summertime upgrade opinions, motor

skidooboy · Apr 1, 2014

I am going to at least put a new top end in my stockish 09 m8 this summer. while it is apart, "you might as well upgrade/update it" comes to mind. it has about 4300 miles on it with just the slp pipe and can, and stm valves on it. i would like a bit more power but, i dont want to "mess" with the sled all the time to keep it tuned. i would like a "stockish" pull and go sled. thinking about these options. we mostly ride northern ontario back country bush roads, powerlines, and gravel pits at 0-2500 feet elevation. usually one trip west to togwotee per year.

top end, and nothing else

top end, and ho head for more compression

top end, rk tek 15 hp head and shim (more compression, and raised port timing)

top end, rk tek head, and rk tek porting, big upgrade

top end, rk tek 925 bb kit. biggest upgrade

i have spoken with Kelsey, he suggested buying HO cyls, and powervalves and either porting them, or running them with the 925 kit. he said the 08-09 lower end and the HO top end are the best of both worlds. but, it comes with added costs and tuning.

buy the time i port the non ho and put the head on it, i am only about 700 from the 925 kit which includes porting, and new pistons.

i am looking for ho cylinders now and i could always sell the stock stuff but, i am torn on what to do. i would really like to get away from premium fuel with all the issues we have finding it where we ride... which kelsey said we can do no matter what.

any help appreciated. Ski

RobertTrivanovic · Apr 1, 2014

I would go for either the option with the head and porting or the BB. Ive never turned a sled into a BB so I honestly cant say.

I ran his 15hp head with porting ect, the whole deal. It ran spot on 100% of the time and believe me there was some wack tuning in the box when I bought my sled and it still ran good. I also bought it like that so I cant comment on the gains.

A BB would be interesting though, I say if you can afford it go with that, might as well get the most outa it!

skidooboy · Apr 3, 2014

anyone else? i was assuming those that had done these mods would chim in. Ski

Hardass · Apr 3, 2014

complete tare down check the crank and put the 925 in there They run awsome

fast8seccamaro · Apr 3, 2014

If money allows I would go for the full rebuild and 925bb especially if your dropping the compression to deal with the cat piss fuel. I have a 925 and rode a stock 800 last weekend and it felt like riding a 600! Lol

av8er · Apr 3, 2014

That is probably what i will do when I need a top end

throw a 925 BB in it. My D&d901 put out 185 HP but noone had one boosted , but there at least a dozen guys on here who have run boosted 925's including KMOD

skidooboy · Apr 10, 2014

has anyone put ho cylinders and head on their non ho bottom end? i am hearing rumblings this is a best of both worlds set up. sounds like the ho has better porting and configuration, and the non ho has the better, bottom and crank. thinking about matching this up with the Rk tek head.

would like to hear what others have found. Ski

Thunder101 · Apr 11, 2014

I have ported HO cyls on a 09 bottom end. HO cyls are not cheep and you need the ex valves.
It would be alot cheeper to just get your cyls ported, call Dakota perf he charges $500 for porting, PCV with his map $350, SLP pipe ,Y,can $700.

or Big Bore for $2000, plus PCV plus a pipe. I dont think the 09 pipe is ideal

Call Dakota pef there 920 works good is the word

skidooboy · Apr 11, 2014

i can get cyls for and valves for ALOT CHEAPER than the big bore (maybe next year).

what did you run for a pipe, y pipe and can the 09 non ho, or the 10-11 ho stuff?

what did you use for pistons, rings, pins, bearings, gaskets ect.. ho or non ho?

what head did you end up with? might want to pic your brain on a pcv map for low elevation if possible. thanks for the help thunder! Ski

Thunder101 · Apr 11, 2014

I had Dakota perf porting on 09 cyls w SLP single pipe,Y and can, worked well. He has a map for his porting with the slp pipe.
Right now I have HO cyls on a 09 bottom end ,ported by Arctic edge and Jaws twin pipes.

skidooboy · Apr 11, 2014

with your HO set up, are you running jaws ho or non ho twin pipes?

