Need Input on a Group K Motor

Indyxc · 07-03-2009, 03:47 PM

I purchased a Stage 2 Group K long block for the Ultra 150/STXR (no carbs, reeds, or exhaust) from a forum member here, that believes it was setup to run on 100 octane. (haven't received the engine yet). He ran race gas on it.

This will be replacing a stock engine, running with stock carbs, stock exhaust, stock timing, stock reeds. On the original engine in my ski the stock engine one cylinder melted the piston rings, and then hit the piston skirt on the side of the block, then pushed the piston pieces through the case.

My questions are:

-How can I verify if this kit is 100 octane or 91 octane? If 100 octane, can I send the heads back in to be modified for 91 octane? The owner says it can be modified backward. How much will this cost?

-The carbs are stock and basically 9 years old. Im not sure why the original engine died (I suspect sand gloging the cooling outlet fitting), but I would like to send the carbs in, have them gone over, and the correct jets installed. How much will this cost?

-Since i didn't buy the engine with the exhaust, can I purchase the exhaust mod separately?

Thanks

Group K · 07-07-2009, 02:30 PM

The 100 octane heads can be made to 91 octane .... we will need to get the heads to check the CC volume...they are not marked 100 octane or 91. Just re-jetting the carbs will be $120 (parts & labor)...if other internal parts are needed, that would be extra. The Exhaust mod kit would be available seperately.

Respectfully, Harry Klemm

Quote:

Originally Posted by Indyxc

I purchased a Stage 2 Group K long block for the Ultra 150/STXR (no carbs, reeds, or exhaust) from a forum member here, that believes it was setup to run on 100 octane. (haven't received the engine yet). He ran race gas on it.

This will be replacing a stock engine, running with stock carbs, stock exhaust, stock timing, stock reeds. On the original engine in my ski the stock engine one cylinder melted the piston rings, and then hit the piston skirt on the side of the block, then pushed the piston pieces through the case.

My questions are:

-How can I verify if this kit is 100 octane or 91 octane? If 100 octane, can I send the heads back in to be modified for 91 octane? The owner says it can be modified backward. How much will this cost?

-The carbs are stock and basically 9 years old. Im not sure why the original engine died (I suspect sand gloging the cooling outlet fitting), but I would like to send the carbs in, have them gone over, and the correct jets installed. How much will this cost?

-Since i didn't buy the engine with the exhaust, can I purchase the exhaust mod separately?

Thanks

Indyxc · 07-08-2009, 01:43 AM

Harry,

Thanks for your input. Before I pull the head off, can I install the engine in the ski, and then do a compression check, and based on that determine which it is? I hate pull it apart to find out it's already 91 octane.

Either way, I'll be sending the carbs over for the rejetting and a quick look over.

Thanks

Indyxc · 07-19-2009, 12:20 PM

Harry,

Turns out the Heads are R&D Heads. Here is a picture of the engine:

http://img17.imageshack.us/img17/8186/img00055ewu.jpg

It is definitely running flat top pistons as seen here:

http://img41.imageshack.us/img41/9259/img00059p.jpg

But what is odd, is the head is not running O-Rings, but the stock head gasket as seen here:
http://img122.imageshack.us/img122/2476/img00060.jpg

I also measured the head dome volume with some water, and it measured right around mid 30 ccs (like 35).

I'm waiting on new reed gaskets to do a compression check. However, from this info can you determine if it is 91 octane kit, or the 101 octane kit? Can the R&D heads be modified for pump gas?

Thanks!