New Engine Questions

S

slackerme

I currently have a 90 superjet with stock 650 in it and factory B pipe. I have been riding stand ups for 2 years and this will be my 3rd. I want to start to learn some tricks and possibly barrel roles.

Anyways Michael Miller screen name blasterboy1980 has offered to take a
61x cylinder and bore it out to 83mm or 740cc and also port it and said I can just take my cylinders off and bolt the new one to it. He also is going to port match my exhuast manifold when i send it to him
My plan with having him do this for me was to save some money and just have him do the cylinders and then later down the road I can ditch the 6m6 cases, stock reeds, and carb and upgrade.

Questions

1. Will 61x cylinders bolt right up to my 6m6 cases?
2. Does this sound like a good idea to you guys for a power gain or is there somethin totaly diff I should do to get what I am looking for?

Thanks
DAN
 
norcal ex

norcal ex

X-H2
Location
San Jose, CA
They will NOT bolt right up. you will have to bore the cases so the sleeves can fit it. Also, boring a 61x to 84 mm is not going to be safe. the sleeves will be very thin. In the long run you will actually be spending more money with more down time. Can I ask how much he wants to charge?
 
S

slackerme

He is boaring to 83mm
$800 total for 61x cylinders ported and bored to 83mm.
pro X pistons
he is going ot port match my manifold and tune my head pipe

So is it going to bolt right up or not??
 
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meatball

meatball

User Title Unavailable
Location
Maryland
yea, your gonna have to modify the cases to make it fit. At this point in time, its much more cost effective just to buy some X or T cases and ditch the 6m6 altogether (still using the crank, and flywheel/stator). You can use the 6m6 cases, but if you get them clearenced by a machine shop it will cost you probably a bit less then a set of 61X cases go for (100 bucks). I would just upgrade it while your at it, with X cases you can still use the same carb.

Oh yeah, and mod the CDI or upgrade so the REV limiter dont hold you back, especially with the B-pipe running at higher then stock RPMS.

What your looking at right now, is basically saving 100 bucks. As when you buy the 61X cylinder with pistons, thats one step shy of having a true 701, just buy the cases to match and get it over with, it will save you 60-80 bucks in the long run (for machining work)

If your saying you'll send him your engine and it will come back with a 61X cylinder, then sure, Im guessing he'll clearance it for the cylinders. There are a few people out there with 6m6 case based engines, but not many, as the intake tract upgrades and reed blocks are better in the 61X and 62T. I say buy a used set of cases, and send him those as well, and sell the 6m6 cases for $50 or so on ebay.
 
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meatball

meatball

User Title Unavailable
Location
Maryland
slackerme said:
He is boaring to 83mm
$800 total for 61x cases ported and bored to 83mm.
pro X pistons
he is going ot port match my manifold and tune my head pipe

So is it going to bolt right up or not??
Click to expand...

you said cases... do you mean cylinders?

EDIT: assuming you mean cylinders, 6m6 cases need modification before 61X or 62T cylinders will fit.
 
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jetskiking

jetskiking

Im done sanding!!!
Location
Dallas Georgia
You could probably get a whole 61x ported shortblock for $800. You will have to clearence the cases. Heres a picture of some clearenced 6m6 cases. You could probably get that much clearence with a dremmel
 

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S

slackerme

yea the problem is I have no clue what to do. I am totaly new to tearing jet ski motors apart.

I was really stoked to buy the cylinders from Micheal but now that I find out they will not fit without modifiying my cases i am bummed.
 
S

slackerme

yea I would have not clue what to do

So basicallt I am stuck in a rut.
Dont want to spend to much money but want to get a more pwerful motor
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
$800 would buy you a decent 61x complete engine, hell there is a 760 for $950 in the classifieds

Do some more research, and ride some more, keep the engine you have as a backup, keep saving buy another more powerful one. or keep learning to BUILD a more powerful one.
 
S

slackerme

Yea I seen that. I want a 701 tho so i dont have to change my eletrical.

I want to find a 701 complete with carbs. I can use my flywheel and startor but I want do the least amout of pieceing a motor togehter.


I guess I will just have to hold out and see what I can find
 
romack991

romack991

homebrewed
Location
Warsaw, IN
just switch the stator and flywheel and run your 6m6 electronics, replace or mod the cdi though.

i wouldnt do the deal you stated in your first post. plenty of much better options. you get that cylinder work for 800. you still have to get new gaskets. rejet carbs. clearance cases, ect ect. not a good plan imho.
 
Speedfreak

Speedfreak

Location
So. IL
Well sounds like it is time to welcome you to the 760 club.

A 90 square with a 760 NICE.... But remember it only starts there next year you will be thinking :thinking: light weight hull or stroker motor :thinking:
 
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