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Engine gurus help

619 Views 5 Replies 5 Participants Last post by  white08450R
Ok this time i want things to be right and i want everything to work properly so instead of playing a gussing game im just going to ask the 450R gods for there assistance, all my parts are trickling in and it time to build it back, im going with the mods listed below in my sig my question is what do i need to do to make sure everything is in order and ready to rock and roll, ill have the help of cheapfast450R building it back which is going to be a BIG help he has the hone tool and all the gauges to check this and that, also with a 14 high compression piston what octan fuel will i need to run and where should i start my jetting?? thanks
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I wouldnt go any lower than 105 octane.


As far as jetting, I would start out with the HRC jetting and go up a few on the Main jet just to be safe.

Your best bet is to set aside some money for a dyno tune as soon as you can get it in and get the most out of your investment and protect it, too.
i run leaded 100 octane in my bikes and they all hjave 14:1 or higher, i would start high and go lower on jetting with a bored carb i would start like 168-170 at least
as whoever bored your carb for jetting specs......only they will know how they have set them up...and whether or not any air bleed mods were performed...

with no air bleed mod.....185+ on the main

with air bleed mod and standard air bleed installed.....168-170 on the main.....

im not familiar with the sparks 14.25:1 piston....but you will want to clay check your machine with that HCIII just in case....


110 TEL fuel is about the cheapest and most common you can readily purchase....so I would go with that.... it is what I run in my machine.....

make sure you deompressor gets readjusted after this install......set to about 60-65psi max....



before you start her up for the first time....turn your idle knob UP.... dont let her idle for extended periods of time.... maybe be ready for a short trail ride.... then come back and check everything out..... have a 'check off' list upon completion.......for OIL (eng and tranny), Coolant, Decomp setting, etc.....so nothing is 'forgotten'...


good luck and enjoy....Greg
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i was hoping the carb was allready set up close to where it should be.....send soyo a pm to ask him what is in it or if he changed any of the jetting??....should be close to what you had in it mabe jetted down some along with a few other changes..... :popc1:

that's some good advise too, greg. i didn't think about a check list...
Alright sounds good 2 heads are better than one thats for sure and cheapfast is a little more picky and observant than me so i should be good, one plus on my bike is i will not have a decompressor setting its automatic on the 08s so that saves little extra time!! thanks for the help parts should be in my posssesion tommorrow!! cant wait to get it back right!!
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