Genesis vs Exup blocks??

weiner127 · Post by **weiner127** » Tue Nov 09, 2010 9:19 pm

Does anyone know what if there's any differences (other than the bore)between the Genesis and Exup blocks?? Long story short I have an 88 Genesis engine running at least the rods (19mm pin) from an 89 or later engine. It has a 1040 kit which I have a broken sleeve in the block. Whats the best option...resleeve that cylinder and rebore it or rebore another complete block. If the blocks are the same it makes it easier to find another or possibly if someone has a block already bored for 1040 with no pistons that they want to part with could make life real easy. It expensive to be this stupid, funny how I seem to end up everyone elses MacGyver'd up stuff, lol. I have brand new 1040 Wisecos.

hotcam · Post by **hotcam** » Wed Nov 10, 2010 3:28 am

I'm 99% certain that the cylinder spacing is bigger on the EXUP series blocks.

The Genesis blocks get up to 1029
and I think that's the max, whereas the EXUP blocks have enough room and
sleeve thickness to get bored up to 1040 without new sleeves,
and the block can be bored to accept bigger sleeves,
takes it to 1070 with no other mods.

That might be related to the broken sleeve?
If you have a Genesis block with original sleeves, can be bored to 1029, and
the previous MacGyver has bored it all the way to 1040, that might make
the sleeve too thin for durability...

spook · Post by **spook** » Wed Nov 10, 2010 4:02 am

hotcam wrote:I'm 99% certain that the cylinder spacing is bigger on the EXUP series blocks.

Ummm, what do you mean by cylinder spacing Cam? I'm fairly certain the blocks have the same cylinder center to center spacing, but as you know the genesis motor starts out .5 mm smaller and so ends up that way after 1.5 mm oversize at 76.5 mm. If your liner has cracked it might have been a Genesis cylinder block bored to 77 mm and hence stressed.

What are the casting numbers on the block you have? 2GH is genesis in Australia, 3GM exup.

hotcam · Post by **hotcam** » Wed Nov 10, 2010 4:24 am

spook wrote: I'm fairly certain the blocks have the same cylinder center to center spacing

Hmm, dunno then. Maybe I'm thinking of carb spacing, but it'd be worth
checking before purchase. I know the genesis is narrower in some aspects
of the engine, but I've never owned one so it's hard to be certain which and
what.

weiner127 · Post by **weiner127** » Wed Nov 10, 2010 1:30 pm

Back in the late 80`s they did make a 1040 kit for Genesis motor but discontinued it, I know because I`m old and was there, lol. Oh well bottom line is that I have a genesis block bored to 1040 with brand new 1040 pistons that I have to use so I`ll have to bore another block or resleeve the broken cylinder and rebore it. If I dont do that I`d have to change the rods and go with a 1029 kit and the $700 I spent on the 1040 pistons would be wasted. Considering I have a block here I`ll just have to find someone to do a quality bore job. Thanks guys.

duke22 · Post by **duke22** » Wed Nov 10, 2010 2:35 pm

I'm fairly sure the Genesis and Exup blocks are interchangeable, I hope so 'cos I'm planning on putting an Exup block in my motor. The castings are different internally to allow for the thicker liners and bigger bore of the later motor, but bolt centres are the same. The only issue I found is that the outside diameter of the liners on the Exup is slightly bigger, which is a (minor) issue with my bored out FZ750 cases.

BTW, my engine machinist looked at the Genesis block and didn't think there would be any problem taking it out to 77mm for the 1040 pistons. I'm just using the Exup because it was there (and for an extra safety margin).

spook · Post by **spook** » Wed Nov 10, 2010 5:24 pm

duke22 wrote:I'm fairly sure the Genesis and Exup blocks are interchangeable, I hope so 'cos I'm planning on putting an Exup block in my motor.

