Interceptor 650 | 865 Big bore kit project | Episode 4 | 865 piston weight VS stock and vibration

[@frederickwoods5943]

Hello again from Virginia, USA; I am the INT750 guy and have commented with you before. Our scales are reading the same, on my scale the stock 78mm piston, wrist pin and rings weighs 300 grams. We show the same weights for stock vs aftermarket wrist pins. Now, my 83.5mm pistons with wrist pin and rings weighs 370 grams. This is the piston in the S&S 750cc (743cc) big bore kit. My pistons have a compression step that I don't see on your 90mm pistons in the video. It is all exactly alike, just smaller liners and Weisco 83.5mm pistons in the 750cc kit. Also appears that the lighter pistons don't vibrate as much. Thank you for this latest video and hope to see more. Fred.

[@ksmotoshed7961]

Hello again Fred! Of course I remember you. I was wondering about the 750 pistons weight, thank you so much for all the info! I'll try to keep making videos regularly!

[@MeAndMyRoyalEnfield]

Nice video. I prefer short videos with good information and you nailed it. I enjoy your intro showing the sight glass 😊

[@ksmotoshed7961]

Thank you!

[@blazesboylan7947]

I didn’t notice any extra vibrations but when the weather gets better here and I’m able to ride again I’ll look for them in the ranges you mentioned. In any case, I’ll gladly deal with a little more vibration for the sake of vastly better torque. Like you said, it’s nothing close to a dealbreaker.

[@ksmotoshed7961]

Thanks for the info! Hope the weather gets better soon. Enjoy riding the 865!

[@williamhannas9342]

Darn it! I hadn't noticed any vibration but now I'll be looking for it. 🙂

[@deltabluesdavidraye]

Hmmm I think that is a large weight increase.But cast pistons are much lighter to begin with.On the average just going to forged Pistons will be a large weight increase and resulting vibration. So cast overbore pistons would likely have a acceptable increase. And they expand less. Forged pistons are stronger but must be looser in the bore because of the expansion. Cast pistons last longer because of this and so does your barrel. With exact same design your cast pistons would be about 45 grams heavier instead of 98 grams heavier.

[@ruahinesrider]

Great information.

[@ksmotoshed7961]

Thank you!

[@TR5T]

I'm just curious how this upgrade rebuild was chosen over the 105-110 rear wheel bhp from the air oil cooled 790/865 Bonnevilles. I do love the stock Interceptor and always have from the 60s. The bike as is comes is just a sweet laid back well made retro.

[@ksmotoshed7961]

I'm not aware of any Bonneville 790/865 producing that much horsepower, (I don't know much about Bonnevilles) but anyway I'm not really chasing numbers and performance. Well, of course I'm enjoying the extra power and it is an objective for this kind of mods, but most of all I just love to do engine work and learn as much as I can in the process. I chose this rebuild because I love my Interceptor as well and I wanna keep it. Also I think that this upgrade doesn't really spoil the retro character and I might dare to say that this bit of extra vibration even adds to it. But I agree that if you only look at the money spent it might not make sense to some people.

[@danielpalumbo6922]

Again , excellent video . And sorry to be a pest . But , Have you done a compression test to see what your cylinder pressure is now , with the new combination of larger displacement, increased compression ratio and longer then stock , intake duration S&S cam ? Cylinder pressure numbers are very interesting , helpful and can be telling when doing engine mods like this . Thanks again .

[@ksmotoshed7961]

Thank you. Don’t worry, for me the main purpose of KZbin is to exchange information. I haven’t yet, but it would be really interesting. I’ve been very busy with other stuff lately, when I find the time I’ll try to do it!

[@deltabluesdavidraye]

Great you make this.

[@ksmotoshed7961]

Thank you!

[@danielpalumbo6922]

Thanks for the info . Excellent video . Does S&S recommend balancing the crank to compensate for the significant difference in piston weights?

[@ksmotoshed7961]

Hi, thanks for watching! I’m not aware of any such recommendation.

[@redzed40]

Interceptor and cat...you got me there lol

[@tridibmazumdar321]

I installed the 865cc big bore kit in continental gt 650 but it is not starting. My mechanic is saying it may be possible due to ecu. I have to flash the ecu first then it will get start . Is this statement correct?

[@TheFatalintention]

i wonder if you can do this with the super meteoro since is the same motor

[@ksmotoshed7961]

I suppose so, but I can't be 100% sure. The big bore kit on Hitchcock's website lists only the Interceptor and Continental GT as compatible bikes. On the S&S site says "for 650 twins".

[@doughoffman9463]

Overall cost of the 865cc conversion (include new camshaft, new fuel injection electronics, etc)?

[@ksmotoshed7961]

Hi, I’m preparing a video with details about the overall cost of the conversion.

[@worldofameiso5491]

From the links you gave in one of your videos I worked out that in the UK it would be over £4,000 - which for a 10 BHP increase is way too expensive. @@ksmotoshed7961

[@kaibersidhu08]

Impact on fuel economy after big bore kit upgrade?

[@ksmotoshed7961]

Hi, its around 20 km/l now. I'm planning to include detailed info about the 865 fuel consumption in one of my next videos! Thanks for watching!

[@r.i.p2464]

​@@ksmotoshed7961 during your next video. Do you mind doing some light input and shifting early like 3000rpms. My bike can average from 29-33kmpl when i ride it that way. Riding it aggressively gives me 20-22.