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Cylinder walls may be too thin.

Agree, since the VTX bore is 2mm greater.
78.74015748031496 thou = 2 mm.

From memory, a 0.060 overbore is as far as I've ever heard of working well....that would be 1.5239999999999998 mm, so I'm going out on the proverbial limb and saying, "No....I don't think it can be bored that far."

There are MANY here who are better bike mechanics than I, so don't assume that's the final word.

But, as a former engine builder who only built small block Chevys, let me also throw this out there:
Fair chance that even if the jug WOULD stand that massive overbore, what are the OTHER differences?
Besides bore dimension?

Would also need to know CRITICAL differences, like:
Wristpin size / length, wristpin placement in the piston, compression height, difference in stroke vs difference in connecting rod length, difference in shape / size of combustion chambers.

If stroke, or rod length is indeed different, does anyone make a stroker rod? Or a stroker piston, with the ring grooves still above CL of the wristpin?

Another Stroker Killer is case interference.
Where's it gonna hit?
And, alas and alack.....it's gonna be tough to predict....unless you are a mechanical engineed and can CAD it all out.
OR unless you spend the bux for custom parts, and mock it all up, only to find.....

As the man who taught me to build engines to turn upstairs and live, useta say: "Serious horsepower costs serious money; how fast do you wanna go?"


I dunno.
But I gotta believe: if the conversion you have in mind was doable, there would be ads showing stroker parts!

JMO.
 

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Fair chance that even if the jug WOULD stand that massive overbore, what are the OTHER differences?
Besides bore dimension?

Would also need to know CRITICAL differences, like:
Wristpin size / length, wristpin placement in the piston, compression height, difference in stroke vs difference in connecting rod length, difference in shape / size of combustion chambers.
My thoughts exactly, Gnarly. You might be able to get the piston to fit, then find out it slams into the valves because it's .010 taller from pin to crown than the 1100 piston. Are the heads shaped the same? Are the crank journals the same? Etc.

You could certainly bore out the 1100 to something else that fits, but I really doubt it would be the VTX1300 piston. You may have more luck boring it out to another manufacturer's smaller engine displacement piston with a shorter pin to crown height, using a longer rod to gain more torque. There's lots of math to say for sure, but custom engine parts add up quickly and a pair of custom connecting rods might cost as much as a rebuilt VT1100.

So, I guess the real question here is, what's your goal?
 

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Neglected to mention: along with length / compression height / stroke, both ends of con rod would need to be examined / compared.
No need in building something perhaps also requiring a special thickness / width con rod bearing.

charlesvt: didn't mean to rain on an otherwise fine idea.
But concerned that you would need to feed this project cubic dollars.
 

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There is a LOT of math that comes into play, even if the wrist pin height is the same on both pistons. However, 2mm in width is only 1mm in radius people :) I see no reason why 1 mm couldnt be taken out of that bore.

But, i do not think you can turn an 1100 into a 1300 that easy. If its a higher comp piston and EVERYTHING is the same except for the bore, its POSSIBLE, but more than likely way more cubic dollars spent than comp points gained in the end.
 

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Im not going get in to number but im just going to say no it can not be done. Honda uses a block jug combo and made it all to thin to keep weight/balnce/ other things down. Ive thought about this a lot myself however if you can trust a motor shop to bore the motor over a large about to re sleave it so you got a strong wall your be able to go to a 1200 cc and you still cant use the 89. You can use a 88.2 or 88.6 cant rember . But now your talking big customer parts needing better cooling and so on for little gain.

There is no replacement for displacement however droping in a 1300 or 1800 vtx motor under a shadow might be something .
 

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A guy tried putting an 1800 in a Fury and too much of the frame needed cutting so he dropped the idea. Plus, shaft drive...
 

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a larger piston will not really increase hp much. if that's what you are looking for then look for a set of 85,86 pistons, they are higher compression. add the 85,86 cams and inner valve springs. you can find the cams and pistons relatively inexpensively on ebay, just make sure the cams are not scored. been done before. the OEM inner valve springs are still available from honda.
 

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Discussion Starter #11
Thanks guys, i actually have a set of 85 pistons and cams already. Was looking at aftermarket parts the other day and came across the higher compression pistons for the vtx, which are actually flat. Thats were this whole idea came from. I was looking at vtx piston pics on ebay and to be honest look similar to the vt, but then again pics dont mean anything. Im going to try to get a hold of a piston to do proper measurements
 

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Good luck with your project, regardless.
And keep us posted!
 

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Agree, since the VTX bore is 2mm greater.
78.74015748031496 thou = 2 mm.


JMO.
No.. It's only a 1mm increase.. if we take 1mm off the bore that is 2mm across the bore.

