2015 YZ250 needs engine Mods

[stimps]

Red Box could be HorsePowerIgnition Belgium.

That's what I have on mine.fully programmable and 2 programs selected via a rocker on the bars.the torque program flattens the transition into the top end and removes any hit. probably a great bit of kit for those wanted to loose power and make it trail friendly. I bet you could do a program that really weakened the power across the board and then have full power for when needed. might be easier than swapping springs and timing changes. full power mode added around 0.5hp and extended the over rev slightly on the dyno.

[CaptainKnobby]

the carb comes with a #7 carb slide, guys have reported huge smiles and better lowend with going to a #8 slide. Rb cuts the stock 7 slide turning it into 8 slide, adds a wing, bores the carb etc.  essential no, but very worth while.

 

And everything ive mentioned makes tuning much easier.

 

When I send the Cylinder  To R&B Design......Do I just call them and let them know to be expecting my cylinder?  Or Just put a note in the box with the cylinder?  Another thing is.....Do I just tell them I want the cylinder Ported for more Low to Mid power?   Or do they have Stages?  Like Stage #1 Port job Stage #2 Ect?

 

I gonna Ride my 450 today cause I have the 2015 2-Stroke in the Basement ready to take apart.   Suppose to rain here tomorrow so Guess I will start so I can have the cylinder shipped to them by next week.

[E36M3E]

I read something interesting on the RB website. They only take money orders or cashiers checks. So don't forget to throw that into the box as well.

[Kinger317]

When I send the Cylinder To R&B Design......Do I just call them and let them know to be expecting my cylinder? Or Just put a note in the box with the cylinder? Another thing is.....Do I just tell them I want the cylinder Ported for more Low to Mid power? Or do they have Stages? Like Stage #1 Port job Stage #2 Ect?

I gonna Ride my 450 today cause I have the 2015 2-Stroke in the Basement ready to take apart. Suppose to rain here tomorrow so Guess I will start so I can have the cylinder shipped to them by next week.

I thought the cylinder and head were going to Gorr? FYI I heard he might cut the 7 into an 8 for free if you're doing porting work. just curious, what changed your mind?

[CaptainKnobby]

I read something interesting on the RB website. They only take money orders or cashiers checks. So don't forget to throw that into the box as well.

 

I seen that and was wondering if I had to use a Money order.  That's cool!  either way.

[CaptainKnobby]

I thought the cylinder and head were going to Gorr? FYI I heard he might cut the 7 into an 8 for free if you're doing porting work. just curious, what changed your mind?

 

I was going to at first.  But at the time I didn't know who all did porting work.  I had just seen on here where Eric Gorr was mentioned a lot and just assumed he was the only one that was a true Porting person with MX bikes.  Around where I am located they are a couple of people that have done it say like 30yrs but didn't know much about em other than hearing from word of mouth of others just mentioning there names.

Anyways when I got on here and asked about engine Mods I got replies on others.  adam8781 mentioned R@B Designs (which I have heard of in the past) but and knew they were MX related but didn't know what all kind of work they done until I looked em up.

 

Seen they were they done Port Jobsalong with Crab mods so I thought I would have them to do my Carb and might as well send them the Cylinder as well.

 

Not saying Eric Gorr is not as good but just thought I would rather send all my stuff in to one place.   All though I have seen more stuff about Eric Gorr  than R&B. and have seen more posts on Eric Gorrs stuff and that was the reason I had decided at the time on Gorr.

 

Still I don't see a lot of post on R&B but what the heck .....They do it also and am sure they are as good.

[CaptainKnobby]

Will I be able able to still run a stock piston after I have the Porting done?  Or will I need to use a wiseco ,Vortex ,ect...ect...  piston kit?    

 

Will this port job cause the bike to have more compression?  if so will I then need to use a higher compression piston like a Wiseco or Vertex or Vortex?  I know there iVetex pistons but not sure on Vortex.

 

I wouldn't think I would need the motor set for more compression unless you get that from a Port job.         

 

 

Kinda answered my own question.   Read on R&B Designs web site that stated that what ever piston was in the cylinder and what ever gaskets was on and O-Rings when you measured the squish is what kind you use when you get there work back from em.

Edited October 31, 2015 by CaptainKnobby

[CaptainKnobby]

Here is some pics I took of my

plug and cylinder and piston along with a picture of solder where I measured my squish. On the cylinder At the top ...just bout couple of inches b4 TDC. There is some spots on the cylinder wall. Like measels or a rash. Wonder what it is or what caused em? BTW....Squish measurements with my calipers were .074 or .073. All three pieces of solder measured either .073 or .074

Edited October 31, 2015 by CaptainKnobby

[adam8781]

rb doesnt do porting. 

 

rb does machine shop work, send them your head and carb. if you want porting work done, send it to gorr.

[CaptainKnobby]

rb doesnt do porting. 

 

rb does machine shop work, send them your head and carb. if you want porting work done, send it to gorr.

 

OH!...... I thought they done porting as well.     If I send my Jug to Gorr.......wont he need the Head (Piece plug goes in) also?       Seems like I read on his web-site that he sets up the squish band on the head , does porting and will clean up the power valve system.       So to me that's saying just send him the whole top end (Cylinder Head and Jug) and he will mill the head to correct the squish and port the cylinder...............is this correct?     if so I will just send R&B my Carb.

