender: Bike: TR1, XT600, SR500-Gespann	Re: XV750E　　Restoration Reply #6 - 09.01.21 at 10:53:16 Later Models (very likely like your 1983 model) already have got the later oilpump, which is rather easily distinguishable by it's bigger pickup screen. Have a look at XV1100, BT1100, XVS1100 oilpumps. All of the affore mentioned models only came with the later oilpump. If the oilpump installed looks like these, then you already have the biggest possible oilpump installed. Regards, Greg
	« Last Edit: 10.01.21 at 16:31:10 by nanno » Frei ist, wer frei denkt! http://greasygreg.blogspot.co.at/
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suzuki Ex Member	Re: XV750E　　Restoration Reply #7 - 10.01.21 at 14:42:46 Thank you In the parts list of XV750E (5K0), the early type oil pump is specified. Take the oil pump out of the crankcase and see if it has a bigger pickup screen. Regards， suzuki
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