Engine build for supercharger

Hi all, I'm new on the forum. My rides a 1976 Z900 & I'm in the process of planning a complete rebuild around a Harris frame. What I'm looking for is some advice, I want to supercharge the engine with the aim of extracting around 120bhp. The advice I need is regarding the engines internals, do I need to upgrade & weld the crank etc. What size is best, I've been told 1075cc is the best comprise of power/reliability.
Any advice would be gratefully received

zedrunner900 wrote: Hi all, I'm new on the forum. My rides a 1976 Z900 & I'm in the process of planning a complete rebuild around a Harris frame. What I'm looking for is some advice, I want to supercharge the engine with the aim of extracting around 120bhp. The advice I need is regarding the engines internals, do I need to upgrade & weld the crank etc. What size is best, I've been told 1075cc is the best comprise of power/reliability.
Any advice would be gratefully received

Welcome and best of luck on the build! For many cases the stock crank is more than adequate for most any HP levels until you get into the "crazy" category of 200+hp from what I understand, for the most part that is also true for the rods. The pistons are often times what need upgrading and if you applying forced induction you will likely need to lower your compression ratio otherwise you will be dealing with loads of detonation as well. Its not the same bike or engine but in 1984 and 1985 Kawi came out with the ZX750E which was the GPz750 Turbo. The stock internals on those were obviously initially engineered to cope with the extreme stresses, but using only factory components that are blueprinted and balanced many many people are regularly seeing 200+HP without upgrading the components themselves unless they are going to a big bore Wiseco kit. The key is making sure that the stock components are balanced and blueprinted and as good as they can be, adjusting compression since you are going from NA to Forced Induction and having the right fueling and spark maps to avoid detonation. You will also likely need to upgrade clutch and some frame strengthening.... just my thoughts though and others are far more experienced and may give different or better advice.

Brett

Thanks Brett,
I've been looking at the Dynatek Dyna 2000 to sort the ignition. What do you mean by blueprinting? Is this somethings I can do (a mechanical youngling) or a professional builder? If it's a professional job is it done during the build or once the engine is finished?
Thanks for your advice!

Blueprinting an engine means to get every single part to perfect specification. For example, the factory may call for pistons that weigh 300 grams +- 10 grams, which means the pistons can weigh between 290-310 grams and still be acceptable.. Blueprinting eliminates the +- business so that each piston weighs exactly the same as the other three. In a blueprinted engine, every part is scrutinized for weight, dimension and such to make them as perfect as possible. To do it right requires a great deal of skill, knowledge and expensive equipment.

You might be interested in this thread. Maybe you can contact Hollywood for some info

www.kzrider.com/forum/11-projects/557199...-kz1000?limitstart=0

To keep it simple, 1015cc to 1075cc (Wiseco or MTC 8 to 1 comp turbo pistons ) will work great with a supercharger.
You won't feel much difference between them and you will easily hit 120 - 160+ hp depending on blower gearing..
Treat the engine build the same as for a turbo as it's forced induction all the same.
Having the crank welded is a MUST .
Set the ign timing at 35 degrees full advance if keeping single plug - around 30/32 degree for twin spark ( 8 plug head ).
If going NA you need a big carb, S&S Super B or G. If injection then around 55mm throttle body.
My 1075cc Drouin supercharged (very basic roots blower) Zed out accelerates a zx10r and spins the rear just sat at tickover so LOTS of crank twisting torque to play with.
What blower do you intend to use ?
Don't go for the common Eaton 45 as it isn't big enough as I'm sure you probably know.
The M90 is the one to use if going the Eaton route.

Brett mentioned the GPZ Turbo but I also remember a Z1000TC (I think it was called) around in the 80s. Might be worth looking into for specs,parts etc.
Another thing to try is;
www.z1ownersclub.co.uk/forum/index.php
A lot of Harris builds gone through there.Plenty of knowledge and experience and you might find someone local that can help you out,hands on.(If youre in Norfolk, UK)
Good luck with it and please post some pictures of the build.Im very partial to a bit of Harris.

davido wrote: I also remember a Z1000TC (I think it was called) around in the 80s. Might be worth looking into for specs,parts etc .

No point looking at Z1R TC specs. They used the stock engine and just bunged a turbo on it with the boost set low.
Stock comp and stock un-welded crank :ohmy:

Do yourself a favor and pay attention to ZED

I could put in my 2 cents but ZED and I read from the same play book.

120 HP is not that much for a souped up Kaw. Much higher numbers can come from boost.

A couple sayings come to mind.

Build it strong so it will last A strong bottom end is a must if you want it to go fast more than once.

Racings cheap, Winning is expensive

Dave

You may want to take a look at the links below for some ideas.....

www.750turbo.com/forum/viewtopic.php?f=9...0c4f130ab0abe63dc916

www.750turbo.com/forum/index.php

Now that is a seriously sweet ride! I've seen pics online of her before. How long did the build take?
As for my girl, I'm thinking 1075cc with yoshi carbs (not sure about the size yet). I'm going to concentrate on the engine build first then sort the blower out (theres a company I've found with a good rep), what did you mean by treating the build the same as a turbo, is that just making sure everything can handle the power or are there parts/techniques only used on forced induction builds? Cheers for letting me pick your brain

You guys are great! Thanks for giving me so much to think about. I haven't ridden for what seams an age due to a lovely lady driving a Volvo 4x4 who thought picking her kids up from school was more important than looking where she was going. Planning this build in my head has been a total life saver! Thanks again

This is my girl