big block oilcooled gsxr750 motors

**Shadowzone** · 17-09-2008, 04:59 PM

I reckon you should leave the head on My Gixxer and nick off and buy your own Clive.

That's what I reckon!!!

**DCRacing** · 17-09-2008, 05:57 PM

What about Cams? heading for a set of adjustable custom grind cams? who would you go to?
Maybe work out where you want the power and get the 748 head flowed and cams to suit. You know more torque or top end HP.

**03gixxerpilot** · 17-09-2008, 07:54 PM

DC yer looking at a set of custom cams on adjustable sprockets, looking at good low to mid range power with a good amount of torque, porting the 750 head would proberly be the best way to go.

Shadowzone i wouldn't touch the head on you gixxer as it is STANDARD, i have my own (x3) that i can choose from, so you can stop worring.

**03gixxerpilot** · 17-09-2008, 08:23 PM

oh yer i forgot i would use ivan tigh for the cams

**latheboy** · 17-09-2008, 08:36 PM

quote:Originally posted by 03gixxerpilot

the nest question to look at is what head to use, i have the standard gsxr 748 head to use, i also have a ported and flowed head to suit a gsxr1100 (was dynoed at 195hp on an gsxr taken out to 1216)
what dose everone think of the two options, good and bad for both

Would either of these heads fit without having to make a spacer plate.... the 748 is meant to be the classic way to do this isn't it, not that it matters you use what you got.. Is the 1216 N/A or boosted thats alot of power..

**03gixxerpilot** · 17-09-2008, 08:49 PM

latheboy both will fit, the spacer goes under the barrels to get the deck hight so it dosent matter,( except of corse in the combustion cc's to get correct comp ratio) and the motor that the 1216 head came of was a sidecar (roadracing) n/a motor

**latheboy** · 18-09-2008, 11:00 AM

PM sent

**03gixxerpilot** · 18-09-2008, 05:08 PM

latheboy replay sent

[8D] also i will be ordering the piston kit tomorrow.

**dinorider** · 21-09-2008, 09:53 AM

another option to your build that I have been concidering is to use 1052 barrells on the 748 short stroke bottom end.I have been told that the piston spacing is the same,also for you to consider is combustion volume.the 748 head will have a smaller volume than the 11 head.valve size will also be something to think about if it`s hp your after.I have both motors the 748 and 749 and will be interested to see the final result.

**03gixxerpilot** · 21-09-2008, 10:09 AM

as i have said previously the heads/cc/comp ratio is no big prob as i have the workshop to adjust those paramaters, i did think about the 1052 barrels and yes they would fit as the piston spacing is the same ( in actual fact i have had the barrels of an 1127 sitting the the top case of the 749 the only thing is that the barrels are much higher than the stroke of the 749 and the piston would be a long way from reaching the top of the barrels and the machine work to bring them back to the correct hight is not the way that i want to go ( it is certianly an option if that is the way you want to go )

Once i have the piston kit and barrels bored out to suit, i need to replace the bearings in the bottom end (both mains and big ends) as they are worn and would not stand up to the new top end (increased compresion) or the estra HP been developed, so i will need another week or two to save up for the bearings, but this time can be used got get the machining on the barrels done

I hope to have the motor finished and ready to go in three to four weeks.

**03gixxerpilot** · 24-09-2008, 04:04 PM

No turning back now one set of serco pistons[

] ordered and payed for, got a good price on the pistons as well

, thanks to Bruce for RHD classis supplies and services.

**03gixxerpilot** · 28-09-2008, 08:51 AM

got this yesterday (saturday morning)
very happy with them, checked out crown heights, valve reliefs, etc and every thing will clear very nicely, the "lump" on the piston is lower than the orignal.

So now i have to build up the bottom end so that i can measure up the barrels for a spacer and decdk hight. Rebuild on the bottom end starts on monday.

**latheboy** · 28-09-2008, 09:25 AM

They left some out of your box

**jmw76** · 28-09-2008, 01:20 PM

Hi Guys,

Just a small bit of advice from a relative novice.
The Wiseco pistons have reasonably sharp edges where the machining has been done to create the valve pockets.
I tend to just break the edge on these (give them a small radius) which gives you a little bit more head room for high compression/high boost applications. Just that little bit more protection against potential detonation.
I run a large bore 1052 (81mm bore) with about 13:1 compression on regular pump gas and have never had a problem.

Cheers

**Tone** · 28-09-2008, 01:25 PM

Cool stuff Clive.Hangin to see how this build goes.[

]
Hope you're writing it [u]all</u> down (costs,labour,parts and aggravation) for us to pick over when done.
Cor! This is exciting!

**03gixxerpilot** · 28-09-2008, 02:04 PM

latheboy they aren't missing

if you know what i meen LOL

jmw76 that is very good advice for engine builders

but it is not that it increases the head room (and by this i take it you meen compression ratio), ( well it dose but by soooooo little it dosent make that much diffrence ) the reason it helps is that the piston dosent develop a hot spot on it and thus cause detonation and or preignition.

Tone, all of what i have done and will be doing on the motor is written down here with the exception of how long i spend on the motor, ( have have spent many nights researching this and that is still ongoinig )

**03gixxerpilot** · 28-09-2008, 02:08 PM

oh yer i forgot to mention the i have also ordered the second base gastek, the head gasket and cam chain as well yesterday.

While we are on the subject on cam chains since i am using the long stroke bottom end, and that is what is going to detremin the deck high ( which will be the same as a standard long stroke motor ) that is the cam chain i am (planing) on using. i allready have the gasket kit for it.

**jmw76** · 28-09-2008, 03:48 PM

03gixxerpilot,
Sorry for any confussion. You are correct! Taking the edge off the sharp bits on the pistons makes stuff all difference to the compression ratio. You just want to get rid of all those potential hot spots that can promote detonation. A guy I know does this religously on all his racing dirt bikes now. Previously he was plagued with detonation issues when just slapping in out of the box Wiseco pistons. He runs well over 13:1 on readily available pump fuel.
Making a reliable high performance engine is all about detail.
Any idiot can make a bomb.

Good luck with your build. It's sounding good so far.

**03gixxerpilot** · 28-09-2008, 04:37 PM

jmw16 there was no confusion i was just clearing it up for any that might of miss understood, i do this religously along with alot of other very improtant high prefromance (and keeping it reliable) engine build teckieques, it is a valid point though as a very simple thing can cause a lot of problems and it is easly resolved.

Thanks for the incoragment everyone it helps keep the motivation up.

**03gixxerpilot** · 10-10-2008, 07:57 PM

ok progress ( or lack there of ) report, i have head and base gaskets, full rebuild gaskets , new cam chain, i have two sets of cases to chose form,( i have already chosen a set ), so now i have to measure the crank to work out which bearing i will need to order, get the crank linished (it has a few very small marks that i want sorted) and then i can assemble the bottom end, in the mean while i can get the spacer made up and get the barrels bored out, unfortuanitly this is going to take awhile to get done due the a lack of money ( work is a bit quiet at the moment).

work on the bottom end will progress in the mean time.

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