 

Not saying they wouldn't do a good job on my Head but if one person has both pieces they could match it up better IMO.

[CaptainKnobby]

This has got me puzzled now.  Is it ok to send one perso the Head and the other person the Cylinder?    Looks like to me they would want both pieces

 

I guess if they don't need both pieces I will send R&B Design my Head to have the Squish set and send my Cylinder to Eric Gorr so he can Port it.

 

Would this be the route most of you all would take?

[AddictedToBling]

This has got me puzzled now.  Is it ok to send one perso the Head and the other person the Cylinder?    Looks like to me they would want both pieces

 

I guess if they don't need both pieces I will send R&B Design my Head to have the Squish set and send my Cylinder to Eric Gorr so he can Port it.

 

Would this be the route most of you all would take?

 

You can send the whole lot to TSP and he'll do the lot. Himself. He doesn't even have an employee.

 

Haven't checked, but the currant AUD should offer you some pretty good value for money. You have to ship the parts already, won't cost a lot more to ship them to Oz.

You'll get $1.72-ish for every 1 USD you spend. Close to double the money.

Before TSP was an option. I sent my top end over to EG. Was no big deal. It might be worth looking into.

 

Did you checkout the links I posted? The bloke is a 2T genius.

http://twostrokeperformance.com.au/

 

Otherwise, I'd send the lot to EG. It would most definitely be best to send him the head and cylinder (entire top end). If you really want to get the carby bored, send that to the other mob.

Edited November 1, 2015 by AddictedToBling

[CaptainKnobby]

You can send the whole lot to TSP and he'll do the lot. Himself. He doesn't even have an employee.

 

Haven't checked, but the currant AUD should offer you some pretty good value for money. You have to ship the parts already, won't cost a lot more to ship them to Oz.

You'll get $1.72-ish for every 1 USD you spend. Close to double the money.

Before TSP was an option. I sent my top end over to EG. Was no big deal. It might be worth looking into.

 

Did you checkout the links I posted? The bloke is a 2T genius.

http://twostrokeperformance.com.au/

 

Otherwise, I'd send the lot to EG. It would most definitely be best to send him the head and cylinder (entire top end). If you really want to get the carby bored, send that to the other mob.

 

I looked over the link you posted for TSPand it seems like good service.  will I still be able to use a stock piston/rings and gaskets and O-rings if I got the head done for the squish and got the cylinder ported?   How much would shipping be from Virginia here in US to TSP? 

[AddictedToBling]

I looked over the link you posted for TSPand it seems like good service.  will I still be able to use a stock piston/rings and gaskets and O-rings if I got the head done for the squish and got the cylinder ported?   How much would shipping be from Virginia here in US to TSP? 

 

Yes.

 

I'd say around $80.00 AUD to post each way. 

[mlatour]

Here is some pics I took of my

plug and cylinder and piston along with a picture of solder where I measured my squish. On the cylinder At the top ...just bout couple of inches b4 TDC. There is some spots on the cylinder wall. Like measels or a rash. Wonder what it is or what caused em? BTW....Squish measurements with my calipers were .074 or .073. All three pieces of solder measured either .073 or .074

📎1446323152883.jpg📎1446323172240.jpg📎1446323189547.jpg📎1446323203180.jpg📎1446323215853.jpg

 

Not sure about those spots on the cylinder wall, have you ever had an engine failure previously ?

 

As for the squish, .074 inches is about 1.88mm, from what I've searched the ballpark numbers

for proper squish height on a late model YZ250 should be in the 1.0mm to 1.3mm range (.040" to .050")

 

Does the cylinder head or piston's top show signs of detonation?

Perhaps that could explain the spots on the cylinder wall.

Edited November 1, 2015 by mlatour

[CaptainKnobby]

Not sure about those spots on the cylinder wall, have you ever had an engine failure previously ?

As for the squish, .074 inches is about 1.88mm, from what I've searched the ballpark numbers

for proper squish height on a late model YZ250 should be in the 1.0mm to 1.3mm range (.040" to .050")

Does the cylinder head or piston's top show signs of detonation?

Perhaps that could explain the spots on the cylinder wall.

I have never noticed any engine failure. The bike has all ways had good power. I took some pics of the piston an posted them. As far as does it show signs of detonation.......I can't see any on top of crown. There is hardly any carbon on top. Piston on one side had blow by on it,so guess I went to long on the ring change.

[rjpjnk]

 

 

As for the squish, .074 inches is about 1.88mm, from what I've searched the ballpark numbers

for proper squish height on a late model YZ250 should be in the 1.0mm to 1.3mm range (.040" to .050")

 

I think .040 is too tight. From my reading it seems .050 is the ideal target.

[mlatour]

Yep unless running 100% race fuel, better to keep a safety margin when tightening the squish height.

[CaptainKnobby]

Yep unless running 100% race fuel, better to keep a safety margin when tightening the squish height.

 

Does Eric Gorr cut down to 0.40? or does he stay at the 0.50 mark?   Reason asking cause I'm sending him my Head and Cylinder this week r him to set Squish and Port the Cylinder.

[mlatour]

You should inform him of the octane rating / type of fuel you run in your YZ.