And I have one on mine.... Must say I did run and check...lol. Thanks for the excersise Cam

I used an exup block freshly bored .5 with my 1029 kit, and the genesis block freshly bored .5 with standard exup pistons. Both can be further bored and used at a later date

weiner127 · Post by **weiner127** » Thu Nov 11, 2010 12:10 am

So the question is now does anyone have a Genesis or Exup block that is bored to 1040 and in good shape that they will part with for a real reasonable price

spook · Post by **spook** » Thu Nov 11, 2010 1:27 am

I would not bore a genesis barrel to 1040. There is probably a good reason Wiseco withdrew the product and reduced the spec to 1029. Like cracked liners.

You generally bore to piston size... buying a block bored already might not work out well. Try Zaid in the for sale section? He had some barrels on offer.

hotcam · Post by **hotcam** » Thu Nov 11, 2010 2:15 am

spook wrote: And I have one on mine.... Must say I did run and check...lol. Thanks for the excersise Cam

No problem, any time I can be wrong and confuse people, just let me know!

spook · Post by **spook** » Thu Nov 11, 2010 2:24 am

sickle44 · Post by **sickle44** » Thu Nov 11, 2010 2:29 am

Not sure if you said you can get away without resleeving for 1070 or not there Cam but indeed you DO need to resleeve for 1070. You are correct in not having to for the 1040 though.

If that's what you said, sorry, just not exactly sure what it was you said, so.......

hotcam · Post by **hotcam** » Thu Nov 11, 2010 2:45 am

I know the EXUP blocks and sleeves are fine for 1040, highly recommended to
resleeve for 1070 although there are people on this forum who say they have
got away without it. As for Genesis I couldn't say.

creed12r · Post by **creed12r** » Thu Nov 11, 2010 8:53 am

hotcam wrote:I know the EXUP blocks and sleeves are fine for 1040, highly recommended to
resleeve for 1070 although there are people on this forum who say they have
got away without it. As for Genesis I couldn't say.

There are very few people running the 1070, as far as I know they have all re-sleeved including me.
It's not just the thickness of the liners, it's the width of the liner flange that the head gasket seals to, if you just bore the liner out, there's not enough meat left to seal the gasses.

duke22 · Post by **duke22** » Thu Nov 11, 2010 2:27 pm

Maybe I'm thinking of carb spacing

The later Thunderace carbs (38BDSRs) do have a different spacing which makes me wonder, how different is the Thunderace motor compared to the Genesis and Exup?

kiwi60 · Post by **kiwi60** » Thu Nov 11, 2010 3:58 pm

The later Thunderace carbs (38BDSRs) do have a different spacing which makes me wonder, how different is the Thunderace motor compared to the Genesis and Exup?

Hmm, could this be a cunning plan being formed...?

sickle44 · Post by **sickle44** » Fri Nov 12, 2010 2:04 am

Just slightly different head is all, can't remember if the valve angles were changed or not.

Pre- Exup motor, I think you are indeed correct Cam, 1029 is the max available. I have seen stuff close to a 1200 for the exup though.

spook · Post by **spook** » Fri Nov 12, 2010 3:36 am

Thunderace has a much lighter crank, and I think different outer carb castings? I think Yamcati made mention of that a while ago. Head and cams I'm not sure about, but it is closely related to the YZF750, and was the fastest of them all! Rings tended to burn oil also. They also have TPI so ecu is more sophisticated

3GM and 4HV cranks side buy side

sickle44 · Post by **sickle44** » Sat Nov 13, 2010 2:41 am

WOW,
Can't believe the difference in Crank size eh?

That's pretty unreal.

Funny how the overall bike was still a fat pig though, didn't even lose weight, and in fact didn't it even gain some, the thunderace?

kiwi60 · Post by **kiwi60** » Sat Nov 13, 2010 3:11 am

Thunderace has a much lighter crank, and I think different outer carb castings? I think Yamcati made mention of that a while ago. Head and cams I'm not sure about, but it is closely related to the YZF750, and was the fastest of them all! Rings tended to burn oil also. They also have TPI so ecu is more sophisticated

3GM and 4HV cranks side buy side

Spook, you might have just given me a few ideas for when I build the next motor

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Genesis vs Exup blocks??

Genesis vs Exup blocks??

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