But the important thing would be if the other sizes all matched, length of piston location and size of gudgeon pin in both pistons, all that boring stuff.

Make your own decision.

John.
 

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No.. It's only a 1mm increase.. if we take 1mm off the bore that is 2mm across the bore.

But the important thing would be if the other sizes all matched, length of piston location and size of gudgeon pin in both pistons, all that boring stuff.

Make your own decision.

John.
Even if it's 1mm vs. 2mm, what's the largest Honda oversized piston for the 1100? From a quick forum search, I found this thread from 8 years ago...

http://www.hondashadow.net/forum/72-technical-discussion/60173-bore-kits-vt1100c.html

And one of the first posts in that thread is:

I can suggest: Designed Performance for help. www.designedperformance.com

A few years ago, using the early design like you/me have, they did a "serious" mod to this type engine. They could help more than us poor smucks who don't have the money/resources for anything more serious than pipes/carb adjustments.

You'll see that they have moved on to the "newer design" Honda VTX engines. But they could be a good source for possible piston/cam makers, valves or interchangable pistons for your project.

Hope this helps.

Bullzeyet
So, seems like a null issue - 1mm vs. 2mm. Even the performance companies adopted the VTX1300 as their platform back in the mid-to-late 2000's. Probably cheaper to find a good 1300 starter bike than upgrade the 1100 to something substantial.
 

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as with any internal combustion engine, preformance is only regulated by how well you are usin what you got. shaving the heads can add compression, full balancing and blueprinting can gain rpm's, porting the heads can gain flow rating, along with increasing valve angles. if you wanna get really hard core, make yourself a fuel injection system and figure out how to add a turbo to that thang!!!!! yeehaw!!!
 

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Even the big bore kit for the 1300 adds minimal HP when coupled with all the other mods. It claimed a 20% increase for slugs, cams and something else i cant remember. But, it needed pipes, intake and fuel controller for that.

We (the Fury guys) found a place that can crack the Honda ECU and reflash it. How does a 21% dyno verified increase with only a Cobra intake and Freedom Performance pipes sound? Everything else was ECU tweaking, raising redline, adding timing advance here and there etc. The guy who have done it say its a totally different bike and very well mannered even when you hammer it.

So, the short lesson is, its easier and possible to tweak what you have rather than tear it all down. That is, if youre FI.
 

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There's an old hot-rodder saying, "There's no replacement for displacement in the top end."

 

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Even the big bore kit for the 1300 adds minimal HP when coupled with all the other mods. It claimed a 20% increase for slugs, cams and something else i cant remember. But, it needed pipes, intake and fuel controller for that.

We (the Fury guys) found a place that can crack the Honda ECU and reflash it. How does a 21% dyno verified increase with only a Cobra intake and Freedom Performance pipes sound? Everything else was ECU tweaking, raising redline, adding timing advance here and there etc. The guy who have done it say its a totally different bike and very well mannered even when you hammer it.

So, the short lesson is, its easier and possible to tweak what you have rather than tear it all down. That is, if youre FI.
Ignetech do programmable units for most bikes, well priced too

I looked at one for mine but didn't here back to me so went OEM.... unfortunately I didn't find that my email provider spammed out there massage until I had the new (Gmail backup received the reply and it was cheaper than OEM)

I have often wondered in the Fury injection could be modded for my bike...that and the ignetec could be interesting....if i had the time and money.... just because i like to tinker
 

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Ignetech do programmable units for most bikes, well priced too

I looked at one for mine but didn't here back to me so went OEM.... unfortunately I didn't find that my email provider spammed out there massage until I had the new (Gmail backup received the reply and it was cheaper than OEM)

I have often wondered in the Fury injection could be modded for my bike...that and the ignetec could be interesting....if i had the time and money.... just because i like to tinker
There is no replacement for displacement at the top end...

supercharging the Valkyrie

Supercharge a Valk 1.5 and you're in a whole different ballgame....
 

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I understand it's an old thread. However, I've been looking into this and this is one of the very few threads on this subject. A piston swap from a 1300 won't work. The pin is 20mm vs 22mm on the 1100 piston. I found something interesting in that the bolt pattern for the cylinders is eerily similar and may be identical. Compare the gaskets. https://www.partzilla.com/product/honda/12191-MBH-003?q_ref=12191-MBH-003
https://www.partzilla.com/product/honda/12191-MEA-671

It may somehow be possible to swap the jugs and then the heads. The bolt pattern has to be the same and timing chain has to line up. What I don't know it's the rod lengths for each engine and the journal diameter. If the lengths are similar and the 1100 journal diameter > or = to the 1300, it could work. A lot of ifs.
 
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