Throttle Junkie35
New member
Ive seen some guy on you tube run them on a hot rod srv, but I asked the same question to some engine builders and they all said that the vmax and srv are two totally different engines and the gains may not be there. No real definitive answer though. It is something I would like to try myself.
NorthofSixty
Member
I replied last night but it did not post.
Yes I have run these pipes on a 1983 SRV engine with Boysen reeds and twin stock 44mm Kehin butterfly carbs in a 1981 SS440 chassie for drag racing. No bottom end at 3400 rpm but with 5000 rpm engagement it was a rocket in 660ft runs. These pipes make power at about 8500 rpm so I used a Comet 208306A primary from a 1981 SRX. If I recall, this particular clutch is a little larger diameter than the stock primary which pushed the stock Yamaha secondary to its absolute max. I used uni-filters because with twin carbs the mag side had limited room with the SS/SRV's gas tank extension. I had to play around a lot with the pilot jets in the carbs to get it to rev off of idle but once the main jets took over there was lots of power. With this set up the 535 fan never stopped pulling in 660 ft.
The SRV stock was a 7000 rpm engine and although I never had any engine problems in the drags I doubt it would hold together for a lake run. I only ran into three minor problems at various times with this set up for drag racing including a cooling fan exploding, a secondary clutch spring failing and a new belt snapping in two. I still have the engine and have never had to tear it down but most other Yamaha 535's I have worked on over the years had signs of significant bearing chatter when I split the in the crank case halves. This was at 7000 rpm so running this engine at 8500 rpm to make useful power with the VMax pipes for any length of time is likely pushing your luck.
Based on my experience I would suggest that running the VMax pipes on an SRV engine for anything other than modified class drags would prove to be disappointing.
At one time I started to switch over the twin carbs to the smaller 38mm Kehin's from the 1980 SS440 to try and improve the bottom end but I never finished the project. Running smaller twin carbs might get you down into the 4000 rpm range for engagement which may be still a bit harsh for non-racing applications. I stayed with Kehin's rather than moving to Mikuni's so I did not have to change the throttle lever and was able to easily adapt a standard dual throttle cable to the stock carbs. Because of he high engagement RPM for drag racing the lack of low end tuning on the Kehin's was never an issue.
I had a hoot building and racing this sled back in the day so I hope some of this is useful.
Yes I have run these pipes on a 1983 SRV engine with Boysen reeds and twin stock 44mm Kehin butterfly carbs in a 1981 SS440 chassie for drag racing. No bottom end at 3400 rpm but with 5000 rpm engagement it was a rocket in 660ft runs. These pipes make power at about 8500 rpm so I used a Comet 208306A primary from a 1981 SRX. If I recall, this particular clutch is a little larger diameter than the stock primary which pushed the stock Yamaha secondary to its absolute max. I used uni-filters because with twin carbs the mag side had limited room with the SS/SRV's gas tank extension. I had to play around a lot with the pilot jets in the carbs to get it to rev off of idle but once the main jets took over there was lots of power. With this set up the 535 fan never stopped pulling in 660 ft.
The SRV stock was a 7000 rpm engine and although I never had any engine problems in the drags I doubt it would hold together for a lake run. I only ran into three minor problems at various times with this set up for drag racing including a cooling fan exploding, a secondary clutch spring failing and a new belt snapping in two. I still have the engine and have never had to tear it down but most other Yamaha 535's I have worked on over the years had signs of significant bearing chatter when I split the in the crank case halves. This was at 7000 rpm so running this engine at 8500 rpm to make useful power with the VMax pipes for any length of time is likely pushing your luck.
Based on my experience I would suggest that running the VMax pipes on an SRV engine for anything other than modified class drags would prove to be disappointing.
At one time I started to switch over the twin carbs to the smaller 38mm Kehin's from the 1980 SS440 to try and improve the bottom end but I never finished the project. Running smaller twin carbs might get you down into the 4000 rpm range for engagement which may be still a bit harsh for non-racing applications. I stayed with Kehin's rather than moving to Mikuni's so I did not have to change the throttle lever and was able to easily adapt a standard dual throttle cable to the stock carbs. Because of he high engagement RPM for drag racing the lack of low end tuning on the Kehin's was never an issue.
I had a hoot building and racing this sled back in the day so I hope some of this is useful.
INLINE4
New member
- Joined
- Jan 6, 2006
- Messages
- 260
Thank you for all the info....!!!! Wow that was allot..... It would be just for drags anyway like 660' on ice...It's a very clean 1984 I have and I do have a set of pipes from a 1983 here..The exhaust manifolds bolt right up to the cylinders ? On the intake side I know RPC at one time made intake manifolds but are very hard to find..Engagement would be around 5K... Thank you so much....
NorthofSixty
Member
The RPC's were a bit pricey so I made my own intakes by chopping one side off of the standard SRV manifold and closing the hole with a piece of aluminum plate with JB Weld. This allowed the carbs to straddle the steering column without interference.
Bob Vehring
New member
The first question should be, what do you want to do, what are you looking for. I understand the common answer would most likely be more power, but its not that simple.
Pipes are designed to work with an engine, but the engine must also be built to work with the pipes. Yes you can bolt up VM pipes to a SRV, yes you can clutch it for 8400 BUT, will your carb, manifold, reeds and porting flow enough to take advantage of that?
The OEM carb and stock intake manifold are defiantly not performance designed. You can find Reichard's or build a twin carb set up. Do you have a large reed or small reed engine? Biggest question is what do you want this to be? If it is your main trail ride best answer by far IMO is look for either a Aaen or PSI trail pipe, nice bump in power, still easy to drive. You can try a DG but be careful with clutching, it falls off drastically if over reved
There is a forum just for SRV, most questions are allready answered there. http://srv540.proboards.com/
Pipes are designed to work with an engine, but the engine must also be built to work with the pipes. Yes you can bolt up VM pipes to a SRV, yes you can clutch it for 8400 BUT, will your carb, manifold, reeds and porting flow enough to take advantage of that?
The OEM carb and stock intake manifold are defiantly not performance designed. You can find Reichard's or build a twin carb set up. Do you have a large reed or small reed engine? Biggest question is what do you want this to be? If it is your main trail ride best answer by far IMO is look for either a Aaen or PSI trail pipe, nice bump in power, still easy to drive. You can try a DG but be careful with clutching, it falls off drastically if over reved
There is a forum just for SRV, most questions are allready answered there. http://srv540.proboards.com/
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