i have a complete slp set up but, it is for the non ho motor. leaning toward the jaws single, or d&d Y pipe, stock HO pipe and jaws can, if i decide to run the HO cyls.

ski

Thunder101 · Apr 11, 2014

Non.
I was told they are the same

skidooboy · Apr 12, 2014

part numbers are different when looking up the pipe and y pipe from cat. from 09 to 10.

i guessing jaws only made one set of twins for both the ho and non ho motors.

i'll be looking for a stock 10-11 ho pipe if anyone has one in decent shape for a reasonable price. Ski

skidooboy · Apr 12, 2014

thunder, did you use a non HO or HO base gasket? Ski

crossfire879 · Apr 12, 2014

I have a 08 M8 and I had my stock cylinders ported and the head shaved by a local (alberta) guy named brent linderman. With his porting and shaved head I also run a full SLP pipe kit and a mix of 108 race fuel. I told him the elevation I usually ride and he gave me numbers for my boondocker box to try and he was basically dead on. The bottom end and mid range power is very noticable. For just a quick little comparison; before the mod on flat ground there is no way the sled would pull the skis off the ground but now its just like riding my dirtbike, mash the throttle and look at the tops of the trees. For the money I spent, I am very pleased with the results. Mixing race fuel is kinda a PITA but it runs way cooler that way. This is all on stock bottom end too by the way.

Thunder101 · Apr 13, 2014

Same base gasket.
Lol Brent is Arctic Edge .
Good fuel helps keeping things alive and dialling things in.

skidooboy · Apr 13, 2014

unless the part numbers supercede to one another... by looking at the part numbers the 09 base gasket is 3007-523, and the 2010 and newer is 3007-874.

this is why i am having a hard time swapping to the HO stuff. i am an OCD person, and a techincal person so, i verify the info, by cross checking ho and non ho part numbers. so when i get conflicting info, i need to get clarification.

i want to know EXACTLY what i need for a COMPLETE installation, without getting in the middle, and finding i need this or that, adding down time, and hidden costs to the "build", or worse... it gets assembled with the wrong parts, and the build fails, and then.... costs REALLY start going up, exponentially.

i would like to order what i need in advance, have it ALL here for the build, tear it down, and put it all back together, and break it in the same day.

right now it appears you can put the HO stuff on the non ho and the cylinders will reward you with extra hp that the non ho stuff can never give you. example, from what i have learned....

if you put stock non ho cyls and head on, and stock HO cyls and head on the non ho bottom end, you will net about 15 hp with the HO stuff.

if you port both the ho and non ho, the ho will net you about 15 more hp after the porting. when going big bore, the ho stuff will net you 15 more there as well. So going with the HO platform stuff on the non ho is a good choice for those planning, stage tuning, or upgrading to porting or big bore later in there sleds life.

i know i need the cyls, head, and powervalves to match the HO cyls. i was told to use the non ho pistons, rings, wristpins, bearings, and clips.

with some gaskets and orings interchanging, that is easy but, some dont.

what i cant figure out is:

what exhaust gaskets to run (ho or non ho)
what base gasket to run (ho or non ho)
what Y pipe to run (ho or non ho)
what pipe and can set up to run (ho or non ho)

if i know what base gasket to run, and what pipe to run, that will tell me what exhaust gaskets to run. once these questions are answered, others that may want to do this, will have answers too.

Ski

bigjb · Apr 14, 2014

One more option to throw in there is the CPC 950 kit. It has it's own cylinders so no worries about getting all the ho stuff. And I think they run the SLP pipe set. Only thing is I'm not sure if it works on the 09 bottom end, might just be for the HO motor.

Thunder101 · Apr 15, 2014

I used a non HO base gasket, I don't recall noticing a difference
Between the base of the cyls.
Bolt patern is a little wider on the exhaust studs ( I ground out the holes
on my manifolds to fit ) but you have to use the HO exhaust gaskets.
D&D has a good y pipe for the HO. Use HO pipe
SLP single pipe kit is a good choice.

skidooboy · Apr 15, 2014

thanks thunder. Ski

summertime upgrade opinions, motor

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