90 PSI Compression test...

[doobyboy26]

Hi I finally did a compression test on the RAPTOR and I got a reading of 90 PSI...hno:

It will start when you push it and let go of the clutch...

What could be causing this low compression ? Thanks !

 

[kevinsranger]

Hi I finally did a compression test on the RAPTOR and I got a reading of 90 PSI...hno:

It will start when you push it and let go of the clutch...

What could be causing this low compression ? Thanks !

pour a half a capful of oil into the spark plug hole and test again, if the compression raises, its piston rings, if it stays the same its valve seats or seals

 

[lbjamm]

Is this the new stroker?

 

[Rapto350]

how would i do a compression test?
what do i need to do it

 

[lbjamm]

A compression gauge.

 

[Rapto350]

wow im an idiot haha

 

[doobyboy26]

Is this the new stroker?

Yeah this is the new 379 HotRods stroker kit...Probably My fault... My K&N air filter was put in the wrong way without the cover...The air filter fell off probably on the first big bump and it sucked in alot of dirt... This is just a hypothesis I believe

 

[Gen1Pat]

That'll do it^^^ . You holding the throttle open when you do the test? You need to.

 

[doobyboy26]

That'll do it^^^ . You holding the throttle open when you do the test? You need to.

Yeah full throttle... Took it to a stealership and I did it with him... He had a digital gauge and at full throttle... He believes the rings...

 

[duneracerweston]

Well. Now you can get a good piston besides that crapy cast one since you screwed the rings with art that dirt.

 

[Gen1Pat]

Yeah^^^ get yourself a nice JE 85mm and do a 388. Just need to get some custom base gaskets made so deck height can be gotten within spec.

 

[lbjamm]

Yeah^^^ get yourself a nice JE 85mm and do a 388. Just need to get some custom base gaskets made so deck height can be gotten within spec.

^That would be Rippin!

 

[doobyboy26]

^That would be Rippin!

HotRods says you got to use their piston for this kit... Will it matter if I use the 85mm JE Piston ? And do you need race gas ?

I'm willing to give it a try if everything can work out.

 

[doobyboy26]

Yeah^^^ get yourself a nice JE 85mm and do a 388. Just need to get some custom base gaskets made so deck height can be gotten within spec.

I used base gasket eliminator on the stroker kit. Could this work for this piston as well ?

 

[Gen1Pat]

Hotrods is (A) playing it safe, and (B) is making so the average "do-it-yourselfer" can install the stroker kit themselves without having to do any numbers crunching. Jasonp is running the 85mm JE 12:1 piston with the +4 crank. You have to talk to him about what gasket thicknesses he ordered from Cometic. I talked to him about it, but, you are best to hear it from the horse's mouth.

You only need race gas IF you run the 12:1 piston. Just get the 10.5:1 and you will be happy with it. Depending on what gasket thicknesses you choose, you can get it closer to 11:1 and be just fine. I'm running 11.5:1 with my stroker, but, I have a special super lightweight forged stroker piston from CP.

 

[Gen1Pat]

Btw, you will need to ADD base gaskets to it to get the deck height correct. Using the JE will put the piston out of the top of the cylinder a little, and you need to litterally raise the cylinder up. Basically what you are doing it making a spacer like some engine builders use for their stroker kits.

 

[jeffsyfm350x]

Yeah this is the new 379 HotRods stroker kit...Probably My fault... My K&N air filter was put in the wrong way without the cover...The air filter fell off probably on the first big bump and it sucked in alot of dirt... This is just a hypothesis I believe

Some friendly advice add a oil cooler..:iagree:

 

[doobyboy26]

Some friendly advice add a oil cooler..:iagree:

Where do you buy that ? And how hard is it to install ? I was thinking on installing a fan

 

[Gen1Pat]

True dat!^^^

 

[jeffsyfm350x]

First you will need a clutch case mod sparkymichigan did mine or I know 1998yamahawrrior makes them to.. Pm one of them.. And this is the cooler you can use its what i have..
http://www.ebay.com/itm/HAYDEN-401-...Parts_Accessories&hash=item53fa7bfb4a&vxp=mtr