1990 superjet 650 switch to 62t 701

[myblackz28]

im looking to get a 62t motor for my 90 superjet, it had a 650 and it blew on me so now i figure wat better time to upgrade. i know i will need the dual carb setup for the 701 62t, but what all would not work? Stator, ebox, starter, flywheel, coffman exhaust? anything atall. please help. thanks!

 

[myblackz28]

anybody have any info for me? or advice? thanks
does the cdi need changed?

 

[Matt_E]

You can keep all your old electrics.
The stator, flywheel, starter will bolt right in. Your CDI will work, but the RPM limit on the 650 is lower. You can get around this by getting an aftermarket ignition like the MSD enhancer or the ATP EPIC.

 

[myblackz28]

ok, ive read some bad things about the msd enhancer, but i will look into the atp. and thank you for the info

 

[myblackz28]

is $650 shipped to much for a 62t with 135 compression? with carbs
at what compression does a motor need a top end rebuild?

 

[tor*p*do]

you should be getting 150 in each cylinder
135 is low, top end is weak

 

[BruceSki]

I have the whole intake side of a 62T for sale if you come across a shortblock. Intake mani to flame arrestors.

 

[Matt_E]

you should be getting 150 in each cylinder
135 is low, top end is weak

This could be easily attributable to a cheap compression tester, hot air temperatures, higher elevation, a slow starter, bad battery, or even higher port timing.

 

[myblackz28]

thanks for the responses. the guy is in page arizona which is 4200 feet above sea level, idk how much that would affect it? i ride once or twice a week, for probably 4-5 hours id guess, how long would you guess expect this top end to last? i will probably look at a top end rebuild from sbt when the time comes, but is there a way to be sure it doesnt hurt the cases and crank? or is it all by chance?

 

[Matt_E]

At 4,200 feet, it doesn't surprise me that he's getting only 135 psi. That sounds normal.

 

[myblackz28]

will the coffman exhaust from my 650 work on the 701 62t? i never got a answer for that. will stock need ported or something? thanks

 

[Matt_E]

It should work. The ports don't quite line up and you will need to either enlarge the bolt holes in the manifold or put timeserts/helicoils into the cylinder holes.

 

[myblackz28]

another question, what and were do i reinforce my hull with for freestyle and big air. figure i would do it now while the engine is out let me know thanks again

 

[Matt_E]

Check the Tech FAQ.

 

[myblackz28]

where do i get the gasket for my coffman exhaust manifold to the coffman pipe?

 

[Penken]

i recently put my coffman sizzler from my old square on my newer rn superjet. 62t/61x.
it was a direct fit. just ordered a 61x exhaust gasket and portmatched it. didnt need to do anything with the bolt holes.
and i used the b-pipe gasket between exhaust manifold and headpipe. works nicley. haven´t had a problem with it.

 

[Matt_E]

The OP is using a 62T cylinder, not a 61X. This is not a direct fit.

 

[mademan9]

I installed a 650 protec pipe on my 62t, all i had to do was make the bolt holes bigger.

 

[myblackz28]

what do i use to pull the flywheel? i have a pulley puller but are the small holes on the flywheel threaded? if so anybody know what size? or is there a easy way to pull it?

 

[BruceSki]

Yes they are threaded. Dont thread them in too far or you will damage your stator. Maybe three or four turns in is all i usually do on the three bolts and then tighten the puller bolt and hit the flywheel with a dead blow hammer. It will pop right off.